Light-emitting elements, lighting devices, light-emitting devices, display devices, and electronic devices

Abstract

To provide a light-emitting element using a plurality of light emitting dopant, which has high light-emitting efficiency, and provide each of a light-emitting device, a light-emitting module, a light-emitting display device, an electronic apparatus, and an illuminating device, in which a power consumption is reduced by using the light-emitting element as mentioned.SOLUTION: By focusing on a Foerster mechanism as one of an intermolecular energy transfer mechanism, an energy transfer in the Foerster mechanism can be efficiently performed by overlapping a light emission wavelength of an energy giving side molecule and a peak having a local maximum on the longest wavelength side in a graph obtained by multiplying an absorption spectrum on the side of receiving energy by a wavelength to the fourth power.SELECTED DRAWING: Figure 2

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 mass-produce them 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 allows for the formation of large-area elements. 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. Each is injected into the light-emitting EL layer, and an electric current flows. Then, the injected electrons and holes By recombining, the luminescent organic compound enters an excited state, and the excited luminescent organic Light can be obtained from compounds.

[0006] Organic compounds can form two types of excited states: singlet excited states and triplet excited states. , singlet excited state (S * ) emits fluorescence, triplet excited state (T * ) Light is emitted from It is called light. Furthermore, the statistical generation ratio of the light-emitting element is S * :T * = It is believed to be 1:3.

[0007] Compounds that emit light from a singlet excited state (hereinafter referred to as fluorescent compounds) emit light at room temperature. Normally, no light emission (phosphorescence) from the triplet excited state is observed, but no light emission (firefly) from the singlet excited state is observed. Only light is observed. Therefore, the internal quantum effect in a light-emitting device using a fluorescent compound is... The theoretical limit of the rate (the ratio of photons generated to the injected carriers) is S * :T * = The figure of 25% is based on the 1:3 ratio.

[0008] On the other hand, if we use a compound that emits light from a triplet excited state (hereinafter referred to as a phosphorescent compound), Luminescence (phosphorescence) from the triplet excited state is observed. Furthermore, phosphorescent compounds exhibit intersystem crossing. Because transitions from singlet excited states to triplet excited states occur easily, the internal quantum efficiency is 1 Theoretically, it is possible to achieve up to 00%. In other words, it is possible to achieve a higher luminescence efficiency than that of fluorescent compounds. Therefore, in order to realize a highly efficient light-emitting element, phosphorescent compounds are 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 phosphorescent compounds theoretically allow for 100% internal quantum efficiency, the device structure and other materials... Without optimizing the combination of ingredients, it is difficult to achieve high efficiency. In particular, different ingredients In a light-emitting element that uses multiple types of phosphorescent compounds of different luminescent colors as luminescent dopants, This involves considering not only energy transfer, but also the efficiency of the energy transfer itself. Without optimization, it is difficult to obtain highly efficient light emission. In fact, in the above-mentioned Patent Document 1, light emission Even if all the dopants are phosphorescent elements, the external quantum efficiency is only about 3-4%. Even considering the light extraction efficiency, the internal quantum efficiency is thought to be less than 20%. Therefore, it must be said that this is a low value for a phosphorescent light-emitting element.

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

[0013] Therefore, in one aspect of the present invention, in a light-emitting element using a plurality of light-emitting dopants, the light-emitting effect The objective is to provide a light-emitting element with a high efficiency. Another aspect of the present invention is the above-mentioned light-emitting element By using this technology, power consumption is reduced in light-emitting devices, display devices, electronic devices, and lighting. The purpose is to provide each device individually.

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

[0015] In this invention, we focus on the Förster mechanism, which is one of the intermolecular energy transfer mechanisms, and energy The peak of the emission spectrum of the energy-donating molecule and the absorption spectrum of the energy-receiving molecule. The peak with the longest wavelength maxima in the characteristic curve obtained by multiplying the spectrum by the fourth power of the wavelength. By applying a combination of molecules such that the above-mentioned Förster mechanism is achieved This enables efficient energy transfer in general. Here, the above energy transfer is general This is not energy transfer from host to dopant, but energy transfer between dopants. One of its characteristics is that the energy transfer efficiency between Dopants is high. Apply a combination of dopants that achieves the desired result, and furthermore, appropriately isolate each dopant molecule. By designing such an element structure, a light-emitting element according to one embodiment of the present invention can be obtained.

[0016] In other words, one aspect of the present invention involves a first phosphorescent compound between a pair of electrodes, and a first host A first light-emitting layer dispersed in the material, and a second phosphorescent compound that exhibits light emission at a longer wavelength than the first phosphorescent compound. The second phosphorescent compound comprises a second light-emitting layer dispersed in a second host material, and the second ε(λ)λ of a phosphorescent compound 4 wherein the wavelength of the maximum value located on the longest wavelength side of the function represented by overlaps with the phosphorescence emission spectrum F(λ) of the first phosphorescent compound. (provided that ε(λ) represents the molar absorptivity of each phosphorescent compound, and is a function of wavelength λ.)

[0017] In another aspect of the present invention, between a pair of electrodes, there are: a first light-emitting layer in which a first phosphorescent compound is dispersed in a first host material; and a second light-emitting layer in which a second phosphorescent compound that emits light at a longer wavelength than the first phosphorescent compound is dispersed in a second host material, wherein the peak comprising the maximum value of the phosphorescence emission spectrum of the first phosphorescent compound and the peak comprising the maximum value located on the longest wavelength side of the function represented by ε(λ)λ of the second phosphorescent compound ε(λ)λ 4 of the second phosphorescent compound overlap with each other. (provided that ε(λ) represents the molar absorptivity of each phosphorescent compound , and is a function of wavelength λ.) and is a function of wavelength λ.)

[0018] In another aspect of the present invention, in the above configuration, the first light-emitting layer further comprises a first organic compound, the first host material and the first organic compound form an exciplex, and the light emission of the first phosphorescent compound is at a longer wavelength than the light emission of the exciplex.

[0019] In another aspect of the present invention, in the above configuration, the wavelength of the maximum value located on the longest wavelength side of the function represented by ε(λ)λ of the first phosphorescent compound 4 wherein the wavelength of the maximum value located on the longest wavelength side of the function represented by overlaps with the emission spectrum of the exciplex. (provided that ε(λ) represents the molar absorptivity of each phosphorescent compound, and is a function of wavelength λ.)

