Light-emitting element

Abstract

To provide a light-emitting element including a plurality of light-emitting dopants emitting light with balance and having high luminous efficiency, and a light-emitting device, a display device, an electronic apparatus, and an illumination device with reduced consumption power by the use of the aforementioned light-emitting element.SOLUTION: A light-emitting element includes a light-emitting layer in which a plurality of light-emitting layers containing different phosphorescence emitting materials are stacked. The light-emitting layer containing a light-emitting material exhibiting light emission with long wavelengths includes two kinds of carrier transport compounds with different transport polarities. The triplet excited energy of a host material in the light-emitting layer on the short wavelength side is higher than that of any one or all of the carrier transport compounds.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to light-emitting devices, display devices, light-emitting devices, and electronic devices using organic compounds as light-emitting materials. And relating to lighting devices. [Background technology]

[0002] In recent years, electroluminescence (EL) Research and development of the light-emitting elements used are actively underway. The basic configuration of these light-emitting elements is as follows: This device consists of a layer containing light-emitting material (EL layer) sandwiched between a pair of electrodes. A voltage is applied to this element. By doing so, light emission can be obtained from the light-emitting material.

[0003] Because these light-emitting elements are self-illuminating, the pixels are more visible compared to liquid crystal displays. It has advantages such as not requiring a backlight, making it a preferred flat panel display element. It is considered suitable. Furthermore, displays using such light-emitting elements are thin and light The ability to produce them in large quantities is a major advantage. Furthermore, their extremely fast response speed is another notable feature. That is the case.

[0004] Since these light-emitting elements can have the light-emitting layer formed as a film, it is possible to obtain light emission in a planar manner. This is possible. Therefore, large-area elements can be easily formed. This is because of the incandescent This is a characteristic that is difficult to obtain with point light sources such as spheres and LEDs, or line light sources such as fluorescent lamps. Therefore, it has high value as a surface light source that can be applied to lighting and other applications.

[0005] In the case of an organic EL element that uses an organic compound as the light-emitting material and has the EL layer between a pair of electrodes, By applying a voltage between a pair of electrodes, electrons are released from the cathode and holes from the anode. They are respectively injected into the light-emitting EL layer, and current flows. Then, the injected electrons and holes recombine to excite the light-emitting organic compound to an excited state, and light emission can be obtained from the excited light-emitting organic compound.

[0006] The types of excited states formed by the organic compound include a singlet excited state and a triplet excited state. Among them, the light emission from the singlet excited state (S * ) is fluorescence, and the light emission from the triplet excited state (T * ) is called phosphorescence. Also, the statistical generation ratio in the light-emitting device is S :T * : * = 1:3.

[0007] In a compound that emits light from the singlet excited state (hereinafter referred to as a fluorescent compound), at room temperature, usually, the light emission from the triplet excited state (phosphorescence) is not observed, and only the light emission from the singlet excited state (fluorescence) is observed. Therefore, the theoretical limit of the internal quantum efficiency (the ratio of photons generated with respect to the injected carriers) in a light-emitting device using a fluorescent compound is based on S :T = 1:3 and is set to 25%. * :T * = 1:3.

[0008] On the other hand, if a compound that emits light from the triplet excited state (hereinafter referred to as a phosphorescent compound) is used, the light emission from the triplet excited state (phosphorescence) is observed. Also, since the phosphorescent compound is prone to intersystem crossing ( the transition from the singlet excited state to the triplet excited state), the internal quantum efficiency can theoretically reach 1 00%. That is, a higher light emission efficiency than that of the fluorescent compound can be realized. For these reasons, in order to realize a highly efficient light-emitting device, a phosphorescent compound is used. The development of light-emitting elements has been actively pursued in recent years.

[0009] Patent Document 1 describes a light-emitting region having multiple light-emitting dopants, and the light-emitting dopants A white light-emitting element that emits light is disclosed. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Special Publication No. 2004-522276 [Overview of the project] [Problems that the invention aims to solve]

[0011] Although it is theoretically possible to achieve an internal quantum efficiency of 100% with phosphorescent compounds, Achieving high efficiency is difficult without optimizing the structure and combination with other materials. In particular, using multiple types of phosphorescent compounds with different bands (emission colors) as luminescent dopants In optical devices, energy transfer must be considered, as well as the transfer of energy It is difficult to obtain highly efficient light emission without optimizing the efficiency of the device itself. In fact, the above patent document In Reference 1, even if all the light-emitting dopants are phosphorescent elements, their external quantum efficiency is 3-4%. This is the extent of it. Even considering the light extraction efficiency, the internal quantum efficiency is less than 20%. It is thought to be present, but it must be said that it is a low value for a phosphorescent light-emitting element.

[0012] Furthermore, in addition to increasing luminescence efficiency, multi-color light-emitting devices using dopants of different emission colors are also available. In this case, it is necessary for each color of Dopant to emit light in a balanced manner. Achieving efficiency while maintaining the balance of light emission from each Dopant is no easy task.

[0013] Therefore, in one aspect of the present invention, in a light-emitting element using multiple light-emitting dopants, the multiple The aim is to provide a light-emitting element with high luminescence efficiency while ensuring that a sufficient number of dopants emit light in a balanced manner. The aim is to reduce power consumption. Furthermore, one aspect of the present invention involves using the above-mentioned light-emitting element to achieve low power consumption. The purpose is to provide reduced-size light-emitting devices, display devices, electronic devices, and lighting devices, respectively. .

[0014] The present invention only needs to solve one of the above-mentioned problems. [Means for solving the problem]

[0015] In the present invention, a light-emitting element is provided in which each of the multiple light-emitting layers is made of a different phosphorescent material. Among the multiple light-emitting layers, the light-emitting layers containing light-emitting materials that exhibit long-wavelength emission are each imported. It contains two types of carrier transport compounds with different transport polarities, and among multiple light-emitting layers, short-wavelength light emission The light-emitting layer containing a light-emitting material exhibiting the same properties includes a host material, and the triplet excitation of the host material The energy of any or all of the above carrier transport compounds is greater than the triplet excitation energy of The present invention provides a light-emitting element characterized by high energy transfer efficiency between hosts. By applying combinations of host materials and carrier transport compounds that result in a higher rate, A light-emitting element according to one aspect of the present invention can be obtained.

[0016] In other words, one aspect of the present invention involves placing a first phosphorescent compound and a first phosphorescent compound between the anode and the cathode. A first light-emitting layer comprising a material, a second phosphorescent compound, a first electron-transporting compound, and a first The device comprises a second light-emitting layer containing a hole-transporting compound, and the emission wavelength of the second phosphorescent compound This wavelength is longer than the emission wavelength of the first phosphorescent compound, and triplet excitation of the first host material. The electromotive force is obtained from three of the first electron-transporting compound and the first hole-transporting compound. The excitation energy is greater than or equal to the doublet excitation energy, and the first and second light-emitting layers are arranged in contact with each other. It is an optical element.

[0017] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, in which a first electron transport function is achieved. This light-emitting element is characterized by the formation of an excitation complex between the compound and the first hole-transporting compound. .

[0018] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the first host material is It is an electron-transporting compound, and the first light-emitting layer is provided on the cathode side of the second light-emitting layer. Its distinguishing feature is its light-emitting element.

[0019] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the first host material is It is a hole-transporting compound, and the first light-emitting layer is provided on the anode side of the second light-emitting layer. Its distinguishing feature is its light-emitting element.

[0020] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the first light-emitting layer is the The mixture further comprises two host materials, the second host material being a hole transporting compound, and the second host material is a hole transporting compound. The triplet excitation energy of the material is obtained from the first electron-transporting compound and the first hole-transporting compound. This light-emitting element is characterized by having a triplet excitation energy greater than or equal to that of any of the materials.

[0021] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the first light-emitting layer is the The mixture further comprises two host materials, the second host material being an electron transport compound, and the second host material is an electron transport compound. The triplet excitation energy of the material is obtained from the first electron-transporting compound and the first hole-transporting compound. This light-emitting element is characterized by having a triplet excitation energy greater than or equal to that of any of the materials.

[0022] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the first host material and This is a light-emitting element characterized by the second host material forming an excitation complex.

[0023] Furthermore, another configuration of the present invention involves a first phosphorescent compound and a first host between the anode and cathode. A first light-emitting layer containing a material, a second phosphorescent compound, a first electron-transporting compound, and a first A second light-emitting layer containing a hole-transporting compound, a third phosphorescent compound and a second electron-transporting compound A third light-emitting layer comprising a compound and a second hole-transporting compound, and a second phosphorescent compound The emission wavelength of the third phosphorescent compound is longer than the emission wavelength of the first phosphorescent compound. The emission wavelength of the compound is longer than that of the second phosphorescent compound, and the first host The triplet excitation energy of the material is for the first electron-transport compound and the first hole-transport compound. The triplet excitation energy is greater than or equal to that of any of the following: the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer This is a light-emitting element in which the light layers are arranged in this order of contact.

[0024] Furthermore, another configuration of the present invention involves placing a first phosphorescent compound and a first phosphorescent compound between the anode and cathode. A first light-emitting layer comprising a material, a second phosphorescent compound, a first electron-transporting compound, and a first A second light-emitting layer containing a hole-transporting compound, and a third phosphorescent compound and a second electron-transporting compound A third light-emitting layer comprising a compound and a second hole-transporting compound, and a second phosphorescent compound The emission wavelength of the substance is longer than the emission wavelength of the first phosphorescent compound, and the third phosphorescent The emission wavelength of the compound is longer than the emission wavelength of the second phosphorescent compound, and the first phosphorus The triplet excitation energy of the material is obtained from the first electron-transporting compound and the first hole-transporting compound. The triplet excitation energy of any of the substances is greater than or equal to the first electron transport compound and the first The triplet excitation energy of the hole-transporting compound is obtained from the second electron-transporting compound and the second hole The triplet excitation energy of any of the transport compounds is greater than or equal to that of the first luminescent layer and the second luminescent layer. This is a light-emitting element in which the first layer and the third light-emitting layer are arranged in contact with each other in that order.

[0025] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, in which a first electron transport function is achieved. The compound and the first hole-transporting compound form an excited complex, and the second electron-transporting compound and the second This light-emitting device is characterized by the formation of an excitation complex by a hole-transporting compound.

[0026] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the first host material is It is an electron-transporting compound, and the first light-emitting layer is provided on the cathode side of the second light-emitting layer. Its distinguishing feature is its light-emitting element.

[0027] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the first host material is It is a hole-transporting compound, and the first light-emitting layer is provided on the anode side of the second light-emitting layer. Its distinguishing feature is its light-emitting element.

[0028] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the first light-emitting layer is the The mixture further comprises two host materials, the second host material being a hole transporting compound, and the second host material is a hole transporting compound. The triplet excitation energy of the material is obtained from the first electron-transporting compound and the first hole-transporting compound. This light-emitting element is characterized by having a triplet excitation energy greater than or equal to that of any of the materials.

[0029] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the first light-emitting layer is the The mixture further comprises two host materials, the second host material being an electron transport compound, and the second host material is an electron transport compound. The triplet excitation energy of the material is obtained from the first electron-transporting compound and the first hole-transporting compound. This light-emitting element is characterized by having a triplet excitation energy greater than or equal to that of any of the materials.

[0030] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the first host material and This is a light-emitting element characterized by the second host material forming an excitation complex.

[0031] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, in which a first electron transport function is achieved. This light-emitting device is characterized in that the compound and the second electron-transporting compound are identical.

[0032] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, in which a first hole transport function is activated. This light-emitting device is characterized in that the compound and the second hole-transporting compound are identical.

[0033] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, in which a first electron transport function is achieved. The compound and the second electron-transporting compound are identical, and the first hole-transporting compound and the second hole-transporting compound are identical. This light-emitting device is characterized by having the same pore transport compound.

[0034] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the film thickness of the second light-emitting layer This is a light-emitting element whose wavelength is between 2 nm and 20 nm.

[0035] Furthermore, another configuration of the present invention is a light-emitting element having the above configuration, wherein the film thickness of the second light-emitting layer This is a light-emitting element whose wavelength is between 5 nm and 10 nm.

[0036] Another aspect of the present invention is a light-emitting device, a light-emitting display device, and a light-emitting display device, each equipped with the above-described light-emitting element. These are electronic devices and lighting equipment.

[0037] In this specification, the term "light-emitting device" includes image display devices that use light-emitting elements. Also, a connector for the light-emitting device, for example, an anisotropic conductive film, TCP (Tape Carrier) A module with an er Package attached, and a printed circuit board is installed at the end of the TCP. The module or light-emitting device is equipped with a COG (Chip On Glass) system. Modules with directly mounted ICs (integrated circuits) are also included in the definition of light-emitting devices. This also includes light-emitting devices used in lighting fixtures and the like. [Effects of the Invention]

[0038] In one aspect of the present invention, a light-emitting element with high luminescence efficiency can be provided. In one aspect of the present invention, the By using optical elements, power consumption is reduced in light-emitting devices, light-emitting display devices, and electronic devices. We can provide either a lighting device or a lighting device. [Brief explanation of the drawing]

[0039] [Figure 1] Conceptual diagram of a light-emitting element. [Figure 2] Conceptual diagram of a light-emitting element. [Figure 3] Conceptual diagram of an active matrix light-emitting device. [Figure 4] Conceptual diagram of a passive matrix type light-emitting device. [Figure 5]Conceptual diagram of an active matrix light-emitting device. [Figure 6] Conceptual diagram of an active matrix light-emitting device. [Figure 7] Conceptual diagram of a lighting device. [Figure 8] A diagram representing electronic devices. [Figure 9] A diagram representing electronic devices. [Figure 10] A diagram representing a lighting device. [Figure 11] A diagram representing a lighting device. [Figure 12] A diagram showing an in-vehicle display device and lighting system. [Figure 13] A diagram representing electronic devices. [Figure 14] Emission spectrum of light-emitting element 1. [Figure 15] Brightness-current efficiency characteristics of light-emitting element 1. [Figure 16] Brightness-external quantum efficiency characteristics of light-emitting element 1. [Figure 17] Voltage-luminance characteristics of light-emitting element 1. [Figure 18] Brightness-power efficiency characteristics of light-emitting element 1. [Figure 19] Emission spectra of light-emitting element 2 and light-emitting element 3. [Figure 20] Brightness-current efficiency characteristics of light-emitting element 2 and light-emitting element 3. [Figure 21] Brightness-external quantum efficiency characteristics of light-emitting element 2 and light-emitting element 3. [Figure 22] Voltage-luminance characteristics of light-emitting element 2 and light-emitting element 3. [Figure 23] Brightness-power efficiency characteristics of light-emitting element 2 and light-emitting element 3. [Figure 24] Emission spectrum of light-emitting element 4. [Figure 25] Brightness-current efficiency characteristics of the light-emitting element 4. [Figure 26] Brightness-external quantum efficiency characteristics of light-emitting element 4. [Figure 27] Voltage-luminance characteristics of light-emitting element 4. [Figure 28] Brightness-power efficiency characteristics of the light-emitting element 4. [Figure 29] Normalized brightness time variation of light-emitting element 4. [Figure 30] Phosphorescent spectrum of 35DCzPPy. [Figure 31] Phosphorescent spectrum of PCCP. [Figure 32] Phosphorescent spectrum of 2mDBTPDBq-II. [Figure 33] Phosphorescent spectrum of PCBA1BP. [Figure 34] Phosphorescent spectrum of 2mDBTBPDBq-II. [Figure 35] Phosphorescent spectrum of PCBNBB. [Modes for carrying out the invention]

[0040] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is as follows Not limited to the description, the form and details thereof may be described without departing from the spirit and scope of the present invention. Those skilled in the art will readily understand that the invention can be modified in various ways. Therefore, the present invention is as follows: This should not be interpreted as being limited to the contents described in the embodiments.

[0041] (Embodiment 1) First, the operating principle of a light-emitting element according to one aspect of the present invention will be described. The main point of the present invention is the first A phosphorescent compound and a second phosphorescent compound that exhibits longer wavelength emission than the first phosphorescent compound. Using compounds, both the first phosphorescent compound and the second phosphorescent compound are efficiently made to emit light. This method aims to obtain highly efficient multi-color light-emitting elements.

[0042] A common method for obtaining a multicolor light-emitting element using phosphorescent compounds involves some kind of host material One possible method involves dispersing multiple phosphorescent compounds with different emission colors in appropriate ratios within a material. However, in this method, the phosphorescent compound that exhibits the longest wavelength emission will emit light. Because it becomes cheaper, the element structure for obtaining multicolor emission (especially each phosphorescent in the host material) Designing and controlling the concentration of chemical compounds is extremely difficult.

[0043] Another method for obtaining multicolor light-emitting elements is to stack light-emitting elements of different colors in series, so to speak. One example is a tandem structure consisting of a blue light-emitting element, a green light-emitting element, and a red light-emitting element. By stacking these three elements in series and emitting light simultaneously, multi-colored light (in this case, white light) can be easily obtained. The element structure can be optimized for each of the blue, green, and red elements, so the design... Control is relatively easy. However, because three elements are stacked, the number of layers increases, and production Manufacturing becomes complicated. Also, problems arise with electrical contact at the connection points of each element (the so-called intermediate layer). This can lead to an increase in the driving voltage, i.e., power loss.

[0044] On the other hand, in one aspect of the present invention, a light-emitting element is provided with a first phosphorescent compound and a first HO between a pair of electrodes. A first light-emitting layer containing a stront material, and a second phosphorescent compound that exhibits light emission at a longer wavelength than the first phosphorescent compound. A second catalyst comprising two phosphorescent compounds, a first electron transport compound, and a first hole transport compound. This is a light-emitting element in which an optical layer and a light-emitting element are stacked. At this time, the triplet excitation energy of the first host material This is the triplet excitation energy of either the first electron-transporting compound or the first hole-transporting compound. - Higher, the first and second light-emitting layers are in contact with each other, unlike a tandem structure. It is provided.

