Light-emitting device and display device

Abstract

Provided are a light-emitting device and a display device having good characteristics. The light-emitting device includes a first electrode, a second electrode, an intermediate layer between the first electrode and the second electrode, a first light-emitting layer between the first electrode and the intermediate layer, a second light-emitting layer between the intermediate layer and the second electrode, the first light-emitting layer including a first light-emitting center substance, and the second light-emitting layer including a second light-emitting center substance. The first light-emitting layer contains a first light-emitting center substance, the second light-emitting layer contains a second light-emitting center substance, the first light-emitting center substance is a phosphorescent light-emitting substance having a light-emitting peak in the wavelength region of 440-500 nm, and the difference between the maximum peak wavelength in the PL spectrum of the first light-emitting center substance and the maximum peak wavelength in the PL spectrum of the second light-emitting center substance is 30 nm or less. A color gamut of light emitted by each of the first light emitting layer and the second light emitting layer is different from a color gamut of light emitted by the light emitting layer included in at least one of the plurality of adjacent light emitting devices.

Description

Technical Field

[0001] One aspect of the present invention relates to a light-emitting device. Note that this aspect of the present invention is not limited to the aforementioned technical field. The technical field of one aspect of the invention disclosed in this specification relates to an object, method, or manufacturing method. Furthermore, one aspect of the present invention relates to a process, machine, manufacture, or composition of matter. Therefore, specifically, examples of the technical field of one aspect of the present invention disclosed in this specification include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, lighting devices, energy storage devices, memory devices, imaging devices, electronic devices, methods for driving these devices, or methods for manufacturing these devices. Background Technology

[0002] In recent years, display devices have been expected to be used for a variety of purposes. Examples of applications as large display devices include home television sets (also known as televisions or television receivers), digital signage, and public information displays (PIDs). Furthermore, as portable information terminals, smartphones and tablets with touch panels are under development.

[0003] In addition, there is a demand for high-definition display devices. Development of devices requiring high-definition displays, such as those for Virtual Reality (VR), Augmented Reality (AR), Substitutional Reality (SR), and Mixed Reality (MR), is very active.

[0004] As a display device, light-emitting devices, including light-emitting devices (also known as light-emitting elements), are under development. Light-emitting devices (also known as "EL devices" or "EL elements") that utilize the electroluminescence (EL) phenomenon have the characteristics of being easy to achieve in thin and lightweight form; being able to respond to input signals at high speed; and being able to be driven by DC constant voltage power supplies, etc., and have been applied to display devices.

[0005] In particular, series-type light-emitting devices have attracted attention due to their high current efficiency. Patent Documents 1 and 2 disclose series-type light-emitting devices with different coating methods.

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2005-317548 [Patent Document 2] Japanese Patent Application Publication No. 2023-161850 Summary of the Invention

[0007] One objective of this invention is to provide a light-emitting device with excellent characteristics. Furthermore, one objective of this invention is to provide a light-emitting device with good luminous efficiency. Furthermore, one objective of this invention is to provide a light-emitting device with high reliability. Furthermore, one objective of this invention is to provide a light-emitting device with low driving voltage. Finally, one objective of this invention is to provide a light-emitting device with both high reliability and low driving voltage.

[0008] Furthermore, one objective of this invention is to provide a light-emitting device capable of providing a display device with good characteristics. Another objective of this invention is to provide a light-emitting device capable of providing a display device with good luminous efficiency. Another objective of this invention is to provide a light-emitting device capable of providing a display device with good reliability. Another objective of this invention is to provide a display device with low driving voltage. Finally, one objective of this invention is to provide a light-emitting device capable of providing both low driving voltage and good reliability in a display device.

[0009] Furthermore, one objective of this invention is to provide any one of a low-power organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device. Another objective of this invention is to provide any one of a highly reliable electronic device and a lighting device. Finally, one objective of this invention is to provide any one of a novel organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device.

[0010] Note that the description of these objectives does not preclude the existence of other objectives. Note that one embodiment of the invention does not necessarily require achieving all of the aforementioned objectives. Furthermore, objectives other than those described above are clearly present in the specification, drawings, and claims, and can be derived from the description in the specification, drawings, and claims.

[0011] One aspect of the present invention is a light-emitting device comprising a first electrode, a second electrode, an intermediate layer, a first light-emitting layer, and a second light-emitting layer. The intermediate layer is located between the first electrode and the second electrode, the first light-emitting layer is located between the first electrode and the intermediate layer, and the second light-emitting layer is located between the intermediate layer and the second electrode. The first light-emitting layer contains a first light-emitting center material, and the second light-emitting layer contains a second light-emitting center material. The first light-emitting center material is a phosphorescent material having a light emission peak in a wavelength region of 440 nm to 500 nm. The difference between the maximum peak wavelength in the PL spectrum of the first light-emitting center material and the maximum peak wavelength in the PL spectrum of the second light-emitting center material is less than 30 nm. The color gamut of the light emitted by the first light-emitting layer and the second light-emitting layer is different from the color gamut of the light emitted by at least one of the light-emitting layers included in a plurality of adjacent light-emitting devices.

[0012] In the above-mentioned light-emitting device, the first light-emitting center material is the same as the second light-emitting center material.

[0013] In addition, in the above-mentioned light-emitting devices, the first light-emitting center material is a platinum complex.

[0014] In addition, the above-mentioned light-emitting device also includes a first hole transport layer between the first electrode and the first light-emitting layer and a second hole transport layer between the intermediate layer and the second light-emitting layer. The first hole transport layer or the second hole transport layer has a stacked structure comprising at least a first layer containing a first organic compound and a second layer containing a second organic compound. The second layer is in contact with the first light-emitting layer or the second light-emitting layer. The first organic compound comprises an amine skeleton and a polycyclic hydrocarbon, and the second organic compound has a π-electron-rich polycyclic heteroaromatic ring.

[0015] In addition, the above-mentioned light-emitting device also includes a first electron transport layer between the second light-emitting layer and the second electrode. The first electron transport layer includes a layer containing a third organic compound having a triazine skeleton, and the intermediate layer includes a first mixed layer of lithium or a lithium compound and a fourth organic compound having a phenanthroline skeleton.

[0016] In addition, in the above-mentioned light-emitting device, the first electron transport layer includes a second mixed layer of lithium or lithium compound and a fifth organic compound having a triazine framework, the second mixed layer being between the second electrode and a layer containing a third organic compound.

[0017] Furthermore, in the aforementioned light-emitting device, the first light-emitting layer comprises a first light-emitting center material, a sixth organic compound, and a seventh organic compound; the second light-emitting layer comprises a second light-emitting center material, an eighth organic compound, and a ninth organic compound; the combination of the sixth organic compound and the seventh organic compound forms a first excitocomplex; the combination of the eighth organic compound and the ninth organic compound forms a second excitocomplex; the light-emitting end of the first excitocomplex on the short wavelength side of the PL spectrum is located at a shorter wavelength compared to the absorption end of the first light-emitting center material on the long wavelength side of the absorption spectrum; and the light-emitting end of the second excitocomplex on the short wavelength side of the PL spectrum is located at a shorter wavelength compared to the absorption end of the second light-emitting center material on the long wavelength side of the absorption spectrum.

[0018] One aspect of the present invention is a display device comprising a light-emitting device A and a light-emitting device B with a different emission color than the light-emitting device A. The light-emitting device A includes a first electrode A, a second electrode A, an intermediate layer A, a first light-emitting layer A, and a second light-emitting layer A. The intermediate layer A is located between the first electrode A and the second electrode A. The first light-emitting layer A is located between the first electrode A and the intermediate layer A. The second light-emitting layer A is located between the intermediate layer A and the second electrode A. The first light-emitting layer A contains a first light-emitting center material A, and the second light-emitting layer A contains a second light-emitting center material A. Both the first and second light-emitting center materials A are phosphorescent materials having emission peaks in a wavelength region of 440 nm or higher and 500 nm or lower. The maximum peak wavelength in the PL spectrum of the first light-emitting center material A is similar to that of the second light-emitting center material A. The difference in the maximum peak wavelength of the photoluminescence (PL) spectrum of the light-emitting center material A is less than 30 nm. The light-emitting device B includes a first electrode B, a second electrode B, an intermediate layer B, a first light-emitting layer B, and a second light-emitting layer B. The intermediate layer B is located between the first electrode B and the second electrode B. The first light-emitting layer B is located between the first electrode B and the intermediate layer B. The second light-emitting layer B is located between the intermediate layer B and the second electrode B. The first light-emitting layer B contains the first light-emitting center material B. The second light-emitting layer B contains the second light-emitting center material B. The difference in the maximum peak wavelength of the PL spectrum of the first light-emitting center material B and the maximum peak wavelength of the PL spectrum of the second light-emitting center material B is less than 30 nm. The color gamut of the light emitted by the first light-emitting layer A and the second light-emitting layer A is different from the color gamut of the light emitted by the first light-emitting layer B and the second light-emitting layer B.

[0019] One aspect of the present invention is a display device comprising a light-emitting device A, a light-emitting device B with a different emission color than light-emitting device A, and a light-emitting device C with a different emission color than both light-emitting device A and light-emitting device B. Light-emitting device A includes a first electrode A, a second electrode A, an intermediate layer A, a first light-emitting layer A, and a second light-emitting layer A. The intermediate layer A is located between the first electrode A and the second electrode A. The first light-emitting layer A is located between the first electrode A and the intermediate layer A. The second light-emitting layer A is located between the intermediate layer A and the second electrode A. The first light-emitting layer A contains a first light-emitting center material A. Layer A contains a second luminescent center material A. Both the first and second luminescent center materials A are phosphorescent materials. The difference between the maximum peak wavelength in the PL spectrum of the first luminescent center material A and the maximum peak wavelength in the PL spectrum of the second luminescent center material A is less than 30 nm. The light-emitting device B includes a first electrode B, a second electrode B, an intermediate layer B, a first luminescent layer B, and a second luminescent layer B. The intermediate layer B is located between the first electrode B and the second electrode B. The first luminescent layer B is located between the first electrode B and the intermediate layer B. The second luminescent layer B is located between the intermediate layer B and the second electrode B. Light layer B contains a first luminescent center material B, and a second luminescent layer B contains a second luminescent center material B. Both the first and second luminescent center materials B are phosphorescent materials. The difference between the maximum peak wavelength in the PL spectrum of the first luminescent center material B and the maximum peak wavelength in the PL spectrum of the second luminescent center material B is less than 30 nm. The light-emitting device C includes a first electrode C, a second electrode C, an intermediate layer C, a first luminescent layer C, and a second luminescent layer C. The intermediate layer C is located between the first electrode C and the second electrode C, and the first luminescent layer C is located between the first electrode C and the intermediate layer C. The second luminescent layer C... Layer C is located between the intermediate layer C and the second electrode C. The first light-emitting layer C contains a first light-emitting center material C, and the second light-emitting layer C contains a second light-emitting center material C. Both the first and second light-emitting center materials C are phosphorescent materials. The difference between the maximum peak wavelength in the PL spectrum of the first light-emitting center material C and the maximum peak wavelength in the PL spectrum of the second light-emitting center material C is less than 30 nm. The color gamut of the light emitted by the first and second light-emitting layers A is different from the color gamut of the light emitted by the first, second, and third light-emitting layers B and C.

[0020] In addition, one aspect of the present invention is a light-emitting device, which includes a light-emitting device having the above-described structures and a transistor or substrate.

[0021] In addition, one aspect of the present invention is an electronic device that includes a light-emitting device having the above-described structure, as well as a detection unit, an input unit, or a communication unit.

[0022] Note that the light-emitting device in this specification includes image display devices that use light-emitting devices. Furthermore, the light-emitting device sometimes includes modules such as: modules where connectors, such as anisotropic conductive films or TCP (Tape Carrier Package), are mounted on the light-emitting device on a substrate; modules where printed circuit boards are provided at the ends of the TCP; or modules where ICs (integrated circuits) are directly mounted on the light-emitting device via COG (Chip On Glass) packaging. Moreover, lighting devices and the like sometimes include light-emitting devices.

[0023] According to one aspect of the present invention, a light-emitting device with good characteristics can be provided. Furthermore, according to one aspect of the present invention, a light-emitting device with good luminous efficiency can be provided. Furthermore, according to one aspect of the present invention, a light-emitting device with good reliability can be provided. Furthermore, according to one aspect of the present invention, a light-emitting device with low driving voltage can be provided. Furthermore, according to one aspect of the present invention, a light-emitting device with both good reliability and low driving voltage can be provided.

[0024] Furthermore, according to one aspect of the present invention, a light-emitting device capable of providing a display device with good characteristics can be provided. Furthermore, according to one aspect of the present invention, a light-emitting device capable of providing a display device with good luminous efficiency can be provided. Furthermore, according to one aspect of the present invention, a light-emitting device capable of providing a display device with good reliability can be provided. Furthermore, according to one aspect of the present invention, a display device with low driving voltage can be provided. Furthermore, according to one aspect of the present invention, a light-emitting device capable of providing both low driving voltage and good reliability in a display device can be provided.

[0025] Furthermore, any one of the following can be provided: a low-power organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device. Furthermore, any one of the following can be provided: a highly reliable electronic device and a lighting device. Furthermore, any one of the following can be provided: a novel organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device.

[0026] Note that the description of these effects does not preclude the existence of other effects. One aspect of the invention does not necessarily require all of the aforementioned effects. Effects other than those described above can be extracted from the specification, drawings, and claims. Attached Figure Description

[0027] Figure 1A and Figure 1B This is a diagram showing the light-emitting device; Figure 2 This is a diagram showing the light-emitting device; Figure 3A and Figure 3B This is a diagram showing the light-emitting device; Figure 4 This is a diagram showing the light-emitting device; Figure 5A and Figure 5B This is a diagram illustrating a display device according to one aspect of the present invention; Figure 6A and Figure 6B These are the top view and cross-sectional view of the light-emitting device; Figures 7A to 7E This is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figure 8A and Figure 8B This is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figures 9A to 9D This is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figures 10A to 10C This is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figures 11A to 11C This is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figures 12A to 12C This is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figures 13A to 13G This is a top view showing an example of the structure of a pixel; Figures 14A to 14I This is a top view showing an example of the structure of a pixel; Figure 15A and Figure 15B This is a perspective view showing an example of the structure of a display module; Figure 16A and Figure 16B This is a cross-sectional view showing an example of the structure of a display device; Figure 17 This is a perspective view showing an example of the structure of a display device; Figure 18 This is a cross-sectional view showing an example of the structure of a display device; Figure 19 This is a cross-sectional view showing an example of the structure of a display device; Figure 20A This is a cross-sectional view showing an example of the structure of a display device. Figure 20B and Figure 20C This is a top view showing an example of the structure of a display device; Figure 21 This is a cross-sectional view showing an example of the structure of a display device; Figure 22A This is a cross-sectional view showing an example of the structure of a display device. Figure 22B and Figure 22CThis is a top view showing an example of the structure of a display device; Figures 23A to 23D This is a diagram illustrating an example of an electronic device; Figures 24A to 24F This is a diagram illustrating an example of an electronic device; Figures 25A to 25G This is a diagram illustrating an example of an electronic device; Figure 26 It is a diagram illustrating the structure of the sample; Figure 27 It is a diagram illustrating the structure of the sample; Figure 28 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 29 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 30 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 31 This is a graph illustrating the absorption spectrum and PL spectrum of the organic compound used in the sample; Figure 32 This is a graph illustrating the absorption spectrum and PL spectrum of the organic compound used in the sample; Figure 33 This is a graph illustrating the absorption spectrum and PL spectrum of the organic compound used in the sample; Figure 34 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 35 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 36 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 37 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 38 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 39 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 40 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 41 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 42 This is a graph illustrating the PL spectrum of the organic compound used in the sample; Figure 43 This is a graph showing the brightness-current density characteristics of the sample; Figure 44 This is a graph showing the brightness-voltage characteristics of the sample; Figure 45 This is a graph showing the current efficiency-brightness characteristics of the sample; Figure 46 This is a graph showing the current density-voltage characteristics of the sample; Figure 47 This is a graph showing the electroluminescence spectrum of the sample; Figure 48 This is a graph showing the blue indicator – current density characteristics – of the sample; Figure 49 This is a graph showing the brightness-current density characteristics of the sample; Figure 50 This is a graph showing the brightness-voltage characteristics of the sample; Figure 51 This is a graph showing the current efficiency-brightness characteristics of the sample; Figure 52 This is a graph showing the current density-voltage characteristics of the sample; Figure 53 This is a graph showing the electroluminescence spectrum of the sample; Figure 54 This is a graph showing the brightness-current density characteristics of the sample; Figure 55 This is a graph showing the brightness-voltage characteristics of the sample; Figure 56 This is a graph showing the current efficiency-brightness characteristics of the sample; Figure 57 This is a graph showing the current density-voltage characteristics of the sample; Figure 58 This is a graph showing the electroluminescence spectrum of the sample; Figure 59 This is a graph illustrating the absorption spectrum and PL spectrum of the organic compound used in the sample; Figure 60 This is a graph illustrating the absorption spectrum and PL spectrum of the organic compound used in the sample; Figure 61 This is a graph showing the brightness-current density characteristics of the sample; Figure 62 This is a graph showing the brightness-voltage characteristics of the sample; Figure 63 This is a graph showing the current efficiency-brightness characteristics of the sample; Figure 64 This is a graph showing the current density-voltage characteristics of the sample; Figure 65 This is a graph showing the electroluminescence spectrum of the sample; Figure 66 This is a graph showing the blue indicator – current density characteristics – of the sample; Figure 67 This is a graph showing the brightness-current density characteristics of the sample; Figure 68 This is a graph showing the brightness-voltage characteristics of the sample; Figure 69 This is a graph showing the current efficiency-brightness characteristics of the sample; Figure 70 This is a graph showing the current density-voltage characteristics of the sample; Figure 71 This is a graph showing the electroluminescence spectrum of the sample; Figure 72 This is a graph showing the brightness-current density characteristics of the sample; Figure 73 This is a graph showing the brightness-voltage characteristics of the sample; Figure 74 This is a graph showing the current efficiency-brightness characteristics of the sample; Figure 75 This is a graph showing the current density-voltage characteristics of the sample; Figure 76 This is a graph showing the electroluminescence spectrum of the sample. Detailed Implementation

[0028] The embodiments will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and those skilled in the art will readily understand that its methods and details can be varied in many ways without departing from the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited to the contents described in the embodiments shown below.

[0029] Note that in the structure of the invention described below, the same reference numerals are used across different figures to denote the same parts or parts having the same function, without omitting repeated descriptions. Furthermore, when denoteing parts with the same function, the same shading lines are sometimes used without additional reference numerals.

[0030] Furthermore, for ease of understanding, the positions, sizes, and extents of the constituent elements shown in the accompanying drawings may not represent their actual positions, sizes, and extents. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and extents shown in the accompanying drawings.

[0031] Furthermore, depending on the situation or state, the "film" and "layer" can be interchanged. For example, a "conductive layer" can be changed into a "conductive film." Additionally, for example, an "insulating film" can be changed into an "insulating layer."

[0032] Note that in this specification, etc., devices manufactured using metal masks or FMMs (Fine Metal Masks) are sometimes referred to as devices with MM (Metal Mask) structures. Furthermore, in this specification, etc., devices manufactured without metal masks or FMMs are sometimes referred to as devices with MML (Metal Mask Less) structures.

[0033] In this specification and other materials, holes or electrons are sometimes referred to as "carriers." Specifically, a hole injection layer or electron injection layer is sometimes called a "carrier injection layer," a hole transport layer or electron transport layer is called a "carrier transport layer," and a hole blocking layer or electron blocking layer is called a "carrier blocking layer." Note that sometimes it is not possible to clearly distinguish between the aforementioned carrier injection layer, carrier transport layer, and carrier blocking layer. Furthermore, sometimes a single layer functions as two or three of the carrier injection layer, carrier transport layer, and carrier blocking layer. In addition, the term "layer" is sometimes used to simply describe "injection layer," "transport layer," and "blocking layer." Similarly, other layers such as "light-emitting layer" or "intermediate layer" are sometimes also referred to as "layer."

[0034] In this specification, the light-emitting device (also referred to as a light-emitting element) includes an EL layer between a pair of electrodes. The EL layer includes at least a light-emitting layer. In this specification, the light-receiving device (also referred to as a light-receiving element) includes at least an active layer serving as a photoelectric conversion layer between a pair of electrodes. In this specification, one of the pair of electrodes is sometimes referred to as a pixel electrode and the other as a common electrode.

[0035] In this specification, a conical shape refers to a shape in which at least a portion of the side surface of a constituent element is inclined relative to the substrate surface. For example, it is preferable to have an area with an inclined side surface and a substrate surface (also referred to as a cone angle) of less than 90°. Note that the side surface of the constituent element and the substrate surface do not necessarily have to be completely flat; they can also be approximately planar with slight curvature or approximately planar with slight irregularities.

[0036] Note that the light-emitting devices described in this specification include image display devices using organic EL devices. Furthermore, light-emitting devices sometimes include modules such as: modules where the organic EL device is fitted with connectors such as anisotropic conductive films or TCP (Tape Carrier Package); modules where printed circuit boards are provided at the ends of the TCP; or modules where an IC (integrated circuit) is directly mounted on the organic EL device via COG (Chip On Glass) packaging. Moreover, lighting devices and the like sometimes include light-emitting devices.

[0037] Implementation Method 1 A series-connected light-emitting device has a structure in which multiple light-emitting units are stacked with an intermediate layer (charge-generating layer) sandwiched between a pair of electrodes. Each light-emitting unit includes a light-emitting layer, and light can be emitted from any of the light-emitting layers by flowing current through it. The current efficiency of a series-connected light-emitting device with this structure is much higher than that of a non-series-connected light-emitting device, so it can be used in display devices that require high brightness or high reliability.

[0038] Series-type light-emitting devices (LEDs) easily produce white light due to their multiple light-emitting layers. Therefore, white filters are commonly used to achieve full-color display devices employing series-type LEDs. Furthermore, color conversion methods that use stacked blue light-emitting layers and color conversion layers, such as quantum dots, have also been practically applied.

[0039] On the other hand, some display devices that use separate coating and series-type light-emitting devices as a full-color method have also been put into practical use. Light-emitting devices using separate coating have little or no energy loss in color filters or color conversion layers, thus achieving higher luminous efficiency compared to the two methods mentioned above.

[0040] Furthermore, the light-emitting layer of the tandem light-emitting device is preferably separate from the light-emitting layer of at least one of the adjacent light-emitting devices. Alternatively, the light-emitting layer of the tandem light-emitting device preferably includes a light-emitting layer different from the light-emitting layer of at least one of the adjacent light-emitting devices. Alternatively, the color of the light emitted by the tandem light-emitting device is preferably different from the color of the light emitted by the adjacent light-emitting devices. Alternatively, the light-emitting core material included in the light-emitting layer of the tandem light-emitting device is preferably different from the light-emitting core material included in the light-emitting layer of at least one of the adjacent light-emitting devices.

[0041] The light-emitting device of the present invention having the above-described structure can be a light-emitting device with high current efficiency, low energy loss, and good characteristics. A display device using such a light-emitting device, according to one aspect of the present invention, can be a display device with low power consumption, high reliability, and good visibility, capable of displaying at high brightness.

[0042] Next, a light-emitting device according to one aspect of the present invention will be described in detail with reference to the accompanying drawings. Figure 1A The light-emitting device 130 of one embodiment of the present invention is shown. The light-emitting device of one embodiment of the present invention is a series-type light-emitting device, wherein an organic compound layer 103 (also referred to as an EL layer) is included between a first electrode 101 including an anode and a second electrode 102 including a cathode. The organic compound layer 103 includes a first light-emitting unit 501 including a first light-emitting layer 113_1, a second light-emitting unit 502 including a second light-emitting layer 113_2, and an intermediate layer 160.

[0043] Furthermore, this embodiment uses a light-emitting device comprising one intermediate layer 160 and two light-emitting units as an example for explanation; however, a light-emitting device comprising n (n is an integer greater than or equal to 1) intermediate layers and n+1 light-emitting units can also be used. For example, Figure 1B The light-emitting device 130 shown is an example of a series-connected light-emitting device with n=2, including a first light-emitting unit 501, a first intermediate layer 160_1, a second light-emitting unit 502, a second intermediate layer 160_2, and a third light-emitting unit 503.

[0044] The color gamut of the light emitted by the light-emitting layers in each light-emitting unit is preferably the same.

[0045] In one aspect of the invention, a phosphorescent material (hereinafter also referred to as a phosphorescent material) is used as the light-emitting center material contained in the first light-emitting layer 113_1 or the second light-emitting layer 113_2. In particular, it is preferable to use the phosphorescent material in a light-emitting device that emits blue light.

[0046] It is known that in current-excited organic EL devices, the generation probability of singlet excited states to triplet excited states is 1:3. The theoretical limit of the internal quantum efficiency of a light-emitting device using a fluorescent material that can only use singlet excited states for emission is 25%. On the other hand, since phosphorescent materials can convert singlet excited states into triplet excited states through intersystem crossing, it is theoretically possible to realize a light-emitting device with an internal quantum efficiency of 100%, which is a higher luminous efficiency light-emitting device compared to fluorescent materials.

[0047] For example, organometallic complexes can be used as phosphorescent materials that exhibit blue light emission. These complexes can use heavy metals such as platinum (Pt), palladium (Pd), iridium (Ir), Ru (ruthenium), Re (rhenium), Au (gold), and Os (osmium) as the central metal. Furthermore, the heterocycle is preferably coordinated to the central metal, and the heterocycle can be a six-membered ring such as a pyridine ring, pyrazine ring, triazine ring, or pyrimidine ring; or a five-membered ring such as a pyrazole ring, indole ring, or triazole ring. A structure in which both the five-membered and six-membered rings are coordinated to the central metal can also be used. Furthermore, the organometallic complex preferably contains a nitrogen-containing heterocyclic carbene coordinated to the central metal. Additionally, the heterocycle preferably has an alkyl group as a substituent. For example, when using a pyridine ring as the heterocycle, it is preferable to have an alkyl group at the 4-position of the pyridine ring, more preferably an alkyl group containing deuterium. Alternatively, it is preferable to have alkyl groups at the 3- and 5-positions of the pyridine ring, more preferably an alkyl group containing deuterium. Furthermore, it is preferable that the pyridine ring has a phenyl group at the 4 position, and it is also preferable that the phenyl group has an alkyl structure.

[0048] Because the carbon-deuterium bond has a larger bond dissociation energy than the carbon-protium bond, in organometallic complexes with a pyridine ring, bonding a deuterium-containing alkyl group to the carbon atoms at the 3 and 5 positions of the pyridine ring, which have increased spin density in the triplet excited state, can stabilize the molecular structure. Furthermore, it can suppress bond dissociation in the excited state, thereby improving the stability of the organometallic complex. Additionally, bonding a deuterium-containing alkyl group to the carbon atoms at the 3 and 5 positions of the pyridine ring, where the lowest unoccupied molecular orbitals (LUMOs) are concentrated, can improve the stability of the organometallic complex in the LUMO-accepting state, i.e., the reduced state.

[0049] Furthermore, in organometallic complexes with a pyridine ring, the steric hindrance effect on the phenyl group at the 4-position of the pyridine ring is achieved by bonding an alkyl group containing deuterium. This can suppress the rotation of the phenyl group, thereby improving the thermal properties of the organometallic complex, such as its sublimation properties. Additionally, it can suppress vibrations in the organometallic complex and inhibit thermal deactivation from the excited state.

[0050] Furthermore, by bonding the phenyl group to the carbon atom at the 4-position adjacent to the carbon atoms at the 3- and 5-positions of the pyridine ring in the LUMO distribution cluster, the distribution of LUMO can be diffused. Additionally, this can stabilize LUMO and improve the stability of organometallic complexes in the reduced state.

[0051] Furthermore, in organometallic complexes with a pyridine ring, the planarity of the organometallic complex can be improved by bonding a phenyl group to the carbon atom at the 4-position of the pyridine ring. Therefore, when this organometallic complex is used as the luminescent center material of the luminescent layer in a light-emitting device, a stronger molecular orientation is induced, making it easier to orient in a direction horizontal to the substrate plane. Additionally, when the organometallic complex emits light, light is emitted in a direction perpendicular to the transition dipole moment associated with the luminescence of the organometallic complex. Therefore, when the direction of the transition dipole moment of the organometallic complex is parallel to the substrate plane, the amount of light emitted from the organometallic complex in the direction perpendicular to the substrate plane increases, thereby improving the light extraction efficiency of the light-emitting device. Therefore, it is preferable that the organometallic complex is oriented such that the transition dipole moment associated with the luminescence of the organometallic complex is horizontal to the substrate plane.

[0052] Furthermore, when the phenyl group at the 4-position of the pyridine ring has an alkyl group, intermolecular interactions can be suppressed. For example, in the light-emitting layer of a light-emitting device, by using an organometallic complex of one embodiment of the present invention as the light-emitting center material, the interaction between the light-emitting center material and the host material (one or more if there are multiple host materials) can be prevented, thereby improving the luminous efficiency of the light-emitting device.