[0020] Furthermore, in another aspect of the present invention, in the above configuration, the maximum value of the emission spectrum of the excited complex The mountains included and the first phosphorescent compound ε(λ)λ 4 The longest wavelength side of the function represented by This is a light-emitting element where the peak containing the local maximum value overlaps. (where ε(λ) is each phosphor (This represents the molar extinction coefficient of a photoactive compound, as a function of wavelength λ.)

[0021] Furthermore, in another aspect of the present invention, in the above configuration, the first phosphorescent compound is 500 nm The second phosphorescent compound has a phosphorescent emission peak in the range of up to 600 nm. This is a light-emitting element that has a phosphorescent emission peak in the range of m to 700 nm.

[0022] Furthermore, in another aspect of the present invention, in the above configuration, the electron-hole recombination region is the first light emission It is a light-emitting element that is a layer.

[0023] Furthermore, in another aspect of the present invention, in the above configuration, the first light-emitting layer is positioned above the anode of the second light-emitting layer. Located on the side, at least the second light-emitting layer is a light-emitting element with higher electron transport properties than hole transport properties. He is a child.

[0024] Furthermore, in another aspect of the present invention, in the above configuration, the first light-emitting layer is positioned above the anode of the second light-emitting layer. Located on the side, the first host material and the second host material both possess electron transport properties. It is an optical element. Furthermore, among materials with electron transport properties, those with higher electron transport properties than those with hole transport properties are preferred. materials preferred

[0025] Another aspect of the present invention is, in the above configuration, the first light-emitting layer is more cathode than the second light-emitting layer. Located on the side, at least the second light-emitting layer is a light-emitting element with higher hole transport properties than electron transport properties. He is a child.

[0026] Another aspect of the present invention is, in the above configuration, the first light-emitting layer is more cathode than the second light-emitting layer. Located on the side, the first host material and the second host material both have hole transport properties. It is an optical element. Furthermore, among materials with hole transport properties, those with higher hole transport properties than those with higher electron transport properties are preferred. A good material is preferred.

[0027] Furthermore, in another aspect of the present invention, in the above configuration, the first light-emitting layer and the second light-emitting layer are relative to each other. It is a light-emitting element that is stacked in contact with the other element.

[0028] 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.

[0029] In this specification, the term "light-emitting device" includes image display devices that use light-emitting elements. Furthermore, a connector, such as an anisotropic conductive film, or TCP (Tape C) is attached to the light-emitting element. Modules with the Arrier Package installed, print distribution to the TCP destination A module equipped with a wire plate, or a light-emitting element, with a COG (Chip On Glass) The formula includes all modules on which ICs (integrated circuits) are directly mounted as light-emitting devices. Furthermore, this also includes light-emitting devices used in lighting fixtures and the like. [Effects of the Invention]

[0030] One aspect of the present invention can provide a light-emitting element with high luminescence efficiency. One aspect of the present invention can provide the light-emitting element By using this, a light-emitting device, a light-emitting display device, an electronic device, and a power-saving device can be produced with reduced power consumption. We can provide lighting equipment. [Brief explanation of the drawing]

[0031] [Figure 1] Conceptual diagram of a light-emitting element. [Figure 2] Diagram illustrating energy transfer in the light-emitting layer. [Figure 3] A diagram illustrating the movement of Förster. [Figure 4] Conceptual diagram of an active matrix light-emitting device. [Figure 5] Conceptual diagram of a passive matrix type light-emitting device. [Figure 6] Conceptual diagram of an active matrix light-emitting device. [Figure 7] Conceptual diagram of an active matrix light-emitting device. [Figure 8] Conceptual diagram of a lighting device. [Figure 9] A diagram representing electronic devices. [Figure 10] A diagram representing electronic devices. [Figure 11] A diagram representing a lighting device. [Figure 12] A diagram illustrating lighting and display devices. [Figure 13] A diagram showing an in-vehicle display device and lighting system. [Figure 14] A diagram representing electronic devices. [Figure 15] Brightness-current efficiency characteristics of light-emitting element 1. [Figure 16] Voltage-luminance characteristics of light-emitting element 1. [Figure 17] Brightness-external quantum efficiency characteristics of light-emitting element 1. [Figure 18] Brightness-power efficiency characteristics of light-emitting element 1. [Figure 19] Emission spectrum of light-emitting element 1. [Figure 20] A diagram illustrating the Förster movement of light-emitting element 1. [Figure 21] A diagram illustrating the Förster movement of light-emitting element 1. [Figure 22] A diagram illustrating the Förster movement of light-emitting element 1. [Figure 23] PL spectra of 2mDBTPDBq-II, PCBA1BP, and mixed films thereof. [Figure 24]Brightness-current efficiency characteristics of light-emitting element 2. [Figure 25] Voltage-luminance characteristics of light-emitting element 2. [Figure 26] Brightness-external quantum efficiency characteristics of light-emitting element 2. [Figure 27] Brightness-power efficiency characteristics of light-emitting element 2. [Figure 28] Emission spectrum of light-emitting element 2. [Figure 29] This figure shows the reliability test results for light-emitting element 2. [Figure 30] Brightness-current efficiency characteristics of the light-emitting element 3. [Figure 31] Voltage-luminance characteristics of light-emitting element 3. [Figure 32] Brightness-external quantum efficiency characteristics of light-emitting element 3. [Figure 33] Brightness-power efficiency characteristics of light-emitting element 3. [Figure 34] Emission spectrum of light-emitting element 3. [Figure 35] Brightness-current efficiency characteristics of the light-emitting element 4. [Figure 36] Voltage-luminance characteristics of light-emitting element 4. [Figure 37] Brightness-external quantum efficiency characteristics of light-emitting element 4. [Figure 38] Brightness-power efficiency characteristics of the light-emitting element 4. [Figure 39] Emission spectrum of light-emitting element 4. [Figure 40] Brightness-current efficiency characteristics of the light-emitting element 5. [Figure 41] Voltage-luminance characteristics of light-emitting element 5. [Figure 42] Brightness-external quantum efficiency characteristics of the light-emitting element 5. [Figure 43] Brightness-power efficiency characteristics of the light-emitting element 5. [Figure 44] Emission spectrum of light-emitting element 5. [Figure 45] A diagram illustrating the Förster movement of the light-emitting element 4. [Figure 46] A diagram illustrating the Förster movement of the light-emitting element 4. [Figure 47] A diagram illustrating the Förster movement of the light-emitting element 5. [Figure 48] A diagram illustrating the Förster movement of the light-emitting element 5. [Figure 49] A diagram illustrating the Förster movement of the light-emitting element 5. [Modes for carrying out the invention]

[0032] 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.