[0045] Figure 1 schematically shows the element structure of a light-emitting element according to one embodiment of the present invention described above. Figure 1 shows the first Electrode 101, second electrode 102, and EL layer 103 are shown. The EL layer 103 has a small amount A light-emitting layer 113 is provided, and other layers can be provided as appropriate, as shown in Figure 1. In this configuration, the hole injection layer 111, the hole transport layer 112, the electron transport layer 114, and the electron injection layer 11 A configuration in which 5 is provided is shown as a hypothetical example. Note that the first electrode 101 functions as an anode. The second electrode 102 is assumed to function as a cathode.

[0046] Furthermore, Figures 1(a) and 1(b) show enlarged views of the light-emitting layer 113 in the light-emitting element. Figures 1(a) and 1(b) show the first light-emitting layer 113a, the second light-emitting layer 113b, and the 2 A combined light-emitting layer 113, a first phosphorescent compound 113Da, and a second phosphorescent compound 1 13Db, first host material 113Ha1, first carrier transport compound 113H1, Two carrier transport compounds, 113H2, are shown. Figure 1(b) shows the first emission. This is a schematic diagram showing the case where layer 113a further contains a second host material 113Ha2. Note that the first host material 113Ha1 and the first carrier transport compound 113H1 are the same. The materials may also be different, such as a second host material 113Ha2 and a second carrier transport compound. 113H2 may be the same or a different material. Also, the first light-emitting layer 113a and the second light-emitting layer The light layer 113b may be on either the anode side or the cathode side. Also, the first H Either the host material 113Ha1 or the second host material 113Ha2 is an electron transport compound. One is a substance, and the other is a hole transporter compound. Similarly, the first carrier transporter compound 113 H1 and the second carrier transport compound 113H2 are both electron transport compounds, one of which is an electron transport compound, and the other is It is a hole-transporting compound.

[0047] The setting of the recombination region within the light-emitting layer is determined by the first host material 113Ha1 contained in each light-emitting layer. Second host material 113Ha2, first carrier transport compound 113H1 and second carrier The mixture ratio of the rear transportable compound 113H2 can be adjusted. First host material Material 113Ha1 and second host material 113Ha2, first carrier transport compound 113H As described above, one of the two carrier transport compounds 1 and 2, 113H2, is an electron transport compound. One compound is a sexual compound, and the other is a hole-transporting compound. Therefore, by changing the mixing ratio of these compounds... This allows for adjustment of the carrier transport properties of each light-emitting layer, resulting in control of the recombination region. This can be done easily.

[0048] Furthermore, if excitons are directly generated in the second light-emitting layer 113b, the first phosphorescent compound 11 Because it is difficult to obtain 3Da emission, the carrier recombination region is inside the first light-emitting layer 113a, Preferably, this is near the interface between the first light-emitting layer 113a and the second light-emitting layer 113b.

[0049] In this way, the carrier recombination region is formed by the first light-emitting layer 113a and the second light-emitting layer 113b In order to be near the interface, if the first light-emitting layer 113a is on the anode side, the first light-emitting layer If 113a is on the cathode side, the first light-emitting layer 113a is made to be electron-transporting. This is sufficient. Then, by making the second light-emitting layer 113b have opposite transport properties, The bonding region can be located near the interface between the first light-emitting layer 113a and the second light-emitting layer 113b. Furthermore, in order to make the carrier recombination region within the first light-emitting layer 113a, the above configuration is required. Based on this, the bipolarity of the first light-emitting layer 113a should be increased.

[0050] In the configuration shown in Figure 1(a), if the first light-emitting layer 113a is on the anode side, then the first The host material 113Ha1 is used for hole transport, and when it is on the cathode side, the first host material 11 3Ha1 is made electron transportable, and the second light-emitting layer 113b is the first carrier transportable compound 113 By changing the mixing ratio of H1 and the second carrier transport compound 113H2, The carrier transport properties should be adjusted to be opposite to those of the light-emitting layer 113a.

[0051] In the case of a second light-emitting layer 113b and a first light-emitting layer 113a as shown in Figure 1(b) This involves changing the mixing ratio of electron-transporting compounds and hole-transporting compounds contained within the light-emitting layer. The transportability of each can be adjusted accordingly.

[0052] However, if the recombination region is inside the first light-emitting layer 113a, or between the first light-emitting layer and the second light-emitting layer If it is an interface, then the second phosphorescent compound 113D is compared with the first phosphorescent compound. In some cases, the emission intensity ratio due to b becomes small. Therefore, in one aspect of the present invention, Figure 1 In configuration (a), the triplet excitation energy of the first host material 113Ha1 is the first Either the carrier transport compound 113H1 or the second carrier transport compound 113H2. Select a combination of materials such that it is greater than one or both of them. The triplet excitation energy due to carrier recombination is partially transferred to the first host material 113H a1 to the first carrier transport compound 113H1 and the second carrier transport compound 113H It moves to either or both of the triplet excitation levels of the second phosphorescent compound 113Db. It can be made to emit light.

[0053] Furthermore, as shown in Figure 1(b), a second host material 113H is added to the first light-emitting layer 113a. If a2 is present, the triplet excitation energy of the second host material 113Ha2 is also the same as that of the first host material. Either carrier transport compound 113H1 or second carrier transport compound 113H2. Alternatively, choose one that is greater than both. This will result in carrier recombination The triplet excitation energy is partially transferred from the second host material 113Ha2 to the first carrier. Either one or both of the transportable compound 113H1 and the second carrier transportable compound 113H2. It can move to the triplet excitation level and cause the second phosphorescent compound 113Db to emit light. ru.

[0054] Thus, triples account for 75% of the excitation energy generated by carrier recombination. By adopting a configuration that takes into account the transfer of excitation energy, the second phosphorescent compound 11 3Db emission can be obtained at the desired intensity.

[0055] On the other hand, singlet excitation of the first host material 113Ha1 or the second host material 113Ha2 Energy is transferred between the first carrier transport compound 113H1 and the second carrier transport compound 1 If it is higher than that of 13H2, movement will occur due to the Dexter mechanism. Also, in this case... If the first host material 113Ha1 or the second host material 113Ha2 is fluorescent, Energy transfer also occurs through the Förster mechanism.

[0056] Here, in order to obtain a light-emitting element with higher luminescence efficiency, energy transfer to a phosphorescent compound is performed. Let's consider this. In this explanation, the substance that provides energy to phosphorescent compounds is referred to as We'll call it the host material.

[0057] Since carrier recombination occurs in both the host material and the phosphorescent compound, in order to improve the luminescence efficiency it is necessary to enhance the energy transfer from the host material to the phosphorescent compound . Two mechanisms, the Dexter mechanism and the Förster mechanism, have been proposed for the energy transfer from the host material to the phosphorescent compound .

[0058] The energy transfer efficiency Φ from the host molecule to the guest molecule ET is represented by the following formula. k r represents the rate constant of the luminescence process (fluorescence when discussing energy transfer from the singlet excited state, phosphorescence when discussing energy transfer from the triplet excited state), k represents the rate constant of the non-luminescence process n (thermal deactivation or intersystem crossing), and τ represents the measured lifetime of the excited state .

[0059]

Equation

[0060] First, from the above formula, it can be seen that in order to increase the energy transfer efficiency Φ ET , the rate constant k of the energy transfer h ) should be much larger than the other competing rate constants k →g r +k n (=1 / τ). And in order to increase the rate constant k h * →g * -6 of the energy transfer, in both the Förster mechanism and the Dexter mechanism, the emission spectrum of the host molecule (fluorescence spectrum when discussing energy transfer from the singlet excited state ​​​When discussing energy transfer from triplet excited states, use phosphorescent spectra and guest The one with the greater overlap with the absorption spectrum of the molecule (or phosphorescent compound in the second light-emitting layer). That's good.

[0061] Here, we consider the overlap between the emission spectrum of the host molecule and the absorption spectrum of the phosphorescent compound. In order to do this, the absorption spectrum of phosphorescent compounds shows the absorption at the longest wavelength (lowest energy) side. Storage space is important.

[0062] In the absorption spectra of phosphorescent compounds, it is thought to be the component that contributes most strongly to emission. The absorption band is located near the absorption wavelength corresponding to the direct transition from the ground state to the triplet excited state, This is the absorption band that appears at the longest wavelength. From this, the emission spectrum of the host material ( The fluorescence spectrum and phosphorescence spectrum are the longest wavelengths of the absorption spectrum of phosphorescent compounds. It is considered preferable that the absorption band on the longer side overlaps with the longer side.

[0063] For example, in organometallic complexes, particularly luminescent iridium complexes, the absorption band on the longest wavelength side and And, a broad absorption band often appears around 500-600 nm. This absorption band is, Primarily, triplet MLCT (Metal to Light Charge Transistor) It originates from the sfer transition. However, the absorption band contains the triplet π-π * Transition or singlet MLCT Some absorption originates from transitions, and these overlap, resulting in the longest wavelength side of the absorption spectrum. It is thought to form a broad absorption band. Therefore, the guest material is an organometallic complex. When using the material (especially iridium complexes), the broad, which is present at the longest wavelength, is such that A state in which the absorption band and the emission spectrum of the host material largely overlap is preferable.

[0064] Let's first consider the energy transfer from the triplet excited state of the host material. From the discussion, it can be seen that in energy transfer from triplet excited states, the phosphorescence spectrum of the host material The goal is to maximize the overlap between the absorption band of Tol and the longest wavelength absorption band of the phosphorescent compound.

[0065] However, the problem here is the energy from the singlet excited state of the host molecule. It is a transfer of energy. In addition to energy transfer from the triplet excited state, energy transfer from the singlet excited state is also involved. If we also want to perform ghee transfer efficiently, then, as discussed above, we need the phosphorescent spectrum of the host material. Furthermore, the fluorescence spectrum is designed to overlap with the longest wavelength absorption band of the guest material. In other words, the fluorescence spectrum of the host material must be the same as the phosphorescence spectrum. If the host material is not designed to be in a similar position, the singlet excited state of the host material and This means that energy transfer from both the excited and triplet excited states cannot be performed efficiently. It will become.

[0066] However, generally speaking, singlet excitation levels and triplet excitation levels are very different (singlet excitation level >Trilet excitation level) Therefore, the emission wavelength of fluorescence and the emission wavelength of phosphorescence are also very different (fluorescence emission Light wavelength (emission wavelength of phosphorescence). For example, it is often used in light-emitting devices using phosphorescent compounds. The 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP) that can be found at 500 nm It has a phosphorescent spectrum in the vicinity, but the fluorescence spectrum is around 400 nm, 1 There is a gap of 00 nm. Even considering this example, the fluorescence spectrum of the host material is Designing a host material so that it aligns with the position of the light spectrum is extremely difficult. That is the case.

[0067] Furthermore, in some materials, the singlet excitation level is at a higher energy level than the triplet excitation level. Therefore, the fluorescence spectrum will be close to the absorption spectrum at the longest wavelength end of the guest material. The triplet excitation level of the host material at a certain wavelength is lower than the triplet excitation level of the guest material. Put it away.

[0068] Here, we will discuss excited complexes, which are excited states composed of two types of materials. The optical spectrum consists of the shallower HOMO level and the deeper LUMO level of the two materials. Because it exhibits emission originating from the energy difference, it has a longer wavelength than the fluorescence spectrum of the original substance alone. The emission has a spectrum on the side. Therefore, the triple of the two compounds that form the excitation complex Singlet excitation while keeping the term excitation energy higher than the triplet excitation energy of the guest material. This allows for maximum energy transfer from one state to the next.

[0069] Furthermore, the excited complex is in a state where the triplet excited level and the singlet excited level are in close proximity. Therefore, the fluorescence spectrum and phosphorescence spectrum are located at almost the same position. From this, Absorption corresponding to the transition from the singlet ground state to the triplet excited state of a to molecule (absorption of the guest molecule) The fluorescence spectrum of the excited complex is located in the broad absorption band at the longest wavelength end of the spectrum. Because both the toll and phosphorescence spectra can be significantly superimposed, energy transfer efficiency High-performance light-emitting elements can be obtained.

[0070] Thus, in the second light-emitting layer, the first carrier transport compound 113H1 and the second The carrier transport compound 113H2 is preferably a combination that forms an excited complex. Furthermore, the lowest energy absorption band of the second phosphorescent compound 113Db and the By overlapping the emission spectra of the excited complex, it is possible to obtain a light-emitting element with better luminescence efficiency. Yes, it is possible. Also, the peak of the lowest energy absorption band of the second phosphorescent compound 113Db. The difference between the wavelength and the energy equivalent of the peak wavelength of the emission spectrum of the excited complex is 0.2e A value below V results in greater overlap between spectra, which is a desirable configuration.

[0071] Furthermore, in the case of a configuration as shown in Figure 1(b), the first host material 113Ha1 and the The host material 113Ha2 is preferably a combination that forms an excited complex. Furthermore, the lowest energy absorption band of the first phosphorescent compound and the emission band of the excited complex are... By overlapping the vectors, a light-emitting element with better luminescence efficiency can be obtained. The peak wavelength of the lowest energy absorption band of phosphorescent compound 113Da and the excitation If the difference in the energy equivalent of the peak wavelengths of the emission spectra of the complex is 0.2 eV or less, The overlap between the vectors is large, resulting in a desirable configuration.

[0072] As mentioned above, the luminescence of the excited complex is due to the shallower of the two materials that make up the excited complex. This originates from the energy difference between the HOMO level and the deeper LUMO level. Therefore, excitation When complexes are used as hosts, the emission spectrum can be altered by changing the combination of materials. Because the wavelength can be changed, it is possible to emit light that matches the absorption on the long-wavelength side of phosphorescent compounds. It can be obtained through I Ching.

[0073] Furthermore, the first host material 113Ha1 and the second host material 113Ha2 are the first phosphorus To prevent the photocatalytic compound 113Da from being quenched, a higher concentration than the first phosphorescent compound 113Da is used. It is preferable that it has a triplet excitation energy. Also, the first carrier transport compound Substance 113H1 and the second carrier transport compound 113H2 are used to form the second phosphorescent compound 113 To prevent the quenching of Db, a triplet excitation energy higher than that of the second phosphorescent compound 113Db is used. It is preferable that it contains energy.

[0074] A light-emitting element having the above configuration has high luminous efficiency and a well-balanced distribution of phosphors. This allows for the creation of a light-emitting element that can obtain light emission from a photochemical compound.

[0075] First host material 113Ha1, second host material 113Ha2, first carrier transport It can be used as the active compound 113H1 and the second carrier transport compound 113H2. Examples of electron-transporting and hole-transporting compounds include the following compounds. Note that either the first host material 113Ha1 or the second host material 113Ha2 is One is an electron-transporting compound, the other is a hole-transporting compound, and the first is a carrier-transporting compound. 113H1 and the second carrier transport compound 113H2 are both electron transport compounds. One is a substance, and the other is a hole-transporting compound. Also, when selecting these combinations, excitation It is preferable to select a combination that forms a complex.

[0076] Examples of electron-transporting compounds include bis(10-hydroxybenzo[h]quinolinato)berylli Mu(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolate)(4-pheny Luphenolate (aluminum(III)) (abbreviation: BAlq), bis(8-quinolinolate) Zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolate] Lead(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolate] Metal complexes such as lead(II) (abbreviation: ZnBTZ), and 2-(4-biphenylyl)-5-( 4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3 -(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1, 2,4-Triazole (abbreviation: TAZ), 1,3-Bis[5-(p-tert-butylf [benzene]-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9 H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetri Il)tris(1-phenyl-1H-benzoimidazole) (abbreviation: TPBI), 2-[ 3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzoimida Heterocyclic compounds having a polyazole skeleton, such as zole (abbreviation: mDBTBIm-II) and , 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxa Phosphorus (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4-I) [biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPD) Bq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl] Dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-( Phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4 ,6-Bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDB) Heterocyclic compounds having a diazine skeleton such as TP2Pm-II, and 3,5-bis[3-( 9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1, 3,5-tri[(3-pyridyl)phen-3-yl]benzene (abbreviation: TmPyPB) Examples include heterocyclic compounds having a pyridine skeleton, and π-electron-deficient heteroaromatic compounds. Preferred. Among those mentioned above, heterocyclic compounds having a diazine skeleton and those having a pyridine skeleton. Heterocyclic compounds are preferred due to their good reliability. In particular, diazines (pyrimidines and pyrazines) are preferred. Heterocyclic compounds with a ) skeleton exhibit high electron transport properties and contribute to reducing the driving voltage.

[0077] The hole transport compound is 4,4'-bis[N-(1-naphthyl)-N-phenylamino]bi Phenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl Nyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bi Su[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]bife Nyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl) Triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylflu Oren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4' -(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCB) A1BP), 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: PC) BANB), 4, 4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol) 9,9-dimethyl-N- Phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-phenyl Luolen-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl -9H-carbazole-3-yl)phenyl]-spiro-9,9'-bifluoren-2- Compounds having an aromatic amine skeleton, such as amines (abbreviated as PCBASF), and 1,3-bis (N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)benzene Phenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenyl Lucarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H-carbazole) Compounds having a carbazole skeleton, such as (PCCP) (abbreviation: PCCP), and 4,4',4''- (Benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P- II) 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl) )phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl]dibenzothiophene Phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene ( Compounds containing a thiophene skeleton, such as (abbreviated as DBTFLP-IV), and 4,4',4'' -(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-I) I) 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl Compounds containing a furan skeleton, such as yl dibenzofuran (abbreviation: mmDBFFLBi-II) Examples include compounds, and π-electron-rich heteroaromatic compounds are preferred. Among those mentioned above, aromatic a Compounds with a mine skeleton or a carbazole skeleton are highly reliable, Furthermore, it is preferable because it has high hole transportability and contributes to reducing the drive voltage.