[0053] Therefore, the organometallic complex of one aspect of the present invention can be applied, for example, to the light-emitting layer of a light-emitting device. Furthermore, the organometallic complex of one aspect of the present invention can be applied, for example, to a layer in contact with the light-emitting layer of a light-emitting device.

[0054] The following are specific examples of organic compounds that exhibit blue phosphorescence with emission peaks in the wavelength region above 440 nm and below 500 nm. Examples include (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-[5-(methyl-d3)-4-phenyl-2-pyridyl-κN]carbazole-2,1-diyl-κC)platinum(II) (abbreviated as Pt(mmtBubOcz5m4ppy-d3)) as shown in structural formula (400) and (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-(4-tert-butyl-2-pyridyl-κN)-6-(5-cyano-2-methylphenyl)carbazole-2,1-diyl-κC) as shown in structural formula (401). Platinum(II) (abbreviated as: Pt(mmtBubOm5CPcztBupy)), with structural formula (402) {[9-(4-tert-butyl-2-pyridinyl-κN)-[3,9'-bi-9H-carbazole]-2,1-diyl-κC]oxy-9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-diyl-κC} Platinum(II) (abbreviated as: Pt(cztBucpyOtBucpy)), with structural formula (403) {[9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-diyl-κC]oxy-9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-diyl-κC} Platinum (II) (abbreviated as: Pt(tBucpy2O)), with structural formula (404) {[9-(2-pyridyl-κN)carbazole-2,1-diyl-κC]oxy-9-(2-pyridyl-κN)carbazole-2,1-diyl-κC} Platinum (II) (abbreviated as: PtNON), with structural formula (405) {2-{4-methyl-3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-[3,5-di(methyl-d3)-4-phenyl-2-pyridyl-κN]carbazole-2,1-diyl-κC) Platinum (II) (abbreviated as: Pt(Me-mmtBubOc)} z35dm4ppy-d6)), the structure (406) shows {[3-(3,5-di-tert-butylphenyl)-9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-diyl-κC]oxy-9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-diyl-κC}platinum(II) (abbreviated as: Pt(mmtBuptBucpyOtBucpy)), the structure (407) shows (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylide-κC2]phenoxy-κC2}-9-[3,5-di(methyl-d3)-4-phenyl-2-pyridinyl-κN]carbazole-2,1-Diyl-κC)platinum(II) (abbreviated as: Pt(mmtBubOcz35dm4ppy-d6)), the structure (408) showing (2-{5-tert-butyl-3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-[3,5-di(methyl-d3)-4-phenyl-2-pyridyl-κN]carbazole-2,1-diyl-κC)platinum(II) (abbreviated as: Pt(tBu-mmtBubOcz35dm4ppy-d6)), the structure (409) showing {2-(3-{3-[2,6-di(phenyl-d5)phenyl]benzimidazol-1-yl-2- The following are examples of platinum (II) with the structure (410): 2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-[4-tert-butylphenyl-3,5-di(methyl-d3)-2-pyridinyl-κN]carbazole-2,1-diyl-κC)platinum (II) (abbreviated as Pt(mmtBubOcz35dm4tBuppy-d6)). In addition, examples include PtON1 shown in structural formula (411), PtON7 shown in structural formula (412), PtON1-Me shown in structural formula (413), PtON1-tBu shown in structural formula (414), PtON1-NMe2 shown in structural formula (415), PtON6-tBu shown in structural formula (416), PtON7-dtb shown in structural formula (417), PtN1N shown in structural formula (418), and PtN1N shown in structural formula (419). PtN1pyCl (shown in formula 19), PtON7-tBu (shown in formula 420), Pt(ppzOczpy) (shown in formula 421), Pt(ppzOczpy-m) (shown in formula 422), Pt(ppzOczpy-2m) (shown in formula 423), PdN1N (shown in formula 424), PdN1N-dm (shown in formula 425), and PdN6N (shown in formula 426), etc.

[0055] [Chemical Formula 1]

[0056] [Chemical Formula 2]

[0057] [Chemical Formula 3]

[0058] In addition, organometallic iridium compounds with a 4H-triazole skeleton, such as tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviated as [Ir(mpptz-dmp)3]) and tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazol)iridium(III) (abbreviated as [Ir(Mptz)3]), can also be used. Complexes; organometallic iridium complexes with a 1H-triazole skeleton, such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazole]iridium(III) (abbreviated as [Ir(Mptz1-mp)3]) and tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Prptz1-Me)3]); fac-tris[1-(2,6-diisocyanate] [Ir(iPrpim)3](propylphenyl)-2-phenyl-1H-imidazolium]iridium(III) (abbreviated as [Ir(iPrpim)3]), [tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviated as [Ir(dmpimpt-Me)3]), [tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazolium-2-yl] Organometallic iridium complexes with an imidazole skeleton, such as α-κN3}-4-cyanophenyl-κC)iridium(III) (abbreviated as CNImIr); organometallic complexes with a benzimidazole skeleton, such as tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III) (abbreviated as [Ir(cb)3]); bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ Iridium(III) tetrakis(1-pyrazolyl)borate (abbreviated as: FIr6), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ Iridium(III) picolinate (abbreviated as FIRPIC), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinium-N,C 2’ Iridium(III)pyridinecarboxylate (abbreviated as: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’Organometallic iridium complexes such as iridium(III) acetylacetone (abbreviated as FIracac) with phenylpyridine derivatives having electron-withdrawing groups as ligands; and platinum complexes such as (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylide-κC2]phenoxy-κC2}-9-(4-tert-butyl-2-pyridyl-κN)carbazole-2,1-diyl-κC1)platinum(II) (abbreviated as PtON-TBBI).

[0059] By using the aforementioned phosphorescent materials, light-emitting devices with high luminous efficiency can be provided.

[0060] Note that when the above-mentioned organic compounds exhibiting blue phosphorescence are used in the luminescent layer, the host material preferably includes at least one of a compound having a heteroaromatic ring, a compound having a carbazole skeleton, and a compound having an aromatic amine skeleton.

[0061] Compounds with heteroaromatic rings are used as electron transport hosts, while compounds with carbazole skeletons or aromatic amine skeletons are used as hole transport hosts. Combining electron and hole transport hosts readily forms exciplexes, which are therefore preferred.

[0062] Furthermore, by including the phosphorescent material and exciton complex in the luminescent layer, the luminescent efficiency can be improved due to the efficient Exciplex-Triplet Energy Transfer (ExTET) that transfers energy from the exciton complex to the luminescent material. Additionally, this structure allows for the simultaneous achievement of high efficiency, low-voltage operation, and long lifetime in the light-emitting device.

[0063] In particular, in one embodiment of the tandem light-emitting device of the present invention, at least one of the light-emitting layers comprises a light-emitting center material, a first host material, and a second host material. The light-emitting center material is preferably a phosphorescent material. Furthermore, both the first and second host materials are organic compounds and are combinations forming an excimer complex. One embodiment of the tandem light-emitting device of the present invention has a structure in which energy is transferred from the excimer complex formed by the first and second host materials to the light-emitting center material, causing the light-emitting center material to emit light. This improves the efficiency of excitation energy transfer to the light-emitting center material, thereby enabling a high-efficiency and high-reliability light-emitting device. Furthermore, it also allows for a reduction in the driving voltage.

[0064] As a combination of materials for efficiently forming excitocomplexes, the HOMO energy level of the hole-transporting material is preferably higher than or equal to the HOMO energy level of the electron-transporting material. Furthermore, the LUMO energy level of the hole-transporting material is preferably higher than or equal to the LUMO energy level of the electron-transporting material. Additionally, the difference between the HOMO energy level of the hole-transporting material and the HOMO energy level of the electron-transporting material is preferably 0.2 eV or higher. Furthermore, the difference between the LUMO energy level of the hole-transporting material and the LUMO energy level of the electron-transporting material is preferably 0.2 eV or higher. In this structure, holes are easily injected into the hole-transporting material, and electrons are easily injected into the electron-transporting material, which is therefore preferred. Note that the LUMO and HOMO energy levels of the material can be determined from the electrochemical properties (reduction potential and oxidation potential) measured by cyclic voltammetry (CV), or by photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, etc. When comparing values ​​of different compounds, it is preferable to use values ​​estimated by the same measurement for comparison.

[0065] Furthermore, the HOMO energy level of the phosphorescent material is preferably lower than that of the material with hole transport capability, and the LUMO energy level of the phosphorescent material is preferably higher than that of the material with electron transport capability. That is, the energy difference between the LUMO and HOMO energy levels of the phosphorescent material is preferably greater than the energy difference between the LUMO energy level of the material with electron transport capability and the HOMO energy level of the material with hole transport capability. This suppresses the formation of exciton complexes between the phosphorescent material and either the material with hole transport capability or the material with electron transport capability, thereby providing a highly efficient light-emitting device.

[0066] Note that phosphorescent materials possess the ability to convert triplet excitation energy into luminescence. Triplet excited states are more energy-stable than singlet excited states. Therefore, phosphorescent materials can exhibit luminescence with energies less than the energy difference between the LUMO and HOMO levels. Even if the energy difference between the LUMO and HOMO levels of the phosphorescent material is greater than the energy difference between the LUMO level of an electron-transporting material and the HOMO level of a hole-transporting material, as long as the luminescence energy exhibited by the phosphorescent material, or the migration energy calculated from the absorption spectrum, is less than or equal to the energy difference between the LUMO level of the electron-transporting material and the HOMO level of the hole-transporting material, or less than or equal to the luminescence energy of the exciton complex formed by the electron-transporting and hole-transporting materials, the excitation energy can be transferred from the exciton complex to the phosphorescent material, thus achieving efficient luminescence from the phosphorescent material.

[0067] Furthermore, to ensure that the phosphorescent material exhibits high luminescence energy (short wavelength), a high lowest triplet excitation level (T1 level) is preferable. Therefore, the ligands for the heavy metal atoms coordinated in the phosphorescent material are preferably those with a high T1 level, low electron acceptability, and a high LUMO level. Phosphorescent materials with this structure tend to have molecular structures with both high LUMO and high HOMO levels, making them prone to hole acceptance. In cases where the phosphorescent material has a molecular structure that readily accepts holes, its HOMO level is sometimes higher than that of materials with hole transport capabilities. However, even under the above circumstances, as long as the energy difference between the LUMO and HOMO levels of the phosphorescent material is greater than the energy difference between the LUMO level of the electron transport material and the HOMO level of the hole transport material, the luminescence energy exhibited by the phosphorescent material or the migration energy calculated from the absorption spectrum is less than or equal to the energy difference between the LUMO level of the electron transport material and the HOMO level of the hole transport material, or less than or equal to the luminescence energy of the excitocomplex formed by the electron transport material and the hole transport material, the excitation energy can be transferred from the excitocomplex formed by the electron transport material and the hole transport material to the phosphorescent material, thereby obtaining efficient luminescence from the phosphorescent material.

[0068] Note that the formation of excitocomplexes can be confirmed, for example, by comparing the photoluminescence (PL) spectra of a hole-transporting material, the PL spectra of an electron-transporting material, and the PL spectra of a hybrid film formed by mixing these materials. When the PL spectrum of the hybrid film is observed to shift towards a longer wavelength (or to have a new peak at a longer wavelength) compared to the PL spectra of each material, it indicates the formation of an excitocomplex. Alternatively, by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and the transient PL of a hybrid film formed by mixing these materials, when a difference in transient response is observed, such as the hybrid film having a longer lifetime component or a higher proportion of delayed components compared to the transient PL lifetimes of each material, it indicates the formation of an excitocomplex. Furthermore, the aforementioned transient PL can be referred to as transient electroluminescence (EL). In other words, by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and the transient EL of a hybrid film of these materials, and observing the differences in transient responses, the formation of an excitocomplex can be confirmed.

[0069] For example, when the first host material and the second host material form an excimer complex, the emitting end of the photoluminescence (PL) spectrum of the excimer complex is preferably located at a shorter wavelength than the absorption end of the absorption spectrum of the luminescent center material. When the PL spectrum of the excimer complex and the absorption end of the luminescent center material have the above-mentioned positional relationship, energy transfer can be performed efficiently.

[0070] Furthermore, the peak wavelength of the PL spectrum of the excimer complex formed from the first and second host materials is preferably shorter than the peak wavelength of the PL spectrum of the luminescent center material. Moreover, the difference between the peak wavelength of the PL spectrum of the excimer complex and the peak wavelength of the PL spectrum of the luminescent center material is preferably 30 nm or less. When the peak wavelengths of the PL spectrum of the excimer complex and the PL spectrum of the luminescent center material have the above-described relationship, energy transfer can be performed efficiently.

[0071] Furthermore, the difference between the peak wavelength of the PL spectrum of the excimer complex formed from the first host material and the wavelength of the absorption end on the longer wavelength side of the absorption spectrum of the luminescent center material is preferably less than 30 nm. When the peak wavelength of the PL spectrum of the excimer complex and the wavelength of the absorption end on the longer wavelength side of the absorption spectrum of the luminescent center material have the above-mentioned relationship, energy transfer can be performed efficiently.

[0072] Furthermore, the emitting end of the short-wavelength side of the PL spectrum of the excimer composite formed from the first and second host materials is preferably located at a shorter wavelength than the emitting end of the short-wavelength side of the PL spectrum of the luminescent center material. Moreover, the difference between the emitting end of the short-wavelength side of the PL spectrum of the excimer composite and the emitting end of the short-wavelength side of the PL spectrum of the luminescent center material is more preferably within 0.3 eV. When the emitting end of the short-wavelength side of the PL spectrum of the excimer composite and the emitting end of the short-wavelength side of the PL spectrum of the luminescent center material have the above-described relationship, energy transfer can be performed efficiently.

[0073] Note that the emitting end of the PL spectrum on the short wavelength side can be calculated by drawing a tangent at the point where the absolute value of the slope of the peak (or shoulder) observed at the shortest wavelength of the PL spectrum is the largest, and then calculating the intersection of this tangent with the horizontal axis or baseline. Similarly, the absorbing end of the absorption spectrum on the long wavelength side can be calculated by drawing a tangent at the point where the absolute value of the slope of the peak (or shoulder) observed at the longest wavelength of the absorption spectrum is the largest, and then calculating the intersection of this tangent with the horizontal axis or baseline.

[0074] When measuring the photoluminescence (PL) spectrum of the excitocomplex, it is preferable to use a co-evaporation deposition film of a first host material and a second host material. The mixing ratio of the first host material and the second host material can be any of the weight ratio, volume ratio, and molar ratio, with the first host material:second host material ratio being 1:19 to 19:1, preferably 1:9 to 9:1, and more preferably 3:7 to 7:3. Furthermore, the PL spectrum of the film containing the mixed first and second host materials can also be measured using the spectrum of a film containing the first host material:second host material in a 1:1 ratio. On the other hand, the sample state when measuring the PL or absorption spectrum of the luminescent center can be a thin film or a solution; from the viewpoint of verifying the state of isolated molecules, a solution is preferred. As the solvent for this solution, a solvent with low polarity, such as toluene or chloroform, is preferred.

[0075] Furthermore, when using a phosphorescent material as the luminescent layer, the T1 energy levels of the first and second host materials are preferably higher than the T1 energy level of the phosphorescent material. The singlet and triplet excitation energies of the first or second host material can be transferred from their S1 and T1 energy levels to the T1 energy level of the phosphorescent material. As a result, the phosphorescent material becomes a triplet excited state and emits phosphorescence.

[0076] Note that the phosphorescent component (phosphorescence spectrum) in the PL spectrum observed at low temperatures (e.g., any temperature in the range of 4K to 80K) can be used as an indicator of the T1 energy level. Specifically, for example, using a thin film deposited as a sample on a quartz substrate with a thickness of 50 nm, the PL spectrum (phosphorescence spectrum) is measured at a measurement temperature of 10K, and the energy of the emitting end on the shorter wavelength side can be regarded as the T1 energy level. The emitting end can be calculated by drawing a tangent at the point where the absolute value of the slope of the peak (or shoulder) observed at the shortest wavelength of the PL spectrum (phosphorescence spectrum) is the largest, and then calculating the T1 energy level based on the intersection of this tangent with the horizontal axis (wavelength) or the baseline.

[0077] In addition, the T1 energy level, as a phosphorescent material, can be determined by measuring the PL spectrum observed at low temperatures (e.g., any temperature in the range of 4K to 80K) or room temperature (e.g., any temperature in the range of 275K to 305K) and taking the energy of the emitting end on the shorter wavelength side as the T1 energy level.

[0078] As a compound with a heteroaromatic ring that can be used as a host material, it is preferable to have a azine skeleton. Examples of azine skeletons include pyridine rings, pyrimidine rings, and triazine rings. These materials can improve electron transport properties. Furthermore, it is preferable to use a carbazole skeleton directly or via an arylene group bonded to the azine skeleton, and to have multiple such carbazole skeletons. Moreover, the multiple carbazole skeletons are preferably not bonded to each other. Thus, by having a carbazole skeleton, electron transport properties can be adjusted. In addition, compounds with a heteroaromatic ring may also contain one or more elements such as silicon, boron, oxygen, and sulfur.

[0079] Furthermore, compounds having a carbazole skeleton preferably have multiple carbazole skeletons. Preferably, they have at least one of the following structures: a structure in which the 3-position of one carbazole skeleton is bonded to the 9-position of another carbazole skeleton; a structure in which the 2-position of one carbazole skeleton is bonded to the 9-position of another carbazole skeleton; a structure in which the 4-position of one carbazole skeleton is bonded to the 9-position of another carbazole skeleton; a structure in which the 1-position of one carbazole skeleton is bonded to the 9-position of another carbazole skeleton; or, a structure in which the 3-position of one carbazole skeleton is bonded to the 3-position of another carbazole skeleton. More preferably, they have multiple of the above structures. Furthermore, compounds having a carbazole skeleton may also contain one or more elements such as silicon, boron, oxygen, and sulfur.

[0080] Furthermore, when two compounds are used as a combination of host materials, both the compound with the heteroaromatic ring and the compound with the carbazole skeleton preferably have multiple carbazole skeletons. In this case, the number of carbazole skeletons contained in the compound with the carbazole skeleton is preferably the same as or greater than the number of carbazole skeletons contained in the compound with the heteroaromatic ring. By employing the aforementioned number of carbazole skeletons, the electron transport and hole transport properties of the host material can be adjusted.

[0081] Furthermore, when both the compound having a heteroaromatic ring and the compound having a carbazole skeleton contain elements such as silicon, boron, oxygen, and sulfur, it is preferable to make the two compounds contain the same elements, as this can improve the characteristics of the light-emitting device using the phosphorescent material.

[0082] Specific examples of organic compounds that can be used as host materials include 9,9'-{6-[3-(triphenylsilyl)phenyl]-1,3,5-triazin-2,4-diyl}bis(9H-carbazole) (abbreviated as SiTrzCz2) as shown in structural formula (450), 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviated as mSiTrz) as shown in structural formula (451), 9-{4-phenyl-6-[3-(triphenylsilyl)phenyl]-1,3,5-triazin-2-yl}-9H-carbazole (abbreviated as SiCzTrz) as shown in structural formula (452), and 9-{4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazin-2-yl}-9H-carbazole (abbreviated as DSiCzTrz) as shown in structural formula (453). Formula (454) shows 9-(biphenyl-4-yl)-3-(4-{[4'-(4,6-diphenyl-1,3,5-triazin-2-yl)biphenyl-4-yl]diphenylsilyl}phenyl)-9H-carbazole (abbreviated as: CzSiTzn), and formula (455) shows 3-{6-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]dibenzothiophene-4-yl}-9- Phenyl-9H-carbazole (abbreviated as mPCDBtPTzn), 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviated as PSiCzCz) as shown in structural formula (456), and [4-(2,12-di-tert-butyl-5,9-dioxa-13b-boronazof[3,2,1-de]anthracene-7-yl)phenyl]triphenylsilane as shown in structural formula (457), etc. Additionally, organic compounds shown in structural formulas (458), (459), and (460) can be used.

[0083] [Chemical Formula 4]

[0084] [Chemical Formula 5]

[0085] By using the above-mentioned main materials in phosphorescent materials, light-emitting devices with high luminous efficiency can be provided.

[0086] In addition, the first light-emitting unit 501 and the second light-emitting unit 502 may also include other functional layers besides the aforementioned light-emitting layer. Figure 1AIn the first light-emitting unit 501, in addition to the first light-emitting layer 113_1, a first hole transport layer 112_1, a hole injection layer 111, and a first electron transport layer 114_1 are also provided. In the second light-emitting unit 502, in addition to the second light-emitting layer 113_2, a second hole transport layer 112_2, a second electron transport layer 114_2, and an electron injection layer 115 are also provided. However, the structure of the organic compound layer 103 of the present invention is not limited to this. It may not have any of the above layers, or it may have other layers.

[0087] Here, in Figure 1A In this design, the first electron transport layer 114_1 and the second electron transport layer 114_2 are single layers, but they can be either single-layer or multilayer structures. Furthermore, the first electron transport layer 114_1 and the second electron transport layer 114_2 do not necessarily have the same structure.

[0088] For example, the first electron transport layer 114_1 can also have a single-layer structure, and the second electron transport layer 114_2 can also have a stacked structure. Specifically, the electron transport layer in the light-emitting unit on the cathode side (e.g., Figure 1A The second electron transport layer 114_2 in the light-emitting unit can also have a stacked structure, and the electron transport layers in other light-emitting units (e.g., Figure 1A The first electron transport layer 114_1 in the middle can also have a single-layer structure.

[0089] In one aspect of the invention, at least one electron transport layer in the light-emitting unit on the cathode side is preferably an organic compound with a triazine framework. Alternatively, a stacked structure using different organic compounds with triazine frameworks can also be employed. In particular, in the stacked layers, the cathode-side layer preferably contains an organic compound with a triazine framework and an alkali metal such as Li. By employing the above structure, electron injection performance can be improved.

[0090] Furthermore, the electron transport layer in the anode-side light-emitting unit (hereinafter also referred to as the anode-side light-emitting unit) of the light-emitting unit disposed on the cathode side can use the same organic compound as the electron transport layer in the cathode-side light-emitting unit, or a different organic compound can be used. For example, an organic compound with a triazine skeleton, different from the organic compound with a triazine skeleton used for the electron transport layer in the cathode-side light-emitting unit, can also be used.

[0091] Note that, in order to reduce power consumption, the electron transport layer in the light-emitting unit on the anode side preferably also contains an organic compound with a triazine framework. In particular, when the same organic compound as that in the electron transport layer of the light-emitting unit on the cathode side is used, the complexity of the manufacturing apparatus can be suppressed, which is also advantageous from the perspective of raw material procurement costs, and is therefore preferred.

[0092] Furthermore, when the electron transport layer in the light-emitting unit on the anode side contains an organic compound without a triazine skeleton, the control of carrier transport becomes easier, thereby providing a light-emitting device with better characteristics. As the organic compound without a triazine skeleton, organic compounds containing a heteroaromatic ring with a pyridine skeleton or an organic compound containing a heteroaromatic ring with a diazine (pyrimidine or pyrazine) skeleton are preferred. Therefore, the electron transport layer in the light-emitting unit on the anode side can use organic compounds with a triazine skeleton, a pyrimidine skeleton, an imidazole skeleton, or an anthracene skeleton.

[0093] Furthermore, the electron transport layer in the light-emitting unit on the anode side can have a stacked structure or a single-layer structure. When it has a stacked structure, it can provide a light-emitting device with high current efficiency, low power consumption, and good characteristics. When it has a single-layer structure, the number of deposition chambers is small, so it is advantageous from a manufacturing cost point of view.

[0094] The electron mobility of the aforementioned triazine-based organic compound, which can be used in the electron transport layer of the light-emitting unit on the anode side and the electron transport layer of the light-emitting unit on the cathode side, is preferably 1 × 10⁻⁶ when the square root of the electric field strength [V / cm] is 600. -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 / Vs or more. Furthermore, any substance other than those mentioned above can be used as long as its electron transport capability is higher than its hole transport capability.

[0095] Organic compounds having a triazine skeleton are preferably compounds having both a triazine skeleton and an aromatic ring. As the aromatic ring, monocyclic aromatic rings, polycyclic aromatic rings, aromatic rings with alkyl substituents, aromatic rings with fluorine substituents, and aromatic rings with cyano substituents are preferred. The triazine skeleton may also have substituents other than the aforementioned aromatic ring, and the aromatic ring may also have substituents other than the aforementioned fluorine, cyano, or alkyl groups. Note that the triazine skeleton is also referred to as a triazine ring, and other skeletons may also be referred to as rings.

[0096] Examples of monocyclic aromatic rings include benzene rings and other aromatic rings, as well as heterocyclic aromatic rings such as pyrrole rings, pyridine rings, pyrimidine rings, and triazine rings. The presence of an aromatic ring as a substituent improves heat resistance; specifically, it increases the glass transition temperature (Tg) and also enhances electron transport properties.

[0097] Examples of polycyclic aromatic rings include naphthalene rings, phenanthrene rings, etc. The compounds include polycyclic aromatic rings, triphenylene rings, fluorene rings, spirodifluorene rings, carbazole rings, dibenzofuran rings, dibenzothiophene rings, oxanthracene rings, indolecarbazole rings, indenecarbazole rings, and other heterocyclic aromatic rings. Compared to compounds containing benzene rings, compounds with polycyclic aromatic rings as substituents can improve heat resistance and are therefore preferred. Furthermore, when the substituent has a ring fused with the aforementioned polycyclic aromatic rings and aromatic rings (benzene rings, naphthyl rings, pyridine rings, etc.), heat resistance can be further improved. Examples of rings fused with polycyclic aromatic rings include benzo[a]fluorene rings, benzo[a]naphtho[a]furan rings, benzo[a]oxanthracene rings, and benzo[a]naphtho[thiophene rings. By providing a layer containing a compound with high heat resistance near the cathode, thermal damage to the device during high-temperature processing such as patterning steps after the formation of this layer or the cathode can be suppressed.

[0098] Furthermore, examples of alkyl groups include methyl, ethyl, propyl, tert-butyl, cyclohexyl, and adamantyl. Using a layer of compounds with alkyl substituents can reduce the refractive index. Therefore, total internal reflection at the interface between this layer and other layers can be reduced, thereby improving light extraction efficiency. Furthermore, by also using the aforementioned substituent-containing compounds in the hole transport layer, the refractive index of the hole transport layer can be reduced. In particular, by using compounds with a triazine skeleton and alkyl groups in the electron transport layer and compounds with an aromatic amine skeleton and alkyl groups in the hole transport layer, the effect of improving light extraction efficiency can be multiplicatively enhanced. Additionally, when the number of carbon atoms in the alkyl group in the organic compound is multiple, preferably three or more, more preferably four or more, and even more preferably five or more, the effect of reducing the refractive index can be improved. Furthermore, using a layer of compounds with fluorine groups as substituents can also reduce the refractive index, so this is preferred. Especially when multiple fluorine groups are present, the effect of increasing the refractive index can be improved. Using compounds with fluorine groups in both the electron transport layer and the hole transport layer is also effective.

[0099] In addition, compounds with cyano groups as substituents can improve electron transport properties, so they are preferred.

[0100] Furthermore, combinations of polycyclic aromatic rings, alkyl groups, fluorinated groups, and cyano groups are preferred as substituents. For example, when polycyclic aromatic rings and cyano groups are present as substituents, both heat resistance and electron transport properties can be improved. Furthermore, when polycyclic aromatic rings and alkyl groups are present, both heat resistance and photoextraction efficiency can be improved. Thus, substituents can be combined and used according to the desired function.

[0101] Furthermore, when the substituent has multiple polycyclic aromatic rings, the heat resistance can be further improved. In this case, it is preferable to have the above-mentioned aromatic rings and the above-mentioned heteroaromatic rings.

[0102] Specific examples of organic compounds with a triazine skeleton include 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobis[9H-fluorene]-2-yl)-1,3,5-triazine (abbreviated: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated: mBnfBPTzn-02), and 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated: mBnfBPTzn-02). =-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indo[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2- {3-[3-(dibenzothiophene-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenylindolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tz) n), 2-[3'-(triphenyl-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1”-triphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 2-[4-(2-naphthyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]oxanthracene]-4-yl-1,3,5-Triazine (abbreviation: βNP-SFx(4)Tzn), 9,9'-{6-[3-(triphenylsilyl)phenyl]-1,3,5-triazine-2,4-diyl}bis(9H-carbazole) (abbreviation: SiTrzCz2), 2-Pheny-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-(biphenyl-3-yl)indolo[2,3-a]carbazole (abbreviation: BP-mBPIcz(II)Tzn), 3-{3-[9H-carbazole] -(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]phenyl}-9-phenyl-9H-carbazole (abbreviation: mPCPDBfTzn), 9,9'-[6-(biphenyl-4-yl)-2-phenyl-1,3,5-triazin-4,3”-diyl]bis(9H-carbazole) (abbreviation: Cz-pmCzBPTzn), 3-phenyl-9-[4-phenyl-6-(9-phenyl-3-dibenzofuranyl)-1,3,5-triazin-2-yl]-9H-carbazole (abbreviation: PDBf-PCzTzn), 9-[4,6-diphenyl-1,3,5-triazin-2-yl)-2-diphenyl [[[3'-(spiro[7H-benzo[c]fluorene-7,9'-[9H]oxanthracene]-2'-yl)biphenyl-3-yl]-1,3,5-triazine (mSbfxBPTzn), 3'-[4-phenyl-6-(spiro[9H-fluorene-9,9'-[9H]oxanthracene]-2'-yl)-1,3,5-triazine-2-yl]biphenyl-4-carboxylonitrile (mpCNBP-SFxTzn), 2,2'-(1,2-naphthyldi-4,1-phenylene)bis[4,6-diphenyl-1,3,5-triazine] Organic compounds containing a heteroaromatic ring with a triazine skeleton, such as [azine] (abbreviated as TznP2N). Particularly preferred are organic compounds with the following structural formulas (500) to (506), namely, TznP2N (500), mSbfxBPTzn (501), mpCNBP-SFxTzn (502), CNBPNPTzn (503), βNP-SFx(4)Tzn (504), mmtBuBP-mDMePyPTzn (505), and mBnfBPTzn (506).