[0033] (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 emission at a longer wavelength than the first phosphorescent compound. By using a compound, 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.

[0034] 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.

[0035] 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.

[0036] On the other hand, in one aspect of the present invention, a light-emitting element is provided between a pair of electrodes, the first phosphorescent compound is the first A first light-emitting layer dispersed in a material, and a first phosphorescent compound that emits light at a longer wavelength than the first phosphorescent compound. A second phosphorescent compound is dispersed in a second host material, and a second light-emitting layer is laminated with it. It is an optical element. In this case, the first light-emitting layer and the second light-emitting layer are not in a tandem structure, but rather It may be installed adjacent to the [unclear].

[0037] Figure 1 schematically shows the element structure of a light-emitting element according to one embodiment of the present invention described above. Figure 1(C) shows The first electrode 101, the second electrode 102, and the EL layer 103 are shown. At least one light-emitting layer 113 is provided, and other layers may be provided as appropriate. In Figure 1(C), the hole injection layer 111, the hole transport layer 112, the electron transport layer 114, and the electron transport layer are shown. A configuration in which a sub-injection layer 115 is provided is shown as a hypothetical example. Note that the first electrode 101 is the anode. The first electrode functions as the first electrode, and the second electrode 102 functions as the cathode.

[0038] 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, the first host material 113Ha, and the second host material 113Hb are shown. Figure 1(b) shows that the first light-emitting layer 113a further contains the first organic compound 113A. This is a schematic diagram of the case. In either case, each phosphorescent compound (1st and 2nd Since the phosphorescent compounds are dispersed in the host material, each phosphorescent compound is dispersed in each host They are isolated from each other by the materials. Note that the first and second host materials are the same. They may be different. Also, the first light-emitting layer 113a and the second light-emitting layer 113b are Either side can be the anode or the cathode.

[0039] In this case, electron exchange interactions (the so-called Dexter mechanism) occur between each phosphorescent compound. Energy transfer due to this is suppressed. That is, the first phosphorescent compound 113Da is excited. Afterward, the excitation energy is converted by the Dexter mechanism to the second phosphorescent compound 113Db This prevents the phenomenon of migration to the next state. Therefore, the second phosphorescence exhibiting the longest wavelength emission... This can suppress the phenomenon in which the chemical compound 113Db primarily emits light. When excitons are directly generated in the light-emitting layer 113b, the second phosphorescent compound 113Db is mainly... Because it would emit light, the carrier recombination region is located within the first light-emitting layer 113a. It is preferable to primarily excite the first phosphorescent compound 113Da.

[0040] However, energy transfer from the first phosphorescent compound 113Da is completely suppressed. Then, the emission of the second phosphorescent compound 113Db will not be obtained. In one aspect of the invention, the excitation energy of the first phosphorescent compound 113Da is partially the second Design the device so that it moves to the phosphorescent compound 113Db. Energy transfer between particles utilizes dipole-dipole interactions (Förster mechanism). This is made possible by [the following].

[0041] Here, we will explain the Förster mechanism. Below, we will discuss the part that provides the excitation energy. The child molecule is called the energy donor, and the molecule that receives the excitation energy is called the energy acceptor. To describe, in one embodiment of the present invention, an energy donor, an energy acceptor All of these are phosphorescent compounds and are isolated from each other by the host material.

[0042] The Förster mechanism does not require direct contact between molecules for energy transfer. Energy transfer through the resonance phenomenon of dipole oscillations between donors and energy acceptors. This occurs. Due to the resonance phenomenon of dipole oscillations, the energy donor becomes the energy acceptor. Energy is transferred, the excited energy donor returns to the ground state, and the ground state energy The energy acceptor becomes excited. The rate of energy transfer by the Förster mechanism is fixed. number k F This is shown in equation (1).

[0043]

number

[0044] In equation (1), ν represents the frequency, and F(ν) is the normalized energy donor. Emission spectrum (When discussing energy transfer from singlet excited states, use fluorescence spectrum) When discussing energy transfer from a triplet excited state, the phosphorescent spectrum is used, and ε( ν) represents the molar extinction coefficient of the energy acceptor, N represents Avogadro's number, and n R represents the refractive index of the medium, and R is the intermolecular distance between the energy donor and the energy acceptor. c represents the distance, τ represents the measured lifetime of the excited state (fluorescence lifetime or phosphorescence lifetime), and c represents light The speed is represented by φ, and φ is the emission quantum yield (when discussing energy transfer from a singlet excited state, it is called a firefly). The photon quantum yield (or phosphorescent photon yield when discussing energy transfer from triplet excited states) is expressed. And, K 2 This is the orientation of the transition dipole moments of the energy donor and energy acceptor. This is a coefficient (0-4) representing the direction. Note that in the case of random orientation, K 2 = 2 / 3

[0045] As can be seen from equation (1), energy transfer by the Förster mechanism (Förster transfer) The conditions for this are: 1. The energy donor and energy acceptor should not be too far apart (distance) 1. The energy donor emits light (related to the emission quantum yield φ), 2. Energy The emission spectrum of the energy donor and the absorption spectrum of the energy acceptor overlap. One example is the action (related to the integral term).

[0046] Here, as explained in Figure 1, each phosphorescent compound (the first and second phosphorescent compounds) These are dispersed within each host material, and each phosphorescent compound is separated from each other by each host material. Because they are separated, the distance R is at least one molecule (more than 1 nm). Therefore, all of the excitation energy generated in the first phosphorescent compound is used in the Förster mechanism. This does not result in energy transfer to the second phosphorescent compound. On the other hand, if R is 1 For the range of 0nm to approximately 20nm, Förster movement is possible. (First and second glues) In order to ensure a distance R of at least one molecule between photochromic compounds, in the host material It is preferable to keep the volume of each phosphorescent compound to be dispersed below a certain level. The concentration of phosphorescent compounds in the light-emitting layer is 10 wt% or less. If the concentration is too low, it is difficult to obtain good properties, therefore, the phosphorescent compound in this embodiment The concentration of is preferably 0.1 wt% or more and 10 wt% or less. In particular, the first phosphorescence The compound is contained in the first light-emitting layer 113a at a concentration of 0.1 wt% to 5 wt%. This is preferable.