[0078] A light-emitting element having the above configuration has good luminescence efficiency and is composed of multiple light-emitting materials This is a light-emitting element capable of obtaining such light. Furthermore, this light-emitting element is different from the tandem type. Therefore, the manufacturing process is not complicated, and power loss due to the intermediate layer is also small. It also has high potential as an optical element.

[0079] Furthermore, as shown in Figures 1(c) and (d), the light-emitting layer 113 is the first light-emitting layer 113a, and the second light-emitting layer It may also be formed with three layers: a light layer 113b and a third light-emitting layer 113c. In this case, the first light-emitting layer 11 The relationship between 3a and the second light-emitting layer 113b is as described above.

[0080] The third light-emitting layer 113c contains a third phosphorescent compound 113Dc and a third carrier transporter Compound 113H3 and a fourth carrier transport compound 113H4 are included. The emission wavelength of the phosphorescent compound 113Dc is longer than that of the second phosphorescent compound 113Db. Furthermore, the third carrier transport compound 113H3 and the fourth carrier transport compound 113H In compound 4, one of the compounds is an electron-transporting compound, and the other is a hole-transporting compound. Used as the third carrier transport compound 113H3 and the fourth carrier transport compound 113H4 The compounds that can be present are the first host material 113Ha1 and the second host material 1 13Ha2, first carrier transport compound 113H1 and second carrier transport compound 1 The compounds listed as usable as 13H2 can be used.

[0081] The third carrier transport compound 113H3 and the fourth carrier transport compound 113H4 are, The first carrier transport compound 113H1 and the second carrier transport compound 113H2, and For the same reasons as with the first host material 113Ha1 and the second host material 113Ha2, It is preferable to form an excited complex. Furthermore, a third phosphorescent compound 113Dc is obtained from the excited complex. To optimize energy transfer to the third phosphorus, the emission spectrum of the excited complex and the third phosphorus It is preferable that the absorption bands on the longest wavelength side of the photochemical compound 113Dc overlap. The peak wavelength of the lowest energy absorption band of phosphorescent compound 113Dc (3), and the excitation If the difference in the energy equivalent of the peak wavelengths of the emission spectra of the complex is 0.2 eV or less, The overlap between the vectors is large, which is a desirable configuration. Furthermore, a third carrier transport capability is achieved. Compound 113H3 and the fourth carrier transport compound 113H4 are the third phosphorescent compound 11 To prevent quenching of 3Dc, a triplet excitation energy higher than that of the third phosphorescent compound 113Dc is used. It is preferable that it has energy.

[0082] The third light-emitting layer 113c is located within the first light-emitting layer 113a, or between the first light-emitting layer 113a and the second The recombination energy in the recombination region near the interface of the light-emitting layer 113b is the recombination energy of the second light-emitting layer 113b It emits light by moving through it. Therefore, the first carrier transport compound 113H The triplet excitation energies of the first and second carrier transport compounds 113H2 are as follows: One of either the transport compound 113H3 or the fourth carrier transport compound 113H4 It is preferable that the energy is greater than the multiplet excitation energy.

[0083] Furthermore, the recombination region is either within the first light-emitting layer 113a, or between the first light-emitting layer 113a and the second light-emitting layer In order to be near the interface of layer 113b, the transport properties of the third light-emitting layer 113c are such that of the second light-emitting layer 1 It is preferable that the transport properties are the same as those of 13b. Furthermore, a third carrier transport compound 11 3H3 and the fourth carrier transport compound 113H4 are electron transport compounds and hole transport compounds. The carrier transport compound is one or both of the first carrier transport compound 113H1 and the second One of the electron transport compound and hole transport compound that constitute the carrier transport compound 113H2 Alternatively, they may be the same as both. This allows the materials constituting each layer to be common, cost This will give you a competitive advantage.

[0084] The light-emitting element of Figure 1, having the configuration of the light-emitting layer 113 as shown in Figures 1(c) and (d), has a first light-emitting layer 11 3a may be formed on either the anode or the cathode side.

[0085] When the first light-emitting layer 113a is formed on the anode side, the first light-emitting layer 113a has hole channels. The second light-emitting layer 113b and the third light-emitting layer 113c are electron-transporting layers. It is preferable that the transportability of the first light-emitting layer is as shown in Figure 1(c) for the first phosphor The material 113Ha1 can be made into a hole-transporting material. Also, in the configuration shown in Figure 1(d) The combination consists of a first host material 113Ha1 and a second host material 113Ha2 (i.e., electron transport). This can be adjusted by changing the mixing ratio of the transporting compound and the hole transporting compound. Similarly, in the second light-emitting layer 113b and the third light-emitting layer 113c, the first carrier transport Changing the mixing ratio of carrier transport compound 113H1 to the fourth carrier transport compound 113H4. This allows for the creation of a light-emitting layer with the desired transportability.

[0086] Furthermore, if the first light-emitting layer 113a is formed on the cathode side, the first light-emitting layer 113a is The electron transport layer is an electron transport layer, and the second light-emitting layer 113b and the third light-emitting layer 113c are hole transport layers. It is preferable that it be a layer. The transportability of the first light-emitting layer 113a is as shown in Figure 1(c). In this case, the first host material 113Ha1 can be an electron-transporting material. Also, Figure 1(d) If the configuration is as follows, the first host material 113Ha1 and the second host material 113Ha2 ( In other words, it is adjusted by changing the mixing ratio of electron-transporting compounds and hole-transporting compounds. This can be done in the second light-emitting layer 113b and the third light-emitting layer 113c as well. A mixture of carrier transport compounds 113H1 to 411H4. By changing the ratio, a light-emitting layer with desired transport properties can be created.

[0087] Furthermore, since energy transfer occurs via the second light-emitting layer 113b, the second light-emitting layer 1 If the film thickness of 13b is too thick, energy transfer will not occur to the third light-emitting layer 113c, and the third Since light emission cannot be obtained from the phosphorescent compound 113Dc, the third light-emitting layer 113c To obtain light emission from the second light-emitting layer 113b, the film thickness of the second light-emitting layer 113b is preferably 2 nm to 20 nm. More preferably, it is 5 nm to 10 nm.

[0088] In this embodiment, the configuration of the light-emitting layer 113 is as shown in Figures 1(c) and 1(d). The light-emitting element consists of a first phosphorescent compound 113Da which is a compound that emits blue light, and a second phosphor... The photoluminescent compound 113Db is a compound that exhibits green light emission, and the third phosphorescent compound 113Dc is By using a compound that exhibits red light emission, good white light emission can be achieved (for example, according to JIS lighting standards). This allows for the production of white light that matches the required specifications. Furthermore, this type of white light also exhibits high color rendering. Furthermore, such white light-emitting elements are highly suitable for use as illumination.

[0089] The light-emitting element having the above configuration is a light-emitting element using multiple light-emitting materials, and emits light This allows for the creation of highly efficient light-emitting elements. Furthermore, the light emission from these multiple light-emitting materials can be distributed. This allows for the creation of a light-emitting element that can be obtained with good performance.

[0090] (Embodiment 2) In this embodiment, Figure 1 shows an example of the detailed structure of the light-emitting element described in Embodiment 1. I will explain below.

[0091] The light-emitting element in this embodiment has an EL layer consisting of multiple layers between a pair of electrodes. In this embodiment, the light-emitting element includes a first electrode 101, a second electrode 102, and a first It consists of an EL layer 103 provided between electrode 101 and second electrode 102. In this embodiment, the first electrode 101 functions as the anode, and the second electrode 102 functions as the cathode. The following explanation assumes that it functions as follows: In other words, the first electrode 101 is more like the second electrode 10 A voltage was applied to the first electrode 101 and the second electrode 102 so that the potential was higher than 2. Sometimes, the device is configured to emit light.

[0092] Since the first electrode 101 functions as an anode, it has a large work function (specifically 4.0e Formed using metals, alloys, conductive compounds, and mixtures thereof (V or higher). Preferred. Specifically, for example, indium tin oxide (ITO) indium oxide-tin oxide containing silicon or silicon oxide, Indium oxide containing zinc oxide, tungsten oxide, and zinc oxide ( Examples include IWZO. These conductive metal oxide films are usually produced by sputtering. Although it is formed by film deposition, it may also be fabricated using methods such as the sol-gel method. Examples of fabrication methods include... Indium oxide-zinc oxide is produced by adding 1-20 wt% zinc oxide to indium oxide. One method involves forming the target using a sputtering technique. Indium oxide (IWZO) containing sten and zinc oxide is a type of indium oxide. This product contains 0.5-5 wt% tungsten oxide and 0.1-1 wt% zinc oxide. It can also be formed by sputtering using a t. In addition, gold (Au), platinum ( Pt, Nickel (Ni), Tungsten (W), Chromium (Cr), Molybdenum (Mo) Iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or metallic materials Examples include nitrides (e.g., titanium nitride). Graphene can also be used. By using the composite material described later in the layer that comes into contact with the first electrode 101 in the EL layer 103, This allows for the selection of electrode materials regardless of the work function.

[0093] The laminated structure of the EL layer 103 is such that the light-emitting layer 113 has the configuration shown in Embodiment 1. As long as it is included, the rest is not particularly limited. For example, hole injection layer, hole transport layer, light-emitting layer, electron The system can be constructed by appropriately combining a transport layer, an electron injection layer, a carrier block layer, and the like. In this embodiment, the EL layer 103 is a hole injection layer 1 that is sequentially stacked on top of the first electrode 101. 11, comprising a hole transport layer 112, an emissive layer 113, an electron transport layer 114, and an electron injection layer 115 Let's explain the structure. The materials that make up each layer are specifically described below.

[0094] The hole injection layer 111 is a layer containing a material with high hole injection potential. This includes molybdenum oxide and vanadium. Uses materials such as zinc oxide, ruthenium oxide, tungsten oxide, and manganese oxide. This can be done. In addition, phthalocyanine (abbreviation: H2Pc) and copper phthalocyanine (abbreviation: Cu Phthalocyanine compounds such as PC, 4,4'-bis[N-(4-diphenylaminophosphate) [phenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4- [bis(3-methylphenyl)amino]phenyl]-N,N'-diphenyl-(1,1' Aromatic amine compounds such as -biphenyl)-4,4'-diamine (abbreviation: DNTPD), or This is poly(ethylenedioxythiophene) / poly(styrenesulfonic acid) (abbreviation: PED). The hole injection layer 111 can also be formed using polymers such as OT / PSS.

[0095] Furthermore, the hole injection layer 111 contains a hole transporting substance and an acceptor substance. Composite materials can be used. Furthermore, the hole-transporting material may contain an acceptor material. By using this method, it is possible to select the material for forming the electrodes regardless of the work function of the electrodes. Yes, it is possible. In other words, not only materials with a large work function can be used as the first electrode 101, but also materials with a large work function. Smaller materials can also be used. Acceptable materials include 7, 7, 8 ,8-Tetracyano-2,3,5,6-Tetrafluoroquinodimethane (abbreviation: F4-TC Examples include NQ, chloranil, etc. Transition metal oxides can also be mentioned. In addition, metal oxides belonging to Groups 4 to 8 in the periodic table can be mentioned. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable because they have high electron-accepting properties. Among them, molybdenum oxide is particularly preferable because it is stable in the atmosphere, has low hygroscopicity, and is easy to handle.

[0096] As the hole-transporting substance used in the composite material, various organic compounds such as aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that as the organic compound used in the composite material, it is preferably an organic compound having high hole-transporting properties. Specifically, it is preferably a substance having a hole mobility of 10 cm / Vs or more. Hereinafter, the organic compounds that can be used as the hole-transporting substance in the composite material will be specifically listed. -6 cm 2 / Vs or more. Hereinafter, the organic compounds that can be used as the hole-transporting substance in the composite material will be specifically listed.

[0097] For example, as the aromatic amine compound, N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N ,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3 ,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be mentioned. (abbreviation: DPA3B), etc. can be mentioned. (abbreviation: DPA3B), etc. can be mentioned.

[0098] ​​​​Carbazole derivatives that can be used in composite materials include, specifically, 3-[N- (9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarb Zol (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3 -yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2) , 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino] Examples include -9-phenylcarbazole (abbreviated as PCzPCN1).

[0099] In addition, other carbazole derivatives that can be used in composite materials include 4,4'- di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N- Carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl- 9-Anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 1,4-bis[ Using 4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc. It is possible to be there.

[0100] Furthermore, examples of aromatic hydrocarbons that can be used in composite materials include 2-tert -butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2- tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3, 5-Diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9 ,10-Bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,1 0-Di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene Cene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAn) th), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA) , 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthrace n, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7- Tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl Chil-9,10-di(2-naphthyl)anthracene, 9,9'-biantril, 10,1 0'-Diphenyl-9,9'-biantryl, 10,10'-bis(2-phenylphenyl Ru)-9,9'-Biantril, 10,10'-Bis[(2,3,4,5,6-Pentaf [phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, Examples include perylene and 2,5,8,11-tetra(tert-butyl)perylene. In addition, pentacene, coronene, etc. can also be used. -6 cm 2 Aromatic hydrocarbons with a hole mobility of / Vs or higher and having 14 to 42 carbon atoms are used. It is preferable to do so.

[0101] Furthermore, aromatic hydrocarbons that can be used in composite materials may have a vinyl skeleton. i. Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2- Diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2- Examples include diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA).

[0102] Also, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphen Nilamine (abbreviation: PVTPA), poly[N-(4-{N’-[4-(4-diphenyl amino)phenyl]phenyl-N’-phenylamino}phenyl)methacrylamide]( abbreviation: PTPDMA), poly[N,N’-bis(4-butylphenyl)-N,N’-bis (phenyl)benzidine](abbreviation: Poly-TPD), etc. can also be used. It is possible.

[0103] By forming a hole injection layer, the injection property of holes becomes good, and it becomes possible to obtain a light emitting element with a small driving voltage. It becomes possible to obtain.

[0104] The hole transport layer 112 is a layer containing a hole transporting substance. Examples of the hole transporting substance include for example, 4,4’-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N’-bis(3-methylphenyl)-N,N’-diphenyl-[1, 1’-biphenyl]-4,4’-diamine (abbreviation: TPD), 4,4’,4’’-tris (N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4’,4 ’’-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4’-bis[N-(spiro-9,9’-bifluorene-2 -yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4’- (9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP), etc. aromatic amine compounds can be used. The substances described here have high hole transportability and are substances mainly having a hole mobility of 10 -6 cm 2 / Vs or more. Also, the above-mentioned composite materials The organic compounds listed as hole-transporting substances in the material can also be used in the hole transport layer 112. Yes, it is possible. Also, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyl carbazole) High molecular weight compounds such as riphenylamine (PVTPA) can also be used. The layer containing the hole-transporting material is not limited to a single layer, but may consist of two or more layers made of the above material. It may also be made into a stacked structure.

[0105] The light-emitting layer 113 has the configuration described in Embodiment 1. The light-emitting element in this form has good luminescence efficiency, and contains multiple phosphorescent compounds. Light emission is obtained with good balance. For the main components of the light-emitting layer 113, please refer to the description in Embodiment 1. I want to be illuminated.

[0106] In the light-emitting layer 113, the first phosphorescent compound 113Da to the third phosphorescent compound 1 As for materials that can be used as 13Dc, the relationship described in Embodiment 1 is There are no particular limitations as long as the combination is available. The first phosphorescent compound 113Da to the third Examples of phosphorescent compounds 113Dc include the following:

[0107] Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H -1,2,4-triazole-3-yl-κN2]phenyl-κC}iridium(III (Abbreviation: Ir(mpptz-dmp)3), Tris(5-methyl-3,4-diphenyl) -4H-1,2,4-Triazolat) Iridium(III) (Abbreviation: Ir(Mptz)3) ), Tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2 ,4-Triazolat] Iridium(III) (abbreviation: Ir(iPrptz-3b)3) organometallic iridium complexes having a 4H-triazole skeleton, such as tris[3-methyl -1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolatoyli Dium(III) (abbreviation: Ir(Mptz1-mp)3), Tris(1-methyl-5-phosphate) Enyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation) Organometallic compounds with a 1H-triazole skeleton, such as Ir(Prptz1-Me)3) Lydium complexes and fac-tris[1-(2,6-diisopropylphenyl)-2-fe [Nyl-1H-imidazole] Iridium(III) (abbreviation: Ir(iPrpmi)3), Tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenate [Like Iridium(III) (abbreviation: Ir(dmpimpt-Me)3)] organometallic iridium complexes having an imidazole skeleton, and bis[2-(4',6'-diph Luorophenyl)pyridinate-N,C 2’ Iridium(III) tetrakis (1-pyra) Zolyl) Borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl) Pyridinate-N,C 2’ Iridium(III) picolinate (abbreviation: Firpic), Bis[2-(3',5'-bistrifluoromethylphenyl)pyridinate-N,C 2’ ] Iridium(III) picolinate (abbreviation: Ir(CF3ppy)2(pic)), bis [2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium (II) I) Phenyromorphs having an electron-withdrawing group, such as acetylacetonate (abbreviation: FIracac) Examples include organometallic iridium complexes with lupyridine derivatives as ligands. These are blue A compound that exhibits phosphorescence, having an emission peak between 440 nm and 520 nm. These are substances. Among those mentioned above, 4H-triazole, 1H-triazole, and imidazole are Organometallic iridium complexes with a polyazole skeleton like this have high hole-trapping properties. Therefore, these compounds are used as the first phosphorescent compound in a light-emitting element according to one aspect of the present invention. The first light-emitting layer is provided on the cathode side of the second light-emitting layer, and the second light-emitting layer If it is a hole-transporting material (specifically, if the second host material is a hole-transporting material), This is preferable because it makes it easier to control the carrier recombination region within the first light-emitting layer. Organometallic iridium complexes with a 4H-triazole skeleton also offer superior reliability and luminescence efficiency. Therefore, it is particularly preferable.