[0103] [Chemical Formula 6]

[0104] Furthermore, as a material that can be used as the electron transport layer in the light-emitting unit on the anode side, it is preferable to have an electron mobility of 1×10⁻⁶ when the square root of the electric field strength [V / cm] is 600. -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 Substances with a value of / Vs or higher. Substances other than those mentioned above can be used as long as their electron transport capacity is higher than their hole transport capacity. As the aforementioned organic compounds, organic compounds having a π-electron-deficient heteroaromatic ring are preferred. For example, one or more of the following are preferred: organic compounds containing a heteroaromatic ring with an azole skeleton, organic compounds containing a heteroaromatic ring with a pyridine skeleton, organic compounds containing a heteroaromatic ring with a diazine skeleton, and organic compounds containing a heteroaromatic ring with a triazine skeleton; organic compounds containing a heteroaromatic ring with a triazine skeleton are particularly preferred.

[0105] As an electron transportable organic compound that can be used as an electron transport layer in a light-emitting unit on the anode side, the electron transportable materials described later can be used. In particular, organic compounds containing heteroaromatic rings with a diazine skeleton, organic compounds containing heteroaromatic rings with a pyridine skeleton, and organic compounds containing heteroaromatic rings with a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing heteroaromatic rings with a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing heteroaromatic rings with a triazine skeleton have high electron transportability, which can reduce the driving voltage.

[0106] In another aspect of the invention, in a tandem light-emitting device, the intermediate layer 160 preferably comprises an organic compound having a phenanthroline skeleton.

[0107] The preferred electron mobility of the above-mentioned organic compounds with a phenanthroline skeleton is 1 × 10⁻⁶ when the square root of the electric field strength [V / cm] is 600. -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 / Vs or more. Furthermore, any substance other than those mentioned above can be used as long as its electron transport capability is higher than its hole transport capability.

[0108] As an organic compound having a phenanthroline skeleton, a compound having both a phenanthroline skeleton and an aromatic ring is preferred. As the aromatic ring, a monocyclic aromatic ring, a polycyclic aromatic ring, or the like is preferred.

[0109] Examples of monocyclic aromatic rings include benzene rings, pyrrole rings, pyridine rings, and pyrimidine rings. Furthermore, polycyclic aromatic rings preferably have a naphthalene ring, a phenanthrene ring, etc. Aromatic rings such as polycyclic aromatic rings, triphenylene rings, fluorene rings, phenanthrene rings, and pyrrole rings are preferred. In particular, having multiple of the above-mentioned polycyclic aromatic rings can improve heat resistance or electron transport properties.

[0110] As organic compounds with a phenanthrene-coral skeleton, examples include red phenanthrene-coral (BPhen), copper hydroxide (BCP), 2,9-bis(naphthyl-2-yl)-4,7-diphenyl-1,10-phenanthrene-coral (NBPhen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthrene-coral) (mPPhen2P), 2-[3-(2-triphenylene)phenyl]-1,10-phenanthrene-coral (mTpPPhen), and 2-phenyl-9 Organic compounds containing heteroaromatic rings with a phenanthrene skeleton, such as -(2-triphenyl)-1,10-phenanthroline (abbreviated: Ph-TpPhen), 2-[4-(9-phenanthyl)-1-naphthyl]-1,10-phenanthroline (abbreviated: PnNPhen), and 2-[4-(2-triphenyl)phenyl]-1,10-phenanthroline (abbreviated: pTpPPhen), are particularly preferred.

[0111] [Chemical Formula 7]

[0112] In one embodiment of the light-emitting device of the present invention, the intermediate layer can be of any structure as long as it contains an organic compound having a phenanthroline skeleton, and electrons can be injected into the light-emitting unit on the anode side and holes can be injected into the light-emitting unit on the cathode side by applying a voltage between the first and second electrodes. Note that, as Figure 1A As shown, the intermediate layer 160 preferably has a stacked structure of a first layer 161 containing an organic compound and a second layer 162 located closer to the cathode than the first layer.

[0113] The first layer preferably contains metals or metal compounds in addition to organic compounds. The metals in the metal compounds are preferably the following elements: alkali metals such as Li (Group 1 elements); alkaline earth metals such as Mg and Ca (Group 2 elements); Group 3 elements including lanthanides such as Y, Eu, and Yb; Group 11 elements such as Cu, Ag, and Au; Group 12 elements such as Zn; and earth metals such as Al and In (Group 13 elements).

[0114] Note that the first layer can also be a stacked structure of a layer containing an organic compound and a layer containing a metal or metal compound located closer to the cathode than the layer containing the organic compound, or it can be a mixed layer of an organic compound and a metal or metal compound. Furthermore, when the first layer is a mixed layer, fewer deposition chambers are required, manufacturing costs are reduced, and the stability of the light-emitting device is improved, making it a preferred option.

[0115] In the case of a mixture of organic compounds and metals or metal compounds, when analyzing the first layer in the thickness direction, the distribution of organic compounds and metals or metal compounds shows roughly the same trend. That is, if the distribution of organic compounds is fixed, the distribution of metals or metal compounds is also roughly fixed. In a stacked structure containing layers of organic compounds and layers containing metals or metal compounds, sometimes metals or metal compounds are detected in areas outside the layers containing those layers due to diffusion. However, because they exhibit a different distribution than the organic compounds, analytical results can be distinguished between diffusion and mixing.

[0116] Furthermore, when analyzing the first layer in the thickness direction, if the thickness of the region where metal or metal compound is detected is 10 nm or more, preferably 15 nm or more, and more preferably 20 nm or more, the first layer can be considered to be a mixed layer composed of an organic compound and a metal or metal compound.

[0117] In particular, the metal in the aforementioned metal or metal compound is preferably a substance that is a donor to the organic compound having a phenanthroline skeleton. Examples of substances that are donors to the organic compound having a phenanthroline skeleton include metals from Group 1 and Group 2, with lithium or lithium compounds being particularly preferred. Specifically, Li, lithium fluoride (LiF), lithium oxide (Li₂O), and 8-hydroxyquinoline-lithium (Liq) are preferred. When the first layer contains an organic compound having a phenanthroline skeleton and a substance that is a donor to this organic compound, electrons are generated through charge separation. When a voltage is applied between the first and second electrodes, these electrons are injected into the light-emitting unit on the anode side through the organic compound having a phenanthroline skeleton. Thus, one embodiment of the light-emitting device of the present invention can be a light-emitting device with a low driving voltage.

[0118] In addition to the organic compounds mentioned above, organic compounds with a phenanthroline skeleton are preferably organic compounds containing an electron-donating substituent. The phenanthroline skeleton readily interacts with metals, etc. By further providing electron-donating groups to such organic compounds with a phenanthroline skeleton, the electron density of the phenanthroline skeleton increases, thereby further facilitating interaction with metals or metal compounds. In particular, when metals from Groups 3, 11, 12, and 13 are used as the metal or metal compound, the rise in driving voltage can be suppressed, thereby providing a tandem light-emitting device with excellent characteristics.

[0119] Specific examples of electron-donating groups include alkyl, alkoxy, aryloxy, alkylamino, arylamino, and heterocyclic amino groups. However, the preferred electron-donating group introduced onto the phenanthroline ring is not limited to these. Any group that can increase the electron density of the phenanthroline ring by being introduced onto it can be used as an electron-donating group. Furthermore, the electron-donating group can also be introduced into the phenanthroline ring via an arylene group such as a p-phenylene group, which is preferably para-phenylene.

[0120] Structural formulas (203) to (213) show specific examples of organic compounds containing a phenanthroline skeleton with electron-donating substituents.

[0121] [Chemical Formula 8]

[0122] Furthermore, when the first layer comprises a Group 1 or Group 2 organic compound, particularly lithium or a lithium compound, having an organic compound with a phenanthroline skeleton including electron-donating substituents, it can provide a tandem light-emitting device with lower driving voltage and better reliability, and is therefore preferred. Moreover, when the first layer comprises a Group 1 or Group 2 organic compound, particularly lithium or a lithium compound, having an organic compound with a phenanthroline skeleton including electron-donating substituents, it can suppress the rise in driving voltage when processing the organic compound layer of the light-emitting device using photolithography, and is therefore preferred.

[0123] In the intermediate layer having the above structure, organic compounds having a phenanthroline skeleton are particularly preferred to be organic compounds having a 1,10-phenanthroline skeleton in the phenanthroline skeleton, because the two nitrogen atoms contained in the above organic compounds can coordinate to a metal, thereby facilitating interaction with the metal or metal compounds.

[0124] When electron-donating groups are introduced into the 1,10-phenanthroline skeleton, these groups are preferably substituted at the 4 and 7 positions. By introducing electron-donating groups at the 4 and 7 positions of the 1,10-phenanthroline skeleton, the electron density of the nitrogen atoms at the 1 and 10 positions can be increased, thereby facilitating interactions with metals or metal compounds.

[0125] The first layer may also contain an organic compound different from the organic compound having a phenanthroline skeleton. Furthermore, this organic compound is preferably an organic compound with electron transport properties. In particular, this organic compound preferably has two or more heteroaromatic rings bonded or fused together, and these two or more heteroaromatic rings have a total of three or more heteroatoms. By including such an organic compound in the first layer, heat resistance and electron transport properties can be improved.

[0126] The second layer 162 preferably comprises an organic compound with hole-transporting properties. Furthermore, the second layer 162 preferably also comprises a receptor-like substance, which is preferably an organic compound that is receptor-like to the organic compound with hole-transporting properties. As the receptor-like substance, an organic compound having at least one of a halogen group and a cyano group is particularly preferred, and an organic compound having at least one of a fluorine group and a cyano group is more preferred. Furthermore, the total number of halogen (fluorine) and cyano groups contained in the organic compound is more preferably 4 or more.

[0127] In the case where the second layer 162 contains an organic compound with hole-transporting properties and a substance that is an acceptor of the organic compound with hole-transporting properties, holes are generated through charge separation. When a voltage is applied between the first electrode and the second electrode, these holes are injected into the light-emitting unit on the cathode side through the organic compound with hole-transporting properties. Thus, one embodiment of the light-emitting device of the present invention can be a light-emitting device with a low driving voltage.

[0128] The intermediate layer may also include a third layer 163 between the first layer 161 and the second layer 162.

[0129] The third layer contains an electron-transmitting material and has the functions of smoothly transferring electrons between the first layer 161 and the second layer 162 to reduce the driving voltage, and reducing the interaction between the first layer 161 and the second layer 162 to improve reliability.

[0130] Furthermore, the thickness of the third layer 163 is preferably 1 nm or more and 10 nm or less, more preferably 2 nm or more and 5 nm or less, thereby suppressing the rise of the driving voltage.

[0131] The light-emitting device of one embodiment of the present invention having the above-described structure can be a light-emitting device with high current efficiency, low energy loss, and good characteristics. Furthermore, the display device of one embodiment of the present invention using such a light-emitting device can be a display device with low power consumption, high reliability, and good visibility, capable of displaying at high brightness.

[0132] Furthermore, in one embodiment of the tandem light-emitting device of the present invention, the first hole transport layer 112_1 and the second hole transport layer 112_2 preferably use organic compounds having an amine backbone and polycyclic aromatic hydrocarbons, more preferably use organic compounds having an amine backbone and polycyclic aromatic hydrocarbons, and even more preferably use organic compounds having an amine backbone and a fluorene backbone. Organic compounds having an amine backbone and a fluorene backbone have good reliability and high hole transport capacity, which can reduce power consumption.

[0133] Alternatively, the first hole transport layer 112_1 and the second hole transport layer 112_2 can also adopt a stacked structure. Specifically, as the hole transport layer in contact with the first light-emitting layer 113_1 or the second light-emitting layer 113_2, a material with good hole transport properties, low electron transport properties, and a high LUMO energy level is used. In particular, it is preferred to use a material whose LUMO energy level is higher than that of the material constituting the light-emitting layer (at least the host material, preferably the material constituting the light-emitting layer, the material with the largest composition ratio among the materials constituting the light-emitting layer, or the material with the highest LUMO energy level among the materials constituting the light-emitting layer), preferably a material that is 0.30 eV or higher. Organic compounds with π-electron-rich polycyclic heteroaromatic rings, especially organic compounds with a carbazole skeleton, are mostly organic compounds with high LUMO energy levels and are suitable for the first hole transport layer 112_1 and the second hole transport layer 112_2.

[0134] By using a material with a stacked structure for the first hole transport layer 112_1 and a LUMO energy level higher than that of the material constituting the light-emitting layer in the layer contacting the first light-emitting layer 113_1, electrons can be prevented from passing through the first electrode 101 side from the first light-emitting layer 113_1. Similarly, by using a material with a stacked structure for the second hole transport layer 112_2 and a LUMO energy level higher than that of the material constituting the light-emitting layer in the layer contacting the second light-emitting layer 113_2, electrons can be prevented from passing through the intermediate layer 160 from the second light-emitting layer 113_2, thus enabling the manufacture of a display device with high efficiency and long lifespan.

[0135] Furthermore, when using a phosphorescent material as the light-emitting layer, the T1 energy level of the organic compound used in the first hole transport layer 112_1 and the second hole transport layer 112_2 is preferably higher than the T1 energy level of the phosphorescent material. In particular, by employing this structure as the layer in contact with the light-emitting layer within the hole transport layer, the excitation energy of excitons generated in the light-emitting layer due to carrier recombination can be prevented from diffusing to the layer in contact with the light-emitting layer, thereby achieving a light-emitting device with high luminous efficiency. Furthermore, when using a blue phosphorescent material as the light-emitting layer, by using an organic compound whose T1 energy level is lower than that of the phosphorescent material in the layer in contact with the light-emitting layer, a stable and highly reliable light-emitting device can be achieved. Moreover, as the layer in contact with the anode side and the cathode side of the light-emitting layer, by using an organic compound in one layer with a T1 energy level higher than that of the phosphorescent material and an organic compound in the other layer with a T1 energy level lower than that of the phosphorescent material, a light-emitting device with high luminous efficiency and high reliability can be achieved. However, when organic compounds with significantly low T1 energy levels are used in the layer in contact with the light-emitting layer, the luminous efficiency tends to decrease. Therefore, the energy difference between the T1 energy level of the phosphorescent material and the T1 energy level of the organic compound used in the layer in contact with the light-emitting layer should be 0.1 eV or more, preferably 0.2 eV or more, and 1.0 eV or less, preferably 0.5 eV or less. This can avoid a decrease in luminous efficiency and thus obtain a stable and reliable light-emitting device.

[0136] In other words, by making the first hole transport layer 112_1 and the second hole transport layer 112_2 have different polycyclic aromatic rings and adopt a stacked structure of organic compounds with different combination characteristics, the design freedom of the display device can be improved.

[0137] Specifically, as the organic compound that can be used in the first hole transport layer 112_1 and the second hole transport layer 112_2, an organic compound having an aromatic amine skeleton is preferably used. Examples of aromatic rings in organic compounds having an aromatic amine skeleton include monocyclic aromatic rings and polycyclic aromatic rings. Furthermore, these aromatic rings may also have alkyl groups as substituents.

[0138] Examples of monocyclic aromatic rings include benzene rings and other aromatic rings, as well as heterocyclic aromatic rings such as pyrrole rings and furan rings. Having an aromatic ring as a substituent can improve heat resistance, resulting in an increase in the glass transition temperature (Tg). Furthermore, having an aromatic ring as a substituent can adjust the transport properties of charge carriers such as holes or electrons. Moreover, having multiple of the above-mentioned monocyclic aromatic rings can further improve Tg; for example, a biphenyl or terphenyl structure is preferred. A p-phenylene, m-phenylene, or ortho-phenylene structure may also be included. Having at least one of the m-phenylene or ortho-phenylene structures not only improves the solubility of the compound, making manufacturing easier, but also reduces the refractive index. Furthermore, when the compound has three or more benzene rings, such as a terphenyl structure, including an aromatic ring having at least two of the p-phenylene, m-phenylene, and ortho-phenylene structures is preferred, as it can adjust not only solubility and refractive index but also the transport properties of charge carriers.

[0139] Note that when the benzene ring is used as a linker, it is usually called phenylene, but to avoid complexity, it is sometimes called phenyl even when used as a linker. The same applies to other aromatic rings; when used as a linker, they are sometimes called aryl instead of arylene, or sometimes heteroarylene instead of heteroarylene. Additionally, the description of the benzene ring is sometimes replaced with "benzene structure" or "benzene skeleton," and other substituents (aromatic rings, etc.) are also referred to using this replacement.

[0140] Examples of polycyclic aromatic rings include naphthalene rings, phenanthrene rings, etc. Aromatic rings, including polycyclic aromatic rings, triphenylene rings, fluorene rings, spirodifluorene rings, carbazole rings, dibenzofuran rings, dibenzothiophene rings, xanthene rings, and other heterocyclic aromatic rings, are preferred. Compared to compounds with monocyclic aromatic rings, compounds with polycyclic aromatic rings as substituents can improve heat resistance and are therefore preferred. Furthermore, compounds having multiple of the aforementioned polycyclic aromatic rings are preferred. When multiple polycyclic aromatic rings are present, they can be the same or different polycyclic aromatic rings. Examples of structures using the same ring include those with multiple aromatic rings, those with multiple heterocyclic aromatic rings, and those with one or more aromatic rings and one or more heterocyclic aromatic rings. Using the same aromatic ring can lead to reduced raw material costs and simplified synthesis procedures. Additionally, when different aromatic rings are used, the transport properties of charge carriers such as holes or electrons, or the heat transfer rate (Tg), can be adjusted depending on the type of aromatic ring used. As an example of a case with multiple polycyclic aromatic rings, structures with carbazole and dibenzofuran rings, structures with two, three or more carbazole rings, and structures with two, three or more rings can be cited.

[0141] Furthermore, when the substituent has a ring that is fused with an aromatic ring (such as the aforementioned monocyclic aromatic ring), the heat resistance can be further improved. Examples of rings that are fused with an aromatic ring include benzo[a]fluorene ring, benzo[a]naphthofuran ring, benzo[a]oxanthracene ring, and benzo[a]naphthothiophene ring.

[0142] Furthermore, both monocyclic aromatic rings and polycyclic aromatic rings described above can be used as substituents. Examples include structures where a monocyclic aromatic ring is used as a linker between the nitrogen in the amine skeleton and the polycyclic aromatic ring. For instance, structures using a phenylene ring between the nitrogen and fluorene ring, structures using a phenylene ring between the nitrogen and carbazole ring, or structures using a phenylene ring between the nitrogen and dibenzo[a]fluorene ring are also examples. Additionally, structures in which multiple polycyclic aromatic rings are bonded to a single phenylene ring used as a linker are also effective. These multiple polycyclic aromatic rings can be the same aromatic ring or different aromatic rings. For example, in compounds where both the carbazole ring and the dibenzo[a]fluorene ring are bonded to a single phenylene ring, the functions of both the carbazole ring and the dibenzo[a]fluorene ring can be obtained while simultaneously increasing the temperature gradient (Tg).

[0143] Furthermore, examples of alkyl groups include methyl, ethyl, propyl, tert-butyl, cyclohexyl, and adamantyl. Using a compound with alkyl substituents as a layer can reduce the refractive index. Therefore, total internal reflection at the interface between this layer and other layers can be reduced, thereby improving light extraction efficiency. Furthermore, by also using the aforementioned substituent-containing compounds in the hole transport layer, the refractive index of the hole transport layer can be reduced. In particular, by using compounds having an aromatic amine skeleton and alkyl groups in the hole transport layer, the effect of improving light extraction efficiency can be multiplied and enhanced. Additionally, when the number of carbon atoms in the alkyl group in the organic compound is multiple, preferably three or more, more preferably four or more, and even more preferably five or more, the effect of reducing the refractive index can be improved. Furthermore, when multiple alkyl groups are bonded to one aromatic ring, the refractive index can be further reduced, which is preferred. In this case, the multiple alkyl groups can be the same or different. For example, one benzene ring can be bonded to two or three tert-butyl groups. Furthermore, in the case of multiple aromatic rings, when alkyl groups are bonded to two or more aromatic rings, the refractive index can be reduced. Furthermore, by having alkyl groups in a portion of the multiple aromatic rings, the refractive index can be adjusted. For example, in the case of three aromatic rings, structures in which two aromatic rings have alkyl groups and the other aromatic ring does not have an alkyl group can be cited.

[0144] Specific examples of organic compounds having an aromatic amine skeleton are shown in the following structural formulas (300) to (330). Particularly preferred are BBASF (4) as shown in structural formula (300), oBBASF as shown in structural formula (301), BBAFLP (4) as shown in structural formula (302), oFBiSF (2) as shown in structural formula (303), FBiSF (4) as shown in structural formula (304), oFBiSF as shown in structural formula (305), FBimFLP as shown in structural formula (306), FBimMemFLP as shown in structural formula (307), SF (4)FAF as shown in structural formula (308), FrBBiFLP as shown in structural formula (309), tBu-oFBiSF (2) as shown in structural formula (310), FBiFLPB as shown in structural formula (311), DBfBBFLP (2) as shown in structural formula (312), FLP2oBP as shown in structural formula (313), PCAFLP (2)-02 as shown in structural formula (314), and structural formula (315). 15) tBu2FoFBi, (316) oFrTPPnox, (317) mPDBfBNBN, (318) BBAaBnf(7), (319) DBfBB1TP, (320) BOx3Am, (321) BBA2BP, (322) PCBBi1BP, (323) YGBBi1BP-02, (324) YGBBi1BP, (325) PCBBi1TP, (326) YGBBiPDBf, (327) BPPCA, (328) PCBBiF, (329) DBf-YGBBi1BP, (330) YGTPDBfB.

[0145] [Chemical Formula 9]

[0146] [Chemical Formula 10]

[0147] [Chemical Formula 11]

[0148] [Chemical Formula 12]

[0149] For example, as the first hole transport layer 112_1 and the second hole transport layer 112_2, it is particularly preferred to use organic compounds having an amine skeleton and a polycyclic heteroaromatic ring, which are organic compounds represented by structural formulas (300) to (330).

[0150] Furthermore, as the layer in contact with the light-emitting layer in the first hole transport layer 112_1 and the second hole transport layer 112_2, an organic compound having a π-electron-rich polycyclic heteroaromatic ring without an amine skeleton is preferably used. Specific examples of organic compounds used in the layers in contact with the light-emitting layer in the first hole transport layer 112_1 and the second hole transport layer 112_2 include 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviated: PSiCzCz) as shown in structural formula (350), 9'-[3-(triphenylsilyl)phenyl]-9'H-9,3':6',9”-tricarbazole (abbreviated: PSiCzGI) as shown in structural formula (351), and 9,9”-(1,3-phenylene)bis(3,9'-bi- 9H-carbazole (abbreviated as mCzCz2P), 1,3-bis(N-carbazole)benzene (abbreviated as mCP) as shown in structural formula (353), 9,9”-[3,3'-(diphenylsilyl)diphenyl]bis(3,9'-bi-9H-carbazole) (abbreviated as mCzCz2PSi) as shown in structural formula (354), 3,3'-9H-carbazole-9-yl-biphenyl (abbreviated as mCBP) as shown in structural formula (359), 9'-phenyl-9'H-9,3':6',9”-tricarbazole (abbreviated as PhCzGI) as shown in structural formula (360), and other structures 12-[3-(9H-carbazole-9-yl)phenyl]-5,12-dihydro-5-phenyl-indole[3,2-a]carbazole (abbreviated as mCzPICz) as shown in formula (361), 5,12-bis[3-(9H-carbazole-9-yl)phenyl]-5,12-dihydro-indole[3,2-a]carbazole (abbreviated as mCzP2ICz) as shown in formula (362), and 5-[3-(9H-carbazole-9-yl)phenyl]-5,12-dihydro-12-phenyl-indole[3,2-a]carbazole (abbreviated as mCzPICz) as shown in formula (363) -02), 12,12'-(1,4-phenylene)bis(5,12-dihydro-5-phenyl-indole[3,2-a]carbazole) shown in structural formula (364) (abbreviated as ICz2P), 12,12'-(1,3-phenylene)bis(5,12-dihydro-5-phenyl-indole[3,2-a]carbazole) shown in structural formula (365) (abbreviated as mICz2P), 5,5'-(1,3-phenylene)bis(5,12-dihydro-12-phenyl-indole[3,2-a]carbazole) shown in structural formula (366) (abbreviated as mICz2P-02), etc. Additionally, organic compounds shown in structural formulas (355) to (358) can be used. For example, when the organic compounds shown in structural formulas (350) to (366) are used in a blue light-emitting device, they can be used in the layers that are in contact with the light-emitting layer in the first hole transport layer 112_1 and the second hole transport layer 112_2.In addition, the organic compounds shown in structural formulas (350) to (366) can also be used as the host material for the light-emitting layer of a blue light-emitting device.

[0151] [Chemical Formula 13]

[0152] [Chemical Formula 14]

[0153] Furthermore, when the first hole transport layer 112_1 and the second hole transport layer 112_2 adopt a stacked structure, as the layer in contact with the light-emitting layer, it is preferable to select an organic compound whose LUMO energy level and T1 energy level are higher than those of the material constituting the light-emitting layer (at least the host material, preferably the material constituting the light-emitting layer). Specifically, organic compounds having π-electron-rich heteroaromatic rings or polycyclic heteroaromatic rings can be used. As a specific example of a π-electron-rich heteroaromatic ring or polycyclic heteroaromatic ring, a carbazole skeleton can be given. The carbazole skeleton is stable and has good reliability, so it is preferred. In addition, it is more preferable to use an organic compound having two or more carbazole skeletons. Bicarbazole is stable and has good reliability, so it is preferred, especially the bicarbazole skeleton in which any two carbazole groups are bonded to each other at any one of the 2 to 4 positions has strong donor properties, so it is preferred. Examples of bicarbazole skeletons include 2,2'-bi-9H-carbazole skeletons, 3,3'-bi-9H-carbazole skeletons, 4,4'-bi-9H-carbazole skeletons, 2,3'-bi-9H-carbazole skeletons, 2,4'-bi-9H-carbazole skeletons, and 3,4'-bi-9H-carbazole skeletons. Furthermore, bicarbazole skeletons in which any one of the 2 to 4 positions and two carbazole groups at the 9 position are bonded to each other exhibit a larger band gap and a higher excitation energy level, making them suitable for blue light-emitting devices. Examples of bicarbazole skeletons include 2',9'-bi-9H-carbazole skeletons, 3,9'-bi-9H-carbazole skeletons, and 4,9'-bi-9H-carbazole skeletons. Specifically, examples include 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviated as PSiCzCz), 9'-phenyl-9'H-9,3':6',9”-tricarbazole (abbreviated as PhCzGI), 12-[3-(9H-carbazole-9-yl)phenyl]-5,12-dihydro-5-phenyl-indole[3,2-a]carbazole (abbreviated as mCzPICz), and 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), etc.

[0154] Here, in the multiple layers (e.g., hole transport layer, intermediate layer, light-emitting layer, electron transport layer, capping layer, etc.) included in the light-emitting device, the compounds used in one layer and the compounds used in another layer can be different compounds and have the same aromatic ring (monocyclic or polycyclic aromatic ring) as substituents. By making different compounds also have the same aromatic ring, it is expected that the raw material cost or the synthesis steps will be reduced when manufacturing the compound.

[0155] Examples of aromatic rings that can be used in the aforementioned compounds include fused rings (also called fused structures), such as those of naphthene, fluorene, benzofluorene, triphenylene, benzonaphthofuran, xanthene, benzooxanthene, spirofluorenexanthene (also known as SFx), spirobenzofluorenexanthene (also known as Sbfx), carbazole, benzocarbazole, dibenzofuran, dibenzothiophene, and benzonaphthothiophene. Their structures are shown below. Note that in the cases where the aromatic rings shown below have substituents, either a carbon or nitrogen atom is bonded.

[0156] [Chemical Formula 15]

[0157] Furthermore, these fused rings can be used to adjust the carrier transport or Tg depending on the bonding positions (also called bonding sites) with other groups, and therefore can be used in various layers. For example, it is preferable to use a naphthalene ring with a bonding site at the 1-position as an electron transport layer material and a naphthalene ring with a bonding site at the 2-position as a hole transport layer material. It is also preferable to use a naphthalene ring with a bonding site at the 2-position as the host material of the luminescent layer and a naphthalene ring with a bonding site at the 1-position as the hole transport layer material. Furthermore, when using a naphthalene ring as a linker, it is preferable to use a naphthalene ring with bonding sites at both the 1- and 2-positions as an electron transport layer material and a naphthalene ring with bonding sites at both the 1- and 6-positions as the host material of the luminescent layer. Thus, it is preferable to use fused rings with different bonding sites for the compounds used in one layer and those used in another layer.