[0047] The first phosphorescent compound 113Da and the first phosphorescent compound which exhibits emission at a longer wavelength than the first phosphorescent compound. In a light-emitting element according to one aspect of the present invention using the second phosphorescent compound 113Db, each phosphorescent A schematic diagram of Förster transfer between chemical compounds is shown in Figure 2. In Figure 2, electrode 10, This configuration shows a first light-emitting layer 113a and a second light-emitting layer 113b stacked between poles 11. Note that one of electrodes 10 and 11 functions as the anode and the other as the cathode. This is an electrode capable of performing a bio-transformation. As shown in Figure 2(A), first, the first phosphorescent compound 113Da is used to produce singlet excited state (S a ) is a triplet excited state (T a It will be converted to ). In other words, the excitons in the first light-emitting layer 113a are basically T a It can be summarized as follows.

[0048] Next, this T aThe energy of the excitons in the state is partially converted directly into light, but the By utilizing the Luster mechanism, some of the second phosphorescent compound 113Db is triple-entered. Waking state (T b It can move to ). This is because the first phosphorescent compound 113Da is emitted. It is photoactive (high phosphorescence quantum yield φ) and the second phosphorescent compound 113Db is monocrystalline. It has direct absorption corresponding to the electron transition from the ground state to the triplet excited state (triplet excited state). This is due to the existence of an absorption spectrum of the initial state. If these conditions are met, T a From T b A triplet-triplet Förster move becomes possible.

[0049] Furthermore, the singlet excited state of the second phosphorescent compound 113Db (S b ) is the first phosphorescence Triplet excited state of compound 113Da (T a ) is often more energetic than, therefore, as mentioned above In many cases, it does not contribute much to the energy transfer. Therefore, it is omitted here. Of course, the singlet excited state of the second phosphorescent compound 113Db (S b ) is the first phosphorescence Triplet excited state of compound 113Da (T a If the energy is lower than ), then the energy Ghee transfer may occur. In this case, the singlet excited state of the second phosphorescent compound 113Db ( S b The energy transferred to the second phosphorescent compound 113Db via intersystem crossing is then converted to the triplet. Excited state (T b Energy is transferred to this, and it participates in light emission.

[0050] Furthermore, the above-mentioned Förster migration is efficiently generated between phosphorescent compounds that act as dopants. Therefore, in order to design it so that no energy is transferred to the host material, the first and second hosts The material does not have an absorption spectrum in the emission region of the first phosphorescent compound 113Da. This is preferable. In this way, without using a host material (specifically, a second host material) By allowing direct energy transfer between dopants, the process of transferring excess energy is eliminated. This configuration is preferable because it suppresses the generation of trails and leads to high luminous efficiency.

[0051] Furthermore, the first host material is designed so as not to quench the first phosphorescent compound, It is preferable that the compound has a higher triplet excitation energy than the compound.

[0052] As described above, the basic concept of one aspect of the present invention is, first, the first and second phosphorescence A first glue that exhibits short-wavelength emission while isolating the chemical compound using a host material and a layered structure. The device structure primarily uses photosensitive compounds for excitation. Therefore, within a certain distance (~20nm), Förster-type energy transfer is one Because it occurs in the part, the excitation energy of the first phosphorescent compound is partially converted to the second phosphorescence. The mixture can be transferred, and luminescence can be obtained from each of the first and second phosphorescent compounds.

[0053] However, in one embodiment of the present invention, a more important point is to consider the energy transfer. This involves the selection of materials and the device structure.

[0054] First, in order to generate a Förster transfer, the emission quantum yield φ on the energy donor side must be Although it needs to be high, in one embodiment of the present invention, phosphorescent compounds (specifically, phosphorescent quantum Since a luminescent compound with a yield of 0.1 or higher is used, no problems arise. The important point is formula (1 Increasing the integral term of ) That is, the emission spectrum F(ν) of the energy donor and the energy The key is to effectively overlap the molar extinction coefficients ε(ν) of the energy acceptors.

[0055] Generally, in the wavelength region where the molar extinction coefficient ε(ν) of the energy acceptor is large, We just need to superimpose the Giedner emission spectra F(ν) (that is, the product of F(ν)ε(ν)) It is thought that (making it larger would be better). However, this is not always the case in the Förster mechanism. However, this is not true. This is because the integral term in equation (1) is inversely proportional to the fourth power of the frequency ν, This is because wavelength dependence exists.

[0056] To make it easier to understand, let's first rearrange equation (1). If the wavelength of light is λ, then ν = c Since / λ, equation (1) can be rewritten as shown in equation (2) below.

[0057]

number

[0058] In other words, the integral term becomes larger as the wavelength λ increases. To put it simply, the longer the wavelength... This means that energy transfer is more likely to occur. In other words, the molar extinction coefficient ε(λ) It's not as simple as just needing F(λ) to overlap in a large wavelength region, but rather ε(λ)λ 4 but We must ensure that F(λ) overlaps over a large region.

[0059] Therefore, as the second phosphorescent compound 113Db in the light-emitting element of one aspect of the present invention To improve the energy transfer efficiency from the first phosphorescent compound 113Da, the first The peak of the emission spectrum of phosphorescent compound 113Da where the maximum value is located, and the second peak ε(λ)λ of phosphorescent compound 113Db 4 The pole located at the longest wavelength end of the function represented by A phosphorescent compound is used in which peaks with high values ​​overlap.

[0060] Furthermore, the second phosphorescent compound is ε(λ)λ 4 The pole located at the longest wavelength end of the function represented by The wavelength of the largest value overlaps with the phosphorescent emission spectrum F(λ) of the first phosphorescent compound. This is preferable. Also, the above maximum value of the emission spectrum of the first phosphorescent compound 113Da exists A wavelength range having half the intensity of the above maximum value in the mountain where it is located, and a second phosphorescent compound ε(λ)λ 4 For the function represented by the above, half of the above maximum value is found at the peak where the above maximum value exists. When there is an overlap in the wavelength ranges that have intensity, the overlap between the spectra becomes larger, so preferable.

[0061] 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.