[0108] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: Ir(mppm)3), Tris(4-t-butyl-6-phenylpyrimidinato)iridium Mu(III) (abbreviation: Ir(tBuppm)3), (acetylacetonate)bis(6-Me Iridium(III) (abbreviation: Ir(mppm)2) acac)), (acetylacetonato)bis(6-tert-butyl-4-phenylpyryl) Iridium(III) (abbreviation: Ir(tBuppm)2(acac)), (A Cetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]yl Dium(III) (abbreviation: Ir(nbppm)2(acac)), (acetylacetonate )bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridi Um(III) (abbreviation: Ir(mpmppm)2(acac)), (acetylacetonate )Bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: Ir(dpp) organometallic iridium complexes having a pyrimidine skeleton such as m)2(acac)), and (A Cetylacetonato)bis(3,5-dimethyl-2-phenylpyradinata)iridium(I II) (Abbreviation: Ir(mppr-Me)2(acac)), (acetylacetonato)bis (5-Isopropyl-3-methyl-2-phenylpyradinate) Iridium(III) (abbreviated) Organometallic compounds with a pyrazine skeleton, such as Ir(mppr-iPr)2(acac)). iridium complexes and tris(2-phenylpyridinato-N,C) 2’ ) Iridium (III ) (Abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N,C) 2’ ) Iridiu β(III)acetylacetonate (abbreviation: Ir(ppy)2(acac)), bis(be) Iridium(III) acetylacetonate (abbreviation: Ir(bz) q)2(acac), Tris(benzo[h]quinolinato) iridium(III) (abbreviation) :Ir(bzq)3), Tris(2-phenylquinolinato-N,C) 2’ ) Iridium (I II) (Abbreviation: Ir(pq)3), Bis(2-phenylquinolinato-N,C) 2’ ) Iridi P(III) acetylacetonate (abbreviation: Ir(pq)2(acac)) In addition to organometallic iridium complexes with a lysine skeleton, tris(acetylacetonate)(mono Phenanthroline Terbium(III) (abbreviation: Tb(acac)3(Phen)) Examples include rare earth metal complexes. These are compounds that mainly exhibit green phosphorescence. It has an emission peak in the 500nm-600nm range. Among those mentioned above, pyrimidine and pyramidine have a peak emission in the 500nm-600nm range. Organometallic iridium complexes with a diazine skeleton, such as din, have poor hole-trapping properties. It has high electron trapping properties. Therefore, these compounds are used in a light-emitting element according to one embodiment of the present invention. The first phosphorescent compound used is configured such that the first light-emitting layer is located on the anode side of the second light-emitting layer. If the second light-emitting layer is electron-transporting (specifically, if the second host material is electron-transporting) (In the case of a carrier transport material), it is easy to control the carrier recombination region within the first light-emitting layer. Therefore, it is preferable. Furthermore, organometallic iridium complexes having a pyrimidine skeleton are reliable. It is particularly preferable because it also exhibits outstanding luminous efficiency.

[0109] Also, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimid Nato-iridium(III) (abbreviation: Ir(5mdppm)2(dibm)), bis[4 ,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium (III) (Abbreviation: Ir(5mdppm)2(dpm)), Bis[4,6-di(naphthalene) iridium(III) (abbreviation: 1-yl)pyrimidinato) (dipivaloylmethanato) Organometallic iridium with a pyrimidine skeleton, such as Ir(d1npm)2(dpm)). Complexes, and (acetylacetonato)bis(2,3,5-triphenylpyradinato)iridium Mu (III) (abbreviation: Ir(tppr)2(acac)), Bis (2,3,5-triphenes) Iridium(III) (Abbreviation: Ir(tpp)) r)2(dpm)),(acetylacetonate)bis[2,3-bis(4-fluorophenicol) Iridium(III) (abbreviation: Ir(Fdpq)2(acac)) iridium organometallic complexes having a pyrazine skeleton, such as tris(1-phenylisopropyl alcohol). Norinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(piq)3), bis(1- Phenylisoquinolinate-N,C 2’ ) Iridium(III) acetylacetonate (abbreviated) Name: Organometallic iridium with a pyridine skeleton, such as Ir(piq)2(acac)). In addition to the complex, 2,3,7,8,12,13,17,18-octaethyl-21H,23H- Platinum complexes such as porphyrin platinum(II) (abbreviated as PtOEP), and tris(1,3- Diphenyl-1,3-propanedionato)(monophenanthroline) europium(II) I) (Abbreviation: Eu(DBM)3(Phen)), Tris[1-(2-tenoyl)-3,3 ,3-trifluoroacetonate](monophenanthroline) europium(III) (abbreviated) Examples include rare earth metal complexes such as Eu(TTA)3(Phen)*. These are, This compound exhibits red phosphorescence and has an emission peak between 600 nm and 700 nm. Among those mentioned above, organometallic compounds with a diazine skeleton, such as pyrimidines and pyrazines, are particularly noteworthy. Dium complexes have weak hole-trapping properties and high electron-trapping properties. Therefore, diazine bone An organometallic iridium complex having a specific property is used as the second phosphorescent compound, and the first luminescence When the layer is located on the cathode side of the second light-emitting layer, and the second light-emitting layer is hole-transporting, Specifically, if the second host material is a hole transport material, the carrier recombination region is the second This is preferable because it makes it easier to control within the light-emitting layer 1. Organometallic iridium complexes are particularly preferred because they offer outstanding reliability and luminescence efficiency. Furthermore, organometallic iridium complexes with a pyrazine skeleton can produce red luminescence with good chromaticity. Therefore, applying it to white light-emitting elements can improve color rendering.

[0110] Furthermore, in addition to the phosphorescent compounds described above, from among known phosphorescent light-emitting materials, the first phosphorus You may select and use photo-active compound 113Da to a third phosphorescent compound 113Dc.

[0111] Note that phosphorescent compounds (first phosphorescent compound 113Da to third phosphorescent compound 1) Instead of 13Dc), use materials that exhibit thermally activated delayed fluorescence (TAD F) Materials may be used. Here, delayed fluorescence has a spectrum similar to that of normal fluorescence. However, it refers to luminescence with an exceptionally long lifespan. Its lifespan is 10 -6 10 seconds or more, preferably 10 - 3 It is more than a second. Specifically, as thermally activated delayed fluorescence materials, fullerenes and their derivatives, Examples include acridine derivatives such as proflavin and eosin. Also, magnesium (M g) Zinc (Zn), Cadmium (Cd), Tin (Sn), Platinum (Pt), Indium ( Examples include metal-containing porphyrins containing in (I) or palladium (Pd), etc. Examples of porphyrins containing this genus include protoporphyrin-tin fluoride complexes (SnF2). (Proto IX)), Mesoporphyrin-tin fluoride complex (SnF2(Meso I X)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), Proporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro II) I-4Me)), Octaethylporphyrin-tin fluoride complex (SnF2(OEP)), Ethioporphyrin-tin fluoride complex (SnF2(Etio I)), octaethylpor Examples include phylin-platinum chloride complex (PtCl2OEP). Furthermore, 2-(biphenyl Lu-4-yl)-4,6-bis(12-phenylindoro[2,3-a]carbazole- π-electron-rich heteroaromatic rings such as 11-yl)-1,3,5-triazine (PIC-TRZ) Furthermore, heterocyclic compounds having a π-electron-deficient heteroaromatic ring can also be used. A substance in which an excess heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is a π-electron-excess heteroaromatic ring. The donor properties of the aromatic ring and the acceptor properties of the π-electron-deficient heteroatomic ring both become stronger, resulting in S1 and T This is particularly preferable because it reduces the energy difference of 1.

[0112] The above-mentioned first host material 113Ha1, second host material 113Ha2, and first carrier It can be used as transportable compound 113H1 to the fourth carrier transportable compound 113H4. Since the possible materials were clearly stated in Embodiment 1, we will omit repeating that information.

[0113] The light-emitting layer 113 can be co-deposited using vacuum deposition, or as a mixed solution using inkjet or spin They can be manufactured using methods such as coating or dip coating.

[0114] The electron transport layer 114 is a layer containing an electron-transporting material. For example, tris(8-quinoli) Aluminum (abbreviation: Alq), Tris(4-methyl-8-quinolinolato)al Minium (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beri Rium (abbreviation: BeBq2), bis(2-methyl-8-quinolinolate)(4-phenyl Enola aluminum (abbreviation: BAlq), etc., quinoline skeleton or benzoquinoline skeleton It is a layer consisting of metal complexes having a specific property. In addition, bis[2-(2-hydroxyphenyl] [Nyl)benzoxazolate]zinc (abbreviation: Zn(BOX)2), bis[2-(2-hydro Oxazoles such as oxyphenyl benzothiazolat [zinc (abbreviation: Zn(BTZ)2)] Metal complexes having thiazole ligands can also be used. In addition, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3 ,4-oxadiazole (abbreviation: PBD) and 1,3-bis[5-(p-tert-butyric acid) [Oxadiazole-2-yl]benzene (abbreviation: OXD-7) ), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl) -1,2,4-triazole (abbreviation: TAZ), vasophenanthroline (abbreviation: BPhe n) Vasocuproine (abbreviated as BCP) can also be used. It has high electron transport properties, mainly 10 -6 cm 2 It is a substance with an electron mobility of / Vs or greater. Furthermore, the electron-transporting host material described above may be used for the electron transport layer 114.

[0115] Furthermore, the electron transport layer 114 is not limited to a single layer, but can also consist of two or more layers made of the above material. It may also be considered as a layered structure.

[0116] Furthermore, a layer for controlling the movement of electron carriers may be provided between the electron transport layer and the light-emitting layer. This involves adding a small amount of a substance with high electron-trapping properties to a material with high electron-transporting properties as described above. This layer adjusts the carrier balance by suppressing the movement of electron carriers. This becomes possible. In such a configuration, electrons penetrate the light-emitting layer, causing emission. It is highly effective in suppressing problems that may arise (for example, a decrease in the lifespan of the device).

[0117] Furthermore, between the electron transport layer 114 and the second electrode 102, electrons are in contact with the second electrode 102. An injection layer 115 may be provided. The electron injection layer 115 may be lithium fluoride (LiF), Alkali metals such as cesium fluoride (CsF) and calcium fluoride (CaF2) or Alkaline earth metals or compounds thereof can be used. For example, those with electron transport properties. A layer made of a substance contains alkali metals, alkaline earth metals, or compounds thereof. A material having electron transport properties can be used as the electron injection layer 115. By using a layer containing alkali metals or alkaline earth metals, This is more preferable because electron injection from the second electrode 102 is performed efficiently.

[0118] The material forming the second electrode 102 has a small work function (specifically 3.8 eV) The following can be used: metals, alloys, electrically conductive compounds, and mixtures thereof. Specific examples of such cathode materials include lithium (Li) and cesium (Cs). Potassium metals, as well as magnesium (Mg), calcium (Ca), and strontium (Sr) Elements belonging to Group 1 or Group 2 of the periodic table, and alloys containing these elements (MgAg Rare earth metals such as AlLi, europium (Eu), ytterbium (Yb), and Examples include alloys containing these. However, between the second electrode 102 and the electron transport layer By providing an electron injection layer, regardless of the magnitude of the work function, Al, Ag, and indioxide can be used. Various conductive materials such as indium-tin oxide, silicon, or silicon oxide-containing indium-tin oxide. An electrically conductive material can be used as the second electrode 102. These conductive materials are sputtered The film can be formed using methods such as the ring method, inkjet method, and spin coating method.

[0119] Furthermore, various methods can be used to form the EL layer 103, regardless of whether they are dry or wet methods. This can be done using methods such as vacuum deposition, inkjet printing, or spin coating. It is permissible to do so. Furthermore, different film deposition methods may be used for each electrode or layer. .

[0120] The electrodes can also be formed using a wet process with the sol-gel method, or they can be formed using a metallic base material. It may also be formed by a wet method using a t. Alternatively, dry methods such as sputtering or vacuum deposition may be used. It may also be formed using [a specific method / tool].

[0121] The light-emitting element having the above configuration has a first electrode 101 and a second electrode 102 between them. The resulting potential difference causes an electric current to flow, and in the light-emitting layer 113, which is a layer containing a highly luminescent material, Holes and electrons recombine and emit light. In other words, an luminescent region is formed in the luminescent layer 113. It is structured in such a way that it can be used.

[0122] The light is emitted through either the first electrode 101 or the second electrode 102, or both. It is removed to the outside. Therefore, either the first electrode 101 or the second electrode 102 Alternatively, both may consist of translucent electrodes. Only the first electrode 101 is a translucent electrode. In this case, the light is extracted through the first electrode 101. Also, the second electrode 102 If the electrode is transparent, the light is extracted through the second electrode 102. When both electrode 101 and electrode 102 are translucent electrodes, light emission occurs. It passes through the first electrode 101 and the second electrode 102 and is extracted from both.

[0123] The layer provided between the first electrode 101 and the second electrode 102 is as described above. It is not limited to this. However, if the light-emitting region and the metal used in the electrodes or carrier injection layer are close together The first electrode 101 and the second electrode are positioned so as to suppress quenching caused by contact. A configuration is preferred in which a light-emitting region is provided at a location away from 102 where holes and electrons recombine.

[0124] Furthermore, the hole transport layer and electron transport layer in contact with the light-emitting layer 113, and especially the light emission in the light-emitting layer 113, are also important. The carrier transport layer in contact with the region is responsible for energy transfer from excitons generated in the light-emitting layer. In order to suppress this, the triplet excitation energy of the material constituting the light-emitting layer is the triplet excitation It is preferable to use materials with higher energy levels.

[0125] The light-emitting element in this embodiment is fabricated on a substrate made of glass, plastic, or the like. That's all. As for the order of fabrication on the substrate, even if you stack them in order from the first electrode 101 side, The electrodes 102 and 2 may be stacked in order from the electrode 102 side. The light-emitting device forms one light-emitting element on one substrate. It is acceptable to have only one such light-emitting element, but it is also acceptable to form multiple light-emitting elements on a single substrate. By creating multiple of these, it is possible to create lighting devices with divided elements or passive matrix type light-emitting devices. It can be manufactured. Furthermore, a thin film can be applied to a substrate made of glass, plastic, etc. A transistor (TFT) is formed, and a light-emitting element is fabricated on an electrode electrically connected to the TFT. This may also be done. This allows for an active matrix that controls the driving of the light-emitting elements by the TFT. A light-emitting device of this type can be fabricated. The structure of the TFT is not particularly limited. (Example: Staggered TFT) It can be a TFT or an inverse staggered TFT. Also, regarding the crystallinity of the semiconductor used in the TFT... However, this is not particularly limited; amorphous semiconductors or crystalline semiconductors may be used. Furthermore, the driving circuit formed on the TFT substrate also consists of N-type and P-type TFTs. It may be either N-type TFT or P-type TFT, or it may consist of only one of them. That is also acceptable.

[0126] Furthermore, this embodiment can be appropriately combined with other embodiments.

[0127] (Embodiment 3) In this embodiment, a light-emitting element (hereinafter referred to as a stacked element) is configured by stacking multiple light-emitting units. The embodiment of (also known as) will be explained with reference to Figure 2. This light-emitting element has a first electrode and a second electrode. This is a light-emitting element having multiple light-emitting units between two electrodes. One light-emitting unit is It has a similar configuration to the EL layer 103 shown in Figure 1. In other words, the light-emitting element shown in Figure 1 is This is a light-emitting element having one light-emitting unit, and in this embodiment, multiple light-emitting units are It can be described as a light-emitting element.

[0128] In Figure 2, a first light-emitting unit is located between the first electrode 501 and the second electrode 502. The first light-emitting unit 511 and the second light-emitting unit 512 are stacked together, and the first light-emitting unit 511 and the second A charge generation layer 513 is provided between the light-emitting unit 512 and the first electrode 501. The first electrode 101 and the second electrode 102 correspond to the first electrode 101 and the second electrode 102 in Figure 1, respectively. Furthermore, the same thing described in the explanation of Figure 1 can be applied. Also, the first light-emitting unit The 511 and the second light-emitting unit 512 may have the same configuration or different configurations. .

[0129] The charge generation layer 513 contains a composite material of an organic compound and a metal oxide. The composite material of the compound and metal oxide can be used in the hole injection layer 111 shown in Figure 1. Composite materials can be used. Examples of organic compounds include aromatic amine compounds and carbazoles. Compounds, aromatic hydrocarbons, polymer compounds (oligomers, dendrimers, polymers, etc.) Various compounds can be used. Specifically, organic compounds with a hole mobility of 1× 10 -6 cm 2 It is preferable to use one that is greater than or equal to / Vs. Other substances with high pore transport properties may also be used. Organic compounds and metallic acids Composite materials of this material exhibit excellent carrier implantation and carrier transport properties, enabling low voltage operation and low Current drive can be achieved. Note that the anode side of the light-emitting unit is in contact with the charge generation layer. If this is the case, the charge generation layer can also act as the hole transport layer of the light-emitting unit, The light-emitting unit does not need to have a hole transport layer.