[0158] Furthermore, when multiple layers use the same fused ring, it is preferable to use different substituents, such as using a fused ring bonded with a cyano group (naphthalene ring, etc.) as an electron transport layer material, and using a fused ring bonded with an alkyl group (naphthalene ring, etc.) as a hole transport layer material. Materials corresponding to the properties required for each layer can be provided.

[0159] Furthermore, aromatic rings with structural isomers can be used, not limited to the same aromatic ring. By using aromatic rings with structural isomers, the same starting materials can sometimes be used as described above, thus reducing raw material costs or shortening the synthetic steps. For example, as structural isomers of the benzo[b]naphtho[2,1-d]furan ring (also known as the aBnf skeleton), the benzo[b]naphtho[2,3-d]furan ring (also known as the Bnf(II) skeleton), and the benzo[b]naphtho[1,2-d]furan ring (also known as the Bnf skeleton) are three examples of fused structures, depending on the position of the fused ring in the benzene ring. The specific structures of these skeletons are shown below. In the benzo[b]naphtho[furan] ring shown below, where substituents are present, any carbon or nitrogen atom is bonded.

[0160] [Chemical Formula 16]

[0161] When using aromatic rings with structural isomorphism, the aforementioned aBnf framework can be used as the electron transport layer material, the aforementioned Bnf(II) framework can be used as the host material of the luminescent layer, and the aforementioned Bnf can be used as the hole transport layer material. Since the properties (carrier transport, HOMO, LUMO, etc.) of materials using aromatic rings with structural isomorphism differ, appropriate aromatic rings can be used according to the required properties of each layer. This not only allows for the adjustment of Tg, reduction of raw material costs, and shortening of synthesis steps, but also enables the improvement of properties.

[0162] Furthermore, the main materials in each light-emitting layer of the red, green, and blue light-emitting devices preferably contain aromatic rings with structural isomerism. Additionally, when different materials are used for the hole transport layers of each color, aromatic rings with structural isomerism may also be included. Furthermore, in the case of multiple electron transport layers, these multiple layers preferably also contain aromatic rings with structural isomerism. The same applies when multiple hole transport layers are included. Thus, the multiple materials used in the light-emitting device preferably contain aromatic rings with structural isomerism. Furthermore, in the case of a fused ring structure, aromatic rings with structural isomerism can also be referred to as aromatic rings with equal molecular weights but different fusion positions. This is not limited to benzo[a]naphtho[furan] rings; the same applies to other aromatic rings mentioned above (benzo[a]fluorene ring, benzo[a]oxane ring, spirobenzo[a]fluoreneoxane ring, benzo[a]carbazole ring, benzo[a]naphtho[thiophene ring, etc.). As mentioned above, "benzonaphthofuran ring" is a term that includes structural isomers such as aBnf, Bnf(II), and Bnf, and other fused rings are also terms that include structural isomers.

[0163] Note that each fused ring in the structural formula can also have substituents. Different compounds can have the same substituents or represent different substituents.

[0164] In addition, the first light-emitting unit 501 and the second light-emitting unit 502 may also include other functional layers besides the aforementioned light-emitting layer, hole transport layer, and electron transport layer. They are not limited to this. Figure 1A The structure shown can be configured without any of the aforementioned layers, or with other layers. Typical examples of other layers include carrier blocking layers and exciton blocking layers.

[0165] Furthermore, when using a phosphorescent material, the T1 energy level of the organic compound used in the carrier blocking layer is preferably higher than that of the phosphorescent material. By employing this structure, the excitation energy of excitons generated in the luminescent layer due to carrier recombination can be prevented from diffusing into the carrier blocking layer, thereby enabling a light-emitting device with high luminous efficiency. Furthermore, when using a blue phosphorescent material as the luminescent layer, using an organic compound whose T1 energy level is lower than that of the phosphorescent material in the carrier blocking layer enables a stable and highly reliable light-emitting device. Moreover, as the layer contacting the anode side and the carrier blocking layer contacting the cathode side of the luminescent layer, using an organic compound in one layer with a T1 energy level higher than that of the phosphorescent material and an organic compound in the other layer with a T1 energy level lower than that of the phosphorescent material enables a light-emitting device with both high luminous efficiency and high reliability. However, when organic compounds with significantly low T1 energy levels are used in the carrier blocking layer, the luminous efficiency tends to decrease. Therefore, the energy difference between the T1 energy level of the phosphorescent material and the T1 energy level of the organic compound used in the carrier blocking layer should be 0.1 eV or more, preferably 0.2 eV or more, and 1.0 eV or less, preferably 0.5 eV or less. This can avoid the decrease in luminous efficiency and thus obtain a stable and reliable light-emitting device.

[0166] The first electrode 101 is an electrode including an anode. The first electrode 101 may also have a multilayer structure, in which case the layer in contact with the organic compound layer 103 is used as the anode. The anode is preferably formed using a metal, alloy, conductive compound, or mixture thereof with a high work function (specifically 4.0 eV or higher). Specifically, examples include indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, and indium oxide (IWZO) containing tungsten oxide and zinc oxide. While these conductive metal oxide films are typically deposited by sputtering, they can also be formed using sol-gel methods. Examples of formation methods include sputtering a method using a target containing 1 wt% to 20 wt% zinc oxide to form indium oxide. Furthermore, IWZO can also be formed by sputtering a target containing 0.5 wt% to 5 wt% tungsten oxide and 0.1 wt% to 1 wt% zinc oxide to form indium oxide. In addition, materials used for the anode include, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or nitrides of metallic materials (e.g., titanium nitride). Furthermore, graphene can also be used as a material for the anode. Moreover, by using the composite material constituting the first layer 161 (also called the P-type layer) of the aforementioned intermediate layer 160 as the layer in contact with the anode (typically a hole injection layer), the work function can be disregarded when selecting the electrode material.

[0167] Hole injection layer 111 is in contact with the anode and has the function of easily injecting holes into organic compound layer 103 (first light-emitting unit 501). Hole injection layer 111 can be formed by using phthalocyanine compounds or complexes such as phthalocyanine (H2Pc), copper phthalocyanine (CuPc), etc.; aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (DNTPD), etc.; or polymers such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS), etc.

[0168] Furthermore, the hole injection layer 111 can also be formed using a substance with electron-accepting properties. As such a substance, organic compounds with electron-withdrawing groups (halogen groups, cyano groups, etc.) can be used, such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinone dimethylethane (abbreviated: F4-TCNQ), chloroquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviated: F6-TCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-yl)malononitrile, etc. In particular, compounds such as HAT-CN, which have electron-withdrawing groups bonded to fused aromatic rings with multiple heteroatoms, are thermally stable and therefore preferred. Furthermore, [3] axylene derivatives having electron-withdrawing groups (especially halogen groups such as fluorine groups, cyano groups, etc.) are particularly preferred due to their very high electron-acceptance properties. Specifically, examples include: α,α',α”-1,2,3-cyclopropanetrimethylenetri[4-cyano-2,3,5,6-tetrafluorophenylacetonitrile], α,α',α”-1,2,3-cyclopropanetrimethylenetri[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)phenylacetonitrile], and α,α',α”-1,2,3-cyclopropanetrimethylenetri[2,3,4,5,6-pentafluorophenylacetonitrile]. In addition to the aforementioned organic compounds, molybdenum oxides, vanadium oxides, ruthenium oxides, tungsten oxides, and manganese oxides can also be used as acceptor substances. Transition metal oxides. Furthermore, hole injection layers 111 can be formed by using phthalocyanine compounds or complexes such as phthalocyanine (H2Pc), copper phthalocyanine (CuPc), etc.; aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (DNTPD), etc.; or polymers such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS), etc. Substances with acceptor properties can extract electrons from adjacent hole transport layers (or hole transport materials) by means of an applied electric field.

[0169] Furthermore, the hole injection layer 111 is preferably formed of a composite material comprising the aforementioned acceptor material and a hole transport substance.

[0170] Various organic compounds, such as aromatic amines, heteroaromatic compounds, aromatic hydrocarbons, and polymers (oligomers, dendritic polymers, polymers, etc.), can be used as hole-transporting substances for composite materials. Preferably, a hole mobility of 1×10⁻⁶ is used. -6 cm 2 Substances with a density of / Vs or higher. Substances with hole-transporting properties used in composite materials are preferably compounds having fused aromatic rings or π-electron-rich heteroaromatic rings. As fused aromatic rings, anthracene rings, naphthalene rings, etc., are preferred. Furthermore, as π-electron-rich heteroaromatic rings, fused aromatic rings having at least one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton are preferred; specifically, carbazole rings, dibenzothiophene rings, or rings fused with these rings to aromatic or heteroaromatic rings are preferred.

[0171] The hole-transporting material is more preferably composed of any one of a carbazole backbone, a dibenzofuran backbone, a dibenzothiophene backbone, and an anthracene backbone. In particular, it can be an aromatic amine having substituents comprising a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthyl ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. Note that when these hole-transporting materials are N,N-bis(4-biphenyl)amino groups, long-lifetime light-emitting devices can be manufactured, and therefore they are preferred.

[0172] Specifically, examples of substances with hole transport capabilities include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4”-phenyltriphenylamine (abbreviated as: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviated as: BBABnf(6)), and N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan -8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4”-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4”-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4”-(6;1 4,4'-diphenyl-4”-(7;1'-binathyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4”-(7;1'-binathyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4”-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4”-(6;2'-binathyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4”-(7;2'-binathyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4”-(4;2'-binathyl-1-yl)triphenylamine (abbreviation: BBAβNαNB) ), 4,4'-diphenyl-4”-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenyl)-4'-(2-naphthyl)-4”-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4”-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4”-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-Diphenyl-4”-[4'-(carbazole-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tri(biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4”-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirodi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis(biphenyl-4-yl)-9,9'-spirodi[9H-fluorene) -2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirodi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluorene-9-yl) Triphenylamine (abbreviated as BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluorene-9-yl)phenyl]triphenylamine (abbreviated as BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBA1BP), 4,4'-diphenyl-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBA1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBANB), 4,4'-di(1-naphthyl)-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBANB), 4,4'-di(1-naphthyl)-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBANB), 4,4'-di(1-naphthyl)-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine The following amino acids are listed: N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirodi[9H-fluorene]-2-amine (abbreviated as: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviated as: PCBiF), N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi-9H-fluorene-4-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi-9H-fluorene-3-amine, and N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi-9H-fluorene-3-amine.9'-spirodi-9H-fluorene-2-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi-9H-fluorene-1-amine, 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviated: PSiCzCz), 9'-[3-(triphenylsilyl)phenyl]-9'H-9,3':6',9”-tricarbazole (abbreviated: PSiCzGI), etc.

[0173] In addition, as substances with hole transport capabilities, the following aromatic amine compounds can also be used: N,N'-bis(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B), etc.

[0174] By forming a hole injection layer 111, hole injection capability can be improved, thereby obtaining a light-emitting device with low driving voltage.

[0175] Furthermore, organic compounds with receptors can be easily deposited in substances with receptors using vapor deposition, making them easy-to-use materials.

[0176] Furthermore, the hole transport layers (first hole transport layer 112_1, second hole transport layer 112_2) are formed by comprising an organic compound with hole transport properties. The organic compound with hole transport properties preferably has a concentration of 1×10⁻⁶. -6 cm 2 Hole mobility of / Vs or higher. In addition to the organic compounds with amine and fluorene skeletons mentioned above, organic compounds with hole transport properties may also be used as needed.

[0177] Examples of substances with hole-transporting capabilities include: 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (TPD), N,N'-bis(9,9'-spirobis[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (mBPAFLP), and 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (PCBA1BP). Compounds with aromatic amine skeletons, such as 4,4'-diphenyl-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCCNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluorene-2-amine (abbreviation: PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirodi[9H-fluorene]-2-amine (abbreviation: PCBASF);1,3-Bis(N-carbazolyl)benzene (mCP), 4,4'-bis(N-carbazolyl)biphenyl (CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (mBPCCBP) ), 9-(2-naphthyl)-9'-3,3'-bi-9H-carbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1”-triphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1”-triphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1”-triphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1”-triphenyl]-3-yl-3,3'-9H,9'H-bicarbazole [Biphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1”-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1”-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1”-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenyl-2-yl)-3,3'-9H Compounds with a carbazole skeleton, such as 9'H-bicarbazole (abbreviated as PCCzTp), 9,9'-bis(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenyl-2-yl)-9'-[1,1':3',1”-triphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, N,N'-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi-9H-fluorene-1-amine, and 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviated as PSiCzCz);Compounds with a thiophene skeleton, such as 4,4',4”-(benzyl-1,3,5-triyl)tris(dibenzothiophene) (abbreviated as DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III), and 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV); and compounds with a furan skeleton, such as 4,4',4”-(benzyl-1,3,5-triyl)tris(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Compounds with an aromatic amine backbone and compounds with a carbazole backbone are preferred due to their good reliability, high hole transport capacity, and ability to reduce driving voltage. Furthermore, organic compounds with hole transport capacity, exemplified as composite materials for the hole injection layer 111, can also be suitably used as materials constituting the hole transport layer 112 (first hole transport layer 112_1, second hole transport layer 112_2).

[0178] Furthermore, the first hole transport layer 112_1 and the second hole transport layer 112_2 preferably contain organic compounds having the same skeleton, and more preferably contain the same compound.

[0179] The luminescent layers (first luminescent layer 113_1 and second luminescent layer 113_2) preferably comprise a luminescent center material and a host material. Furthermore, the luminescent layers may also comprise other materials. Note that at least one of the luminescent layers uses a phosphorescent material as the luminescent center material. In particular, it is preferable to use the aforementioned phosphorescent material that emits blue light as the luminescent center material.

[0180] Furthermore, the first light-emitting layer 113_1 and the second light-emitting layer 113_2 are preferably light-emitting layers that emit light in similar colors. For example, in display devices, red, green, and blue pixels are mostly used to display full color. In light-emitting devices used for red pixels, both the first light-emitting layer 113_1 and the second light-emitting layer 113_2 emit red light; in light-emitting devices used for green pixels, both light-emitting layers emit green light; and in light-emitting devices used for blue pixels, both light-emitting layers emit blue light. In this case, the light-emitting center material contained in the first light-emitting layer 113_1 and the light-emitting center material contained in the second light-emitting layer 113_2 are preferably compounds whose maximum peak wavelength difference in their PL spectra is 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less. Furthermore, it is more preferable that the light-emitting center material contained in the first light-emitting layer 113_1 and the light-emitting center material contained in the second light-emitting layer 113_2 are the same.

[0181] The luminescent center can be a fluorescent luminescent substance, a phosphorescent luminescent substance, a substance exhibiting thermally activated delayed fluorescence (TADF), or other luminescent substances.

[0182] In the luminescent layer, fluorescent luminescent materials that can be used as luminescent centers include, for example, the following substances. Note that other fluorescent luminescent materials can also be used.

[0183] Examples include 5,6-bis[4-(10-phenyl-9-anthrayl)phenyl]-2,2'-bipyridine (abbreviated as PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthrayl)biphenyl-4-yl]-2,2'-bipyridine (abbreviated as PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluorene-9-yl)phenyl]pyrene-1,6-diamine (abbreviated as 1,6FLPAPrn), and N,N'-bis(3-methylphenyl)-N N'-bis[3-(9-phenyl-9H-fluorene-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthrayl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl) -2-Anthracene)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthrayl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCPAPA), N,N”-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(N N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthrayl)phenyl]-9H-carbazole-3-amine (abbreviated as 2PCAPPA), N-[4-(9,10-diphenyl-2-anthrayl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as 2DPAPPA), N,N,N',N',N",N",N"',N"'-octaphenyldibenzo[g,p] -2,7,10,15-Tetraamine (abbreviated as: DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthrayl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviated as: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthrayl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviated as: 2PCABPhA), N-(9,10-diphenyl-2-anthrayl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthrayl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as: 2DPABPhA), 9,10-bis( Biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 545T, N,N'-diphenylquinactone (abbreviation: DPQd), rubrene, 5,12-bis(biphenyl-4-yl)-6,11-diphenylbenzotetraphenyl (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]vinyl}-6-methyl-4H-pyran-4-yl)malononitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazin-9-yl)ethylene] [2-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-yl}malononitrile (abbreviation: DCM2), N,N,N',N'-tetra(4-methylphenyl)[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhTD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-yl}malononitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-yl}malononitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-yl}malononitrile 3,6,7-Tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-4H-pyran-4-ylidene)malonium (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b]naphtho[1,[2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazole-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. In particular, fused aromatic diamine compounds, represented by pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, have good hole trapping properties and high luminescence efficiency or good reliability, and are therefore preferred. ,

[0184] In the light-emitting layer, in addition to the aforementioned blue phosphorescent material, materials that are green or red can also be used as the light-emitting center material.

[0185] For example, when red, green, and blue pixels are used in a display device to display full color, a light-emitting device with high luminous efficiency can be obtained by using phosphorescent materials in all red, green, and blue pixels.

[0186] For example, besides tris(4-methyl-6-phenylpyrimidine)iridium(III) (abbreviated as [Ir(mppm)3]), tris(4-tert-butyl-6-phenylpyrimidine)iridium(III) (abbreviated as [Ir(tBuppm)3]), (acetylacetonate)bis(6-methyl-4-phenylpyrimidine)iridium(III) (abbreviated as [Ir(mppm)2(acac)]), (acetylacetonate)bis(6-tert-butyl-4-phenylpyrimidine)iridium(III) (abbreviated as [Ir(tBuppm)2(acac)]), (acetylacetonate)bis[6-(2-norborneol)-4-phenylpyrimidine]iridium(III) (abbreviated as [Ir(nbppm)2(acac)]), (acetylacetonate)bis[5-methyl- Organometallic iridium complexes with a pyrimidine skeleton, such as 6-(2-methylphenyl)-4-phenylpyrimidinium[Ir(mpmppm)2(acac)] and (acetylacetonate)bis(4,6-diphenylpyrimidinium)iridium[Ir(dppm)2(acac)]; organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonate)bis(3,5-dimethyl-2-phenylpyrazine)iridium[Ir(mppr-Me)2(acac)] and (acetylacetonate)bis(5-isopropyl-3-methyl-2-phenylpyrazine)iridium[Ir(mppr-iPr)2(acac)]; and tris(2-phenylpyridinium-N,C 2’ Iridium(III) (abbreviated as: [Ir(ppy)3]), bis(2-phenylpyridinium-N,C) 2’ Iridium(III) acetylacetone (abbreviated as [Ir(ppy)2(acac)]), bis(benzo[h]quinoline)iridium(III) acetylacetone (abbreviated as [Ir(bzq)2(acac)]), tri(benzo[h]quinoline)iridium(III) (abbreviated as [Ir(bzq)3]), tri(2-phenylquinoline-N,C 2’ Iridium(III) (abbreviated as: [Ir(pq)3]), bis(2-phenylquinoline-N,C) 2’Iridium(III) acetylacetone (abbreviated as: [Ir(pq)2(acac)]), [2-d3-methyl-8-(2-pyridyl-κN)benzofurano[2,3-b]pyridin-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviated as: [Ir(5mppy-d3)2(mbfpypy-d3)), {2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofurano[2,3-b]pyridin-7-yl-κC}bis{5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridinyl-κN]phenyl-κC Iridium (III) (abbreviated as: Ir(5mtpy-d6)2(mbfpypy-iPr-d4)), [2-d3-methyl-(2-pyridyl-κN)benzofurano[2,3-b]pyridin-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium (III) (abbreviated as: [Ir(ppy)2(mbfpypy-d3)), [2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium (III) (abbreviated as: Ir(ppy)2(mdppy)), [2-(4-d3-methyl-5-phenyl-2-pyridyl-κN2)phenyl [-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κC]iridium(III) (abbreviated as: [Ir(5mppy-d3)2(mdppy-d3)]), [2-methyl-(2-pyridyl-κN)benzofurano[2,3-b]pyridyl-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviated as: [Ir(ppy)2(mbfpypy)]), [2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium (abbreviated as: [Ir(ppy)2(mdppy)]), tri{2-[5-(methyl ... Besides organometallic iridium complexes with a pyridine skeleton, such as (2-{1-(5-tert-butylbiphenyl-2-yl)-4-[3-tert-butyl-5-(4-phenyl-2-pyridyl-κN)phenyl-κC6]-2-benzimidazolyl-κN3}-4,6-di-tert-butylphenol-κO)platinum(II) (abbreviated as Pt(tBudppymmtBubiz-tBubp)), [2-(4-(3,5-di-tert-butylphenyl)-6-{3-[4-(5'-tert-butyl[1,1':3',Organometallic platinum complexes such as [1”-terphenyl]-2'-yl)-2-pyridyl-κN]phenyl-κC2}-2-pyridyl-κN]phenol-κO}platinum(II) (abbreviated as Pt(4tButpppypyp-mmtBup)) and rare earth metal complexes such as tri(acetylacetonate)(monophenanthroline)terbium(III) (abbreviated as [Tb(acac)3(Phen)]) are used. These substances are primarily compounds exhibiting green phosphorescence and possessing emission peaks in the wavelength region greater than 500 nm and less than 600 nm. Furthermore, organometallic iridium complexes with a pyrimidine skeleton are particularly preferred due to their exceptionally superior reliability and luminescent efficiency.

[0187] In addition, examples include organometallic iridium complexes with a pyrimidine skeleton, such as (diisobutyrylmethane)bis[4,6-bis(3-methylphenyl)pyrimidinium]iridium(III) (abbreviated as: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinium](dineopentylmethane)iridium(III) (abbreviated as: [Ir(5mdppm)2(dpm)]), and bis[4,6-bis(naphthyl-1-yl)pyrimidinium](dineopentylmethane)iridium(III) (abbreviated as: [Ir(d1npm)2(dpm)]). Organometallic iridium complexes with a pyrazine skeleton, such as bis(2,3,5-triphenylpyrazine)iridium(III) (abbreviated as [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazine)(dineopentylmethane)iridium(III) (abbreviated as [Ir(tppr)2(dpm)]), and (acetylacetonate)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviated as [Ir(Fdpq)2(acac)]); tris(1-phenylisoquinoline-N,C 2’ Iridium(III) (abbreviated as: [Ir(piq)3]), bis(1-phenylisoquinoline-N,C) 2’Organometallic iridium complexes with a pyridine skeleton include iridium(III) acetylacetone (abbreviated as [Ir(piq)2(acac)]), (3,7-diethyl-4,6-nonanedione-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolinyl-κN]phenyl-κC]iridium(III), (3,7-diethyl-4,6-nonanedione-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl-κC]iridium(III). Platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviated as PtOEP); and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenyroline)eup(III) (abbreviated as [Eu(DBM)3(Phen)]) and tris[1-(2-thiophenecarboxyl)-3,3,3-trifluoroacetone](monophenyroline)eup(III) (abbreviated as [Eu(TTA)3(Phen)]). These substances are red phosphorescent compounds with emission peaks in the 600 nm to 700 nm wavelength region. Furthermore, organometallic iridium complexes with a pyrazine framework can achieve red emission with good chromaticity.

[0188] In addition to the phosphorescent compounds mentioned above, other known phosphorescent compounds may also be used.

[0189] Fullerenes and their derivatives, acridines and their derivatives, and eosin derivatives can be used as TADF materials. In addition, metal porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) can also be used. Examples of metalloporphyrins include, for instance, protoporphyrin-tin fluoride complexes represented by the following structural formulas: protoporphyrin-tin fluoride complex (SnF2(ProtoIX)), mesotoporphyrin-tin fluoride complex (SnF2(MesoIX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), tetramethyl coprophyrin-tin fluoride complex (SnF2(Copro III-4Me), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), protoporphyrin-tin fluoride complex (SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (PtCl2OEP).

[0190] [Chemical Formula 17]

[0191] In addition, the following structural formulas can also be used: 2-(biphenyl-4-yl)-4,6-bis(12-phenylindol[2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviated as: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as: PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3, Heterocyclic compounds such as 5-triazine (abbreviated as PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviated as PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-oxazanthracene-9-one (abbreviated as ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridin)phenyl]sulfone (abbreviated as DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (abbreviated as ACRSA) are heterocyclic compounds with one or both of the following: π-electron-rich heterocyclic rings and π-electron-deficient heterocyclic rings. This heterocyclic compound possesses both π-electron-rich and π-electron-deficient heteroaromatic rings, exhibiting high electron and hole transport capabilities, and is therefore preferred. Among the skeletons with π-electron-deficient heteroaromatic rings, pyridine, diazine (pyrimidine, pyrazine, pyridazine), and triazine skeletons are stable and reliable, and are therefore preferred. In particular, benzofuran-pyrimidine, benzothiophene-pyrimidine, benzofuran-pyrazine, and benzothiophene-pyrazine skeletons exhibit high acceptor activity and good reliability, and are therefore preferred. Furthermore, among the skeletons with π-electron-rich heteroaromatic rings, acridine, phenoxazine, phenothiazine, furan, thiophene, and pyrrole skeletons are stable and reliable, and it is preferred to have at least one of these skeletons. Moreover, dibenzofuran skeletons are preferred as furan skeletons, and dibenzothiophene skeletons are preferred as thiophene skeletons. As the pyrrole skeleton, indole, carbazole, indole-carbazole, bicarbazole, and 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeletons are particularly preferred. In substances where π-electron-rich and π-electron-deficient heteroaromatic rings are directly bonded, the π-electron-rich heteroaromatic ring exhibits high electron-donating and electron-accepting properties, while the energy difference between the S1 and T1 energy levels is smaller, resulting in highly efficient thermally activated delayed fluorescence; therefore, it is particularly preferred. Note that aromatic rings bonded with electron-withdrawing groups such as cyano groups can also be used instead of π-electron-deficient heteroaromatic rings. Furthermore, aromatic amine skeletons and phenazine skeletons can be used as π-electron-rich skeletons.Furthermore, as π-electron-deficient skeletons, the following can be used: oxanthracene skeleton, thioxanthene dioxide skeleton, oxadiazole skeleton, triazole skeleton, imidazole skeleton, anthraquinone skeleton, boron-containing skeletons such as phenylborane and boranthrene, aromatic rings with nitrile or cyano groups such as benzonitrile or cyanobenzene, heteroaromatic rings, carbonyl skeletons such as benzophenone, phosphine oxide skeletons, sulfone skeletons, etc. Thus, π-electron-deficient and π-electron-rich skeletons can be used to replace at least one of the π-electron-deficient and π-electron-rich heteroaromatic rings.

[0192] [Chemical Formula 18]

[0193] Furthermore, TADF materials that are in thermal equilibrium between singlet and triplet excited states can also be used as TADF materials. Because of their short luminescence lifetime (excitation lifetime), these TADF materials can suppress efficiency degradation in the high-brightness region of light-emitting devices. Specifically, materials with the following molecular structures can be cited as examples.

[0194] [Chemical Formula 19]

[0195] TADF materials refer to materials with a small energy difference between the S1 and T1 levels and the ability to convert triple excitation energy into single excitation energy through antisystem crossing. Therefore, they can upconvert triple excitation energy into single excitation energy (antisystem crossing) with minimal thermal energy, efficiently generating singlet excited states. Furthermore, triple excitation energy can be converted into luminescence.

[0196] In addition, the excitocomplex formed by the two substances in the excited state has the function of converting triple excitation energy into single excitation energy due to the extremely small difference between the S1 and T1 energy levels.

[0197] Note that the phosphorescence spectrum observed at low temperatures (e.g., 77K to 10K) can be used as an indicator of the T1 energy level. For TADF materials, it is preferable that the difference between S1 and T1 is 0.3 eV or less, more preferably 0.2 eV or less, when the wavelength energy of the extrapolated line obtained by drawing a tangent at the tail of the short-wavelength side of the fluorescence spectrum is taken as the S1 energy level and the wavelength energy of the extrapolated line obtained by drawing a tangent at the tail of the short-wavelength side of the phosphorescence spectrum is taken as the T1 energy level.

[0198] Furthermore, when using TADF material as the luminescent material, the S1 energy level of the host material is preferably higher than that of the TADF material. Additionally, the T1 energy level of the host material is preferably higher than that of the TADF material.

[0199] In addition to the organic compounds mentioned above, materials with electron transport properties and / or materials with hole transport properties, as well as various charge carrier transport materials such as the TADF material mentioned above, can also be used as the main material for the light-emitting layer.

[0200] As a material with hole transport capabilities, organic compounds having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton are preferred. As a π-electron-rich heteroaromatic ring, a fused aromatic ring comprising at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton is preferred; specifically, a carbazole ring, a dibenzothiophene ring, or a ring fused with these rings to an aromatic ring or heteroaromatic ring is preferred.

[0201] More preferably, such hole-transporting substances have any one of a carbazole backbone, a dibenzofuran backbone, a dibenzothiophene backbone, and an anthracene backbone. In particular, they can be aromatic amines having substituents comprising a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthyl ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. Note that when these hole-transporting substances are organic compounds comprising N,N-bis(4-biphenyl)amino groups, long-lifetime light-emitting devices can be manufactured, and therefore they are preferred.