[0062] To deepen our understanding of the composition of such phosphorescent compounds, the following explanation will use specific examples. Here, the first phosphorescent compound 113Da is defined as the following compound (1) (bis[ 2-(6-tert-butyl-4-pyrimidinyl-κN3)phenyl-κC](2,4- pentandionato-κ 2 O,O') Iridium(III) (Abbreviation: Ir(tBuppm)) 2(acac))) exhibits longer wavelength emission than the first phosphorescent compound 113Da. As the phosphorescent compound 113Db, the following compound (2) (bis(2,3,5-tripheny) Iridium(III) (Abbreviation: Ir(tppr)) Let's explain using examples of the cases where )2(dpm))) are used.

[0063] [ka]

[0064] Figure 3(a) shows the molar extinction coefficient ε(λ) of compound (2), which is the second phosphorescent compound, and ε (λ)λ 4 This shows that the molar extinction coefficient ε(λ) decreases as the wavelength increases. We go down, ε(λ)λ 4 This is around 550 nm (in the triplet MLCT absorption band of compound (2)). It has a local maximum at the corresponding (λ) point. As can be seen from this example, 4 Due to the influence of the section, the second Phosphorescent compounds ε(λ)λ 4 This is the absorption band located on the longest wavelength side (triplet MLCT absorption). The band has a local maximum value.

[0065] On the other hand, Figure 3(b) shows the photoluminescence (PL) spectrum F(λ) of compound (1). And the ε(λ)λ of compound (2) 4 This shows that compound (1) is the first phosphorescent compound. It is a compound that exhibits green emission with an emission peak around 545 nm. This first phosphorus The PL spectrum F(λ) of the photosensitive compound is ε(λ)λ of the second phosphorescent compound. 4 Maximum value In the vicinity, ε(λ)λ 4 There is a large overlap between the first phosphorescent compound and the second Energy transfer occurs to the phosphorescent compound 2 via the Förster mechanism. Since the maximum values ​​correspond to the triplet MLCT absorption band, it is a triplet-triplet Förster type. This is energy transfer (T in Figure 2) a -T b Energy transfer). At this time, the first phosphorus The emission peak wavelength of the PL spectrum F(λ) of the photoactive compound and the ε(λ) of the second phosphorescent compound. λ)λ 4 If the wavelength difference of the maximum value is 0.2 eV or less, energy transfer will occur efficiently. This is a preferred configuration. The emission peak wavelength of the PL spectrum F(λ) of compound (1) 546 nm, ε(λ)λ of compound (2) 4 The wavelength of the maximum value is 543 nm, and the difference is At 3 nm, this corresponds to 0.01 eV. Therefore, the energy between compound (1) and compound (2) It can be seen that energy transport is carried out very efficiently.

[0066] Furthermore, from the above, the second phosphorescent compound has the longest wavelength side of its absorption spectrum. Direct absorption corresponding to the electronic transition from the multiplet ground state to the triplet excited state (e.g., triplet ML) It is preferable to have CT absorption. With such a configuration, as shown in Figure 2... This results in efficient triplet-triplet energy transfer.

[0067] Furthermore, in order to obtain the recombination region described above, if the first light-emitting layer 113a is located on the anode side... Preferably, at least the second light-emitting layer 113b is electron-transporting, and the first light-emitting layer 1 Both 13a and the second light-emitting layer 113b may be electron-transporting. When 113a is located on the cathode side, at least the second light-emitting layer 113b is hole-transporting. Preferably, both the first light-emitting layer 113a and the second light-emitting layer 113b are hole-transporting. It's okay to have it.

[0068] Here, in the first light-emitting layer 113a, further, the first host material 113Ha The peak where the maximum value of the torluminescence (PL) spectrum F(λ) exists, and the first phosphorescence ε(λ)λ of compounds 4 The peak of the function represented by the function where the maximum value located at the longest wavelength side exists It is preferable for the size to be large.

[0069] However, typically, the photoluminescence (PL) spectrum F(λ) of the host material The peak where the maximum value of exists, and the ε(λ)λ of the guest material (first phosphorescent compound 113Da). 4 It is difficult to superimpose the peak where the maximum value of the function represented by the function at the longest wavelength side exists. Yes, because normally, the photoluminescence (PL) of a host material is fluorescence emission. Fluorescence emission originates from higher energy levels than phosphorescence emission, therefore the fluorescence spectrum... The wavelength is close to the longest wavelength absorption spectrum of the guest material (the triplet excited state of the guest material). The triplet excitation energy levels of the host material at wavelengths such that the triplet excitation energy of the guest material This is because there is a high probability that the energy level will fall below the electromotive force level. If the energy level falls below the triplet excitation energy level of the guest material, the guest material The triplet excitation energy is transferred to the host material, leading to a decrease in luminescence efficiency. .

[0070] Therefore, in this embodiment, the first light-emitting layer 113a is further composed of the first organic compound 113 A is included, and the first host material 113Ha and the first organic compound 113A are excited complex 11 It is preferable that the combination forms 3Ec (also called excyplex) (Figure) 1(b), Figure 2(B)). In Figure 2(B), 10 and 11 are electrodes, and electrode 10 and electrode 2(B) are electrodes. In the diagram, one of the 11 components functions as the anode and the other as the cathode. The singlet excited state of c is represented by Se, and the triplet excited state by Te, and the first phosphorescent compound 11 The singlet excited state of 3Da is represented by Sa, and the triplet excited state by Ta, and it is the second phosphorescent compound. The singlet excited state of 113Db is represented by Sb, and the triplet excited state by Tb.

[0071] In this case, when carriers (electrons and holes) in the first light-emitting layer 113a recombine, The first organic compound 113A and the first host material 113Ha undergo electron and hole recombination. When energy is obtained, the excited complex 113Ec is formed. Fluorescence from the excited complex 113Ec. The luminescence is due to the fluorescence of the first organic compound 113A and the first host material 113Ha. The emission has a spectrum with longer wavelengths than the vector, but the excited complex 113Ec is singlet. The excited state Se and the triplet excited state Te share the characteristic of having very similar energies. Therefore, the PL spectrum F(λ) is the emission from the singlet excited state of the excited complex 113Ec. The peak where the maximum value of exists, and the ε(λ)λ of the guest material (first phosphorescent compound 113Da). 4 The peak where the maximum value is located on the longest wavelength side of the function represented by (triplet excitation of guest material) By superimposing the absorption spectrum of the initial state Ta, the energy from Se to Ta can be calculated. This allows for the maximum possible increase in both the movement and the energy transfer from Te to Ta. At that time, the emission peak wavelength of the excited complex 113Ec and the guest material (first phosphorescent compound 113 ε(λ)λ of Da) 4 If the wavelength difference of the maximum value is 0.2 eV or less, energy transfer is This configuration is preferable because it is carried out efficiently. Also, the first organic compound 113A and the first The triplet excitation energy level of the host material 113Ha is adjusted by the first phosphorescent compound 113Da It is preferable to keep the excitation energy level above the triplet excitation energy level.