[0130] Furthermore, the charge generation layer 513 consists of a layer containing a composite material of an organic compound and a metal oxide, and other materials. The layers composed of these may be formed as a laminated structure. For example, an organic compound and a metal oxide A layer containing composite materials, and one compound selected from among electron-donating materials, and a compound with high electron transport properties. It may be formed by laminating layers containing the composite material. Alternatively, a composite material of an organic compound and a metal oxide may be formed. A layer containing the material and a transparent conductive film may be laminated together to form the structure.

[0131] In any case, the electric light sandwiched between the first light-emitting unit 511 and the second light-emitting unit 512 When a voltage is applied to the first electrode 501 and the second electrode 502, the charge generation layer 513 generates a charge on one side. Any device that injects electrons into one light-emitting unit and holes into the other light-emitting unit will suffice. For example, in Figure 2, the potential of the first electrode is higher than the potential of the second electrode. When a voltage is applied, the charge generation layer 513 injects electrons into the first light-emitting unit 511. The method should involve injecting holes into the second light-emitting unit 512.

[0132] Figure 2 illustrates a light-emitting element having two light-emitting units, but there are three or more light-emitting elements. The same method can be applied to light-emitting elements formed by stacking units. Like a light-emitting element in a state, multiple light-emitting units are separated between a pair of electrodes by a charge generation layer. By arranging them in this way, high-brightness light emission is possible while maintaining a low current density, and the element has a long lifespan. This enables the realization of a child. Furthermore, it allows for the creation of a light-emitting device that can be driven at low voltage and consumes low power. Cut.

[0133] Furthermore, by making the light-emitting color of each light-emitting unit different, the entire light-emitting element... This allows you to obtain light emission of the desired color. For example, a light-emitting element having two light-emitting units. In this configuration, the first light-emitting unit produces red and green light, and the second light-emitting unit produces blue light. By doing so, it is also possible to obtain a light-emitting element that emits white light as a whole.

[0134] Furthermore, the configuration of the light-emitting layer 113 is such that at least one of the multiple units is... Because it is used, the manufacturing process for the unit can be reduced, This allows us to provide multi-color light-emitting elements that are advantageous for practical application.

[0135] The above configuration may be appropriately combined with other embodiments or other configurations within this embodiment. This is possible.

[0136] (Embodiment 4) In this embodiment, a light-emitting device using the light-emitting elements described in Embodiments 1 to 3 is provided. I will explain this.

[0137] In this embodiment, the light-emitting element is manufactured using the light-emitting elements described in Embodiments 1 to 3. The light-emitting device will be explained using Figure 3. Figure 3(A) is a top view showing the light-emitting device. Figure 3(B) is a cross-sectional view of Figure 3(A) cut along lines AB and CD. This light-emitting device The drive circuit section (source line drive circuit), shown by the dotted line, controls the emission of light from the light-emitting element. It includes a path (601), a pixel section (602), and a drive circuit section (gate line drive circuit) (603). 604 is the sealing substrate, 605 is the sealing material, and the area inside the sealing material 605 is a space. It's set to 607.

[0138] The routing wiring 608 is connected to the source line drive circuit 601 and the gate line drive circuit 603. FPC (Flexible Printed Circuit) is a wiring used to transmit signals and serves as an external input terminal. (Lindt Circuit) Video signal, clock signal, start signal, reset signal from 609 Receives, etc. Note that only FPC is shown in the diagram here, but this FPC has print A circuit board (PWB) may be attached. The light-emitting device in this specification includes light-emitting This includes not only the device itself, but also the state in which the FPC or PWB is attached to it. do.

[0139] Next, the cross-sectional structure will be explained using Figure 3(B). The drive circuit is located on the element substrate 610. A section and a pixel section are formed, but here, the source line drive circuit 601 is the drive circuit section. This shows one of the pixels in the pixel section 602.

[0140] The source line drive circuit 601 uses an n-channel TFT 623 and a p-channel TFT 62 A CMOS circuit is formed by combining it with 4. In addition, the drive circuit is a variety of CMOS circuits It may also be formed using PMOS or NMOS circuits. In this embodiment, the substrate The image above shows a driver integrated with a drive circuit, but this is not always necessary; the drive circuit can be... It can also be formed on an external surface rather than on the substrate.

[0141] Furthermore, the pixel section 602 includes a switching TFT 611 and a current control TFT 612 and It is formed by a plurality of pixels, each including a first electrode 613 electrically connected to a drain. Furthermore, an insulator 614 is formed covering the end of the first electrode 613. Here, positive It is formed by using a photosensitive acrylic resin film of a mold.

[0142] Furthermore, in order to ensure good coverage, the upper or lower end of the insulator 614 has a curvature. A curved surface is formed. For example, as the material for the insulator 614, a positive-type photosensitive material is used. When krill is used, the radius of curvature (0.2 μm to 3 μm) is only present at the upper end of the insulator 614. It is preferable to give it a curved surface. Also, as the insulator 614, a negative type photosensitive resin, Alternatively, any of the positive-type photosensitive resins can be used.

[0143] An EL layer 616 and a second electrode 617 are formed on the first electrode 613, respectively. Here, the material used for the first electrode 613 which functions as an anode is, work function It is desirable to use a material with a large ion content. For example, ITO film or silicon-containing ink Dium-tin oxide film, indium oxide film containing 2-20 wt% zinc oxide, titanium nitride film, In addition to single-layer films such as chromium films, tungsten films, Zn films, and Pt films, titanium nitride films and aluminum films are also available. Lamination with a film mainly composed of aluminum, titanium nitride film and aluminum-based film and titanium nitride film A three-layer structure with a tan film can be used. Furthermore, a laminated structure can improve the resistance of the wiring. It has low resistance, provides good ohmic contact, and can also function as an anode. ru.

[0144] Furthermore, the EL layer 616 can be coated using a deposition method with a deposition mask, an inkjet method, or a spin coat. It is formed by various methods such as the law. The EL layer 616 is formed by Embodiments 1 to 3 It includes the configuration described above. Furthermore, other materials constituting the EL layer 616 include: It may be a low-molecular-weight compound or a high-molecular-weight compound (including oligomers and dendrimers). .

[0145] Furthermore, the material used for the second electrode 617, which is formed on the EL layer 616 and functions as a cathode As for materials, materials with a low work function (Al, Mg, Li, Ca, or alloys of these) It is preferable to use a compound (such as MgAg, MgIn, AlLi, etc.). Note that the EL layer 616 If the light generated passes through the second electrode 617, the second electrode 617 is defined as having a film thickness A thin metal film and a transparent conductive film (ITO, indigo oxide containing 2-20 wt% zinc oxide) Lamination with indium tin oxide containing um and silicon, zinc oxide (ZnO), etc. is used. That's good.

[0146] The first electrode 613, the EL layer 616, and the second electrode 617 form a light-emitting element. The light-emitting element is a light-emitting element having the configuration of Embodiments 1 to 3. The pixel portion is formed by multiple light-emitting elements, but in this embodiment The optical device has a light-emitting element as described in Embodiments 1 to 3, and other configurations. It may include both the light-emitting element and the light-emitting element.

[0147] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, A light-emitting element is placed in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The structure is equipped with child 618. Furthermore, the space 607 is filled with a filler material. In addition to cases where an inert gas (such as nitrogen or argon) is filled, it is also filled with sealant 605. In some cases, a recess is formed in the sealing substrate and a desiccant 625 is placed there, which reduces the effects of moisture. This configuration is preferable because it can suppress deterioration caused by [unspecified factor].

[0148] Furthermore, it is preferable to use epoxy resin or glass frit for the sealant 605. Furthermore, it is desirable that these materials be as impermeable to moisture and oxygen as possible. In addition to glass substrates and quartz substrates, FRP (Fiberg) is also used as a material for the encapsulating substrate 604. Glass-reinforced plastics), PVF (polyvinyl fluoride) ), a plastic substrate made of polyester or acrylic can be used.

[0149] As described above, a light-emitting element is manufactured using the light-emitting elements described in Embodiments 1 to 3. A light-emitting device can be obtained.

[0150] The light-emitting device in this embodiment has the light-emitting elements described in Embodiments 1 to 3. Because it is used, a light-emitting device with good characteristics can be obtained. Specifically, the implementation The light-emitting element shown in Embodiments 1 to 3 has good luminous efficiency and reduces power consumption. It can be made into a light-emitting device. Furthermore, it is a light-emitting element with a low driving voltage, A light-emitting device can be obtained.

[0151] As described above, this embodiment describes an active matrix type light-emitting device. However, a passive matrix type light-emitting device may also be used. Figure 4 shows the application of the present invention. The passive matrix type light-emitting device fabricated by [method] is shown. Figure 4(A) shows the light-emitting device. The perspective view shown, Figure 4(B), is a cross-sectional view obtained by cutting Figure 4(A) along the X and Y lines. In Figure 4, On the substrate 951, an EL layer 955 is provided between the electrode 952 and the electrode 956. The end of the electrode 952 is covered with an insulating layer 953. And on the insulating layer 953 is a partition layer 9 54 is provided. The side walls of the partition layer 954 are such that as they get closer to the substrate surface, one side wall It has a slope such that the distance between it and the other side wall becomes narrower. In other words, the short of the partition wall layer 954 The cross-section in the lateral direction is trapezoidal, with the base (facing the same direction as the surface direction of the insulating layer 953) and insulating The side in contact with layer 953 is the upper side (which faces the same direction as the plane direction of insulating layer 953, and the insulating layer 9 It is shorter than the side that does not touch 53. In this way, by providing the partition layer 954, static electricity, etc. This can prevent defects in the light-emitting element caused by this process. Furthermore, it can be used in passive matrix type light-emitting devices. In this case, the light-emitting element described in Embodiments 1 to 3 operates at a low drive voltage. This allows for operation with low power consumption. Furthermore, Embodiments 1 to the following By including the light-emitting element described in Embodiment 3, it can be driven with low power consumption. Furthermore, by having the light-emitting element described in Embodiments 1 to 3, a highly reliable It can be used as a light-emitting device.

[0152] Furthermore, in order to achieve full-color display, the light from the light-emitting element must be able to escape to the outside of the light-emitting device. A colored layer or color conversion layer can be placed on the optical path. Examples of a light-emitting device with a luminescent coating are shown in Figures 5(A) and (B). Figure 5(A) shows substrate 1001, Base insulating film 1002, gate insulating film 1003, gate electrodes 1006, 1007, 1008 , first interlayer insulating film 1020, second interlayer insulating film 1021, peripheral portion 1042, pixel portion 10 40, drive circuit section 1041, first electrodes 1024W, 1024R, 1024G of the light-emitting element , 1024B, partition wall 1025, EL layer 1028, second electrode 1029 of light-emitting element, sealing group The plate 1031, sealing material 1032, etc. are shown in the diagram. Also, the colored layer (red colored layer 10 34R, the green colored layer 1034G, and the blue colored layer 1034B are provided on the transparent substrate 1033. A black layer (black matrix) 1035 may also be provided. The transparent substrate 1033, which has a black layer, is aligned and fixed to the substrate 1001. Furthermore, the colored layer and the black layer are covered with an overcoat layer 1036. In this form, there is an emissive layer through which light does not pass through the colored layer and exits to the outside, and a layer through which light passes through each colored layer. There is a light-emitting layer that emits light to the outside, and light that does not pass through the colored layer is white, and light that passes through the colored layer is Since these are red, blue, and green, images can be represented using four colored pixels.

[0153] Furthermore, in the light-emitting device described above, light is taken to the substrate 1001 on which the TFT is formed. Although the light-emitting device was designed with a bottom-emission structure, the light-emitting element was directed towards the sealing substrate 1031. It can also be used as a light-emitting device with an extraction structure (top emission type). Top emission type Figure 6 shows a cross-sectional view of the light-emitting device. In this case, the substrate 1001 is a substrate that does not transmit light. It is possible. Until the connecting electrode that connects the TFT and the anode of the light-emitting element is fabricated, the bottom It is formed in the same way as an emission-type light-emitting device. Then, the third interlayer insulating film 1037 is attached to the electrode. It is formed covering 1022. This insulating film may also play a planarizing role. Third interlayer The insulating film 1037 is formed using the same material as the second interlayer insulating film, as well as other known materials. It is possible.

[0154] The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting element are positive here. This is referred to as the electrode, but it can also be the cathode. Furthermore, top-emission type light emission as shown in Figure 6. In the case of a device, it is preferable that the first electrode be a reflective electrode. The configuration of the EL layer 1028 is The configuration is as described in Embodiments 1 to 3, and white light emission is obtained. The element structure is as follows. In a configuration that can obtain white light emission, if two EL layers are used, Blue light is emitted from the light-emitting layer of one EL layer, and orange light is emitted from the light-emitting layer of the other EL layer. A configuration that allows light to be obtained, or blue light from the light-emitting layer of one EL layer to the other E One possible configuration is one in which red and green light can be obtained from the light-emitting layer in the L layer. When three EL layers are used, red, green, and blue light emission can be obtained from each light-emitting layer. By doing so, a light-emitting element that emits white light can be obtained. If the configuration shown in Embodiments 1 to 3 is applied, the configuration for obtaining white light emission is this Of course, this is not limited to that.

[0155] The colored layer is placed on the optical path through which light from the light-emitting element exits to the outside. A bottle like the one in Figure 5(A) In the case of a emission-type light-emitting device, a transparent substrate 1033 is covered with a colored layer 1034R, 1034 It can be provided by providing G, 1034B and fixing it to the substrate 1001. As shown in Figure 5(B), the colored layer is placed between the gate insulating film 1003 and the first interlayer insulating film 1020. It may also be configured to be installed in the following way. If the structure is a top emission as shown in Figure 6, the colored layer (red A seal with a colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B. Sealing can also be performed with a sealing substrate 1031. The sealing substrate 1031 has a position between the pixels. A black layer (black matrix) 1035 may be provided. A colored layer (red Colored layer 1034R, green colored layer 1034G, blue colored layer 1034B) and black layer (black The black matrix may be covered by an overcoat layer 1036. The substrate 1031 shall be a light-transmitting substrate.

[0156] When a voltage is applied between the pair of electrodes of the resulting organic light-emitting element, a white light-emitting region 10 is produced. 44W can be obtained. Also, by combining it with a colored layer, a red light-emitting region 1044R can be obtained. A blue light-emitting region 1044B and a green light-emitting region 1044G are obtained. Since the light-emitting device uses the light-emitting elements described in Embodiments 1 to 3, This makes it possible to create light-emitting devices that require little power.

[0157] Furthermore, while we have shown an example of full-color display using four colors—red, green, blue, and white—this is not particularly limited to... Alternatively, full-color display may be performed using three colors: red, green, and blue.

[0158] Furthermore, this embodiment can be freely combined with other embodiments.

[0159] (Embodiment 5) In this embodiment, the light-emitting element described in Embodiments 1 to 3 is used as an illumination device. An example of its use will be explained with reference to Figure 7. Figure 7(B) is a top view of the lighting device, and Figure 7(A) is This is a cross-sectional view of ef in Figure 7(B).

[0160] The lighting device in this embodiment has a light-transmitting substrate 400 which is a support, and a first An electrode 401 is formed. The first electrode 401 is formed in Embodiments 1 to 3. This corresponds to the first electrode 101.

[0161] An auxiliary electrode 402 is provided on the first electrode 401. In this embodiment, the first Since we have shown an example where light emission is extracted from the electrode 401 side, the first electrode 401 is made of a translucent material. Formed by the material. The auxiliary electrode 402 is provided to compensate for the low conductivity of the translucent material. This is caused by a voltage drop due to the high resistance of the first electrode 401 within the light-emitting surface. It has the function of suppressing brightness unevenness. The auxiliary electrode 402 is made of at least the material of the first electrode 401. Formed using a material with higher conductivity than the material, preferably a material with high conductivity such as aluminum. It is preferable to form it using a thick material. Note that the auxiliary electrode 402 is in contact with the first electrode 401. It is preferable that the surface other than the part to be removed is covered with an insulating layer. This is because it can be removed. This is to suppress light emission from the upper part of the auxiliary electrode 402, thereby suppressing a decrease in power efficiency. Therefore, the voltage is supplied to the second electrode 404 at the same time as the formation of the auxiliary electrode 402. A pad 412 may be formed.

[0162] An EL layer 403 is formed on the first electrode 401 and the auxiliary electrode 402. Embodiment 3 has the configuration described in Embodiments 1 to 3. Please refer to the relevant description. Note that the EL layer 403 is viewed from a planar perspective than the first electrode 401. Making it slightly larger suppresses short circuits between the first electrode 401 and the second electrode 404. This configuration is preferable because it can also serve as an insulating layer.

[0163] The EL layer 403 is covered to form the second electrode 404. The second electrode 404 is in Embodiment 1 This corresponds to the second electrode 102 in Embodiment 3 and has a similar configuration. In this state, since the light is extracted from the first electrode 401 side, the second electrode 404 is reversed It is preferable to form it with a material that has high emissivity. In this embodiment, the second electrode Voltage is supplied to pad 404 by connecting it to pad 412.

[0164] The above describes the first electrode 401, the EL layer 403, and the second electrode 404 (and auxiliary electrode 402) The lighting device shown in this embodiment has a light-emitting element having ). Because it is a light-emitting element with a high efficiency, the lighting device in this embodiment is a lighting device with low power consumption. It can be placed in this position. Furthermore, since this light-emitting element is a highly reliable light-emitting element, The lighting device in this embodiment can be a highly reliable lighting device.