[0202] As such organic compounds, the organic compounds described later are preferred, for example. Examples of such organic compounds include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviated as TPD), N,N'-bis(9,9'-spirobis[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as mBPAFLP), and 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine. (Abbreviation: PCBA1BP), 4,4'-diphenyl-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (Abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (Abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (Abbreviation: PCCNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluorene-2-amine (Abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirodi[9H Compounds with aromatic amine skeletons, such as [fluorene]-2-amine (abbreviated as PCBASF); 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-bis(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), 3,9-bis(9-phenyl-9H-carbazol-3-yl)-9H-carbazole (abbreviated as PCCzPC), 9-(biphenyl-4-yl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviated as PCCzBP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3...3'-9H,9'H-Bicarbazole (abbreviated as: BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1”-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1”-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1”-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1”-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1”-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1' [3',1”-Triphenyl]-4-yl-3,3'-9H,9'H-Bicarbazole, 9-(2-naphthyl)-9'-(triphenyl-2-yl)-3,3'-9H,9'H-Bicarbazole, 9-phenyl-9'-(triphenyl-2-yl)-3,3'-9H,9'H-Bicarbazole (abbreviated as: PCCzTp), 9,9'-bis(triphenyl-2-yl)-3,3'-9H,9'H-Bicarbazole, 9-(4-biphenyl)-9'-(triphenyl-2-yl)-3,3'-9H,9'H-Bicarbazole, 9-(triphenyl-2-yl)-9'-[1,1':3',1”-Triphenyl]-4-yl-3,3'-9H,9'H-Bicarbazole, N,N-bis Compounds with a carbazole skeleton, such as (9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi-9H-fluorene-1-amine, 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviated as PSiCzCz), and 9'-[3-(triphenylsilyl)phenyl]-9'H-9,3':6',9”-tricarbazole (abbreviated as PSiCzGI); 4,4',4”-(benzyl-1,3,5-triyl)tris(dibenzothiophene) (abbreviated as DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene Compounds with a thiophene skeleton, such as [-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV); and compounds with a furan skeleton, such as 4,4',4”-(benzyl-1,3,5-triyl)tris(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Among these, compounds with an aromatic amine skeleton or a carbazole skeleton are preferred due to their good reliability, high hole transport properties, and ability to reduce the driving voltage. Additionally, organic compounds, as examples of materials with hole transport properties, can also be used.

[0203] As a material with electron transport properties, an organic compound having a π-electron-deficient heteroaromatic ring is preferred. Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include organic compounds containing a heteroaromatic ring with an azole skeleton, organic compounds containing a heteroaromatic ring with a pyridine skeleton, organic compounds containing a heteroaromatic ring with a diazine skeleton, and organic compounds containing a heteroaromatic ring with a triazine skeleton.

[0204] Organic compounds containing heteroaromatic rings with a diazine (pyrimidine, pyrazine, or pyridazine) skeleton, organic compounds containing heteroaromatic rings with a pyridine skeleton, or organic compounds containing heteroaromatic rings with a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing heteroaromatic rings with a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing heteroaromatic rings with a triazine skeleton exhibit high electron transport properties and contribute to reducing the driving voltage. Furthermore, benzofuran-pyrimidine skeletons, benzothiophene-pyrimidine skeletons, benzofuran-pyrazine skeletons, and benzothiophene-pyrazine skeletons are preferred due to their high acceptor activity and reliability.

[0205] As organic compounds with a π-electron-deficient heteroaromatic ring skeleton, the following organic compounds are preferred, for example: 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated: PBD), 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]phenyl (abbreviated: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviated: CO11), 2,2',2”-(1,3,5-phenyltriyl)tris(1-phenyl-1H-benzimidazole) (abbreviated: TP) Organic compounds with azole skeletons, such as BI), 2-[3-(dibenzothiophene-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOS); 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), phenanthroline (abbreviation: BPhen), copper bath (abbreviation: BCP), 2,9-di(naphthyl-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 2,2'-(1,3-phenylene) Organic compounds containing heteroaromatic rings with a pyridine skeleton, such as bis(9-phenyl-1,10-phenanthroline) (abbreviated as mPPhen2P), 2-[3-(2-triphenylene)phenyl]-1,10-phenanthroline (abbreviated as mTpPPhen), 2-phenyl-9-(2-triphenylene)-1,10-phenanthroline (abbreviated as Ph-TpPhen), 2-[4-(9-phenanthyl)-1-naphthyl]-1,10-phenanthroline (abbreviated as PnNPhen), and 2-[4-(2-triphenylene)phenyl]-1,10-phenanthroline (abbreviated as pTpPPhen); and 2-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 2mDBTPDBq). -II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazol-3-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq-III), 2-[3'-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPh] Quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[(3'-dibenzothiophene-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophene-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mP) nP2Pm), 4,6-bis[3-(dibenzothiophene-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophene-4-yl)] [Phenyl]benzofurano[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)(biphenyl-3-yl)]naphtho[1',2':4,5]furano[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2'-binaphthyl)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDB tPBfpm), 2,2'-(pyridin-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(pyridin-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphthyl-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-Bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), 8-(1,1':4',1” terphenyl-3-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofuran[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm) and other organic compounds with diazine skeletons; 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobis[9H-fluorene]-2-yl)-1,3,5 - Triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2- [3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indo[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophene-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridine-3-yl)[3'-(dibenzothiophene-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridine-3-yl)[3'-(dibenzothiophene-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: TmPPPyTz), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenylindole[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 2-[3'-(triphenyl-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazine]-4,6-diphenyl-1,3,5-triazine5-Triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1”-triphenyl)-4-yl-1-dibenzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 2-[4-(2-naphthyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]oxanthracene]-4- βNP-SFx(4)Tzn, 9,9'-{6-[3-(triphenylsilyl)phenyl]-1,3,5-triazin-2,4-diyl}bis(9H-carbazole) (abbreviated as SiTrzCz2), 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazin (abbreviated as mSiTrz), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl] -11,12-dihydro-12-(biphenyl-3-yl)indolo[2,3-a]carbazole (abbreviation: BP-mBPIcz(II)Tzn), 3-{3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]phenyl}-9-phenyl-9H-carbazole (abbreviation: mPCPDBfTzn), 9,9'-[6-(biphenyl-4-yl)-2-phenyl-1,3,5-triazin-4,3”-diyl]bis(9H- Organic compounds containing heteroaromatic rings with a triazine skeleton, such as carbazole (abbreviated as Cz-pmCzBPTzn), 3-phenyl-9-[4-phenyl-6-(9-phenyl-3-dibenzofuranyl)-1,3,5-triazin-2-yl]-9H-carbazole (abbreviated as PDBf-PCzTzn), and 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzothiophenyl]-2-phenyl-9H-carbazole (abbreviated as PCzDBtTzn), are preferred. Furthermore, organic compounds containing heteroaromatic rings with a diazine skeleton, organic compounds containing heteroaromatic rings with a pyridine skeleton, and organic compounds containing heteroaromatic rings with a triazine skeleton have high reliability and are therefore preferred. In particular, organic compounds containing heteroaromatic rings with a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing heteroaromatic rings with a triazine skeleton have high electron transport properties, which helps to reduce the driving voltage.

[0206] As a TADF material that can be used as the host material, the same materials mentioned above as TADF materials that can be used as luminescent centers can be used. When a TADF material is used as the host material, the triple excitation energy generated by the TADF material is converted into a single excitation energy via antisystem crossing and this energy is transferred to the luminescent material, thereby improving the luminous efficiency of the light-emitting device. In this case, the TADF material is used as an energy donor, and the luminescent material is used as an energy acceptor.

[0207] This is highly effective when the luminescent material is a fluorescent luminescent material. Furthermore, to obtain high luminescent efficiency, the S1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent luminescent material. Additionally, the T1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent luminescent material. Therefore, the T1 energy level of the TADF material is preferably higher than the T1 energy level of the fluorescent luminescent material.

[0208] Furthermore, it is preferable to use a TADF material that exhibits luminescence with a wavelength overlapping the absorption band on the lowest energy side of the fluorescent luminescent material. This allows for efficient transfer of excitation energy from the TADF material to the fluorescent luminescent material, resulting in highly efficient luminescence, and is therefore preferred.

[0209] To efficiently generate a singlet excitation energy from a triplet excitation energy via antisystem crossing, it is preferable to induce carrier recombination within the TADF material. Furthermore, it is preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent luminescent material. For this purpose, the fluorescent luminescent material preferably has a protecting group surrounding the luminescent body (the backbone that causes luminescence) of the fluorescent luminescent material. This protecting group is preferably a substituent without π bonds, preferably a saturated hydrocarbon; specifically, examples include alkyl groups with 3 or more but less than 10 carbon atoms, substituted or unsubstituted cycloalkyl groups with 3 or more but less than 10 carbon atoms, and trialkylsilyl groups with 3 or more but less than 10 carbon atoms; more preferably, multiple protecting groups are preferred. Substituents without π bonds have almost no function in transporting charge carriers, so they have little effect on charge carrier transport or recombination, allowing the TADF material and the luminescent body of the fluorescent luminescent material to be kept apart. Here, the luminescent body refers to the atomic group (backbone) in the fluorescent luminescent material that causes luminescence. The luminescent material preferably has a π-bonded framework, more preferably an aromatic ring, and even more preferably a fused aromatic ring or a fused heteroaromatic ring. Examples of such luminescent materials include phenanthrene frameworks, stilbene frameworks, acridinone frameworks, phenoxazine frameworks, phenothiazine frameworks, naphthalene frameworks, anthracene frameworks, and fluorene frameworks. The skeleton includes triphenylene skeleton, tetraphenylene skeleton, pyrene skeleton, perylene skeleton, coumarin skeleton, quinacridone skeleton, naphthobisbenzofuran skeleton, etc. In particular, those possessing naphthalene skeleton, anthracene skeleton, fluorene skeleton, etc. Fluorescent materials with skeletons such as triphenylene skeleton, tetraphenylene skeleton, pyrene skeleton, perylene skeleton, coumarin skeleton, quinacridone skeleton, and naphthobisbenzofuran skeleton have high fluorescence quantum yields and are therefore preferred.

[0210] When using a fluorescent luminescent material as the luminescent center, a material with an anthracene framework is preferably used as the host material. By using a material with an anthracene framework as the host material of the fluorescent luminescent material, a luminescent layer with both high luminous efficiency and durability can be achieved. Among the anthracene framework materials used as host materials, those with a diphenylanthracene framework, especially those with a 9,10-diphenylanthracene framework, are chemically stable and therefore preferred. Furthermore, when the host material has a carbazole framework, hole injection / transport is improved, which is also preferred. However, when the host material has a benzo[a]carbazole framework with a benzene ring also fused to the carbazole framework, its HOMO is about 0.1 eV higher than that of a host material with a carbazole framework, making hole injection easier, and therefore it is more preferred. In particular, when the host material has a dibenzo[a]carbazole framework, its HOMO is about 0.1 eV higher than that of a host material with a carbazole framework, which not only makes hole injection easier but also improves hole transport and heat resistance, making it preferred. Therefore, as the host material, a substance having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzo[a]carbazole skeleton or a dibenzo[a]carbazole skeleton) is further preferred. Note that from the viewpoint of hole injection / transportation described above, a benzo[a]fluorene skeleton or a dibenzo[a]fluorene skeleton can also be used instead of a carbazole skeleton. Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviated: PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviated: PCPN), 9-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviated: CzPA), 7-[4-(10-phenyl-9-anthrayl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviated: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthrayl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviated: 2mBnfPPA), and 9-phenyl-10-[4-(9-phenyl-9H-fluorene-9-yl] Biphenyl-4-yl]anthracene (abbreviated as FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviated as α,βADN), 2-(10-phenylanthracene-9-yl)dibenzofuran, 2-(10-phenyl-9-anthyl)benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviated as βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthracene]phenyl}-2-ethyl-1H-benzimidazole (abbreviated as EtBImPBPhA), etc. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA exhibit very good properties and are therefore preferred.

[0211] Furthermore, the host material can also be a mixture of multiple substances. When using a mixed host material, it is preferable to mix materials with electron transport properties and materials with hole transport properties. By mixing materials with electron transport properties and materials with hole transport properties, it is easier to adjust the transport properties of the light-emitting layer 113 and to control the composite region more easily. The weight ratio of the material with hole transport properties to the material with electron transport properties is 1:19 to 19:1, preferably 1:9 to 9:1, and more preferably 3:7 to 7:3.

[0212] Note that phosphorescent materials can be used as part of the above-described mixture. When phosphorescent materials are used as fluorescent materials, they can be used as energy donors to supply excitation energy to the fluorescent materials.

[0213] Furthermore, these mixed materials can also be used to form excimer complexes. By selecting a combination of excimer complexes that form light-emitting excimer complexes with wavelengths overlapping the absorption band on the lowest energy side of the luminescent material, energy transfer can be facilitated, resulting in efficient light emission, which is therefore preferred. Furthermore, this structure allows for a reduction in driving voltage, which is also preferred.

[0214] Note that at least one of the materials forming the excitocomplex can be a phosphorescent material. This allows for the efficient conversion of the triple excitation energy into a single excitation energy via an antisystem crosstalk.

[0215] The first electron transport layer 114_1 is a layer containing a material with electron transport properties. Preferably, the electron mobility of the material with electron transport properties is 1×10⁻⁶ when the square root of the electric field strength [V / cm] is 600. -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 Substances with a value of / Vs or higher. Furthermore, any substance other than those mentioned above can be used as long as its electron transport capability is higher than its hole transport capability. As the aforementioned organic compounds, organic compounds having a π-electron-deficient heteroaromatic ring are preferred. For example, one or more of the following are preferred: organic compounds containing a heteroaromatic ring with an azole skeleton, organic compounds containing a heteroaromatic ring with a pyridine skeleton, organic compounds containing a heteroaromatic ring with a diazine skeleton, and organic compounds containing a heteroaromatic ring with a triazine skeleton; organic compounds containing a heteroaromatic ring with a triazine skeleton are particularly preferred.

[0216] As an organic compound with electron transport properties that can be used in the first electron transport layer 114_1, organic compounds with electron transport properties that can be used as the host material in the first light-emitting layer 113_1 and the second light-emitting layer 113_2 can also be used. In particular, organic compounds containing heteroaromatic rings with a diazine skeleton, organic compounds containing heteroaromatic rings with a pyridine skeleton, and organic compounds containing heteroaromatic rings with a triazine skeleton have good reliability and are therefore preferred. In particular, organic compounds containing heteroaromatic rings with a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing heteroaromatic rings with a triazine skeleton have high electron transport properties and help to reduce the driving voltage.

[0217] As described above, the second electron transport layer 114_2 is a layer containing an organic compound with a triazine skeleton. Its details have already been described above and will not be repeated here.

[0218] Note that the first electron transport layer 114_1 preferably contains an organic compound with a triazine framework, thereby reducing power consumption. In particular, the organic compound with a triazine framework contained in the first electron transport layer 114_1 is preferably the same as the organic compound with a triazine framework contained in the second electron transport layer 114_2, thereby reducing the complexity of the manufacturing equipment and also being advantageous from the viewpoint of raw material procurement costs.

[0219] Furthermore, by including the first electron transport layer 114_1 in an organic compound that does not have a triazine skeleton, the carrier transport properties can be easily controlled, thereby providing a light-emitting device with better characteristics. As the organic compound that does not have a triazine skeleton, organic compounds containing a heteroaromatic ring with a pyridine skeleton or organic compounds containing a heteroaromatic ring with a diazine (pyrimidine or pyrazine) skeleton are preferred.

[0220] The intermediate layer 160 contains organic compounds with a phenanthroline skeleton. For example... Figure 1A As shown, the intermediate layer 160 preferably includes a first layer 161 comprising an organic compound having a phenanthrene skeleton. Furthermore, the intermediate layer 160 preferably includes a second layer 162 comprising a compound with hole-transporting properties and a substance with acceptor properties. Moreover, the second layer 162 is closer to the second electrode 102 than the first layer 161. Additionally, the intermediate layer 160 may also include a third layer 163 between the first layer 161 and the second layer 162.

[0221] The details of the first layer have already been explained above and will not be repeated here.

[0222] Furthermore, the first layer 161 may also contain an organic compound with electron transport properties. As an organic compound with electron transport properties that can be used as such, an organic compound that can also be used as the host material in the first light-emitting layer 113_1 and the second light-emitting layer 113_2 can also be used. Moreover, as such an organic compound, it is preferable to use an organic compound having two or more heteroaromatic rings bonded or fused together, and the two or more heteroaromatic rings containing a total of three or more heteroatoms, thereby further improving the resistance to photolithography and suppressing the rise of the driving voltage.

[0223] Note that the first layer 161 may have a stacked structure of a layer containing an organic compound and a layer containing a metal or metal compound located closer to the cathode than the layer containing the organic compound. It may also be a mixed layer of organic compound and metal or metal compound. When the first layer is a mixed layer, there are fewer deposition chambers, the manufacturing cost is reduced, and it helps to improve the stability of the light-emitting device, so it is preferred.

[0224] In the case of a mixture of organic compounds and metals or metal compounds, when analyzing the first layer 161 in the thickness direction, the distribution of organic compounds and the distribution of metals or metal compounds show approximately the same trend. That is, when the distribution of organic compounds is fixed, the distribution of metals or metal compounds is also approximately fixed. In a stacked structure containing layers of organic compounds and layers containing metals or metal compounds, sometimes metals or metal compounds are detected in areas outside the layers containing metals or metal compounds due to diffusion from those layers. However, because they exhibit a different distribution than that of organic compounds, analytical results can be distinguished between diffusion and mixing.

[0225] The second layer 162 preferably comprises an organic compound with hole-transporting properties. Furthermore, the second layer 162 preferably also comprises a receptor-like substance, which is preferably an organic compound that exhibits receptor-like properties to the organic compound with hole-transporting properties.

[0226] In the case where the second layer 162 is a layer containing an organic compound with hole-transporting properties and a substance that is an acceptor of the organic compound with hole-transporting properties, holes are generated through charge separation. When a voltage is applied between the first electrode 101 and the second electrode 102, these holes are injected into the first light-emitting unit 501 on the cathode side through the organic compound with hole-transporting properties. Thus, the light-emitting device 130 of one embodiment of the present invention can be a light-emitting device with a low driving voltage.

[0227] As organic compounds with hole transport capabilities, various organic compounds such as aromatic amines, heteroaromatic compounds, aromatic hydrocarbons, and polymers (oligomers, dendritic polymers, polymers, etc.) can be used. Preferably, an organic compound with a hole mobility of 1×10⁻⁶ is used. -6 cm 2 Organic compounds with a ratio of / Vs or higher. Furthermore, organic compounds with hole-transporting capabilities are preferably compounds having fused aromatic rings or π-electron-rich heteroaromatic rings. As fused aromatic rings, anthracene rings, naphthalene rings, etc., are preferred. Furthermore, as π-electron-rich heteroaromatic rings, fused aromatic rings having at least one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton are preferred, specifically carbazole rings, dibenzothiophene rings, or rings where these rings are also fused with aromatic or heteroaromatic rings.

[0228] Such hole-transporting organic compounds are more preferably those having a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton. In particular, they can be aromatic amines having substituents comprising a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthyl ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. Note that when these hole-transporting organic compounds are substances comprising N,N-bis(4-biphenyl)amino groups, long-lifetime light-emitting devices can be manufactured, and therefore they are preferred.

[0229] Specifically, as the aforementioned hole-transporting organic compound, the organic compound mentioned above that is a hole-transporting organic compound that can be used in the hole injection layer 111 can also be used.

[0230] As a receptor-like substance, for example, an organic compound that can be used in the hole injection layer 111 can be used. In particular, an organic compound having at least one of a halogen group and a cyano group is preferred, and an organic compound having at least one of a fluorine group and a cyano group is more preferred. Furthermore, the total number of halogen (fluorine) and cyano groups contained in the organic compound is more preferably 4 or more. Examples of organic compounds having at least one of a halogen group and a cyano group include: α,α',α”-1,2,3-cyclopropanetrimethylenetri[4-cyano-2,3,5,6-tetrafluorophenylacetonitrile], α,α',α”-1,2,3-cyclopropanetrimethylenetri[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)phenylacetonitrile], α,α',α”-1,2,3-cyclopropanetrimethylenetri[2,3,4,5,6-pentafluorophenylacetonitrile], etc.

[0231] Furthermore, the acceptor material preferably exhibits electron acceptor properties to organic compounds with hole transport properties. When the acceptor material exhibits electron acceptor properties to organic compounds with hole transport properties, charge separation occurs, and the second layer 162 can be used as a charge generation layer and as an intermediate layer in a tandem light-emitting device. Moreover, in the second layer 162, a signal observed via electron spin resonance is preferably detected. For example, the spin density arising from a signal observed near a g value of 2.00 is preferably 1 × 10⁻⁶. 17 spins / cm 3 The above is preferred to be 1×10 18 spins / cm 3 The above is further preferred to be 1×10 19 spins / cm 3 above.

[0232] The third layer 163 contains an electron transport material and has the functions of preventing the interaction between the first layer 161 and the second layer 162, facilitating electron transfer to reduce the driving voltage, and reducing the interaction between the first layer 161 and the second layer 162 to improve reliability.

[0233] The LUMO energy level of the electron transport material contained in the third layer 163 is preferably the LUMO energy level of the acceptor material in the second layer 162 and the layer in the light-emitting unit on the anode side that is in contact with the first layer 161. Figure 1A Between the LUMO energy levels of the organic compounds contained in the first electron transport layer 114_1 in the first light-emitting unit 501.

[0234] Furthermore, the specific energy level of the LUMO level used as the electron transport material for the third layer 163 is preferably -5.0 eV or higher, more preferably -5.0 eV or higher and -3.0 eV or lower, more preferably -4.30 eV or higher and -3.00 eV or lower, and even more preferably -4.30 eV or higher and -3.30 eV or lower, thereby suppressing the rise of the driving voltage. Furthermore, as the electron transport material used for the third layer 163, phthalocyanine materials or metal complexes having metal-oxygen bonds and aromatic ligands are preferably used.

[0235] Specifically, for electron transporting substances used in the third layer 163, perylene tetracarboxylic acid derivatives such as diquinoxolino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), 2,3,8,9,14,15-hexafluorodiquinoxolino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA-F6), 3,4,9,10-perylene tetracarboxylic acid diimide (abbreviated as PTCDI), and 3,4,9,10-perylene tetracarboxylic acid-bis-benzimidazole (abbreviated as PTCBI), as well as (C60-Ih)[5,6]fullerene (abbreviated as C60) and (C70-D5h)[5,6]fullerene (abbreviated as C70) can be used. Furthermore, compounds having a heterocyclic cyclophenene skeleton can be used; for example, phthalocyanine compounds such as phthalocyanine (abbreviated as H2Pc) can be used. In addition, metal phthalocyanines containing copper, zinc, cobalt, chromium, nickel, etc., and their derivatives, such as copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc), cobalt phthalocyanine (CoPc), iron phthalocyanine (FePc), tin phthalocyanine (SnPc), tin oxide phthalocyanine (SnOPc), titanium oxide phthalocyanine (TiOPc), and vanadium oxide phthalocyanine (VOPc), can be used. In particular, phthalocyanine metal complexes such as copper phthalocyanine or zinc phthalocyanine, or 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine, are preferred.

[0236] In addition, the thickness of the third layer 163 is preferably 1 nm or more and 10 nm or less, more preferably 2 nm or more and 5 nm or less.

[0237] Note that because the second layer 162 in the intermediate layer 160 is used as a hole injection layer, the second light-emitting unit 502 does not have a hole injection layer, but the second light-emitting unit 502 may also have a hole injection layer.

[0238] The second electrode 102 is an electrode that includes a cathode. The second electrode 102 may also have a layered structure, in which case the layer in contact with the organic compound layer 103 serves as the cathode. As the material forming the cathode, metals, alloys, conductive compounds, and mixtures thereof with low work functions (specifically below 3.8 eV) can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) or cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), alloys containing them (MgAg, AlLi), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing them. Specifically, examples include alkali metals, alkaline earth metals, rare earth metals, compounds or complexes thereof, or electronic compounds such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-hydroxyquinoline-lithium (Liq), and ytterbium (Yb). Examples of electronic compounds include mixed oxides of calcium and aluminum that add electrons at high concentrations. Furthermore, two or more of the aforementioned materials can be mixed and used. When the second electrode 102 has a multilayer structure, materials with good conductivity can be used for the portion other than the cathode, regardless of the work function.

[0239] Note that the second electron transport layer 114_2 is preferably in contact with the second electrode 102. By making the second electron transport layer 114_2 in contact with the second electrode 102, a light-emitting device with good electron injection and electron transport properties, low driving voltage, and low power consumption can be obtained.

[0240] Furthermore, if the second electrode 102 is made of a material that is transmissive to visible light, a light-emitting device that emits light from one side of the second electrode 102 can be formed.

[0241] These conductive materials can be deposited using dry methods such as vacuum evaporation and sputtering, as well as inkjet printing and spin coating. Alternatively, they can be formed using wet methods such as sol-gel or wet methods using pastes of metallic materials.

[0242] Furthermore, various methods, whether dry or wet, can be used to form the organic compound layer 103. For example, vacuum evaporation, gravure printing, offset printing, screen printing, inkjet printing, or spin coating can also be used.

[0243] In addition, the aforementioned electrodes or layers can also be formed using different deposition methods.

[0244] Figure 2 This is a diagram showing two adjacent light-emitting devices (light-emitting device 130a, light-emitting device 130b) included in a display device according to one aspect of the present invention.

[0245] The light-emitting device 130a includes an organic compound layer 103a between the first electrode 101a and the second electrode 102 on the insulating layer 175. The organic compound layer 103a has a structure in which a first light-emitting unit 501a and a second light-emitting unit 502a are stacked, with an intermediate layer 160a sandwiched between them. Note that... Figure 2 An example of two stacked light-emitting units is shown, but a structure with three or more stacked light-emitting units can also be used. The first light-emitting unit 501a includes a hole injection layer 111a, a first hole transport layer 112a_1, a first light-emitting layer 113a_1, and a first electron transport layer 114a_1. The intermediate layer 160a includes a second layer 162a, a third layer 163a, and a first layer 161a. The third layer 163a may or may not be included. The second light-emitting unit 502a includes a second hole transport layer 112a_2, a second light-emitting layer 113a_2, and a second electron transport layer 114a_2.

[0246] The light-emitting device 130b includes an organic compound layer 103b between the first electrode 101b and the second electrode 102 on the insulating layer 175. The organic compound layer 103b has a structure in which a first light-emitting unit 501b and a second light-emitting unit 502b are stacked, with an intermediate layer 160b sandwiched between them. Note that... Figure 2 An example of two light-emitting units stacked together is shown, but a structure with three or more light-emitting units stacked together can also be used. The first light-emitting unit 501b includes a hole injection layer 111b, a first hole transport layer 112b_1, a first light-emitting layer 113b_1, and a first electron transport layer 114b_1. The intermediate layer 160b includes a second layer 162b, a third layer 163b, and a first layer 161b. The third layer 163b may or may not be included. The second light-emitting unit 502b includes a second hole transport layer 112b_2, a second light-emitting layer 113b_2, and a second electron transport layer 114b_2.

[0247] The first hole transport layer 112a_1 and the second hole transport layer 112a_2 have a stacked structure. The layer in contact with the light-emitting layer is formed using a material whose LUMO energy level is higher than that of the material constituting the light-emitting layer (at least the main material, preferably the material constituting the light-emitting layer, the material with the largest composition ratio among the materials constituting the light-emitting layer, or the material with the highest LUMO energy level among the materials constituting the light-emitting layer).

[0248] Furthermore, the second electron transport layers 114a_2 and 114b_2 are layers containing organic compounds having a triazine skeleton. The first layers 161a and 161b are layers containing organic compounds having a phenanthroline skeleton.

[0249] The first luminescent layer 113a_1 and the second luminescent layer 113a_2 are preferably luminescent layers exhibiting similar colors. Furthermore, the luminescent center material they contain is preferably a compound whose maximum peak wavelength difference in the PL spectrum is 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less. More preferably, they contain the same luminescent center material. The first luminescent layer 113b_1 and the second luminescent layer 113b_2 are preferably luminescent layers exhibiting similar colors. Furthermore, the luminescent center material they contain is preferably a compound whose maximum peak wavelength difference in the PL spectrum is 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less. More preferably, they contain the same luminescent center material.

[0250] Furthermore, preferably, the first light-emitting layer 113a_1 is separate from the first light-emitting layer 113b_1, and the second light-emitting layer 113a_2 is separate from the second light-emitting layer 113b_2. Furthermore, the emission colors of the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are preferably different from the emission colors of the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2. Furthermore, preferably, the light-emitting center material contained in the first light-emitting layer 113a_1 is different from the light-emitting center material contained in the first light-emitting layer 113b_1, and the light-emitting center material contained in the second light-emitting layer 113a_2 is different from the light-emitting center material contained in the second light-emitting layer 113b_2.