[0072] As described above, the energy transferred to the first phosphorescent compound 113Da is as follows: Then, a portion moves to the second phosphorescent compound 113Db, and the first phosphorescent compound 113Da Both the first and second phosphorescent compound 113Db emit light efficiently.

[0073] Furthermore, the first phosphorescent compound 113D is derived from the triplet excited state (Te) of the excited complex 113Ec. Energy transfer to a occurs efficiently via the Dexter mechanism. Singlet excited state (Se Energy transfer from ) occurs efficiently by the Förster mechanism of the above configuration, This enables efficient energy transfer in a single system.

[0074] The first organic compound 113A and the first host material 113Ha are used to form excited complexes. Any combination is fine, but compounds that readily accept electrons (electron-trapping compounds) and It is preferable to combine it with a compound that readily accepts holes (a hole-trapping compound). stomach.

[0075] Compounds that readily accept electrons include bis(10-hydroxybenzo[h]quinolinate) ) Beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolate) ( 4-Phenylphenolate)aluminum(III) (abbreviation: BAlq), bis(8-quinol) Linolate) Zinc (II) (abbreviation: Znq), Bis[2-(2-benzoxazolyl)phen [Norato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phen Metal complexes such as [norato]zinc(II) (abbreviation: ZnBTZ) and 2-(4-biphenylyl )-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: P BD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl (Lu)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert [-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OX D-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl [Nyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-be Tris(1-phenyl-1H-benzoimidazole) (abbreviation: TPBI) ), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-be Complex polyazole skeletons such as nzoimidazole (abbreviation: mDBTBIm-II) Ring compounds, and 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h ]Quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene [n-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mD) BTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl- 3-Il]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bi Su[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2) Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4 Heterocyclic compounds having a diazine skeleton, such as 6mDBTP2Pm-II, and 3,5-bi Su[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPP) y), 1,3,5-tri[3-(3-pyridyl)-phenyl]benzene (abbreviation: TmPy Examples include heterocyclic compounds having a pyridine skeleton, such as PB. Among those mentioned above, diazi Heterocyclic compounds with a pyridine skeleton or heterocyclic compounds with a pyridine skeleton are highly reliable. More preferable. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton are more preferable. It offers high transport efficiency and contributes to reducing drive voltage.

[0076] Compounds that readily accept holes include 4,4'-bis[N-(1-naphthyl)-N- Phenylaminobiphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl) -N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TP) D) 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-fe [Nylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfull Oren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'- (9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenyl Min (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H -Carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1 -Naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenyl Mine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl -9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9 -dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl] )phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4- (9-phenyl-9H-carbazole-3-yl)phenyl]spiro-9,9'-biflu Compounds having an aromatic amine skeleton such as olen-2-amine (abbreviated as PCBASF), 1,3-Bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-Di(N-carbazolyl)benzene Bazolyl biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl) -9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H Compounds having a carbazole skeleton, such as (abbreviated as PCCP) -carbazole, and 4,4 ',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluore] [-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[ 4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzo Compounds containing a thiophene skeleton, such as thiophene (abbreviation: DBTFLP-IV), and 4, 4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: D BF3P-II), 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)f [phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II) and other furan bones Examples of compounds having a specific characteristic include compounds having an aromatic amine skeleton and Compounds with a rubazole skeleton are reliable, have high hole transport properties, and are drivable. This is preferable because it also contributes to voltage reduction.

[0077] The first organic compound 113A and the first host material 113Ha are not limited to these. It is not a combination that can form an excited complex, and the photoluminescence (PL) of the excited complex ) The peak where the maximum value of the spectrum F(λ) exists, and the ε(λ)λ of the first phosphorescent compound 4 in The peak of the function, where the maximum value is located at the longest wavelength, coincides with the emission of the excited complex. The spectral peak is greater than the emission spectrum peak of the first phosphorescent compound 113Da. Long wavelengths are also acceptable.

[0078] Furthermore, the first organic compound is a compound that readily accepts electrons and a compound that readily accepts holes. When 113A and the first host material 113Ha are composed, the carrier depends on their mixing ratio. The balance can be controlled. Specifically, the first organic compound 113A and the first H The ratio of the material 113Ha is preferably in the range of 1:9 to 9:1.

[0079] In this configuration, the photoluminescence (PL) spectrum F(λ) of the excited complex is polar The peak where the large value exists, and the ε(λ)λ of the first phosphorescent compound 4 The longest wavelength of the function represented by First host material 1 that constitutes an excited complex in which peaks with local maxima located on the side overlap. Select 13Ha and the first organic compound 113A. The greater the overlap of these peaks, the better. stomach.

[0080] Furthermore, the first phosphorescent compound ε(λ)λ 4 The pole located at the longest wavelength end of the function represented by It is preferable that the wavelength of the maximum value overlaps with the photoluminescence (PL) spectrum F(λ) of the excited exciplex . Further, the photoluminescence (PL) spectrum F(λ of the excited exciplex ) has a wavelength range with an intensity half of the maximum value in the peak where the maximum value exists, and the first phosphorescent compound's ε(λ)λ 4 has an overlap with the wavelength range having an intensity half of the maximum value in the peak where the maximum value of the function represented by exists, which is more preferable because the overlap between the spectra increases.

[0081] In this configuration, energy can be efficiently transferred from the excited exciplex composed of the first host material 113Ha and the first organic compound 113A to the first phosphorescent compound 113Da , which makes it possible to further improve the energy transfer efficiency, and thus a light-emitting element with higher external quantum efficiency can be achieved.

[0082] (Embodiment 2) In the present embodiment, an example of the detailed structure of the light-emitting element described in Embodiment 1 will be described below with reference to FIG. 1.