[0165] The light-emitting element having the above configuration is sealed to the sealing substrate 407 using the sealing material 405. The lighting device is completed by stopping it. Either one of the sealant materials 405 is acceptable. Additionally, a desiccant can be mixed into the inner sealing material 405, which will absorb moisture. This allows for improved reliability.

[0166] Furthermore, the pad 412, the first electrode 401, and a portion of the auxiliary electrode 402 are sealed with the sealing material 405. By extending it outwards, it can be used as an external input terminal. An IC chip 420 equipped with a converter or similar may also be provided.

[0167] As described above, the lighting device described in this embodiment has an EL element in Embodiments 1 to 3 Because it has the described light-emitting element, it can be used as a lighting device with low power consumption. This allows for lighting devices with low drive voltages. Furthermore, it enables highly reliable lighting devices. It is possible.

[0168] (Embodiment 6) In this embodiment, the light-emitting element described in Embodiments 1 to 3 is included as a part thereof. Examples of electronic devices will be described. The light-emitting elements described in Embodiments 1 to 3 emit light. This light-emitting element has good efficiency and reduced power consumption. As a result, the following is described in this embodiment. The electronic device can be an electronic device having a light-emitting part with reduced power consumption. Furthermore, the light-emitting elements described in Embodiments 1 to 3 are light-emitting elements with a low driving voltage. Therefore, it is possible to create electronic devices with low drive voltages.

[0169] Examples of electronic devices to which the above light-emitting element is applied include television equipment (television, or television). (also called a revision receiver), monitors for computers, digital cameras, digital Video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices) ), portable game consoles, personal digital assistants, sound playback devices, large game machines such as pachinko machines, etc. These include [examples of electronic devices]. Specific examples of these electronic devices are shown below.

[0170] Figure 8(A) shows an example of a television system. The television system has a housing 710 The display unit 7103 is incorporated into part 1. Also, the housing is connected by the stand 7105. This shows the configuration supporting 7101. The display unit 7103 can display video. The display unit 7103 is capable of composing the light-emitting elements described in Embodiments 1 to 3. It is arranged in a cubic shape. The light-emitting element is designed to be a light-emitting element with good luminescence efficiency. This is possible. Furthermore, it is possible to create a light-emitting element with a low driving voltage. Also, the lifespan It is possible to make the light-emitting element long. Therefore, the display unit 7 composed of the light-emitting element A television device having 103 can be made into a television device with reduced power consumption. Yes, it is possible. Furthermore, it is possible to create a television system with a low drive voltage. Also, reliability This can result in a highly efficient television system.

[0171] The television equipment can be operated using the control switches on the housing 7101 or a separate remote control. This can be done using the device 7110. The remote control device 7110 has an operation key 7109. This allows you to control the channel and volume, and the video displayed on the display unit 7103 It can be operated. Also, the remote control unit 7110 A display unit 7107 that displays the information output from the unit may also be provided.

[0172] The television system shall consist of a receiver, modem, etc. It can receive television broadcasts, and also communicate via wired or wireless connection through a modem. By connecting to a network, one-way (sender to receiver) or two-way (sender to receiver) communication is possible. It is also possible to communicate information between recipients, or between recipients themselves.

[0173] Figure 8(B1) is a computer, consisting of the main unit 7201, the casing 7202, the display unit 7203, and a key - Includes board 7204, external connection port 7205, pointing device 7206, etc. Furthermore, this computer is similar to the one described in Embodiments 1 to 3. It is manufactured by arranging optical elements in a matrix and using them in the display unit 7203. (Figure 8) The computer in B1) may take the form shown in Figure 8(B2). The computer uses a second keyboard 7204 and a pointing device 7206 instead of the first one. A display unit 7210 is provided. The second display unit 7210 is a touch panel type. By operating the input display shown on the second display unit 7210 with a finger or a special pen, This allows input. In addition, the second display unit 7210 not only displays input, but also... It is also possible to display other images. Furthermore, the display unit 7203 is a touch panel. Good. The two screens are connected by a hinge, which makes it easier to store and transport the device. This also prevents problems such as scratches and damage. The data is displayed by arranging the light-emitting elements described in Embodiments 1 to 3 in a matrix. It is manufactured by using it in part 7203. The light-emitting element is a light-emitting element with good luminous efficiency and It is possible to do so. Therefore, a display unit 7203 composed of the light-emitting element is available. Computers can be made into computers with reduced power consumption.

[0174] Figure 8(C) shows a portable gaming machine, which consists of two cabinets, cabinet 7301 and cabinet 7302. The housing 7301 is connected in an openable and closable manner by the connecting part 7303. Display unit manufactured by arranging the light-emitting elements described in Embodiments 1 to 3 in a matrix. The 7304 is incorporated, and the display unit 7305 is incorporated into the housing 7302. The portable gaming machine shown in 8(C) also includes a speaker unit 7306 and a recording medium insertion unit 7307. LED lamp 7308, input means (operation key 7309, connection terminal 7310, sensor 73 11 (Force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical Chemical substances, sound, time, hardness, electric field, electric current, voltage, power, radiation, flow rate, humidity, gradient, vibration Equipped with a function to measure odor or infrared radiation, a microphone (7312), etc. Of course, the configuration of a portable gaming machine is not limited to those described above, and at least the display unit 73 Both or either of 04 and the display unit 7305 are described in Embodiments 1 to 3. It is sufficient to use a display unit made by arranging light-emitting elements in a matrix, and other accessories The configuration can be configured with appropriate equipment. The portable gaming machine shown in Figure 8(C) has a recording medium Functions that read programs or data stored in the body and display them on the display unit, and other portable devices It has the function of sharing information by communicating wirelessly with band-type gaming machines. The functions of a belt-type gaming machine are not limited to those mentioned above, and it can have a variety of functions. A portable gaming machine having a display unit 7304 such as the light-emitting element used in the display unit 7304 Since the child has good luminescence efficiency, it will be used to create a portable gaming machine with reduced power consumption. This is possible. In addition, the light-emitting elements used in the display unit 7304 can be driven with a low drive voltage. Because this is possible, it can be made into a portable gaming machine with a low drive voltage. Also, display The light-emitting element used in part 7304 is a long-life light-emitting element, thus providing high reliability. It can be used as a portable gaming machine.

[0175] Figure 8(D) shows an example of a mobile phone. The mobile phone is built into the housing 7401. In addition to the display unit 7402, there are operation buttons 7403, an external connection port 7404, and a speaker 74 05, it is equipped with a microphone 7406, etc. Note that the mobile phone is an embodiment of 1 to 1. The display unit 7402 is made by arranging the light-emitting elements described in Embodiment 3 in a matrix. The light-emitting element can be made into a light-emitting element with good luminous efficiency. Also, the driving voltage It is possible to create a light-emitting element that is very small. Furthermore, it is possible to create a light-emitting element with a long lifespan. Therefore, a mobile phone having a display unit 7402 composed of the said light-emitting element consumes It is possible to create a mobile phone with reduced power consumption. Also, it is possible to create a mobile phone with a low operating voltage. It is possible to do so. Furthermore, it is possible to create a highly reliable mobile phone.

[0176] The mobile phone shown in Figure 8(D) allows information to be entered by touching the display unit 7402 with a finger or the like. It is also possible to configure it so that you can make a phone call or compose an email. Operations such as this can be performed by touching the display unit 7402 with a finger or the like.

[0177] The display unit 7402 has three main modes. The first is a display that primarily displays images. The first mode is display mode, the second is input mode which is mainly for inputting information such as characters. The third is display mode. This is a display + input mode, which is a combination of two modes: display mode and input mode.

[0178] For example, when making a phone call or composing an email, the display unit 7402 is used for text input. The primary mode is text input, and you should perform the input operation for the characters displayed on the screen. It is preferable to display a keyboard or number buttons on most of the screen of the display unit 7402. It seems so.

[0179] Furthermore, the mobile phone has sensors inside that detect tilt, such as a gyroscope and an accelerometer. By providing an output device, the orientation of the mobile phone (vertical or horizontal) is determined, and the image of the display unit 7402 is displayed accordingly. The display can be configured to switch automatically.

[0180] Furthermore, screen modes can be switched by touching the display unit 7402 or by operating the housing 7401. This is done by operating button 7403. Also, the type of image displayed on display unit 7402 Therefore, it is also possible to switch between them. For example, the image signal displayed on the display unit is a video signal. Switch to display mode if it's data, or to input mode if it's text data.

[0181] Furthermore, in input mode, the signal detected by the optical sensor of the display unit 7402 is detected and displayed If there is no touch input on unit 7402 for a certain period of time, the screen mode will be changed to input mode. You may also control the system to switch from this mode to display mode.

[0182] The display unit 7402 can also function as an image sensor. For example, the display unit 74 By touching device 02 with the palm or fingers, the user can be authenticated by capturing images of their palm print, fingerprints, etc. Furthermore, the display unit may have a backlight that emits near-infrared light or a sensing light that emits near-infrared light. Using the appropriate source, it is also possible to image finger veins, palmar veins, and other veins.

[0183] The configuration shown in this embodiment is achieved by appropriately combining the configurations shown in Embodiments 1 to 5. They can be used together.

[0184] As described above, the scope of application of the light-emitting device equipped with the light-emitting element described in Embodiments 1 to 3 Its applications are extremely broad, making it possible to apply this light-emitting device to electronic equipment in all fields. By using the light-emitting elements described in Embodiments 1 to 3, power consumption can be reduced. You can obtain advanced electronic devices.

[0185] Figure 9 shows a liquid crystal light source as described in Embodiments 1 to 3 applied to a backlight. This is an example of a liquid crystal display device. The liquid crystal display device shown in Figure 9 consists of a housing 901, a liquid crystal layer 902, and It has a light unit 903 and a housing 904, and the liquid crystal layer 902 has a driver IC 905 and It is connected. Also, the backlight 903 is as described in Embodiments 1 to 3. A light-emitting element is used, and current is supplied via terminal 906.

[0186] Applying the light-emitting elements described in Embodiments 1 to 3 to the backlight of a liquid crystal display device As a result, a backlight with reduced power consumption can be obtained. Also, in Embodiment 1 By using the light-emitting element described in Embodiment 3, a surface-emitting illumination device can be manufactured, and large Area-based expansion is also possible. This allows for larger backlight areas, and is useful for liquid crystal display devices. This also makes it possible to increase the area. Furthermore, the light-emitting elements described in Embodiments 1 to 3 can be adapted The light-emitting device used can be made thinner compared to conventional devices, thus enabling the display device to be made thinner. .

[0187] Figure 10 shows the light-emitting element described in Embodiments 1 to 3, which is an electrical lighting device. This is an example of its use in a lamp. The lamp shown in Figure 10 consists of a housing 2001 and a light source 2002 The light source 2002 is the light-emitting element described in Embodiments 1 to 3. It is being done.

[0188] Figure 11 shows the light-emitting element described in Embodiments 1 to 3 in an indoor lighting device 300. This is an example of its use as 1. The light-emitting element described in Embodiments 1 to 3 has a power consumption of Because it is a reduced-power light-emitting device, it can be used as a lighting device with reduced power consumption. Furthermore, since the light-emitting elements described in Embodiments 1 to 3 can be made to have a large area, It can be used as a lighting device for the stack. Also, the following embodiments are described in Embodiments 1 to 3. Because the light-emitting element is thin, it can be used in a miniaturized lighting device.

[0189] The light-emitting elements described in Embodiments 1 to 3 are used in automobile windshields and dashcams. It can also be mounted on a board. Figure 12 shows the devices described in Embodiments 1 to 3. This shows one embodiment of using optical elements in the windshield and dashboard of an automobile. Display area 50 The display area 5005 is provided using the light-emitting elements described in Embodiments 1 to 3. It is possible.

[0190] Display area 5000 and display area 5001 are provided in an actual form on the windshield of an automobile. This is a display device equipped with the light-emitting elements described in Embodiments 1 to 3. The light-emitting element described in embodiment 3 is made of a first electrode and a second electrode made of a light-transmitting electrode. This will result in a display device that is transparent, allowing the other side to be seen through, a so-called see-through display device. This is possible. If the display is see-through, even if it is installed on the windshield of a car. It can be installed without obstructing the view. Furthermore, the transistor used for driving is When providing such a device, organic transistors made of organic semiconductor materials or oxide semiconductors are used. It is best to use transistors that are transparent to light, such as transistors.

[0191] The display area 5002 is provided in the pillar portion and is as described in Embodiments 1 to 3. This is a display device equipped with an optical element. The display area 5002 is an imaging means provided on the vehicle body. By displaying these images, the view obstructed by the pillars can be compensated for. Similarly, the display area 5003 provided on the dashboard is obscured by the vehicle body. The blind spots are compensated for by displaying images from imaging devices installed on the outside of the vehicle. This can enhance safety. By projecting images to complement the parts that are not visible, This allows for a more natural and seamless safety check.

[0192] Display areas 5004 and 5005 display navigation information, speedometer and tachometer It provides various information such as the meter reading, mileage, fuel level, gear status, and air conditioning settings. It is possible to change the display items and layout as needed to suit the user's preferences. This information can be provided in display areas 5000 to 5003. It is possible to use the display area 5000 to the display area 5005 as an illumination device. It is also possible.

[0193] The light-emitting elements described in Embodiments 1 to 3 are light-emitting elements with high luminous efficiency. This can be done. Furthermore, it can be a light-emitting device with low power consumption. Therefore, the display area Even with many large screens such as area 5000 or display area 5005, the battery is not burdened. Because it requires less weight to be placed on it and can be used comfortably, Embodiments 1 to 1 The light-emitting device or lighting device using the light-emitting element described in Embodiment 3 is a vehicle-mounted light-emitting device or lighting device. It can be suitably used as a device.

[0194] Figures 13(A) and 13(B) show examples of foldable tablet devices. 3(A) is in the open state, and the tablet terminal consists of a housing 9630 and a display unit 9631a Display unit 9631b, display mode switching switch 9034, power switch 9035, It has a power mode selector switch 9036, a fastener 9033, and an operation switch 9038. The tablet terminal is equipped with the light-emitting elements described in Embodiments 1 to 3. By using the light-emitting device in either or both of the display unit 9631a and the display unit 9631b It is made.

[0195] The display unit 9631a can be partially designated as a touch panel area 9632a, and the display will be Data can be entered by touching the operation key 9637. Note that the display unit 963 In 1a, as an example, one half of the area has a display-only function, and the other half of the area The diagram shows a configuration that includes touch panel functionality, but is not limited to this configuration. Display unit 963 The entire area of ​​1a may also be configured to have touch panel functionality. For example, the display unit 96 The entire surface of 31a is used as a touch panel with keyboard buttons, and the display unit 9631b is displayed. It can be used as a screen.

[0196] In addition, in the display unit 9631b, similar to the display unit 9631a, one of the display units 9631b The section can be designated as the touch panel area 9632b. Additionally, the touch panel keyboard... By touching the location where the display switch button 9639 is displayed with your finger or stylus, Keyboard buttons can be displayed on the display unit 9631b.

[0197] Furthermore, if you touch the touch panel area 9632a and the touch panel area 9632b simultaneously... You can also input "chi".

[0198] Additionally, the display mode switch 9034 selects the display orientation, such as portrait or landscape. You can switch between modes, such as black and white or color display. Power saving mode switching. Switch 9036 is detected by an optical sensor built into the tablet device when it is in use. The display brightness can be optimized according to the amount of light. In addition to sensors, other detection devices such as gyroscopes, accelerometers, and other sensors that detect tilt It may be built-in.

[0199] Furthermore, Figure 13(A) shows an example where the display area of ​​display unit 9631b and display unit 9631a are the same. However, this is not particularly limited, and one size may be different from the other. The quality of the display may also differ. For example, one display panel can provide a higher resolution display than the other. You can also use "ru".

[0200] Figure 13(B) shows the closed state, and in this embodiment, the tablet terminal has a casing. Body 9630, solar cell 9633, charge / discharge control circuit 9634, battery 9635, DCD An example is shown that includes a C converter 9636. Note that in Figure 13(B), the charge / discharge control circuit 963 As an example of 4, consider a configuration having a battery 9635 and a DC-DC converter 9636. It is showing.

[0201] Note that the tablet device is foldable, so when not in use, the casing 9630 is closed. This can be done. Therefore, the display units 9631a and 9631b can be protected. We can provide tablet devices that are highly durable and reliable from a long-term use perspective.

[0202] In addition, the tablet devices shown in Figures 13(A) and 13(B) are also available in various forms. Functions to display information (still images, videos, text images, etc.), calendar, date or time, etc. A function that displays information on the display unit, and a touch input operation or editing of the information displayed on the display unit. It has input capabilities, and functions to control processing through various software (programs), etc. It is possible.

[0203] The touch panel is powered by a solar cell 9633 mounted on the surface of the tablet device. It can be supplied to the display unit or the video signal processing unit, etc. Note that the solar cell 9633 is If provided on one or two sides of the housing 9630, efficient charging of the battery 9635 This configuration is preferable because it allows for the following actions to be performed.

[0204] Furthermore, the configuration and operation of the charge / discharge control circuit 9634 shown in Figure 13(B) are shown in Figure 13( A block diagram is shown and explained in C). Figure 13(C) shows solar cell 9633, battery 9 635, DC-DC converter 9636, converter 9638, switch SW1 to SW3 The display unit 9631 is shown, along with the battery 9635 and the DC-DC converter 963 6. Converter 9638 and switches SW1 to SW3 control the charge and discharge as shown in Figure 13(B). This corresponds to circuit 9634.