[0251] Furthermore, the hole injection layers 111a and 111b, the first hole transport layers 112a_1 and 112b_1, the first electron transport layers 114a_1 and 114b_1, the intermediate layers 160a and 160b (the second layers 162a and 162b, the third layers 163a and 163b, and the first layers 161a and 161b), the second hole transport layers 112a_2 and 112b_2, and the second electron transport layers 114a_2 and 114b_2 can each be continuous layers or separated between the light-emitting devices 130a and 130b. By using continuous layers, productivity is improved, thereby enabling the manufacture of inexpensive light-emitting devices. By using layers separated between the light-emitting devices, materials suitable for the emitted color can be used, thereby enabling the manufacture of light-emitting devices or display devices with excellent characteristics. In particular, by using continuous layers as the second electron transport layer 114a_2 and the second electron transport layer 114b_2, both the light-emitting device 130a and the light-emitting device 130b can become light-emitting devices with good characteristics, which is preferred.

[0252] The continuous layers mean that the second electron transport layer 114a_2 and the second electron transport layer 114b_2 are made of the same material. That is, by using the same material to construct the second electron transport layer 114a_2 and the second electron transport layer 114b_2, both the light-emitting device 130a and the light-emitting device 130b can become light-emitting devices with good characteristics. Furthermore, it is more preferable that the second electron transport layer 114a_2 and the second electron transport layer 114b_2 have the same structure, and even more preferably, they have the same structure.

[0253] Furthermore, when the luminescent center material contained in the first luminescent layer 113a_1 is different from the luminescent center material contained in the first luminescent layer 113b_1, and the luminescent center material contained in the second luminescent layer 113a_2 is different from the luminescent center material contained in the second luminescent layer 113b_2 (for example, in the following cases: the first luminescent layer 113a_1 and the second luminescent layer 113a_2 are blue fluorescent luminescent layers, and the first luminescent layer 113b_1 and the second luminescent layer 113b_2 are green fluorescent luminescent layers). The light-emitting layers are phosphorescent; the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are blue phosphorescent layers, and the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2 are red phosphorescent layers; or the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are green phosphorescent layers, and the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2 are red phosphorescent layers. The carrier balances of the light-emitting layers in light-emitting devices 130a and 130b are different. Therefore, in many cases, in order to enable light-emitting devices 130a and 130b to perform their respective functions, it is necessary to select and use appropriate intermediate layers and electron transport layers respectively. However, by using layers containing organic compounds with a triazine skeleton as the second electron transport layer 114a_2 and the second electron transport layer 114b_2, and using layers containing organic compounds with a phenanthroline skeleton as the first layer 161a and the first layer 161b, both the second electron transport layer 114a_2 and the second electron transport layer 114b_2 can perform their functions even if they have the same structure. In other words, both productivity and performance can be improved simultaneously. Furthermore, the first layer 161a and the first layer 161b can also have the same structure.

[0254] Note that a continuous layer refers to the so-called common layer formed across both light-emitting devices 130a and 130b.

[0255] Figure 3A yes Figure 2A variation is shown below. Since light-emitting devices 130a and 130b emit different colors, the optical path lengths between the electrodes can be amplified using a microcavity structure. Therefore, in light-emitting device 130b1, the distance between the electrodes can be adjusted by increasing the thickness of the light-emitting layer, as in light-emitting layers 113b_11 and 113b_21. Alternatively, the optical path length can be changed by increasing the thickness of the functional layer or by adding functional layers, as in hole transport layer 112b_21.

[0256] Figure 3B The diagram shows three adjacent light-emitting devices (light-emitting device 130a, light-emitting device 130b1, and light-emitting device 130c) included in a display device according to one aspect of the present invention.

[0257] The light-emitting device 130c includes an organic compound layer 103c between the first electrode 101c and the second electrode 102 on the insulating layer 175. The organic compound layer 103c has a structure in which the first light-emitting unit 501c and the second light-emitting unit 502c are stacked separated by an intermediate layer 160c. Note that although... Figure 3B An example of two stacked light-emitting units is shown, but three or more light-emitting units can also be stacked. The first light-emitting unit 501c includes a hole injection layer 111c, a first hole transport layer 112c_1, a first light-emitting layer 113c_1, and a first electron transport layer 114c_1. The intermediate layer 160c includes a second layer 162c, a third layer 163c, and a first layer 161c. The third layer 163c may or may not be included. The second light-emitting unit 502c includes a second hole transport layer 112c_2, a second light-emitting layer 113c_2, and a second electron transport layer 114c_2.

[0258] The wavelength of the emitted color of the light-emitting device 130c is assumed to be shorter than that of the light-emitting devices 130a and 130b1. The distance between the electrodes of the light-emitting device 130c is adjusted by setting the thickness of the first light-emitting layer 113c_1 and the second light-emitting layer 113c_2 to be thinner than the light-emitting layers of the other two light-emitting devices.

[0259] The second electron transport layer 114c_2 is a layer containing organic compounds with a triazine skeleton. The first layer 161c is a layer containing organic compounds with a phenanthroline skeleton.

[0260] The first luminescent layer 113c_1 and the second luminescent layer 113c_2 are preferably luminescent layers that emit light in similar colors. Furthermore, the luminescent center materials they contain are preferably compounds whose maximum peak wavelength difference in the PL spectrum is less than 30 nm, more preferably less than 20 nm, even more preferably less than 10 nm, and even more preferably, they contain the same luminescent center material.

[0261] Furthermore, preferably, the first light-emitting layer 113a_1 is separate from the first light-emitting layer 113c_1, and the second light-emitting layer 113a_2 is separate from the second light-emitting layer 113c_2. Furthermore, the emission colors of the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are preferably different from the emission colors of the first light-emitting layer 113c_1 and the second light-emitting layer 113a_2. Furthermore, preferably, the light-emitting center material contained in the first light-emitting layer 113a_1 is different from the light-emitting center material contained in the first light-emitting layer 113c_1, and the light-emitting center material contained in the second light-emitting layer 113a_2 is different from the light-emitting center material contained in the second light-emitting layer 113c_2.

[0262] Note that the following example is shown: hole injection layer 111a and hole injection layer 111c, first hole transport layer 112a_1 and first hole transport layer 112c_1, first electron transport layer 114a_1 and first electron transport layer 114c_1, intermediate layer 160a and intermediate layer 160c (second layer 162a and second layer 162c, third layer 163a and third layer 163c, first layer 161a and first layer 161c), and second hole transport layer 112a_2 and second hole transport layer 112c_2 are independent layers between light-emitting device 130a and light-emitting device 130c, while second electron transport layer 114a_2 and second electron transport layer 114c_2 are continuous layers. Thus, a light-emitting device can include both continuous and separate layers. Therefore, a light-emitting device or display device that achieves a balance between productivity and performance can be manufactured. In particular, the second electron transport layer 114a_2 and the second electron transport layer 114c_2 are preferably continuous layers, thereby enabling both the light-emitting device 130a and the light-emitting device 130c to become light-emitting devices with good characteristics.

[0263] For example, in the case where two of the three-color light-emitting devices contain fluorescent light-emitting centers and one contains phosphorescent light-emitting centers, it is preferable that the carrier transport layer is formed as a continuous layer in the light-emitting device containing the fluorescent light-emitting center, and that the carrier transport layer is formed as a separate layer from the light-emitting devices emitting other colors in the light-emitting device containing the phosphorescent light-emitting center. Alternatively, in the case where two of the three-color light-emitting devices contain phosphorescent light-emitting centers and one contains fluorescent light-emitting centers, it is preferable that the carrier transport layer is formed as a continuous layer in the light-emitting device containing the phosphorescent light-emitting center, and that the carrier transport layer is formed as a separate layer from the light-emitting devices emitting other colors in the light-emitting device containing the fluorescent light-emitting center.

[0264] Additionally, refer to Figure 4 This invention describes a light-emitting device according to one aspect of the present invention. Figure 4 for Figures 2 to 3B The modified example of the light-emitting device described herein shows a schematic diagram of two adjacent light-emitting devices, namely light-emitting device 130a and light-emitting device 130b, which are formed on the same insulating surface.

[0265] The light-emitting device 130a is located on the insulating layer 175 and includes a first electrode 101a having an anode, a second electrode 102 having a cathode, and an organic compound layer 103a. The organic compound layer 103a is located between the first electrode 101a and the second electrode 102. In addition, the organic compound layer 103a has a structure in which a first light-emitting unit 501a and a second light-emitting unit 502a are stacked with an intermediate layer 160a sandwiched between them.

[0266] The first light-emitting unit 501a includes a first hole transport layer 112a_1 (hole transport layer 112a_1a and hole transport layer 112a_1b), a first light-emitting layer 113a_1, and a first electron transport layer 114a_1. The intermediate layer 160a includes a first layer 161a and a second layer 162a. The second light-emitting unit 502a includes a second hole transport layer 112a_2 (hole transport layer 112a_2a and hole transport layer 112a_2b), a second light-emitting layer 113a_2, a second electron transport layer 114a_2, and an electron injection layer 115. Therefore, it can be said that the intermediate layer 160a is located between the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2.

[0267] Furthermore, in the light-emitting device 130a, the first light-emitting unit 501a preferably includes a hole injection layer 111a. Additionally, the intermediate layer 160a may include a third layer 163a between the first layer 161a and the second layer 162a. Note that, as with the second light-emitting unit 502a, when the anode side of the light-emitting unit is in contact with the intermediate layer 160a, the second layer 162a located on the cathode side of the intermediate layer 160a can also be used as a hole injection layer for the second light-emitting unit 502a, so the hole injection layer 111 may not be provided in this light-emitting unit. In other words, it is preferable to provide the hole injection layer 111 according to the desired performance of the light-emitting device.

[0268] Here, the light-emitting device 130b may also have a different structure than the light-emitting device 130a. For example, Figure 4 The difference between the light-emitting device 130b and the light-emitting device 130a lies in the structure of the first hole transport layer 112a_1 and the second hole transport layer 112a_2. When different light-emitting materials are used in the light-emitting layers of the light-emitting device 130a and the light-emitting layer of the light-emitting device 130b, it is preferable to form an appropriate layer structure according to each light-emitting material. By forming structures separately in each light-emitting device to obtain the most suitable characteristics, the overall characteristics of the light-emitting device can be improved.

[0269] The light-emitting device 130b is located on the insulating layer 175 and includes a first electrode 101b having an anode, a second electrode 102 having a cathode, and an organic compound layer 103b. The organic compound layer 103b is located between the first electrode 101b and the second electrode 102. In addition, the organic compound layer 103b has a structure in which a first light-emitting unit 501b and a second light-emitting unit 502b are stacked with an intermediate layer 160b sandwiched between them.

[0270] The first light-emitting unit 501b includes a first light-emitting layer 113b_1. The intermediate layer 160b includes a first layer 161b and a second layer 162b. The second light-emitting unit 502b includes a second light-emitting layer 113b_2 and an electron injection layer 115. Alternatively, the intermediate layer 160b can be described as being located between the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2.

[0271] Note that, preferably, in the light-emitting device 130b, the first light-emitting unit 501b includes, in addition to the first light-emitting layer 113b_1, a hole injection layer 111b, a first hole transport layer 112b_1, and a first electron transport layer 114b_1. The second light-emitting unit 502b preferably includes, in addition to the second light-emitting layer 113b_2 and the electron injection layer 115, a second hole transport layer 112b_2 and a second electron transport layer 114b_2. Furthermore, the intermediate layer 160b may include a third layer 163b between the first layer 161b and the second layer 162b. Note that, as with the second light-emitting unit 502b, when the anode side of the light-emitting unit is in contact with the intermediate layer 160b, the second layer 162b located on the cathode side of the intermediate layer 160b can also be used as a hole injection layer for the second light-emitting unit 502b, so the hole injection layer 111 may not be provided in this light-emitting unit. In other words, it is preferable to provide the hole injection layer 111 according to the desired performance of the light-emitting device.

[0272] Note that in one embodiment of the light-emitting device of the present invention, it is not necessary to provide a light-emitting device with the structure shown in light-emitting device 130b; multiple light-emitting devices having only the structure shown in light-emitting device 130a may also be used. In the light-emitting device, by unifying the structure of the light-emitting devices, the complexity of the manufacturing apparatus can be suppressed.

[0273] Note that, although in Figure 4 The illustration shows an example where each organic compound layer includes two light-emitting units, but this is not the only embodiment of the invention. Each organic compound layer may also include three or more light-emitting units. By stacking multiple light-emitting units with an intermediate layer sandwiched between a pair of electrodes, a light-emitting device that can emit light with high brightness while maintaining low current density and has high reliability can be realized. Furthermore, a light-emitting device with low power consumption can also be realized.

[0274] Furthermore, the light-emitting device 130, light-emitting device 130a, or light-emitting device 130b may also be light-emitting devices manufactured using lithography technology. That is, a portion of the organic compound layer in each of the light-emitting devices 130, 130a, and 130b can be manufactured using a lithography process. When using a light-emitting device manufactured using lithography technology, at least the first light-emitting layer 113_1 or the second light-emitting layer 113_2, as well as the organic compound layer closer to the first electrode 101 than the aforementioned layers, are processed simultaneously, so that the ends of these layers are substantially aligned in the vertical direction.

[0275] The light-emitting device of the present invention having this structure can be a light-emitting device with high current efficiency, low energy loss, and good characteristics. A display device using this light-emitting device, according to one embodiment of the present invention, can be a display device with low power consumption, high reliability, and good visibility, capable of displaying at high brightness. Furthermore, this embodiment can be freely combined with other embodiments.

[0276] The above-described structure exhibits particularly significant effects when used in a separately coated tandem light-emitting device according to one aspect of the present invention. As the separately coated tandem light-emitting device will be described later, the red, green, and blue light-emitting devices have different layer structures and are stacked, thus increasing the variety and amount of materials used. Therefore, as described above, by employing a structure using the same fused rings in multiple layers, a structure where the same fused rings are bonded at different positions, or a structure using fused rings with structural isomer relationships, in addition to manufacturing effects such as reduced raw material costs or simplified synthesis steps, effects on physical properties such as adjustment of Tg or carrier transport can also be achieved. Furthermore, by using this material in a separately coated tandem light-emitting device according to one aspect of the present invention, a light-emitting device suitable for mass production can be realized.

[0277] Implementation Method 2 In this embodiment, refer to Figure 5A and Figure 5B A display device manufactured using the light-emitting device shown in Embodiment 1 will be described. Note that... Figure 5A This is a top view showing the display device, and Figure 5B It is along Figure 5A The diagram shows a cross-sectional view of lines AB and CD cut off. The display device, as a unit for controlling the light emission of the light-emitting devices, includes a driving circuit section (source line driving circuit) 601 (indicated by dashed lines), a pixel section 602, and a driving circuit section (gate line driving circuit) 603. Furthermore, symbol 604 represents a sealing substrate, symbol 605 represents a sealing material, and the inner side surrounded by the sealing material 605 is a space 607.

[0278] Note that the guide wiring 608 is used to transmit signals input to the source line drive circuit 601 and the gate line drive circuit 603, and to receive video signals, clock signals, start signals, reset signals, etc., from the FPC (flexible printed circuit) 609, which serves as an external input terminal. Note that although only the FPC is shown here, it can also be equipped with a printed circuit board (PWB). The display device described in this specification includes not only the display device body but also the display device equipped with an FPC or PWB.

[0279] Below, refer to Figure 5B Explanation of the cross-sectional structure. Although a driving circuit section and a pixel section are formed on the element substrate 610, only one pixel of the source line driving circuit 601 and pixel section 602 is shown here.

[0280] In addition to substrates made of glass, quartz, organic resin, metal, alloy, semiconductor, etc., the component substrate 610 can also use plastic substrates made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester or acrylic resin.

[0281] There are no particular restrictions on the structure of the transistors used in the pixel and driving circuitry. For example, anti-interleaved transistors or interleaved transistors can be used. Alternatively, top-gate transistors or bottom-gate transistors can also be used. There are no particular restrictions on the semiconductor materials used in the transistors; for example, silicon, germanium, silicon carbide, gallium nitride, etc., can be used. Alternatively, oxide semiconductors containing at least one of indium, gallium, and zinc, such as In-Ga-Zn metal oxides, can be used.

[0282] There are no particular restrictions on the crystallinity of the semiconductor material used in transistors; amorphous semiconductors or crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors with crystalline regions in some of their components) can be used. Crystalline semiconductors are preferred because they can suppress transistor performance degradation.

[0283] Here, oxide semiconductors are preferably used in semiconductor devices such as transistors disposed in the aforementioned pixels and driving circuits, and in transistors for touch sensors, etc., which will be described later. Oxide semiconductors with a wider bandgap than silicon are particularly preferred. By using oxide semiconductors with a wider bandgap than silicon, the off-state current of the transistors can be reduced.

[0284] The aforementioned oxide semiconductor preferably contains at least indium (In) or zinc (Zn). Furthermore, the aforementioned oxide semiconductor is more preferably an oxide semiconductor containing oxides represented by In-M-Zn type oxides (M being metals such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0285] In particular, as a semiconductor layer, an oxide semiconductor film is preferably used that has a plurality of crystal portions in which the c-axis is oriented in a direction perpendicular to the surface of the semiconductor layer or the top surface of the semiconductor layer, and no grain boundaries are identified between adjacent crystal portions.

[0286] By using the aforementioned materials as semiconductor layers, variations in electrical characteristics can be suppressed, resulting in transistors with high reliability.

[0287] Furthermore, because the transistors with the aforementioned semiconductor layer have low off-state currents, the charge stored in the capacitors through the transistors can be maintained for extended periods. By using such transistors in pixels, the driving circuit can be stopped while maintaining the grayscale of each pixel. As a result, electronic devices with extremely low power consumption can be realized.

[0288] To stabilize transistor characteristics, a base film is preferably provided. As the base film, inorganic insulating films such as silicon oxide, silicon nitride, silicon oxynitride, and silicon oxynitride can be used and fabricated as a single layer or in stacks. The base film can be formed by sputtering, CVD (Chemical Vapor Deposition) methods (plasma CVD, thermal CVD, MOCVD (Metal-Organic CVD), etc.), ALD (Atomic Layer Deposition), coating, printing, etc. Note that a base film is optional if not required.

[0289] Note that FET623 represents one of the transistors formed in the source line drive circuit 601. Furthermore, the drive circuit can also be formed using various CMOS, PMOS, or NMOS circuits. Although this embodiment shows an integrated driver type with the drive circuit formed on the substrate, this structure is not mandatory; the drive circuit can also be formed externally instead of on the substrate.

[0290] Furthermore, the pixel unit 602 is formed by a plurality of pixels, each of which includes a switching FET 611, a current control FET 612, and a first electrode 613 electrically connected to the drain of the current control FET 612. However, it is not limited to this and a pixel unit combining three or more FETs and capacitors may also be used.

[0291] Note that the insulator 614 is formed in such a way that it covers the end of the first electrode 613. Here, a positive photosensitive acrylic resin film can be used to form the insulator 614.

[0292] Furthermore, the upper or lower end of the insulator 614 is formed as a curved surface to obtain good coverage for the subsequently formed organic compound layer, etc. For example, when using a positive photosensitive acrylic resin as the material of the insulator 614, it is preferable that only the upper end of the insulator 614 includes a curved surface with a radius of curvature (0.2 μm to 3 μm). Negative or positive photosensitive resins can be used as the insulator 614.

[0293] An organic compound layer 616 and a second electrode 617 are formed on the first electrode 613. Here, a material with a high work function is preferably used as the material for the first electrode 613, which serves as the anode. For example, in addition to single-layer films such as ITO films, indium tin oxide films containing silicon, indium oxide films containing 2 wt% to 20 wt% zinc oxide, titanium nitride films, chromium films, tungsten films, Zn films, and Pt films, multilayer films composed of titanium nitride films and films with aluminum as the main component, as well as three-layer structures composed of titanium nitride films, films with aluminum as the main component, and titanium nitride films, can also be used. Note that when a multilayer structure is used, the resistance of the wiring can be lower, good ohmic contact can be obtained, and it can be used as the anode.

[0294] Furthermore, the organic compound layer 616 is formed using various methods such as vapor deposition using a vapor deposition mask, inkjet printing, and spin coating. The organic compound layer 616 includes the structure shown in Embodiment 1. Additionally, low-molecular-weight compounds or high-molecular-weight compounds (including oligomers and dendritic polymers) may be used as other materials constituting the organic compound layer 616.

[0295] Furthermore, as the material used for the second electrode 617 formed on the organic compound layer 616 and used as a cathode, a material with a low work function (Al, Mg, Li, Ca, or their alloys and compounds (MgAg, MgIn, AlLi, etc.)) is preferably used. Note that when light generated in the organic compound layer 616 is transmitted through the second electrode 617, a stack consisting of a thinned metal film and a transparent conductive film (ITO, indium oxide containing 2 wt% to 20 wt% zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.) is preferably used as the second electrode 617.

[0296] Furthermore, the light-emitting device is formed of a first electrode 613, an organic compound layer 616, and a second electrode 617. This light-emitting device is the same as that shown in Embodiment 1. Additionally, the pixel portion is composed of multiple light-emitting devices, and the display device of this embodiment may also include both the light-emitting device shown in Embodiment 1 and light-emitting devices with other structures.

[0297] Furthermore, by attaching the sealing substrate 604 to the element substrate 610 using a sealing material 605, the light-emitting device 618 is disposed within a space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. Note that the space 607 is filled with a filler; this filler can be an inactive gas (nitrogen, argon, etc.) or a sealing material. It is preferable to form a recess in the sealing substrate and place a desiccant therein to suppress deterioration caused by moisture.

[0298] Furthermore, epoxy resin and glass powder are preferably used as sealing materials 605. These materials are also preferably those that minimize the permeability of moisture and oxygen. In addition to glass substrates and quartz substrates, plastic substrates made of FRP (fiber reinforced plastics), PVF (polyvinyl fluoride), polyester, acrylic resin, etc., can also be used as materials for the sealing substrate 604.

[0299] Although Figure 5A and Figure 5B Although not shown, a protective film can also be provided on the second electrode. The protective film can be formed from an organic resin film or an inorganic insulating film. Alternatively, the protective film can be formed to cover the exposed portion of the sealing material 605. Furthermore, the protective film can be provided to cover the surface and side surfaces of a pair of substrates, the exposed sides of the sealing layer, the insulating layer, etc.

[0300] As a protective membrane, materials that are not easily permeable to water and other impurities can be used. Therefore, it can effectively prevent water and other impurities from diffusing from the outside to the inside.

[0301] Materials constituting the protective film can include oxides, nitrides, fluorides, sulfides, ternary compounds, metals, or polymers. For example, materials containing aluminum oxide, hafnium oxide, hafnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide, titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide, cerium oxide, scandium oxide, erbium oxide, vanadium oxide, or indium oxide can be used; materials containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, gallium nitride, etc.; nitrides containing titanium and aluminum; oxides containing titanium and aluminum; oxides containing aluminum and zinc; sulfides containing manganese and zinc; sulfides containing cerium and strontium; oxides containing erbium and aluminum; and oxides containing yttrium and zirconium can be used.

[0302] The protective film is preferably formed using a deposition method with good step coverage. One such method is the ALD (Alternating Deposition) method. Materials that can be formed using the ALD method are preferably used for the protective film. The ALD method can form a dense protective film with reduced or uniform thickness, minimizing defects such as cracks and pinholes. Furthermore, it can reduce damage to the machined component during the formation of the protective film.

[0303] For example, by forming a protective film using the ALD method, a uniform protective film with few defects can be formed on the top, sides, and back of a surface or touch panel with a complex uneven shape.

[0304] As described above, a display device manufactured using the light-emitting device shown in Embodiment 1 can be obtained.

[0305] Because the light-emitting device in this embodiment uses the light-emitting device shown in Embodiment 1, a light-emitting device with excellent characteristics can be obtained. Specifically, the light-emitting device shown in Embodiment 1 has high luminous efficiency, thereby enabling a low-power display device. Furthermore, the light-emitting device shown in Embodiment 1 has high reliability, thereby enabling a highly reliable display device. Moreover, the light-emitting device shown in Embodiment 1 can have good chromaticity and high color purity, thereby enabling a display device with good display quality.

[0306] Furthermore, this embodiment can be freely combined with other embodiments.

[0307] Implementation Method 3 like Figure 6A and Figure 6B As shown, a plurality of light-emitting devices 130 are formed on an insulating layer 175 to constitute a display device. In this embodiment, a display device according to one aspect of the present invention will be described in detail.

[0308] The display device 100 includes a pixel section 177 in which a plurality of pixels 178 are arranged in a matrix. The pixels 178 include sub-pixels 110R, 110G, and 110B.

[0309] In this specification, for example, when describing the common content among subpixels 110R, 110G, and 110B, they are sometimes referred to as subpixel 110. Similarly, when describing the common content among other constituent elements distinguished by letters, symbols with omitted letters are sometimes used.

[0310] Subpixel 110R emits red light, subpixel 110G emits green light, and subpixel 110B emits blue light. This allows an image to be displayed on pixel unit 177. In this embodiment, a subpixel of three colors—red (R), green (G), and blue (B)—is used as an example, but combinations of other colors of subpixels can also be used. Furthermore, the number of subpixels is not limited to three; four or more can be used. Examples of four subpixels include: a subpixel of four colors—R, G, B, and white (W); a subpixel of four colors—R, G, B, and yellow (Y); and a subpixel of four colors—R, G, B, and infrared (IR); etc.

[0311] In this specification, the row direction is sometimes referred to as the X direction and the column direction as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly.

[0312] exist Figure 6A In the example shown, subpixels of different colors are arranged in the X direction, and subpixels of the same color are arranged in the Y direction. Note that subpixels of different colors can also be arranged in the Y direction, and subpixels of the same color can also be arranged in the X direction.

[0313] A connecting portion 140 may be provided on the outer side of the pixel portion 177, and a region 141 may also be provided thereon. The region 141 is provided between the pixel portion 177 and the connecting portion 140. An organic compound layer 103 is provided in the region 141. In addition, a conductive layer 151C is provided in the connecting portion 140.

[0314] exist Figure 6A In the example shown, region 141 and connecting portion 140 are located to the right of pixel portion 177, but there are no particular restrictions on the position of region 141 and connecting portion 140. Furthermore, region 141 and connecting portion 140 may be one or more.

[0315] Figure 6B It is along Figure 6A An example of a cross-sectional view of the dashed-dot line A1-A2 in the diagram. For example... Figure 6BAs shown, the display device 100 includes an insulating layer 171, a conductive layer 172 on the insulating layer 171, an insulating layer 173 on the insulating layer 171 and the conductive layer 172, an insulating layer 174 on the insulating layer 173, and an insulating layer 175 on the insulating layer 174. The insulating layer 171 is disposed on a substrate (not shown). The insulating layers 175, 174, and 173 are provided with openings leading to the conductive layer 172, and a plug 176 is disposed such that it is inserted into the openings.

[0316] In the pixel section 177, a light-emitting device 130 is disposed on the insulating layer 175 and the plug 176. Furthermore, a protective layer 131 is disposed to cover the light-emitting device 130. A substrate 120 is bonded to the protective layer 131 by a resin layer 122. Additionally, an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are preferably disposed between adjacent light-emitting devices 130.

[0317] Figure 6B Cross-sections of multiple inorganic insulating layers 125 and multiple insulating layers 127 are shown, but when viewed from above the display device 100, the inorganic insulating layers 125 and insulating layers 127 are preferably formed as a connected layer. In other words, the insulating layer 127 is preferably an insulating layer having an opening on the first electrode.

[0318] exist Figure 6B Light-emitting devices 130R, 130G, and 130B are shown as light-emitting devices 130. The light-emitting devices 130R, 130G, and 130B emit different colors from each other. For example, light-emitting device 130R may emit red light, light-emitting device 130G may emit green light, and light-emitting device 130B may emit blue light. Furthermore, light-emitting devices 130R, 130G, or 130B may also emit other visible or infrared light.

[0319] One aspect of the display device of the present invention may include a top-emission structure (top emission structure) that emits light in a direction opposite to that of the substrate on which the light-emitting device is formed. Furthermore, another aspect of the display device of the present invention may also include a bottom emission structure.

[0320] Examples of luminescent materials contained in the light-emitting device 130 include organic compounds or organometallic complexes, such as substances that emit fluorescence (fluorescent materials), substances that emit phosphorescence (phosphorescent materials), and substances that exhibit thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) materials). Alternatively, inorganic compounds such as quantum dots may also be used.

[0321] The light-emitting device 130R has the structure shown in Embodiment 1. The light-emitting device 130R includes a first electrode (pixel electrode) composed of conductive layers 151R and 152R, an organic compound layer 103R on the first electrode, a common layer 104 on the organic compound layer 103R, and a second electrode (common electrode) 102 on the common layer. Note that the common layer 104 may be omitted, but its presence reduces damage to the organic compound layer 103R during processing, and is therefore preferred. When the common layer 104 is provided, it is preferably an electron injection layer. Furthermore, when the common layer 104 is provided, the stacked structure of the organic compound layer 103R and the common layer 104 corresponds to the organic compound layer 103.

[0322] The light-emitting device 130G has the structure shown in Embodiment 1. The light-emitting device 130G includes a first electrode (pixel electrode) composed of conductive layers 151G and 152G, an organic compound layer 103G on the first electrode, a common layer 104 on the organic compound layer 103G, and a second electrode (common electrode) 102 on the common layer. Furthermore, the common layer 104 may not be provided, but its provision reduces damage to the organic compound layer 103G during processing, and is therefore preferred. When the common layer 104 is provided, it is preferably an electron injection layer. Additionally, when the common layer 104 is provided, the stacked structure of the organic compound layer 103G and the common layer 104 corresponds to the organic compound layer 103.