[0083] The light-emitting element in the present embodiment has an EL layer composed of a plurality of layers between a pair of electrodes. In the present embodiment, the light-emitting element is composed of a first electrode 101, a second electrode 102, and an EL layer 103 provided between the first electrode 101 and the second electrode 102. In the present embodiment, the following description is given on the assumption that the first electrode 101 functions as an anode and the second electrode 102 functions as a cathode. That is, a voltage is applied to the first electrode 101 and the second electrode 102 such that the potential of the first electrode 101 is higher than that of the second electrode 10 2 when a voltage is applied to the first electrode 101 and the second electrode 102 so that the potential of the first electrode 101 is higher than that of the second electrode 102. ​​​​Sometimes, the device is configured to emit light.

[0084] 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.

[0085] 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 structure is constructed by appropriately combining a transport layer, electron injection layer, carrier block layer, intermediate layer, etc. Yes, it is possible. In this embodiment, the EL layer 103 is a hole layer that is sequentially stacked on top of the first electrode 101. Injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, electron injection layer 115 The following describes the configuration having the following characteristics. The materials that make up each layer are specifically shown below.

[0086] 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 (abbreviated as H2Pc) and copper phthalocyanine (CuPC) can be used. Phthalocyanine compounds such as 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 Aromatic amine compounds such as phenyl-4,4'-diamine (abbreviation: DNTPD), or por Li(ethylenedioxythiophene) / Poly(styrenesulfonic acid)(PEDOT / PSS) The hole injection layer 111 can also be formed by polymers such as ).

[0087] 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. This 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 small work function can be used. Examples of acceptor substances include 7,7,8 ,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TC NQ), chloranil, and the like. Transition metal oxides can also be mentioned as acceptor substances. Further, oxides of metals belonging to Groups 4 to 8 in the periodic table of elements can also be mentioned as acceptor substances. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable because of their high electron acceptability . Among these, molybdenum oxide is particularly preferable because it is stable in the atmosphere, has low hygroscopicity, and is easy to handle .

[0088] As the hole-transporting substance used in the composite material, aromatic amine compounds, carbazole derivative s, aromatic hydrocarbons, polymer compounds (oligomers, dendrimers, polymers, etc.), and various organic compounds can be used. The organic compound used in the composite material is preferably an organic compound with high hole-transporting property. Specifically, it is preferably a substance having a hole mobility of 10 -6 cm 2 / Vs or higher. Hereinafter, organic compounds that can be used as hole-transporting substances in the composite material are specifically listed.

[0089] For example, as aromatic amine compounds, N,N'-di(p-tolyl)-N,N'-diph enyl-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'-diph Phenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3 ,5-Tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene Examples include (abbreviated as DPA3B).

[0090] 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).

[0091] 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.

[0092] 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'-Biantrill, 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.

[0093] 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).

[0094] Also, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphen Nylamine (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 High molecular weight compounds such as (phenyl)benzidine (abbreviated as Poly-TPD) can also be used. can.

[0095] By forming a hole injection layer, hole injection performance is improved, and a low driving voltage is required. This makes it possible to obtain optical elements.

[0096] The hole transport layer 112 is a layer containing a hole-transporting substance. The hole-transporting substance is: For example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated) Name: NPB) or 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-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), etc. Aromatic amine compounds and the like can be used. The substances described herein have high hole transport properties. , mainly 10 -6 cm 2 It is a material having a hole mobility of / Vs or greater. Also, the above-mentioned composite material 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.

[0097] The light-emitting layer 113 is a layer containing a first phosphorescent compound and a second phosphorescent compound. Since the optical layer 113 has the configuration described in Embodiment 1, The light-emitting element in this can be made into a light-emitting element with very good luminous efficiency. Light-emitting layer 113 For details on the main components, please refer to the description in Embodiment 1.

[0098] In the light-emitting layer 113, the first phosphorescent compound and the second phosphorescent compound are used. The materials that can achieve this are combinations having the relationships described in Embodiment 1. There are no particular limitations. For example, the first phosphorescent compound and the second phosphorescent compound could be... The following are some examples:

[0099] Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H -1,2,4-triazole-3-yl-κN 2 ]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'-bis(trifluoromethyl)phenyl]pyridinate-N,C 2 ’ Iridium(III) picolinate (abbreviation: Ir(CF3ppy)2(pic)), Bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ ]iridium( III) FIracac, which has an electron-withdrawing group Examples include organometallic iridium complexes with phenylpyridine derivatives as ligands. These are blue This compound exhibits colored phosphorescence and has an emission peak between 440 nm and 520 nm. These are compounds. Among those mentioned above, 4H-triazole, 1H-triazole, and imidazole are particularly noteworthy. Organometallic iridium complexes with a polyazole skeleton, such as those described above, exhibit high hole-trapping properties. Therefore, these compounds are used as the first phosphorescent compound in the light-emitting element according to one aspect of the present invention. It is used as an object, and the first light-emitting layer is provided on the cathode side of the second light-emitting layer, and the second light When the optical layer is hole-transporting (specifically, when 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. Furthermore, organometallic iridium complexes with a 4H-triazole skeleton offer improved reliability and luminescence efficiency. It is particularly preferable because it also excels in other areas.

[0100] 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-phenylpyradinato)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 are particularly important. 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.