[0205] First, let's explain an example of how the solar cell 9633 operates when generating electricity using ambient light. The electricity generated by the solar panel is converted to DC to provide the voltage needed to charge the 9635 battery. The DC converter 9636 performs either a boost or a buck. Then, the display unit 9631 operates as follows: When power charged by solar cell 9633 is used, turn on switch SW1. The converter 9638 will boost or lower the voltage to the required level for the display unit 9631. When you do not want to display anything on the display unit 9631, turn SW1 off and turn SW2 on. The configuration should be designed to charge the 9635 battery.

[0206] While the solar cell 9633 is shown as an example of a power generation method, the power generation method is not particularly limited. It is not limited to other power generation devices such as piezoelectric elements (piezoelectric elements) and thermoelectric elements (Peltier elements). The battery 9635 may be charged by some means. A contactless power transmission module that charges by sending and receiving power, or a combination of other charging methods. This configuration is also acceptable, and it does not require a means of generating electricity.

[0207] Furthermore, if the above-mentioned display unit 9631a or 9631b is provided, the shape shown in Figure 13 This is not limited to tablet devices. [Examples]

[0208] Light-emitting element corresponding to one aspect of the present invention as described in Embodiments 1 to 3 of this embodiment The method of producing the offspring and its characteristics will be described below. The structure of the organic compound used in this example is described below. The formula is shown.

[0209] [ka]

[0210] Next, the method for fabricating the light-emitting element of this embodiment is shown.

[0211] First, indium oxide-tin oxide (ITSO) containing silicon oxide is sputtered onto a glass substrate. The first electrode 101 was formed by depositing a film using the ring method. The film thickness was set to 110 nm. The electrode area was set to 2 mm × 2 mm. Here, the first electrode 101 is the anode of the light-emitting element. It is a functional electrode.

[0212] Next, as a pretreatment for forming light-emitting elements on the substrate, the substrate surface is washed with water, and 200 After firing at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0213] Then, 10 -4 A substrate is introduced into a vacuum deposition apparatus where the internal pressure is reduced to approximately Pa, and then vacuum deposition is performed. After vacuum firing at 170°C for 30 minutes in the heating chamber of the apparatus, the substrate is left for approximately 30 minutes. It was allowed to cool.

[0214] Next, the first electrode 101 is formed such that the surface on which the first electrode 101 is formed faces downwards. The prepared substrate is fixed to a substrate holder provided inside the vacuum deposition apparatus, 10 -4 Reduced to approximately Pa After applying pressure, the above structural formula (i) is applied to the first electrode 101 by a vapor deposition method using resistance heating. 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophen By co-depositing (abbreviation: DBT3P-II) and molybdenum(VI) oxide, holes An injection layer 111 was formed. Its film thickness was set to 40 nm, and it was made of DBT3P-II and molybdenum oxide. The ratio of ingredients is adjusted to be 4:2 by weight (=DBT3P-II:molybdenum oxide). Co-evaporation is a method of vapor deposition in which multiple evaporation sources are used to deposit vapor simultaneously within a single processing chamber. It is the law.

[0215] Next, on the hole injection layer 111, 4-phenyl-4'-( represented by the above structural formula (ii) 9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP) 20 A film was deposited to a thickness of nm, forming a hole transport layer 112.

[0216] Furthermore, on the hole transport layer 112, 2-[3-(dibenzo) represented by the above structural formula (iii) is added. Thiofen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBT) PDBq-II) and 4-phenyl-4'-(9-phenyl represented by the above structural formula (iv) -9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP) and the above (2,3,5-triphenylpyradinate)(dipivaloylmethana) represented by structural formula (v) Iridium(III) (abbreviation: [Ir(tppr)2(dpm)]) and a weight ratio of 0 .5:0.5:0.05(=2mDBTPDBq-II:PCBA1BP:[Ir(tp The second light-emitting layer 113b is formed by co-depositing 20 nm so that it becomes pr)2(dpm)]), and The structural formula (vi) is 3,5-bis[3-(9H-carbazole-9-yl)fer [Nyl]pyridine (abbreviation: 35DCzPPy) and the above structural formula (vii), 3,3 '-Bis(9-phenyl-9H-carbazole) (abbreviation: PCCP) and the above structural formula (v iii) Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl) [Phenyl)-4H-1,2,4-triazole-3-yl-κN2]phenyl-κC} Iridium(III) (abbreviation: [Ir(mpptz-dmp)3]) and a weight ratio of 0.5 :0.5:0.06(=35DCzPPy:PCCP:[Ir(mpptz-dmp)3 The first light-emitting layer 113a was formed by co-depositing at a 30 nm depth so that ]) .

[0217] Subsequently, 2-[3-(dibenzothiophenate) represented by the above structural formula (ix) is placed on the light-emitting layer 113. [-4-yl)phenyl]-1-phenyl-1H-benzoimidazole (abbreviation: mDBT) BIm-II) is deposited to a thickness of 10 nm, and further, represented by the above structural formula (x) Bathophenanthroline (abbreviated as BPhen) is deposited to a thickness of 20 nm, and electron transport A transport layer 114 was formed.

[0218] After forming the electron transport layer 114, lithium fluoride (LiF) is then applied to a thickness of 1 nm. The electron injection layer 115 was formed by depositing the material in this manner.

[0219] Finally, as the second electrode 102 that functions as the cathode, aluminum is used with a film thickness of 200 nm. The light-emitting element 1 of this embodiment was fabricated by depositing the material in such a manner.

[0220] In the vapor deposition process described above, resistance heating was used for all deposition steps.

[0221] Table 1 shows the element structure of the light-emitting element 1 obtained as described above.

[0222] [Table 1]

[0223] The light-emitting element 1 is placed in a glove box under a nitrogen atmosphere, and is not exposed to the air. The process involves sealing with a substrate (applying sealing material around the element and sealing at 80°C for 1 hour). Heat treatment was performed.

[0224] The element characteristics of this light-emitting element were measured. The measurements were taken at room temperature (maintained at 25°C). It was done in a relaxed atmosphere.

[0225] Figure 14 shows the emission spectrum when a current of 0.1 mA is passed through the light-emitting element 1. Figure 14 Therefore, the light-emitting element 1 emits blue wavelength light originating from [Ir(mpptz-dmp)3] and [Ir( The emission spectrum shows that both red wavelengths of light originating from tppr)2(dpm) are present. It was discovered that...

[0226] Next, Figure 15 shows the brightness-current efficiency characteristics of the light-emitting element 1, and Figure 15 shows the brightness-external quantum efficiency characteristics. Figure 17 shows the voltage-luminance characteristics, and Figure 18 shows the luminance-power efficiency characteristics. Table 2 shows the main characteristics around 0 cd / m2.

[0227] [Table 2]

[0228] As described above, it was found that the light-emitting element 1 exhibits good element characteristics. In particular, Figure 15 and Figure 1 As can be seen from 6, it has very good luminous efficiency, and the external quantum efficiency is practical brightness (1000 cd / m 2 It showed a high value of 25% in the vicinity of ). Also, from Figure 17, the light-emitting element 1 It can be seen that this light-emitting element has good voltage-brightness characteristics and a low driving voltage. As shown in Figure 18, a light-emitting element with good power efficiency was obtained.

[0229] Thus, the light-emitting element 1 corresponding to one aspect of the present invention has good element characteristics, and there are two types It was found to be a light-emitting device that obtains light from the light-emitting central material in a well-balanced manner. [Examples]

[0230] Light-emitting element corresponding to one aspect of the present invention as described in Embodiments 1 to 3 of this embodiment The method of producing the offspring and its characteristics will be described below. The structure of the organic compound used in this example is described below. The formula is shown. In this embodiment, the light-emitting layer 113 is provided with a first light-emitting layer 113a, a second light-emitting layer 113b and Light-emitting elements 2 and 3, which include a third light-emitting layer 113c, were fabricated.

[0231] [ka]

[0232] Next, the method for fabricating the light-emitting element 2 of this embodiment is shown.

[0233] First, indium oxide-tin oxide (ITSO) containing silicon oxide is sputtered onto a glass substrate. The first electrode 101 was formed by depositing a film using the ring method. The film thickness was set to 110 nm. The electrode area was set to 2 mm × 2 mm. Here, the first electrode 101 is the anode of the light-emitting element. It is a functional electrode.

[0234] Next, as a pretreatment for forming light-emitting elements on the substrate, the substrate surface is washed with water, and 200 After firing at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0235] Then, 10 -4 A substrate is introduced into a vacuum deposition apparatus where the internal pressure is reduced to approximately Pa, and then vacuum deposition is performed. After vacuum firing at 170°C for 30 minutes in the heating chamber of the apparatus, the substrate is left for approximately 30 minutes. It was allowed to cool.

[0236] Next, the first electrode 101 is formed such that the surface on which the first electrode 101 is formed faces downwards. The prepared substrate is fixed to a substrate holder provided inside the vacuum deposition apparatus, 10 -4 Reduced to approximately Pa After pressing, DBT3P-II is deposited onto the first electrode 101 by a deposition method using resistance heating. A hole injection layer 111 was formed by co-depositing molybdenum(VI) oxide. The film thickness was The nm is set to 40 nm, and the ratio of DBT3P-II to molybdenum oxide is 4:2 by weight (=DB The mixture was adjusted to be T3P-II (molybdenum oxide). Note that co-evaporation is a method in which one process This is a vapor deposition method in which deposition is carried out simultaneously from multiple evaporation sources within the laboratory.

[0237] Next, BPAFLP is deposited on the hole injection layer 111 to a thickness of 20 nm, and the holes A transport layer 112 was formed.

[0238] Furthermore, on the hole transport layer 112, 2mDBTPDBq-II, PCBA1BP and [Ir( tppr)2(dpm)] and a weight ratio of 0.5:0.5:0.05 (=2mDBTPDB) q-II:PCBA1BP:[Ir(tppr)2(dpm)]) 10nm Co-deposited to form the third light-emitting layer 113c, and 2mDBTPDBq-II and PCBA1BP on top (acetylacetonato)bis(6-tert-butyl-4-) represented by the structural formula (xi) Phenylpyrimidina) Iridium(III) (Abbreviation: [Ir(tBuppm)2(ac ac)]) and the weight ratio is 0.5:0.5:0.05 (=2mDBTPDBq-II:PC Co-deposit 5nm so that BA1BP:[Ir(tBuppm)2(acac)]) The second light-emitting layer 113b is composed of 35DCzPPy, PCCP and [Ir(mpptz-dmp )3] and the weight ratio 0.5:0.5:0.06 (=35DCzPPy:PCCP:[Ir (mpptz-dmp)3) is co-deposited at 30 nm to form the first light-emitting layer 113a It formed.

[0239] Subsequently, mDBTBIm-II is deposited on the light-emitting layer 113 to a thickness of 10 nm, Furthermore, BPhen was deposited to a thickness of 20 nm to form an electron transport layer 114.

[0240] After forming the electron transport layer 114, lithium fluoride (LiF) is then applied to a thickness of 1 nm. The electron injection layer 115 was formed by depositing the material in this manner.

[0241] Finally, as the second electrode 102 that functions as the cathode, aluminum is used with a film thickness of 200 nm. The light-emitting element 2 of this embodiment was fabricated by depositing the material in such a manner.

[0242] In the vapor deposition process described above, resistance heating was used for all deposition steps.

[0243] Next, the method for fabricating the light-emitting element 3 will be explained. The light-emitting element 3 is the first element of the light-emitting element 2 This was fabricated by changing the film thickness of the light-emitting layer 113b from 5 nm to 10 nm. The other configurations are the same as those of light-emitting element 2.

[0244] Table 3 shows the element structures of the light-emitting element 2 and light-emitting element 3 obtained as described above.

[0245] [Table 3]

[0246] The light-emitting element 2 and the light-emitting element 3 are exposed to the atmosphere inside a glove box in a nitrogen atmosphere. The process of sealing with a glass substrate to prevent leakage (applying a sealing material around the element and sealing at 8 A heat treatment was performed at 0°C for 1 hour.

[0247] The element characteristics of this light-emitting element were measured. The measurements were taken at room temperature (maintained at 25°C). It was done in a relaxed atmosphere.

[0248] Figure 19 shows the emission spectra when a current of 0.1 mA is passed through light-emitting elements 2 and 3. As shown in Figure 19, both light-emitting element 2 and light-emitting element 3 are [Ir(mpptz-dmp)3] The blue wavelength light derived from [Ir(tBuppm)2(acac)] and the green light derived from [Ir(tBuppm)2(acac)] The light emitted contains red wavelengths of light originating from [Ir(tppr)2(dpm)]. It was found to exhibit a vector. In particular, light-emitting element 2 produces light that conforms to the JIS standard for illumination. It emitted light.

[0249] Next, Figure 20 shows the brightness-current efficiency characteristics of light-emitting element 2 and light-emitting element 3, and the brightness-external quantum efficiency characteristics. Efficiency characteristics are shown in Figure 21, voltage-luminance characteristics in Figure 22, and luminance-power efficiency characteristics in Figure 23. Also, 1000 cd / m² 2 Table 4 shows the main characteristics of the vicinity.

[0250] [Table 4]

[0251] As described above, it was found that light-emitting elements 2 and 3 exhibit good element characteristics. As can be seen from Figures 20 and 21, it has very good luminescence efficiency, and the external quantum efficiency is practical. Brightness (1000 cd / m²) 2 In the vicinity of ), it showed a high value exceeding 20%. Also, Figure 2 From 2, the light-emitting element 2 and the light-emitting element 3 have good voltage-brightness characteristics and a low driving voltage. It is clear that it is an optical element. As a result, as shown in Figure 23, it has good power efficiency. It became a light-emitting element.

[0252] Thus, the light-emitting element 2 and light-emitting element 3 corresponding to one aspect of the present invention have good element characteristics. Furthermore, it was found to be a light-emitting element that obtains light from three types of light-emitting central materials in a well-balanced manner. It was. [Examples]

[0253] Light-emitting element corresponding to one aspect of the present invention as described in Embodiments 1 to 3 of this embodiment The method of producing the offspring and its characteristics will be described below. The structure of the organic compound used in this example is described below. The formula is shown. In this embodiment, the light-emitting layer 113 is provided with a first light-emitting layer 113a, a second light-emitting layer 113b and A light-emitting element 4, which includes a third light-emitting layer 113c, was fabricated.

[0254] [ka]

[0255] Next, the method for fabricating the light-emitting element 4 in this embodiment is shown.

[0256] First, indium oxide-tin oxide (ITSO) containing silicon oxide is sputtered onto a glass substrate. The first electrode 101 was formed by depositing a film using the ring method. The film thickness was set to 110 nm. The electrode area was set to 2 mm × 2 mm. Here, the first electrode 101 is the anode of the light-emitting element. It is a functional electrode.

[0257] Next, as a pretreatment for forming light-emitting elements on the substrate, the substrate surface is washed with water, and 200 After firing at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0258] Then, 10 -4 A substrate is introduced into a vacuum deposition apparatus where the internal pressure is reduced to approximately Pa, and then vacuum deposition is performed. After vacuum firing at 170°C for 30 minutes in the heating chamber of the apparatus, the substrate is left for approximately 30 minutes. It was allowed to cool.

[0259] Next, the first electrode 101 is formed such that the surface on which the first electrode 101 is formed faces downwards. The prepared substrate is fixed to a substrate holder provided inside the vacuum deposition apparatus, 10 -4 Reduced to approximately Pa After pressing, DBT3P-II is deposited onto the first electrode 101 by a deposition method using resistance heating. A hole injection layer 111 was formed by co-depositing molybdenum(VI) oxide. The film thickness was The nm is set to 40 nm, and the ratio of DBT3P-II to molybdenum oxide is 4:2 by weight (=DB The mixture was adjusted to be T3P-II (molybdenum oxide). Note that co-evaporation is a method in which one process This is a vapor deposition method in which deposition is carried out simultaneously from multiple evaporation sources within the laboratory.

[0260] Next, on the hole injection layer 111, 4,4'-di(1-naphthol) represented by the above structural formula (xii) is injected. (Tyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine A film (abbreviated as PCBNBB) is deposited to a thickness of 20 nm to form a hole transport layer 112. did.

[0261] Furthermore, on the hole transport layer 112, 2-[3'-(gibe, represented by the above structural formula (xiii)) [Nzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline ( Abbreviations: 2mDBTBPDBq-II) and PCBNBB and [Ir(tppr)2(dpm) ] and, in a weight ratio of 0.5:0.5:0.05 (=2mDBTBPDBq-II:PCBNB A third light-emitting layer is formed by co-depositing 20 nm of material so that B:[Ir(tppr)2(dpm)]). Let 113c be used, and 2mDBTBPDBq-II and PCBNBB and [Ir(tBuppm)2 (acac)] and, in weight ratio 0.5:0.5:0.05 (=2mDBTBPDBq-II :PCBNBB:[Ir(tBuppm)2(acac)]) 10nm co-evaporation This is used to form the second light-emitting layer 113b, and 35DCzPPy, PCCP and [Ir(mpptz- dmp)3] and the weight ratio 0.7:0.3:0.06 (=35DCzPPy:PCCP: The first light-emitting layer 1 is co-deposited at a density of 30 nm so that it becomes [Ir(mpptz-dmp)3]). Formation 13a was created.

[0262] Subsequently, 35DCzPPy is deposited on the light-emitting layer 113 to a thickness of 10 nm, and further Then, BPhen was deposited to a thickness of 20 nm to form an electron transport layer 114.

[0263] After forming the electron transport layer 114, lithium fluoride (LiF) is then applied to a thickness of 1 nm. The electron injection layer 115 was formed by depositing the material in this manner.

[0264] Finally, as the second electrode 102 that functions as the cathode, aluminum is used with a film thickness of 200 nm. The light-emitting element 4 of this embodiment was fabricated by depositing the material in such a manner.