[0323] The light-emitting device 130B has the structure shown in Embodiment 1. The light-emitting device 130B includes a first electrode (pixel electrode) composed of conductive layers 151B and 152B, an organic compound layer 103B on the first electrode, a common layer 104 on the organic compound layer 103B, and a second electrode (common electrode) 102 on the common layer. Furthermore, the common layer 104 may not be provided, but its provision reduces damage to the organic compound layer 103B during processing, and is therefore preferred. When the common layer 104 is provided, it is preferably an electron injection layer. Additionally, when the common layer 104 is provided, the stacked structure of the organic compound layer 103B and the common layer 104 corresponds to the organic compound layer 103.

[0324] In a light-emitting device, one of the pixel electrode and the common electrode is used as the anode, and the other is used as the cathode. Unless otherwise stated, the following explanation assumes that the pixel electrode is used as the anode and the common electrode is used as the cathode.

[0325] Organic compound layers 103R, 103G, and 103B are arranged independently in an island-like manner within each light-emitting device. By arranging the organic compound layers 103 in an island-like manner for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in high-definition display devices. This prevents crosstalk and enables the realization of a display device with extremely high contrast. In particular, it enables a display device with high current efficiency at low brightness.

[0326] An island-like organic compound layer 103 is formed by depositing an EL film and processing it using photolithography.

[0327] In one aspect of the display device of the present invention, the first electrode (pixel electrode) of the light-emitting device preferably has a stacked structure. For example, in Figure 6B In the example shown, the first electrode of the light-emitting device 130 has a stacked structure of conductive layers 151 (conductive layers 151R, 151G, and 151B) and conductive layers 152 (conductive layers 152R, 152G, and 152B). For example, when the display device 100 has a top-emitting structure and the pixel electrode of the light-emitting device 130 is used as the anode, it is preferable that the conductive layer 151 is a layer with high visible light reflectivity, and the conductive layer 152 is, for example, a layer with visible light transmittance and a large work function. When the display device 100 has a top-emitting structure, the higher the visible light reflectivity of the pixel electrode, the more efficient the light extraction of the organic compound layer 103 can be. In addition, when the pixel electrode is used as the anode, the larger the work function of the pixel electrode, the easier it is to inject holes into the organic compound layer 103. Therefore, by having a stacked structure of a conductive layer 151 with high visible light reflectivity and a conductive layer 152 with high work function in the pixel electrode of the light-emitting device 130, the light-emitting device 130 can be a light-emitting device with high light extraction efficiency and low driving voltage.

[0328] When the conductive layer 151 is a layer with high visible light reflectivity, the visible light reflectivity of the conductive layer 151 is preferably, for example, 40% or more and 100% or less, or 70% or more and 100% or less. Furthermore, when the conductive layer 152 is an electrode with visible light transmittance, the visible light transmittance is preferably, for example, 40% or more.

[0329] As the conductive layer 151, a metallic material can be used, for example. Specifically, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys thereof can be used.

[0330] As the conductive layer 152, an oxide containing one or more of indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, conductive oxides including one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, gallium-containing zinc oxide, titanium oxide, gallium-containing indium zinc oxide, aluminum-containing indium zinc oxide, silicon-containing indium tin oxide, and silicon-containing indium zinc oxide are preferred. In particular, silicon-containing indium tin oxide has a large work function, for example, 4.0 eV or more, so it is suitable for use as the conductive layer 152.

[0331] The conductive layer 151 or conductive layer 152 may also have a stacked structure comprising multiple layers of different materials. In this case, the conductive layer 151 may also include a layer using a material that can be used in the conductive layer 152, such as a conductive oxide, and the conductive layer 152 may also include a layer using a material that can be used in the conductive layer 151, such as a metallic material. For example, when the conductive layer 151 has a stacked structure of two or more layers, the layer in contact with the conductive layer 152 may be a layer using a material that can be used in the conductive layer 152.

[0332] Furthermore, the side surfaces of conductive layer 151 or conductive layer 152 preferably have a tapered shape. Specifically, the side surfaces of conductive layer 151 or conductive layer 152 preferably have a tapered shape with a taper angle of less than 90°. Additionally, the ends of insulating layer 156 (insulating layer 156R, insulating layer 156G, and insulating layer 156B) may also have a tapered shape. Specifically, when the ends of insulating layer 156 have a tapered shape with a taper angle of less than 90°, the coverage of structures disposed along the side surfaces of insulating layer 156 can be improved.

[0333] Alternatively, the conductive layer 151 may have a stacked structure of three or more layers. When the conductive layer 151 has a stacked structure of multiple layers, it is sufficient that at least one of the layers constituting the conductive layer 151 has a visible light reflectance higher than that of the conductive layer 152. Furthermore, when the conductive layer 151 has a structure of three or more layers, the outermost conductive layer is preferably made of a material less prone to deterioration compared to the materials used for the intermediate conductive layers. For example, the layer in contact with the insulating layer 175 can be made of a material less prone to migration compared to the materials used for other layers. Moreover, the layer in contact with the insulating layer 175 can be made of a material that is not easily oxidized, and whose oxide resistivity is lower than that of the oxides of the materials used for other layers.

[0334] This expands the range of materials that can be selected for the conductive layer 151. Therefore, by using aluminum or an aluminum-containing alloy as the material constituting the conductive layer 151, a layer with high visible light reflectivity can be formed. Furthermore, aluminum and titanium can be used in combination as the conductive layer 151. While titanium has a lower visible light reflectivity than aluminum, it is less prone to migration even when in contact with the insulating layer 175 compared to aluminum.

[0335] Alternatively, silver or a silver-containing alloy can be used as the conductive layer 151. Silver has a higher visible light reflectance than titanium. Furthermore, silver has the following properties: it is less prone to oxidation than aluminum, and the resistivity of silver oxide is lower than that of aluminum oxide. Therefore, when silver or a silver-containing alloy is used as the conductive layer 151, the visible light reflectance of the conductive layer 151 can be appropriately increased while suppressing the increase in resistance of the pixel electrode due to oxidation. Here, an alloy of silver, palladium, and copper (Ag-Pd-Cu, also denoted as APC) can be used as an example of a silver-containing alloy.

[0336] For example, when the light-emitting device 130 adopts a microcavity structure, the light extraction efficiency of the display device 100 can be appropriately improved by using silver or an alloy containing silver, which are materials with high visible light reflectivity, as the conductive layer 151.

[0337] In addition, when the conductive layer 152 adopts a stacked structure, a microcavity structure can be formed by combining it with the conductive layer 151 by adopting a stacked structure with a visible light reflectivity (for example, the reflectivity of light of a specified wavelength in the range of 400 nm and less than 750 nm) that is different from the visible light reflectivity of the conductive layer 151.

[0338] Thus, by having a multi-layered structure for conductive layer 151 or conductive layer 152, the characteristics of the display device can be improved. For example, the display device 100 can be made into a display device with high light extraction efficiency and high reliability.

[0339] Note that the conductive layer 151 can be formed using lithography. Specifically, a conductive film that will become the conductive layer 151 is first deposited. Next, a photoresist mask is formed on the conductive film that will become the conductive layer 151. Then, the conductive film in areas that do not overlap with the photoresist mask is removed, for example, by etching. Here, by processing the conductive film under conditions where the photoresist mask is easier to retract (shrink) compared to forming the conductive layer 151 in a manner where the sides do not have a tapered shape, i.e., the sides are perpendicular, a conductive layer 151 with a tapered shape on the sides can be formed.

[0340] Alternatively, the conductive layer 152 can be processed simultaneously with the conductive layer 151 using photolithography. In this case, a tapered shape can also be formed on the side of the conductive layer 152.

[0341] Here, when the conductive film is processed under conditions where the resist mask can easily recede (shrink), the conductive film is sometimes easily processed in the horizontal direction. In other words, compared to the case where the conductive layer 151 is formed in a manner with its sides perpendicular, the isotropy of the etching is sometimes higher.

[0342] Furthermore, when the conductive layer 151 has a stacked structure of multiple layers made of different materials, the ease of processing of these multiple layers in the horizontal direction may vary.

[0343] Therefore, as Figure 6B As shown, by providing the insulating layer 156, corrosion in the conductive layer 151 can be suppressed. Therefore, the display device 100 can be manufactured with a high yield. In addition, defects can be suppressed, thereby achieving a display device 100 with high reliability.

[0344] Not easy, such as Figure 6B As shown, the insulating layer 156 preferably has a curved surface. This reduces the likelihood of breaks in the conductive layer 152 covering the insulating layer 156 compared to the case where the insulating layer 156 is perpendicular to its side surface (parallel to the Z direction). Furthermore, when the insulating layer 156 has a tapered shape on its side surface, specifically a tapered shape with a taper angle less than 90°, this also reduces the likelihood of breaks in the conductive layer 152 covering the insulating layer 156 compared to the case where the insulating layer 156 is perpendicular to its side surface. This allows for the manufacture of the display device 100 with a high yield rate. Additionally, it suppresses defects, thereby enabling the realization of a display device 100 with high reliability.

[0345] Next, refer to Figures 7A to 12C The description has Figure 6A An example of a manufacturing method for the display device 100 with the shown structure. The organic compound layer of the light-emitting device included in the display device 100 is formed by a manufacturing process including water treatment. By using the organic compound of one aspect of the present invention in the organic layer of the light-emitting device included in one aspect of the present invention, problems such as dissolution of the layer including the organic compound and penetration of the liquid into the layer using the organic compound can be prevented even when manufacturing by a manufacturing process including water treatment, thereby providing a light-emitting device with good properties.

[0346] [Example of manufacturing method] Thin films (insulating films, semiconductor films, and conductive films, etc.) constituting display devices can be formed using methods such as sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), or alumina deposition (ALD). CVD methods include plasma-enhanced chemical vapor deposition (PECVD) and thermal CVD. Furthermore, metal-organic chemical vapor deposition (MOCVD) is one type of thermal CVD method.

[0347] In addition, the thin films (insulating films, semiconductor films, and conductive films, etc.) constituting the display device can be formed using wet deposition methods such as spin coating, dip coating, spray coating, inkjet coating, dispenser coating, screen printing, offset printing, doctor knife coating, slot coating, roller coating, curtain coating, or doctor blade coating.

[0348] In particular, when manufacturing light-emitting devices, vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet printing can be utilized. Examples of vapor deposition methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam vapor deposition, molecular beam vapor deposition, and vacuum vapor deposition, as well as chemical vapor deposition (CVD). Specifically, functional layers (hole injection layer, hole transport layer, hole blocking layer, light-emitting layer, electron blocking layer, electron transport layer, and electron injection layer, etc.) comprising an organic compound layer can be formed using methods such as vapor deposition (vacuum vapor deposition, etc.), coating methods (dip coating, dye coating, rod coating, spin coating, spray coating), and printing methods (inkjet printing, screen printing, offset printing, flexographic printing, photogravure printing, or microcontact printing, etc.).

[0349] Furthermore, when processing the thin film constituting the display device, it can be processed using techniques such as photolithography. Alternatively, it can be processed using nanoimprinting, sandblasting, or stripping methods. Additionally, island-shaped thin films can be directly formed using deposition methods that utilize metal masks or similar masking techniques.

[0350] As a lithography technique, photolithography can be used, for example. Photolithography typically involves two methods. One is to form a resist mask on the thin film to be processed, for example, by etching the film and then removing the resist mask. The other is to deposit a photosensitive thin film, then expose and develop it to process the film into the desired shape.

[0351] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm), or a mixture of these. Additionally, ultraviolet light, KrF lasers, or ArF lasers can also be used. Furthermore, immersion lithography can also be used. Extreme ultraviolet (EUV) light or X-rays can also be used as the light for exposure. Alternatively, an electron beam can be used instead of the light for exposure. Extreme ultraviolet light, X-rays, or electron beams allow for extremely fine processing and are therefore preferred. Note that when exposure is performed by scanning with a beam such as an electron beam, a photomask is not required.

[0352] In the etching of thin films, dry etching, wet etching, or sandblasting methods can be used.

[0353] Furthermore, in the manufacturing process of light-emitting devices, organic compounds that are excited by absorbing light are used. These excited organic compounds may, under certain circumstances, react with oxygen or water in the atmosphere. That is, when light of the wavelength absorbed by the organic compound is irradiated in the presence of oxygen, deterioration products may sometimes form within the organic compound.

[0354] Therefore, when processing a substrate with organic compounds formed using photolithography, it is preferable to perform the process under appropriately controlled lighting conditions when exposed to the atmosphere. Ideally, the process should be performed under illumination at wavelengths that do not excite organic compounds that are excited by absorbing light. However, to ensure illuminance or color rendering that does not reduce working efficiency, it is preferable to use illumination where the shortest wavelength of the light source's emission spectrum is below 600 nm, and more preferably below 580 nm.

[0355] For illumination, a yellow lamp (fluorescent lamp or light-emitting diode (LED)) that does not contain light with wavelengths shorter than 500 nm is preferred. Alternatively, an orange lamp that does not contain light with wavelengths shorter than 530 nm is preferred. Low-pressure sodium lamps can also be used as the light source. Furthermore, by using optical filters capable of blocking short-wavelength light, various light sources can be used, such as incandescent lamps, fluorescent lamps, LEDs, halogen lamps, and sunlight. For example, bandpass filters and long-pass filters (short-wavelength filtering filters) can be used as optical filters capable of blocking short-wavelength light. By using the above-described illumination, the illuminance of the illumination light can be reduced.

[0356] First, such as Figure 7AAn insulating layer 171 is formed on a substrate (not shown). Next, a conductive layer 172 and a conductive layer 179 are formed on the insulating layer 171, and an insulating layer 173 is formed on the insulating layer 171 to cover the conductive layers 172 and 179. Next, an insulating layer 174 is formed on the insulating layer 173, and an insulating layer 175 is formed on the insulating layer 174.

[0357] As a substrate, a substrate with heat resistance sufficient to withstand subsequent heat treatment can be used. When using an insulating substrate, glass substrates, quartz substrates, sapphire substrates, ceramic substrates, or organic resin substrates can be used. In addition, single-crystal semiconductor substrates or polycrystalline semiconductor substrates made of materials such as silicon or silicon carbide, compound semiconductor substrates made of materials such as silicon-germanium, SOI substrates, and other semiconductor substrates can also be used.

[0358] Next, as Figure 7A As shown, openings leading to the conductive layer 172 are formed in insulating layers 175, 174, and 173. Then, a plug 176 is formed by embedding it into these openings.

[0359] Next, as Figure 7A As shown, a conductive film 151f, which will later become conductive layers 151R, 151G, 151B, and 151C, is formed on the plug 176 and the insulating layer 175. The conductive film 151f can be formed, for example, by sputtering or vacuum evaporation. Alternatively, a metallic material can be used as the conductive film 151f.

[0360] Next, as Figure 7A As shown, a conductive film 152f, which will later become conductive layers 152R, 152G, 152B, and 152C, is formed on a conductive film 151f. The conductive film 152f can be formed, for example, by sputtering or vacuum evaporation. Alternatively, a conductive oxide can be used as the conductive film 152f. Or, the conductive film 152f can be a laminated structure of a film using a metallic material and a film using a conductive oxide on that film. For example, the conductive film 152f can be a laminated structure of a film using titanium, silver, or an alloy containing silver and a film using a conductive oxide on that film.

[0361] Furthermore, the conductive film 152f can be formed using the ALD method. Here, as the conductive film 152f, an oxide containing one or more metals selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. The conductive film 152f can be formed by repeatedly performing a cycle of introducing a precursor (sometimes referred to as a precursor or metal precursor, etc.), purging the precursor, introducing an oxidant (sometimes referred to as a reactant, reactant, or non-metal precursor, etc.), and purging the oxidant. When forming a conductive film 152f from an oxide film containing multiple metals, such as indium tin oxide, the metal composition can be controlled by changing the number of cycles according to the type of precursor.

[0362] For example, in the case of depositing an indium tin oxide film as a conductive film 152f, after introducing an indium-containing precursor, the precursor is purged and an oxidant is introduced to form an In-O film. Next, after introducing a tin-containing precursor, the precursor is purged and an oxidant is introduced to form a Sn-O film. Here, by making the number of cycles for forming the In-O film greater than the number of cycles for forming the Sn-O film, the number of In atoms contained in the conductive film 152f can be greater than the number of Sn atoms.

[0363] Furthermore, for example, when depositing a zinc oxide film as the conductive film 152f, a Zn-O film is formed through the above process. Furthermore, for example, when depositing an aluminum-zinc oxide film as the conductive film 152f, both a Zn-O film and an Al-O film are formed through the above process. Furthermore, for example, when depositing a titanium oxide film as the conductive film 152f, a Ti-O film is formed through the above process. Furthermore, for example, when depositing an indium tin oxide film containing silicon as the conductive film 152f, an In-O film, a Sn-O film, and a Si-O film are formed through the above process. Furthermore, for example, when depositing a zinc oxide film containing gallium, both a Ga-O film and a Zn-O film are formed through the above process.

[0364] As indium-containing precursors, for example, triethylindium, trimethylindium, or [1,1,1-trimethyl-N-(trimethylsilyl)amide]-indium can be used. As tin-containing precursors, for example, tin chloride or tetra(dimethylamide)tin can be used. As zinc-containing precursors, for example, diethylzinc or dimethylzinc can be used. As gallium-containing precursors, for example, triethylgallium can be used. As titanium-containing precursors, for example, titanium chloride, tetra(dimethylamide)titanium, or tetraisopropyl titanate can be used. As aluminum-containing precursors, for example, aluminum chloride or trimethylaluminum can be used. As silicon-containing precursors, for example, trisilylamine, bis(diethylamino)silane, tri(dimethylamino)silane, bis(tert-butylamino)silane, or bis(ethylmethylamino)silane can be used. Additionally, water vapor, oxygen plasma, or ozone gas can be used as oxidants.

[0365] Next, as Figure 7A As shown, a photoresist mask 191 is formed on conductive films 151f and 152f. The photoresist mask 191 can be formed by coating a photosensitive material (photoresist) and then exposing and developing it.

[0366] Next, as Figure 7B As shown, for example, an etching method, specifically a dry etching method, is used to remove the conductive films 151f and 152f in areas that do not overlap with the resist mask 191, forming a pixel electrode including conductive layers 151 and 152. Note that if the conductive film 151f includes a layer of conductive oxide such as indium tin oxide, this layer can also be removed using a wet etching method. Thus, conductive layers 151 and 152 are formed. Note that, for example, when a portion of the conductive film 151f is removed using a dry etching method, a recess may sometimes be formed in the area of ​​the insulating layer 175 that does not overlap with the conductive layer 151.

[0367] Note that after forming conductive layers 152R, 152G, 152B, and 152C by processing conductive film 152f using lithography, conductive film 151f can also be processed using conductive layers 152R, 152G, 152B, and 152C as masks. Specifically, for example, after forming a resist mask, a portion of conductive film 152f can be removed using an etching method. For example, wet etching can be used to remove conductive film 152f. Note that dry etching can also be used to remove conductive film 152f. Then, wet etching is preferably used to remove conductive film 151f.

[0368] Here, it is preferable to perform a hydrophobic treatment on the conductive layer 152. This hydrophobic treatment can change the surface state of the object being treated from hydrophilic to hydrophobic, or it can increase the hydrophobicity of the surface. By performing a hydrophobic treatment on the conductive layer 152, the adhesion between the conductive layer 152 and the organic compound layer 103 to be formed in subsequent processes can be improved, thereby suppressing film peeling. Note that a hydrophobic treatment may not be performed.

[0369] Next, as Figure 7C As shown, the resist mask 191 is removed. The resist mask 191 can be removed, for example, by ashing using oxygen plasma. Alternatively, oxygen gas and Group 18 elements such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He can be used. Alternatively, the resist mask 191 can also be removed by wet etching.

[0370] Next, as Figure 7DAs shown, an insulating film 156f, which will later become insulating layers 156R, 156G, 156B, and 156C, is formed on conductive layers 151R, 152R, 151G, 152G, 151B, 152B, 151C, and 152C, and insulating layer 175. The insulating film 156f can be formed, for example, using CVD, ALD, sputtering, or vacuum evaporation.

[0371] Inorganic materials can be used for the insulating film 156f. For example, inorganic insulating films such as oxide insulating films, nitride insulating films, oxynitride insulating films, or oxynitride insulating films can be used as the insulating film 156f. For instance, silicon-containing insulating films such as oxide insulating films, nitride insulating films, oxynitride insulating films, or oxynitride insulating films can be used as the insulating film 156f. For example, silicon oxynitride can be used as the insulating film 156f.

[0372] Next, as Figure 7E As shown, insulating film 156f is processed to form insulating layers 156R, 156G, 156B, and 156C. For example, insulating layer 156 can be formed by etching the top surface of insulating film 156f in a substantially uniform manner. This planarization process through uniform etching is also known as etch-back. Alternatively, insulating layer 156 can also be formed using photolithography.

[0373] Next, as Figure 8A As shown, an organic compound film 103Rf, which will later become an organic compound layer 103R, is formed on conductive layer 152R, conductive layer 152G, conductive layer 152B, insulating layer 156R, insulating layer 156G, insulating layer 156B and insulating layer 175.

[0374] like Figure 8A As shown, no organic compound film 103Rf is formed on the conductive layer 152C. For example, by using a mask that defines the deposition area (also called a zone mask or coarse metal mask, etc., to distinguish it from a high-precision metal mask), the organic compound film 103Rf can be deposited only in the desired area. By employing a deposition process using a zone mask and a processing process using a resist mask, the light-emitting device can be manufactured with a simpler process.

[0375] The organic compound film 103Rf can be formed, for example, by vapor deposition, specifically by vacuum vapor deposition. Alternatively, the organic compound film 103Rf can also be formed by methods such as transfer printing, printing, inkjet printing, or coating.

[0376] Next, as Figure 8AAs shown, a sacrificial film 158Rf, which will later become a sacrificial layer 158R, and a mask film 159Rf, which will later become a mask layer 159R, are sequentially formed on an organic compound film 103Rf, a conductive layer 152C, and an insulating layer 175.

[0377] Note that in this embodiment, an example is shown where a mask is formed by a two-layer structure of sacrificial membrane 158Rf and mask membrane 159Rf, but the mask can have a single-layer structure or a stacked structure of three or more layers.

[0378] By providing a sacrificial layer on the organic compound film 103Rf, the damage to the organic compound film 103Rf during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-emitting device.

[0379] The sacrificial film 158Rf is a film with high tolerance to the processing conditions of the organic compound film 103Rf, specifically a film with a greater etch selectivity than the organic compound film 103Rf. The mask film 159Rf is a film with a greater etch selectivity than the sacrificial film 158Rf.

[0380] Furthermore, the sacrificial film 158Rf and the mask film 159Rf are formed at a temperature lower than the heat resistance temperature of the organic compound film 103Rf. The substrate temperature for forming the sacrificial film 158Rf and the mask film 159Rf is typically below 200°C, preferably below 150°C, more preferably below 120°C, further preferably below 100°C, and even more preferably below 80°C.

[0381] The sacrificial film 158Rf and the mask film 159Rf are preferably films that can be removed by wet etching. By using wet etching, the damage to the organic compound film 103Rf during the processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced compared to using dry etching.

[0382] The sacrificial film 158Rf and the mask film 159Rf can be formed, for example, by sputtering, ALD (thermal ALD, PEALD), CVD, or vacuum evaporation. Alternatively, they can also be formed using the aforementioned wet deposition methods.

[0383] Furthermore, compared to the mask film 159Rf, the sacrificial film 158Rf, which is formed in contact with the organic compound film 103Rf, is preferably formed using a formation method that causes less damage to the organic compound film 103Rf. For example, compared to sputtering, the sacrificial film 158Rf is more preferably formed using the ALD method or vacuum evaporation method.

[0384] As the sacrificial film 158Rf and the mask film 159Rf, one or more of the following can be used: metal film, alloy film, metal oxide film, semiconductor film, organic insulating film and inorganic insulating film.

[0385] The sacrificial film 158Rf and the mask film 159Rf can be made of metals such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloys containing such metals. Low-melting-point materials such as aluminum or silver are particularly preferred. By using a metal material capable of blocking ultraviolet light as one or both of the sacrificial film 158Rf and the mask film 159Rf, ultraviolet radiation can be suppressed from reaching the organic compound film 103Rf, thus suppressing the degradation of the organic compound film 103Rf, which is therefore preferred.

[0386] Furthermore, metal oxides such as In-Ga-Zn oxide, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), and silicon-containing indium tin oxide can be used as the sacrificial film 158Rf and the mask film 159Rf.

[0387] Note that element M (which is one or more of aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) can also be used to replace gallium.

[0388] Furthermore, the sacrificial film and mask film preferably use films containing materials with light-shielding properties, especially ultraviolet light-shielding properties. As the light-shielding material, various materials such as metals, insulators, semiconductors, and semi-metals with ultraviolet light-shielding properties can be used. Since part or all of the sacrificial film and mask film will be removed in subsequent processes, the sacrificial film and mask film are preferably films that can be processed by etching, and especially preferably films with good processability.

[0389] When using semiconductor materials such as silicon or germanium as sacrificial films and mask films, these materials have high affinity with the semiconductor manufacturing process and are therefore preferred. Alternatively, oxides or nitrides of the aforementioned semiconductor materials can be used. Alternatively, non-metallic materials such as carbon or their compounds can be used. Furthermore, metals such as titanium, tantalum, tungsten, chromium, and aluminum, or alloys containing one or more of these can be used. Additionally, oxides containing the aforementioned metals, such as titanium oxide or chromium oxide, or nitrides such as titanium nitride, chromium nitride, or tantalum nitride can be used.

[0390] Furthermore, by using a film containing a material with UV-blocking properties as a sacrificial film or mask film, it is possible to suppress UV radiation from reaching the organic compound layer, for example, during the exposure process. By suppressing UV damage to the organic compound layer, the reliability of the light-emitting device can be improved.

[0391] Note that films containing materials with UV-blocking properties also produce the same effect when used as materials for the inorganic insulating film 125f described later.

[0392] Various inorganic insulating films can be used as the sacrificial film 158Rf and the mask film 159Rf. In particular, the adhesion between the oxide insulating film and the organic compound film 103Rf is higher than that between the nitride insulating film and the organic compound film 103Rf, and therefore it is preferred. For example, inorganic insulating materials such as alumina, hafnium oxide, or silicon oxide can be used for the sacrificial film 158Rf and the mask film 159Rf. The sacrificial film 158Rf and the mask film 159Rf can each be formed as an alumina film, for example, using the ALD method. By using the ALD method, damage to the substrate (especially to the organic compound layer) can be reduced, and therefore it is preferred.

[0393] For example, an inorganic insulating film (e.g., an alumina film) formed using the ALD method can be used as the sacrificial film 158Rf, and an inorganic film (e.g., an In-Ga-Zn oxide film, an aluminum film, or a tungsten film) formed using the sputtering method can be used as the mask film 159Rf.

[0394] Furthermore, the same inorganic insulating film can be used for both the sacrificial film 158Rf and the inorganic insulating layer 125 to be formed later. For example, an alumina film formed using the ALD method can be used for both the sacrificial film 158Rf and the inorganic insulating layer 125. Here, the sacrificial film 158Rf and the inorganic insulating layer 125 can be deposited under the same or different conditions. For example, by depositing the sacrificial film 158Rf under the same conditions as the inorganic insulating layer 125, the sacrificial film 158Rf can be formed as an insulating layer with high barrier properties against at least one of water and oxygen. On the other hand, the sacrificial film 158Rf is a layer that will be mostly or entirely removed in a later process, so it is preferably easy to process. Therefore, the sacrificial film 158Rf is preferably deposited under conditions with a lower substrate temperature than that of the inorganic insulating layer 125.

[0395] Organic materials can also be used as one or both of the sacrificial film 158Rf and the mask film 159Rf. For example, materials that are chemically stable in solvents that are soluble in at least the uppermost layer of the organic compound film 103Rf can also be used as organic materials. In particular, materials soluble in water or alcohol can be used appropriately. When depositing the above-mentioned materials, it is preferable to apply the materials by a wet deposition method while the materials are dissolved in a solvent such as water or alcohol, and then perform a heat treatment to evaporate the solvent. At this time, it is preferable to perform the heat treatment under a reduced pressure atmosphere, thereby removing the solvent at a low temperature and for a short time, and reducing the thermal damage to the organic compound film 103Rf.

[0396] Sacrificial membrane 158Rf and mask membrane 159Rf can each be made of organic resins such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, alcohol-soluble polyamide resin or perfluoropolymer, etc.

[0397] For example, an organic film (e.g., a PVA film) formed using any one of the above-described wet deposition methods can be used as the sacrificial film 158Rf, and an inorganic film (e.g., a silicon nitride film) formed using sputtering can be used as the mask film 159Rf.

[0398] Next, as Figure 8A As shown, a resist mask 190R is formed on the mask film 159Rf. The resist mask 190R can be formed by coating a photosensitive material (photoresist) and then exposing and developing it.

[0399] The 190R resist mask can also be manufactured using either positive or negative resist materials.

[0400] The resist mask 190R is provided at the position overlapping with the conductive layer 152R. Preferably, the resist mask 190R is also provided at the position overlapping with the conductive layer 152C. This can suppress damage to the conductive layer 152C during the manufacturing process of the display device. Note that the resist mask 190R may also be omitted from the conductive layer 152C. Furthermore, as... Figure 8A As shown in the cross-sectional view between B1 and B2, the resist mask 190R is preferably provided in such a way that it covers the end of the organic compound film 103Rf to the end of the conductive layer 152C (the end on the side of the organic compound film 103Rf).

[0401] Next, as Figure 8BAs shown, a portion of the mask film 159Rf is removed using a resist mask 190R, thereby forming a mask layer 159R. The mask layer 159R remains on the conductive layers 152R and 152C. Then, the resist mask 190R is removed. Next, the mask layer 159R is used as a mask (also called a hard mask) to remove a portion of the sacrificial film 158Rf to form the sacrificial layer 158R.

[0402] The sacrificial film 158Rf and the mask film 159Rf can be processed by wet etching or dry etching, respectively. The processing of the sacrificial film 158Rf and the mask film 159Rf is preferably carried out by isotropic etching.

[0403] By using wet etching, damage to the organic compound film 103Rf can be reduced during the processing of the sacrificial film 158Rf and the mask film 159Rf compared to dry etching. When using wet etching, solutions such as developer, aqueous tetramethylammonium hydroxide (TMAH) solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or mixtures thereof are preferably used.

[0404] When processing the mask film 159Rf, the organic compound film 103Rf is not exposed, so the range of processing methods is wider compared to the case where the sacrificial film 158Rf is processed. Specifically, when processing the mask film 159Rf, even when using an oxygen-containing gas as the etching gas, the degradation of the organic compound film 103Rf can be suppressed.

[0405] Furthermore, when dry etching is used in the processing of the sacrificial film 158Rf, the degradation of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as the etching gas. In the case of using dry etching, for example, a gas containing CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or Group 18 elements such as He is preferably used as the etching gas.

[0406] For example, when using an alumina film formed by the ALD method as the sacrificial film 158Rf, a portion of the sacrificial film 158Rf can be removed by dry etching using CHF3 and He, or CHF3, He, and CH4. Similarly, when using an In-Ga-Zn oxide film formed by sputtering as the mask film 159Rf, a portion of the mask film 159Rf can be removed by wet etching using dilute phosphoric acid. Alternatively, a portion of the mask film 159Rf can be removed by dry etching using CH4 and Ar. Furthermore, when using a tungsten film formed by sputtering as the mask film 159Rf, a portion of the mask film 159Rf can be removed by dry etching using SF6, CF4, and O2, or CF4, Cl2, and O2.

[0407] Resist mask 190R and resist mask 191 can be removed using the same method. Resist mask 190R can be removed, for example, by ashing using oxygen plasma. Alternatively, oxygen gas and Group 18 elements such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He can be used. Alternatively, resist mask 190R can be removed by wet etching. In this case, the sacrificial film 158Rf is located on the outermost surface and the organic compound film 103Rf is not exposed, so damage to the organic compound film 103Rf can be suppressed during the removal process of resist mask 190R. Furthermore, the range of removal methods for resist mask 190R can be expanded.

[0408] Next, as Figure 8B As shown, an organic compound layer 103R is formed by processing an organic compound film 103Rf. For example, a mask layer 159R and a sacrificial layer 158R are used as a hard mask and a portion of the organic compound film 103Rf is removed, thereby forming the organic compound layer 103R.

[0409] Therefore, as Figure 8B As shown, the conductive layer 152R has a stacked structure of residual organic compound layer 103R, sacrificial layer 158R, and mask layer 159R. In addition, conductive layers 152G and 152B are exposed.

[0410] Figure 8B An example is shown where the end of the organic compound layer 103R is located inside the end of the conductive layer 152R. By employing this structure, pixel miniaturization can be achieved, enabling the fabrication of high-definition displays. Note that although in Figure 8B Not shown in the figure, but sometimes the above etching process forms a recess in the area of ​​the insulating layer 175 that does not overlap with the organic compound layer 103R.

[0411] As described above, the resist mask 190R is preferably arranged such that it covers the end of the organic compound layer 103R between the dashed lines B1-B2 and the end of the conductive layer 152C (the end on the side of the organic compound layer 103R). Thus, as... Figure 8BAs shown, the sacrificial layer 158R and the mask layer 159R are arranged such that they cover the end of the organic compound layer 103R to the end of the conductive layer 152C (the end on the side of the organic compound layer 103R) between the dashed lines B1-B2. Therefore, exposure of the insulating layer 175, for example, between the dashed lines B1-B2 can be suppressed. Consequently, exposure of the conductive layer 179 due to the removal of a portion of the insulating layers 175, 174, and 173 by etching or the like can be suppressed. Therefore, unintentional electrical connections of the conductive layer 179 to other conductive layers can be suppressed. For example, short circuits between the conductive layer 179 and the common electrode 155 to be formed in subsequent processes can be suppressed.

[0412] The processing of the organic compound film 103Rf is preferably performed using anisotropic etching. Anisotropic dry etching is particularly preferred. Alternatively, wet etching may also be used.

[0413] When using dry etching, the degradation of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as the etching gas.

[0414] Furthermore, oxygen-containing gases can also be used as etching gases. When the etching gas contains oxygen, the etching rate can be increased. Therefore, etching can be performed under low-power conditions while maintaining a sufficient etching rate. This suppresses damage to the organic compound film 103Rf. Additionally, it suppresses defects such as the adhesion of reaction products generated during etching.

[0415] When using dry etching, it is preferable to use a gas containing one or more Group 18 elements such as H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, He, and Ar as the etching gas. Alternatively, it is preferable to use a gas containing one or more of the above-mentioned gases and oxygen as the etching gas. Oxygen gas may also be used as the etching gas. Specifically, for example, a gas containing H2 and Ar or a gas containing CF4 and He can be used as the etching gas. Furthermore, for example, a gas containing CF4, He, and oxygen can be used as the etching gas. Additionally, for example, a gas containing H2 and Ar and an oxygen-containing gas can be used as the etching gas.

[0416] As described above, in one aspect of the present invention, a mask layer 159R is formed by forming a resist mask 190R on a mask film 159Rf and removing a portion of the mask film 159Rf using the resist mask 190R. Then, an organic compound layer 103R is formed by removing a portion of the organic compound film 103Rf using the mask layer 159R as a hard mask. Therefore, it can be said that the organic compound layer 103R is formed by processing the organic compound film 103Rf using lithography. Alternatively, a portion of the organic compound film 103Rf can be removed using the resist mask 190R. Then, the resist mask 190R can also be removed.

[0417] Next, for example, it is preferable to perform a hydrophobication treatment on the conductive layer 152G. During the processing of the organic compound film 103Rf, the surface state of, for example, the conductive layer 152G sometimes becomes hydrophilic. By performing a hydrophobication treatment on the conductive layer 152G, for example, the adhesion between the conductive layer 152G and the layer to be formed in a later process (here, the organic compound layer 103G) can be improved, thereby suppressing film peeling. Note that a hydrophobication treatment may not be performed.

[0418] Next, as Figure 9A As shown, an organic compound film 103Gf, which will later become an organic compound layer 103G, is formed on conductive layer 152G, conductive layer 152B, insulating layer 156R, insulating layer 156G, insulating layer 156B, mask layer 159R, and insulating layer 175.

[0419] The organic compound membrane 103Gf can be formed using the same method as that used to form the organic compound membrane 103Rf. Furthermore, the organic compound membrane 103Gf can have the same structure as the organic compound membrane 103Rf.

[0420] Next, as Figure 9A As shown, a sacrificial film 158Gf, which will later become a sacrificial layer 158G, and a mask film 159Gf, which will later become a mask layer 159G, are sequentially formed on an organic compound film 103Gf and a mask layer 159R. Then, a photoresist mask 190G is formed. The materials and formation methods of the sacrificial film 158Gf and the mask film 159Gf are the same as those used for the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods of the photoresist mask 190G are the same as those used for the photoresist mask 190R.

[0421] The resist mask 190G is positioned to overlap with the conductive layer 152G.

[0422] Next, as Figure 9BAs shown, a portion of the mask film 159Gf is removed using a resist mask 190G, thereby forming a mask layer 159G. The mask layer 159G remains on the conductive layer 152G. Then, the resist mask 190G is removed. Next, using the mask layer 159G as a mask, a portion of the sacrificial film 158Gf is removed, thereby forming a sacrificial layer 158G. Next, the organic compound film 103Gf is processed to form the organic compound layer 103G. For example, the mask layer 159G and the sacrificial layer 158G are used as a hard mask to remove a portion of the organic compound film 103Gf to form the organic compound layer 103G.

[0423] Therefore, as Figure 9B As shown, a stacked structure of an organic compound layer 103G, a sacrificial layer 158G, and a mask layer 159G remains on the conductive layer 152G. Furthermore, the mask layer 159R and the conductive layer 152B are exposed.

[0424] Next, for example, it is preferable to perform a hydrophobic treatment on the conductive layer 152B. During the processing of the organic compound film 103Gf, the surface state of the conductive layer 152B sometimes becomes hydrophilic. By performing a hydrophobic treatment on the conductive layer 152B, for example, the adhesion between the conductive layer 152B and the layer to be formed in a later process (here, the organic compound layer 103B) can be improved, thereby suppressing film peeling. Note that a hydrophobic treatment may not be performed.

[0425] Next, as Figure 9C As shown, an organic compound film 103Bf, which will later become an organic compound layer 103B, is formed on conductive layer 152B, mask layer 159R, insulating layer 156R, insulating layer 156G, insulating layer 156B, mask layer 159G, and insulating layer 175.

[0426] The organic compound membrane 103Bf can be formed using the same method as that used to form the organic compound membrane 103Rf. Furthermore, the organic compound membrane 103Bf can have the same structure as the organic compound membrane 103Rf.

[0427] Next, as Figure 9C As shown, a sacrificial film 158Bf, which will later become a sacrificial layer 158B, and a mask film 159Bf, which will later become a mask layer 159B, are sequentially formed on an organic compound film 103Bf and a mask layer 159R. Then, a photoresist mask 190B is formed. The materials and formation methods of the sacrificial film 158Bf and the mask film 159Bf are the same as those used for the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods of the photoresist mask 190B are the same as those used for the photoresist mask 190R.

[0428] The resist mask 190B is formed at a position overlapping with the conductive layer 152B.

[0429] Next, as Figure 9D As shown, a portion of the mask film 159Bf is removed using a photoresist mask 190B, thereby forming a mask layer 159B. The mask layer 159B remains on the conductive layer 152B. Then, the photoresist mask 190B is removed. Next, the mask layer 159B is used as a mask to remove a portion of the sacrificial film 158Bf, thereby forming a sacrificial layer 158B. Next, the organic compound film 103Bf is processed to form the organic compound layer 103B. For example, the mask layer 159B and the sacrificial layer 158B are used as a hard mask to remove a portion of the organic compound film 103Bf to form the organic compound layer 103B.

[0430] Therefore, as Figure 9D As shown, a stacked structure of an organic compound layer 103B, a sacrificial layer 158B, and a mask layer 159B remains on the conductive layer 152B. Furthermore, mask layers 159R and 159G are exposed.

[0431] Note that the side surfaces of organic compound layers 103R, 103G, and 103B are preferably perpendicular to or substantially perpendicular to the surface to which they are formed. For example, the angle formed between the surface to which they are formed and these side surfaces is preferably 60 degrees or more and 90 degrees or less.

[0432] As described above, the distance between two adjacent organic compound layers in the organic compound layers 103R, 103G, and 103B formed using photolithography can be reduced to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. This distance can be defined, for example, based on the distance between the opposite ends of two adjacent organic compound layers in the organic compound layers 103R, 103G, and 103B. Thus, by reducing the distance between the island-shaped organic compound layers, a display device with high resolution and a large aperture ratio can be provided. Furthermore, the distance between each first electrode of adjacent light-emitting devices can be reduced, for example, to 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, or 2 μm or less. Moreover, the distance between each first electrode of adjacent light-emitting devices is preferably 2 μm or more and 5 μm or less.

[0433] Next, as Figure 10AAs shown, it is preferable to remove mask layers 159R, 159G, and 159B. Depending on subsequent processes, sacrificial layers 158R, 158G, 158B, mask layers 159R, 159G, and 159B may sometimes remain in the display device. By removing mask layers 159R, 159G, and 159B at this stage, it is possible to prevent them from remaining in the display device. For example, when conductive materials are used in mask layers 159R, 159G, and 159B, removing them beforehand can suppress leakage current and capacitance formation caused by the remaining mask layers 159R, 159G, and 159B.

[0434] Note that although this embodiment uses the case where mask layers 159R, 159G, and 159B are removed as an example, it is also possible to proceed with the process without removing mask layers 159R, 159G, and 159B. For example, when mask layers 159R, 159G, and 159B contain the aforementioned material with UV-blocking properties, proceeding to the next process without removing these mask layers can protect the organic compound layer from UV radiation, which is therefore preferable.

[0435] The mask layer removal process can utilize the same methods as the mask film processing process. In particular, by using wet etching, damage to the organic compound layers 103R, 103G, and 103B can be reduced during mask layer removal compared to using dry etching.

[0436] Alternatively, the mask layer can be removed by dissolving it in a solvent such as water or alcohol. Examples of alcohols include ethanol, methanol, isopropanol (IPA), or glycerol.

[0437] After removing the mask layer, a drying process can be performed to remove water contained in organic compound layers 103R, 103G, and 103B, as well as water adsorbed on the surfaces of organic compound layers 103R, 103G, and 103B. For example, heating treatment can be performed under an inert gas atmosphere or a reduced pressure atmosphere. The heating treatment can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, and more preferably 70°C or higher and 120°C or lower. Using a reduced pressure atmosphere allows for drying at lower temperatures, which is therefore preferred.

[0438] Next, as Figure 10BAs shown, an inorganic insulating film 125f, which will later become an inorganic insulating layer 125, is formed by covering organic compound layer 103R, organic compound layer 103G, organic compound layer 103B, sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B.

[0439] As described later, the insulating film, which will later become the insulating layer 127, is formed by contacting the top surface of the inorganic insulating film 125f. Therefore, the top surface of the inorganic insulating film 125f preferably has high affinity with the material used for the insulating film (e.g., a photosensitive resin composition containing acrylic resin). To improve this affinity, a surface treatment can be performed to hydrophobize (or improve) the top surface of the inorganic insulating film 125f. For example, a silanizing agent such as hexamethyldisilazane (HMDS) is preferably used for treatment. By hydrophobizing the top surface of the inorganic insulating film 125f in this way, the insulating film 127f can be formed with high adhesion. In addition, the above-described hydrophobic treatment can also be performed as a surface treatment.

[0440] Next, as Figure 10C As shown, an insulating film 127f, which will later become an insulating layer 127, is formed on an inorganic insulating film 125f.

[0441] The inorganic insulating film 125f and the insulating film 127f are preferably deposited by a formation method that causes less damage to the organic compound layers 103R, 103G, and 103B. In particular, the inorganic insulating film 125f is formed in contact with the sides of the organic compound layers 103R, 103G, and 103B, so the inorganic insulating film 125f is preferably deposited by a formation method that causes less damage to the organic compound layers 103R, 103G, and 103B than when the insulating film 127f is deposited.

[0442] Furthermore, the inorganic insulating film 125f and the insulating film 127f are each formed at a temperature lower than the heat resistance temperature of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. By increasing the substrate temperature during deposition, an inorganic insulating film 125f with low impurity concentration and high barrier properties against at least one of water and oxygen can be formed even with a thin thickness.

[0443] The substrate temperature for forming the inorganic insulating film 125f and the insulating film 127f is preferably 60°C or higher, 80°C or higher, 100°C or higher, or 120°C or higher and 200°C or lower, 180°C or lower, 160°C or lower, 150°C or lower, or 140°C or lower.

[0444] As the inorganic insulating film 125f, it is preferable to form an insulating film with a thickness of 3 nm or more, 5 nm or more, or 10 nm or more and a thickness of 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less within the above-mentioned substrate temperature range.

[0445] The inorganic insulating film 125f is preferably formed using the ALD method, for example. The ALD method reduces deposition damage and allows for the deposition of films with high coverage, making it preferred. For example, an alumina film is preferably formed using the ALD method as the inorganic insulating film 125f.

[0446] In addition, the inorganic insulating film 125f can also be formed using sputtering, CVD, or PECVD methods, which have higher deposition rates than ALD. This allows for the production of highly reliable display devices with high productivity.

[0447] The insulating film 127f is preferably formed using the wet deposition method described above. The insulating film 127f is preferably formed, for example, by spin coating using a photosensitive material, and more specifically, preferably by using a photosensitive resin composition containing acrylic resin.

[0448] For example, it is preferable to use a resin composition containing a polymer, an acid-generating agent, and a solvent to form the insulating film 127f. The polymer is formed using one or more monomers and has a structure in which one or more structural units (also called constituent units) are repeated regularly or irregularly. As the acid-generating agent, one or both of a compound that generates acid by irradiation and a compound that generates acid by heating can be used. The resin composition may also contain one or more of a photosensitizer, sensitizer, catalyst, adhesive aid, surfactant, and antioxidant.

[0449] Furthermore, it is preferable to perform a heat treatment (also known as pre-baking) after forming the insulating film 127f. This heat treatment is performed at a temperature lower than the heat resistance temperature of the organic compound layers 103R, 103G, and 103B. The substrate temperature during the heat treatment is preferably 50°C or higher and 200°C or lower, more preferably 60°C or higher and 150°C or lower, and even more preferably 70°C or higher and 120°C or lower. This removes the solvent from the insulating film 127f.

[0450] Next, exposure is performed to sensitize a portion of the insulating film 127f with visible light or ultraviolet light. Here, when a positive photosensitive resin composition containing acrylic resin is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the area where the insulating layer 127 will not be formed in a later process. The insulating layer 127 is formed in the area sandwiched between any two of the conductive layers 152R, 152G, and 152B, and around the conductive layer 152C. Therefore, visible light or ultraviolet light is irradiated onto the conductive layers 152R, 152G, 152B, and 152C. Note that when a negative photosensitive material is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the area where the insulating layer 127 will be formed.

[0451] The width of the insulating layer 127 to be formed later can be controlled by the area exposed to the insulating film 127f. In this embodiment, the insulating layer 127 is processed in such a way that it overlaps with the top surface of the conductive layer 151.

[0452] The light used for exposure preferably has an i-line (wavelength 365 nm). Alternatively, the light used for exposure may also have at least one of a g-line (wavelength 436 nm) and an h-line (wavelength 405 nm).

[0453] Here, by providing an oxygen-blocking insulating layer (e.g., an alumina film) as one or both of the sacrificial layer 158 (sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B) and the inorganic insulating film 125f, oxygen diffusion to the organic compound layers 103R, 103G, and 103B can be suppressed. When light (visible light or ultraviolet light) irradiates the organic compound layers, the organic compounds contained in the organic compound layers may sometimes become excited and promote reaction with oxygen in the atmosphere. More specifically, when light (visible light or ultraviolet light) irradiates the organic compound layers in an oxygen-containing atmosphere, oxygen may bond to the organic compounds contained in the organic compound layers. By providing the sacrificial layer 158 and the inorganic insulating film 125f on the island-like organic compound layers, the bonding of oxygen in the atmosphere to the organic compounds contained in the organic compound layers can be suppressed.

[0454] Next, as Figure 11A As shown, the exposed areas in the insulating film 127f are removed by development to form the insulating layer 127a. The insulating layer 127a is formed in the area sandwiched by any two of the conductive layers 152R, 152G, and 152B, and in the area surrounding the conductive layer 152C. Here, when acrylic resin is used for the insulating film 127f, an alkaline solution, such as TMAH, can be used as the developing solution.

[0455] Next, residues from the development process (so-called scum) can also be removed. For example, resid...

Claims

1. A light-emitting device, comprising: First electrode; Second electrode; Intermediate layer; First luminescent layer; as well as Second light-emitting layer, The intermediate layer is located between the first electrode and the second electrode. The first light-emitting layer is located between the first electrode and the intermediate layer. The second light-emitting layer is located between the intermediate layer and the second electrode. The first light-emitting layer contains a first light-emitting center material. The second light-emitting layer contains a second light-emitting center material. The first luminescent center material is a phosphorescent material with an emission peak in the wavelength region above 440 nm and below 500 nm. The difference between the maximum peak wavelength in the PL spectrum of the first luminescent center material and the maximum peak wavelength in the PL spectrum of the second luminescent center material is less than 30 nm. Furthermore, the color gamut of the light emitted by the first light-emitting layer and the second light-emitting layer is different from the color gamut of the light emitted by at least one of the light-emitting layers included in a plurality of adjacent light-emitting devices.

2. The light-emitting device according to claim 1, The first luminescent center substance is the same as the second luminescent center substance.

3. The light-emitting device according to claim 1, The first luminescent center is a platinum complex.

4. The light-emitting device according to claim 1, further comprising: The first hole transport layer between the first electrode and the first light-emitting layer; as well as The second hole transport layer between the intermediate layer and the second light-emitting layer The first hole transport layer or the second hole transport layer has a stacked structure comprising at least a first layer containing a first organic compound and a second layer containing a second organic compound. The second layer is in contact with either the first light-emitting layer or the second light-emitting layer. The first organic compound comprises an amine skeleton and polycyclic hydrocarbons. Furthermore, the second organic compound has a π-electron-rich polycyclic heteroaromatic ring.

5. The light-emitting device according to claim 1, further comprising: The first electron transport layer between the second light-emitting layer and the second electrode The first electron transport layer includes a layer comprising a third organic compound having a triazine skeleton. The intermediate layer comprises a first mixed layer of lithium or a lithium compound and a fourth organic compound having a phenanthrene skeleton.

6. The light-emitting device according to claim 5, The first electron transport layer further includes a second mixed layer of lithium or a lithium compound and a fifth organic compound having a triazine skeleton. The second mixed layer is located between the second electrode and the layer containing the third organic compound.

7. The light-emitting device according to claim 1, The first light-emitting layer comprises the first light-emitting center material, the sixth organic compound, and the seventh organic compound. The second light-emitting layer comprises the second light-emitting center material, the eighth organic compound, and the ninth organic compound. The combination of the sixth organic compound and the seventh organic compound forms a first excitosome complex. The combination of the eighth organic compound and the ninth organic compound forms a second excitosome complex. The emitting end of the first exolytic complex on the short wavelength side of the PL spectrum is located at a shorter wavelength compared to the absorption end of the first luminescent center substance on the long wavelength side of the absorption spectrum. Furthermore, the emitting end on the short wavelength side of the PL spectrum of the second excitocomplex is located at a shorter wavelength compared to the absorption end on the long wavelength side of the absorption spectrum of the second luminescent center material.

8. A display device, comprising: First light-emitting device; as well as A second light-emitting device whose emission color is different from that of the first light-emitting device. The first light-emitting device includes a first electrode, a second electrode, a first intermediate layer, a first light-emitting layer, and a second light-emitting layer. The first intermediate layer is located between the first electrode and the second electrode. The first light-emitting layer is located between the first electrode and the first intermediate layer. The second light-emitting layer is located between the first intermediate layer and the second electrode. The first light-emitting layer contains a first light-emitting center material. The second light-emitting layer contains a second light-emitting center material. Both the first luminescent center material and the second luminescent center material are phosphorescent materials that have luminescence peaks in the wavelength region above 440 nm and below 500 nm. The difference between the maximum peak wavelength in the PL spectrum of the first luminescent center material and the maximum peak wavelength in the PL spectrum of the second luminescent center material is less than 30 nm. The second light-emitting device includes a third electrode, a fourth electrode, a second intermediate layer, a third light-emitting layer, and a fourth intermediate layer. The second intermediate layer is located between the third electrode and the fourth electrode. The third light-emitting layer is located between the third electrode and the second intermediate layer. The fourth light-emitting layer is located between the second intermediate layer and the fourth electrode. The third light-emitting layer contains a third light-emitting center material. The fourth light-emitting layer contains a fourth light-emitting center material. The difference between the maximum peak wavelength in the PL spectrum of the third luminescent center material and the maximum peak wavelength in the PL spectrum of the fourth luminescent center material is less than 30 nm. Furthermore, the color gamut of the light emitted by the first and second light-emitting layers is different from the color gamut of the light emitted by the third and fourth light-emitting layers.

9. A display device, comprising: First light-emitting device; A second light-emitting device whose light-emitting color is different from that of the first light-emitting device; as well as A third light-emitting device whose light-emitting color is different from that of the first and second light-emitting devices. The first light-emitting device includes a first electrode, a second electrode, a first intermediate layer, a first light-emitting layer, and a second light-emitting layer. The first intermediate layer is located between the first electrode and the second electrode. The first light-emitting layer is located between the first electrode and the first intermediate layer. The second light-emitting layer is located between the first intermediate layer and the second electrode. The first light-emitting layer contains a first light-emitting center material. The second light-emitting layer contains a second light-emitting center material. Both the first luminescent center material and the second luminescent center material are phosphorescent materials that have luminescence peaks in the wavelength region above 440 nm and below 500 nm. The difference between the maximum peak wavelength in the PL spectrum of the first luminescent center material and the maximum peak wavelength in the PL spectrum of the second luminescent center material is less than 30 nm. The second light-emitting device includes a third electrode, a fourth electrode, a second intermediate layer, a third light-emitting layer, and a fourth light-emitting layer. The second intermediate layer is located between the third electrode and the fourth electrode. The third light-emitting layer is located between the third electrode and the second intermediate layer. The fourth light-emitting layer is located between the second intermediate layer and the fourth electrode. The third light-emitting layer contains a third light-emitting center material. The fourth light-emitting layer contains a fourth light-emitting center material. The third and fourth luminescent center substances are phosphorescent substances. The difference between the maximum peak wavelength in the PL spectrum of the third luminescent center material and the maximum peak wavelength in the PL spectrum of the fourth luminescent center material is less than 30 nm. The third light-emitting device includes a fifth electrode, a sixth electrode, a third intermediate layer, a fifth light-emitting layer, and a sixth light-emitting layer. The third intermediate layer is located between the fifth electrode and the sixth electrode. The fifth light-emitting layer is located between the fifth electrode and the third intermediate layer. The sixth light-emitting layer is located between the third intermediate layer and the sixth electrode. The fifth light-emitting layer contains a fifth light-emitting center material. The sixth light-emitting layer contains a sixth light-emitting center material. The fifth and sixth luminescent center substances are phosphorescent luminescent substances. The difference between the maximum peak wavelength in the PL spectrum of the fifth luminescent center material and the maximum peak wavelength in the PL spectrum of the sixth luminescent center material is less than 30 nm. Furthermore, the color gamut of the light emitted by the first and second light-emitting layers is different from the color gamut of the light emitted by the third, fourth, fifth, and sixth light-emitting layers.

10. The display device according to claim 8, The first luminescent center substance is the same as the second luminescent center substance.

11. The display device according to claim 8, The first luminescent center is a platinum complex.

12. The display device according to claim 8, further comprising: The first hole transport layer between the first electrode and the first light-emitting layer; as well as The second hole transport layer between the first intermediate layer and the second light-emitting layer The first hole transport layer or the second hole transport layer has a stacked structure comprising at least a first layer containing a first organic compound and a second layer containing a second organic compound. The second layer is in contact with either the first light-emitting layer or the second light-emitting layer. The first organic compound comprises an amine skeleton and polycyclic hydrocarbons. Furthermore, the second organic compound has a π-electron-rich polycyclic heteroaromatic ring.

13. The display device according to claim 8, further comprising: The first electron transport layer between the second light-emitting layer and the second electrode The first electron transport layer includes a layer comprising a third organic compound having a triazine skeleton. Furthermore, the first intermediate layer comprises a first mixed layer of lithium or a lithium compound and a fourth organic compound having a phenanthrene skeleton.

14. The display device according to claim 8, The first intermediate layer and the second intermediate layer are continuous layers.

15. The display device according to claim 9, The first luminescent center substance is the same as the second luminescent center substance.

16. The display device according to claim 9, The first luminescent center is a platinum complex.

17. The display device according to claim 9, further comprising: The first hole transport layer between the first electrode and the first light-emitting layer; as well as The second hole transport layer between the first intermediate layer and the second light-emitting layer The first hole transport layer or the second hole transport layer has a stacked structure comprising at least a first layer containing a first organic compound and a second layer containing a second organic compound. The second layer is in contact with either the first light-emitting layer or the second light-emitting layer. The first organic compound comprises an amine skeleton and polycyclic hydrocarbons. Furthermore, the second organic compound has a π-electron-rich polycyclic heteroaromatic ring.

18. The display device according to claim 9, further comprising: The first electron transport layer between the second light-emitting layer and the second electrode The first electron transport layer includes a layer comprising a third organic compound having a triazine skeleton. Furthermore, the first intermediate layer comprises a first mixed layer of lithium or a lithium compound and a fourth organic compound having a phenanthrene skeleton.

19. The display device according to claim 9, The first intermediate layer and the second intermediate layer are continuous layers.

Images