[0265] In the vapor deposition process described above, resistance heating was used for all deposition steps.

[0266] Table 5 shows the element structure of the light-emitting element 4 obtained as described above.

[0267] [Table 5]

[0268] The light-emitting element 4 is placed in a glove box under a nitrogen atmosphere, and is not exposed to the air. The process involves sealing with a substrate (applying sealing material around the element and sealing at 80°C for 1 hour). Heat treatment was performed.

[0269] The element characteristics of this light-emitting element were measured. The measurements were taken at room temperature (maintained at 25°C). It was done in a relaxed atmosphere.

[0270] Figure 24 shows the emission spectrum when a current of 0.1 mA is passed through the light-emitting element 4. Figure 24 So, the blue wavelength light originating from [Ir(mpptz-dmp)3] and [Ir(tBupp Green light originating from [m)2(acac)], and from [Ir(tppr)2(dpm)] It was found that the emission spectrum included light of all wavelengths of red.

[0271] Next, the brightness-current efficiency characteristics of the light-emitting element 4 are shown in Figure 25, and the brightness-external quantum efficiency characteristics are shown in Figure 2. Figure 27 shows the voltage-luminance characteristics, and Figure 28 shows the luminance-power efficiency characteristics. 0 cd / m 2 Table 6 shows the main characteristics of the vicinity.

[0272] [Table 6]

[0273] As described above, it was found that the light-emitting element 4 exhibits good element characteristics. In particular, Figures 25 and 2 As can be seen from 6, it has very good luminous efficiency, and the external quantum efficiency is practical brightness (1000 cd / m 2 In the vicinity of ), it showed a high value exceeding 20%. Also, from Figure 27, the light-emitting element It can be seen that sub-element 4 has good voltage-brightness characteristics and is a light-emitting element with a low driving voltage. As a result, as shown in Figure 28, a light-emitting element with good power efficiency was obtained.

[0274] Thus, the light-emitting element 4 corresponding to one aspect of the present invention has good element characteristics, and there are three types It was found to be a light-emitting device that obtains light from the light-emitting central material in a well-balanced manner.

[0275] Additionally, the initial brightness is set to 3000 cd / m². 2 The light-emitting element 4 is driven under the condition of constant current density. The results of the reliability test are shown in Figure 29. Figure 29 is the standard with the initial brightness set to 100%. This shows the change in brightness. From this result, the light-emitting element 4 exhibits a small decrease in brightness with respect to the operating time. This indicates that the light-emitting element has good reliability.

[0276] (Reference example 1) In the above-described embodiment, the 35DCzPPy, PCCP, and 2mDBT were used in each light-emitting element. Triplet of PDBq-II, PCBA1BP, 2mDBTBPDBq-II, PCBNBB The excitation energy was measured. Note that the triplet excitation energy was measured using phosphorescence of each substance. The emission was measured and the phosphorescence wavelength was converted to electron volts to determine the value. In this study, each substance was irradiated with excitation light at 325 nm, and measurements were taken at a measurement temperature of 10 K. Measuring energy levels is more accurate when calculated from absorption wavelengths than from emission wavelengths. However, However, the absorption of triplet excitation energy is extremely weak and difficult to measure, therefore Here, by measuring the peak wavelength located at the shortest wavelength end of the phosphorescence spectrum, triple The excitation energy was determined. Therefore, the measured values ​​should be assumed to contain some error.

[0277] The measured phosphorescence is shown in Figures 30 to 35. The measurement results are summarized in Table 7. As can be seen from the results, the 35DCzPPy and PCCP used in the first light-emitting layer were 2mDBTPDBq-II, PCBA1BP, used in the second or third light-emitting layer. It was found that 2mDBTBPDBq-II has a higher triplet excitation energy than PCBNBB. ru.

[0278] [Table 7]

[0279] (Reference example 2) The organometallic complex used in the above examples, (acetylacetonato)bis(6-tert-butyl -4-phenylpyrimidinato)iridium(III) (also known as: bis[2-(6-tert -butyl-4-pyrimidinyl-κN3)phenyl-κC](2,4-pentanedionato- κ 2 O,O') Iridium(III) (Abbreviation: [Ir(tBuppm)2(acac) An example of the synthesis of [Ir(tBuppm)2(acac)] is shown below. vinegar.

[0280] [ka]

[0281] Step 1; 4-tert-butyl-6-phenylpyrimidine (abbreviation: HtBuppm) ) synthesis > First, 22.5g of 4,4-dimethyl-1-phenylpentane-1,3-dione and formaldehyde 50g of Mido was placed in a round-bottom flask fitted with a reflux condenser, and the inside was purged with nitrogen. This reaction vessel The reaction solution was refluxed for 5 hours by heating. After that, this solution was treated with sodium hydroxide solution. The organic layer was poured into a solution and extracted with dichloromethane. The obtained organic layer was then mixed with water and saturated saline solution. The solution was washed and dried with magnesium sulfate. The dried solution was filtered. After removing the flux by distillation, the resulting residue is dissolved in hexane:ethyl acetate = 10:1 (volume ratio) The pyrimidine derivative HtBupp was purified using silica gel column chromatography as the substrate. We obtained m (colorless oil, yield 14%). The synthesis scheme for Step 1 is shown below.

[0282] [ka]

[0283] Step 2; Di-μ-chloro-bis[bis(6-tert-butyl-4-phenylpyryl] Synthesis of midinato iridium(III) (abbreviation: [Ir(tBuppm)2Cl]2) > Next, add 15 mL of 2-ethoxyethanol and 5 mL of water, and the HtBupp obtained in step 1 above. 1.49g of m and 1.04g of iridium chloride hydrate (IrCl3·H2O) were added to a reflux tubing. It was placed in a round-bottom flask, and the flask was purged with argon. Then, microwave (2.4 The mixture was irradiated with 5GHz (100W) for 1 hour to allow the reaction to proceed. After removing the solvent by distillation, the resulting residue was collected. The dinuclear complex [Ir(tBuppm)2Cl]2 was obtained by suction filtration and washing with ethanol (yellow). Green powder, yield 73%. The synthesis scheme for Step 2 is shown below.

[0284] [ka]

[0285] Step 3; (Acetylacetonato)bis(6-tert-butyl-4-phenylpyryl) Iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]) > Furthermore, 40 mL of 2-ethoxyethanol and the dinuclear complex [Ir(tB) obtained in step 2 above are added. [uppm)2Cl] 21.61g, acetylacetone 0.36g, sodium carbonate 1. 27g was placed in a round-bottom flask fitted with a reflux tubing, and the flask was purged with argon. The mixture was then irradiated with microwaves (2.45 GHz, 120 W) for 60 minutes to allow the reaction to proceed. The solvent was then removed by distillation. The resulting residue was filtered by suction with ethanol and washed with water and ethanol. This solid was then processed. Dissolve in chloromethane and use Celite (Wako Pure Chemical Industries, Ltd., catalog number: 531-1) The solution was filtered through a filtration aid consisting of layers of 6855), alumina, and Celite. The resulting solid is then recrystallized in a mixed solvent of dichloromethane and hexane. The target product was obtained as a yellow powder (yield 68%). The synthesis scheme for Step 3 is shown below.

[0286] [ka]

[0287] Nuclear magnetic resonance spectroscopy of the yellow powder obtained in step 3 above ( 1 Analysis results by 1H NMR The results are shown below. From these results, the organometallic complex Ir(tBuppm)2(acac) was obtained. It was discovered that...

[0288] 1 H NMR.δ(CDCl3):1.50(s,18H),1.79(s,6H), 5.26(s,1H),6.33(d,2H),6.77(t,2H),6.85(t, 2H),7.70(d,2H),7.76(s,2H),9.02(s,2H)

[0289] (Reference example 3) In this reference example, the tris{2-[5-(2-methylphenyl)-4- (2,6-dimethylphenyl)-4H-1,2,4-triazole-3-yl-κN2] Phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]) The synthesis method will be explained. The structure of [Ir(mpptz-dmp)3] is shown below.

[0290] [ka]

[0291] <Step 1: Synthesis of N-benzoyl-N'-2-methylbenzoylhydrazide> First, benzoylhydrazine 15.0g (110.0 mmol), N-methyl-2-p 75 ml of lorizinone (NMP) was placed in a 300 ml three-necked flask and stirred under ice cooling. To the mixed solution, add 17.0 g (110.0 mmol) of o-toluyl chloride and N-methyl- A mixed solution of 15 ml of 2-pyrrolizinone (NMP) was slowly added dropwise. After addition, the mixture was left at room temperature for 2 The mixture was stirred for 4 hours. After the predetermined reaction time, the reaction solution was slowly added to 500 ml of water, and white A colored solid precipitated. The precipitated solid was ultrasonically washed alternately with water and 1M hydrochloric acid. After that, hex Ultrasonic cleaning was performed using Sun, and the white of N-benzoyl-N'-2-methylbenzoylhydrazide was removed. 19.5 g of colored solid was obtained with a yield of 70%. The synthesis scheme for Step 1 is shown below.

[0292] [ka]

[0293] <Step 2; N-[1-chloro-1-(2-methylphenyl)methylidene-N'-[1 Synthesis of chloro-(1-phenyl)methylidene]hydrazine Next, N-benzoyl-N'-2-methylbenzoylhydrazide 1 obtained in step 1 above. 2.0 g (47.2 mmol) of toluene was placed in a 500 ml three-necked flask. Add 19.4 g (94.4 mmol) of phosphorus pentachloride to this mixed solution and incubate at 120°C for 6 hours. The mixture was heated and stirred. After the specified reaction time, the reaction solution was slowly poured into 200 ml of water and stirred for 1 hour. After stirring, the organic layer and the aqueous layer were separated, and the organic layer was mixed with water and saturated sodium bicarbonate aqueous solution. It was washed with [a specific method]. After washing, the organic layer was dried with anhydrous magnesium sulfate. From this mixture, a natural [compound] was obtained. By removing magnesium sulfate through filtration and concentrating the filtrate, N-[1-chloro-1- [(2-methylphenyl)methylidene]-N'-[1-chloro-(1-phenyl)methylidene] 12.6 g of a brown liquid of hydrazine was obtained in 92% yield. Synthesis scheme of Step 2 The following is shown.

[0294] [ka]

[0295] <Step 3; 3-(2-methylphenyl)-4-(2,6-dimethylphenyl)-5- Synthesis of phenyl-4H-1,2,4-triazole (abbreviation: Hmpptz-dmp) First, the N-[1-chloro-1-(2-methylphenyl)meth [Lyden]-N'-[1-chloro-(1-phenyl)methylidene]hydrazine 12.6g ( 43.3 mmol), 2,6-dimethylaniline 15.7 g (134.5 mmol), N , Place 100 ml of N-dimethylaniline in a 500 ml round-bottom flask and heat at 120°C for 20 hours The mixture was heated and stirred. After the predetermined reaction time, the reaction solution was slowly added to 200 ml of 1N hydrochloric acid. Dichloromethane was added to this solution and the target substance was extracted into the organic layer. The resulting organic layer was then mixed with water and carbon dioxide. Washed with sodium oxyhydrogen aqueous solution and dried with magnesium sulfate. Sulfuric acid was removed by natural filtration. Magnesium was removed, and the resulting filtrate was concentrated to obtain a black liquid. This liquid was then treated with silica gel. The cells were purified by 12-column chromatography. The developing solvent was ethyl acetate:hexane = 1:5. The resulting fraction was concentrated to obtain a white solid. This solid was then treated with ethyl acetate. Recrystallization was performed to obtain 4.5 g of a white solid of Hmpptz-dmp in a yield of 31%. The synthesis scheme for P3 is shown below.

[0296] [ka]

[0297] <Step 4: Synthesis of [Ir(mpptz-dmp)3]> The ligand Hmpptz-dmp obtained in step 3 above, 2.5g (7.4 mmol), 0.7g (1.5 mmol) of acetylacetonatoiridium(III) was heated to a high temperature. The mixture was placed in a container and degassed. This reaction vessel was then subjected to a 48-hour reaction at 250°C while argon flowed through it. The mixture was heated and stirred. After the reaction for a predetermined time, the resulting solid was washed with dichloromethane, and the green color of the insoluble material was detected. The solid was obtained by suction filtration. This solid was dissolved in toluene, and a layer of alumina and Celite was formed. The fraction was filtered through [a specific filter]. The resulting fraction was concentrated to obtain a green solid. This solid was then [referred to] [a specific filter]. Recrystallization was performed using [method / tool], yielding 0.8 g of green powder in a yield of 45%. Synthesis scheme for Step 4 The following is shown.

[0298] [ka]

[0299] Furthermore, nuclear magnetic resonance spectroscopy of the green powder obtained in step 4 above ( 1 (H-NMR) The analysis results are shown below. From this, it can be concluded that [Ir(mpptz-dmp) It was found that [3] was obtained.

[0300] 1 H-NMR.δ(toluene-d8):1.82(s,9H),1.90(s, 9H),2.64(s,9H),6.56-6.62(m,9H),6.67-6.75 (m,9H),6.82-6.88(m,3H),6.91-6.97(t,3H),7 .00-7.12(m,6H),7.63-7.67(d,3H) [Explanation of symbols]

[0301] 101 First electrode 102 Second electrode 103 EL layer 111 Hole injection layer 112 Hole transport layer 113 Emitting layer 113a First light-emitting layer 113Da First phosphorescent compound 113Ha1 First host material 113Ha2 Second host material 113b Second light-emitting layer 113Db Second phosphorescent compound 113H1 First carrier transport compound 113H2 is the second carrier transport compound. 113c Third luminescent layer 113Dc The third phosphorescent compound 113H3 is a third carrier transport compound. 113H4: The fourth carrier transport compound 114 Electron transport layer 115 Electron injection layer 400 circuit boards 401 First electrode 402 Auxiliary electrode 403 EL layer 404 Second electrode 405 sealant 407 Sealing substrate 412 pads 420 IC chips 501 First electrode 502 Second electrode 511 First light-emitting unit 512 Second light-emitting unit 513 Charge generation layer 601 Drive circuit section (source line drive circuit) 602 pixel section 603 Drive circuit section (gate wire drive circuit) 604 Sealing substrate 605 Sealant 607 Space 608 Wiring 609 FPC (Flexible Printed Circuit) 610 element substrate 611 Switching TFT 612 Current-controlled TFT 613 First electrode 614 Insulators 616 EL layer 617 Second electrode 618 Light-emitting element 623 n-channel TFT 624 p-channel TFT 625 Dry material 901 cabinet 902 Liquid Crystal Layer 903 Backlight Unit 904 cabinet 905 Driver IC 906 terminal 951 circuit board 952 Electrode 953 Insulating layer 954 Partition layer 955 EL layer 956 Electrode 1001 circuit board 1002 Underlying insulating film 1003 Gate Insulator 10:06 Guard Station 1007 🙏 1008 Gate 1020 First interlayer insulating film 1021 Second interlayer insulating film 1022 electrode First electrode of 1024W light-emitting element First electrode of 1024R light-emitting element First electrode of 1024G light-emitting element 1024B First electrode of light-emitting element 1025 Bulkhead 1028 EL layer 1029 Second electrode of light-emitting element 1031 Sealing substrate 1032 Sealant 1033 Transparent base material 1034R Red colored layer 1034G Green colored layer 1034B Blue colored layer 1035 Black Matrix 1036 Overcoat layer 1037 Third interlayer insulating film 1040 pixel section 1041 Drive circuit section 1042 Peripheral area 1044W White light emission area 1044R Red light emission area 1044B Blue light emission region 1044G Green luminescence region 2001 cabinet 2002 light source 3001 Lighting device 5000 display area 5001 Display area 5002 Display area 5003 Display area 5004 Display area 5005 Display area 7101 enclosure 7103 Display section 7105 Stand 7107 Display section 7109 Operation Keys 7110 Remote Control Unit 7201 Main Unit 7202 enclosure 7203 Display section 7204 Keyboard 7205 External connection port 7206 Pointing device 7210 Second display unit 7301 enclosure 7302 enclosure 7303 Connection section 7304 Display section 7305 Display section 7306 Speaker section 7307 Recording media insertion section 7308 LED Lamp 7309 Operation Keys 7310 Connection terminal 7311 Sensor 7401 enclosure 7402 Display section 7403 Operation Buttons 7404 External connection port 7405 Speaker 7406 Microphone 9033 Fastener 9034 Switch 9035 Power switch 9036 Switch 9038 Operation switch 9630 cabinet 9631 Display section 9631a Display section 9631b Display section 9632a Touch panel area 9632b Touch panel area 9633 Solar Cell 9634 Charge / Discharge Control Circuit 9635 Battery 9636 DC-DC converter 9637 Operation Keys 9638 converter 9639 button

Claims

[Claim 1] Between the anode and cathode, there is a first light-emitting layer comprising a first phosphorescent compound and a first host material, and a second light-emitting layer comprising a second phosphorescent compound, a first electron-transporting compound and a first hole-transporting compound. The emission wavelength of the second phosphorescent compound is longer than the emission wavelength of the first phosphorescent compound. The first electron-transporting compound and the first hole-transporting compound are a combination that forms a first excited complex. The difference between the energy equivalent of the peak wavelength of the emission spectrum of the first excited complex and the energy equivalent of the peak wavelength of the lowest energy absorption band of the second phosphorescent compound is within 0.2 eV. The triplet excitation energy of the first host material is greater than or equal to the triplet excitation energy of either the first electron-transporting compound or the first hole-transporting compound. A light-emitting element in which the first light-emitting layer and the second light-emitting layer are in contact with each other.

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