[0101] Also, bis[4,6-bis(3-methylphenyl)pyrimidinato](diisobutyrylmeth (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) -1-yl)pyrimidinato](dipivaloylmethanato) Iridium(III) (abbreviation: I Organometallic iridium complexes with a pyrimidine skeleton, such as r(d1npm)2(dpm)). The body, (acetylacetonato)bis(2,3,5-triphenylpyradinato)iridium (III) (Abbreviation: Ir(tppr)2(acac)), bis(2,3,5-tripheny Iridium(III) (Abbreviation: Ir(tppr)) )2(dpm)), (acetylacetonate)bis[2,3-bis(4-fluorophenyl )Kinoxalinato] Iridium(III) (abbreviation: Ir(Fdpq)2(acac)) iridium organometallic complexes having a pyrazine skeleton, such as tris(1-phenylisoquino Linato-N,C 2’ Iridium(III) (abbreviation: Ir(piq)3), Bis(1-F) Enylisoquinolinato-N,C 2’ Iridium(III) acetylacetonate (abbreviation) Organometallic iridium complexes with a pyridine skeleton, such as :Ir(piq)2(acac)) In addition to the body, 2,3,7,8,12,13,17,18-octaethyl-21H,23H-Po Platinum complexes such as rufiline platinum(II) (abbreviation: PtOEP), and tris(1,3-di Phenyl-1,3-propanedionato)(monophenanthroline) europium(III )(Abbreviation: Eu(DBM)3(Phen)), Tris[1-(2-tenoyl)-3,3, 3-Trifluoroacetonate](monophenanthroline)europium(III) (abbreviation) Examples include rare earth metal complexes such as :Eu(TTA)3(Phen) . These are red This compound exhibits colored phosphorescence and has an emission peak between 600 nm and 700 nm. Among those mentioned above, organometallic iridium having a diazine skeleton, such as pyrimidines and pyrazines. Um complexes have weak hole-trapping properties and high electron-trapping properties. Therefore, diazine skeleton An organometallic iridium complex having the following properties is used as the second phosphorescent compound, and the first light-emitting layer When the second light-emitting layer is located on the cathode side 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 first It is preferable because it becomes easier to control within the light-emitting layer. iridium complexes are particularly preferred because they offer outstanding reliability and luminescence efficiency. Furthermore, organometallic iridium complexes having a pyrazine skeleton yielded a red emission with good chromaticity. Therefore, when applied to white light-emitting elements, it can improve color rendering.

[0102] Furthermore, in addition to the phosphorescent compounds described above, from among known phosphorescent light-emitting materials, the embodiments include Select a first phosphorescent material and a second phosphorescent material having the relationship shown in 1, and use them. That's good too.

[0103] Note that phosphorescent compounds (first phosphorescent compound 113a and second phosphorescent compound 1 13b) Instead, use a material that exhibits thermally activated delayed fluorescence, i.e., thermally activated delayed fluorescence (TADF) ) Materials may be used. Here, delayed fluorescence is a type of fluorescence that 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, and Examples include acridine derivatives such as loflavin and eosin. Also, magnesium (Mg ), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (I n) or metal-containing porphyrins including palladium (Pd), etc. Examples of contained porphyrins include protoporphyrin-tin fluoride complexes (abbreviated as Sn F2(Proto IX)), Mesoporphyrin-Tin Fluoride Complex (Abbreviation: SnF2(M eso IX), hematoporphyrin-tin fluoride complex (abbreviation: SnF2(Hemat o IX)), Coproporphyrin tetramethyl ester-tin fluoride complex (abbreviation: Sn F2(Copro III-4Me)), Octaethylporphyrin-Tin Fluoride Complex ( Abbreviation: SnF2(OEP)), Ethioporphyrin-tin fluoride complex (Abbreviation: SnF2( Etio I)) Octaethylporphyrin-platinum chloride complex (abbreviation: PtCl2(OE Examples include P)). Furthermore, 2-(biphenyl-4-yl)-4,6-bis(12- Phenylindoro[2,3-a]carbazole-11-yl)-1,3,5-triazine (Abbreviation: PIC-TRZ) Complexes having π-excessive and π-deficient complex aromatic rings Ring compounds can also be used. Note that π-excess heteroaromatic rings and π-deficient heteroaromatic rings are directly connected. The bonded substance acts as a donor for π-excess heteroaromatic rings and an acceptor for π-deficient heteroaromatic rings. This is particularly preferable because both properties become stronger, and the energy difference between S1 and T1 becomes smaller.

[0104] The materials that can be used as the first and second host materials described above are not particularly limited. Various carrier transport materials are selected and appropriately combined to obtain the element structure shown in Figure 1. Just match them.

[0105] For example, as a host material having electron transport properties, bis(10-hydroxybenzo[h] (Quinolinato) Beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinato) (4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis (8-Quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxaz [Ryl)phenolate]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazo Metal complexes such as lyl(phenolate)zinc(II) (abbreviation: ZnBTZ) and 2-(4-bi Phenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (Abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert- Tylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p -tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene ( Abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2- Il)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1, 3,5-Benzenetriyl)tris(1-phenyl-1H-benzoimidazole) (abbreviation) :TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl Polyazole skeletons such as -1H-benzoimidazole (abbreviation: mDBTBIm-II) Heterocyclic compounds containing 2-[3-(dibenzothiophen-4-yl)phenyl]dibene Zo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(diben Zothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated) Name: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)bi Phenyl-3-yl dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-Bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6) mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine Heterocyclic compounds having a diazine skeleton, such as (abbreviation: 4,6mDBTP2Pm-II), 3,5-Bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35) DCzPPy), 1,3,5-tri[3-(3-pyridyl)-phenyl]benzene (abbreviation) Examples include heterocyclic compounds having a pyridine skeleton, such as :TmPyPB. However, heterocyclic compounds having a diazine skeleton or a pyridine skeleton are reliable. This is good and preferable. In particular, heterocyclization having a diazine (pyrimidine or pyrazine) skeleton. The composite material exhibits high electron transport properties and contributes to reducing the drive voltage.

[0106] Furthermore, as a host material that possesses hole transport properties, 4,4'-bis[N-(1-naphthyl) -N-phenylamino]biphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl) (Nyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation) :TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N ―phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenyl (Fluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl- 3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFL) P), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphen Nylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl -9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4 -(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)trife Nylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-f Phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3] -yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N- [4-(9-phenyl-9H-carbazole-3-yl)phenyl]spiro-9,9'- Compounds having an aromatic amine skeleton, such as bifluoren-2-amine (abbreviation: PCBASF) For example, 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N -Carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenyl) (nyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl Compounds having a carbazole skeleton, such as -9H-carbazole (abbreviated as PCCP), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene)( Abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-f Luoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldi Compounds containing a thiophene skeleton, such as benzothiophene (abbreviation: DBTFLP-IV) and , 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviated) Name: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluorene-9-I Phenyl dibenzofuran (abbreviation: mmDBFFLBi-II), etc. Examples include compounds having a ranic skeleton. Among those mentioned above, compounds having an aromatic amine skeleton Compounds containing substances or carbazole skeletons are highly reliable and have high hole transport properties. This is preferable because it also contributes to reducing the drive voltage.

[0107] In addition to the host materials described above, other known substances may be used as host materials. Oh, as a host material, a phosphorescent compound with a triplet level (between the ground state and the triplet excited state) It is preferable to select a material that has a triplet level greater than the energy difference. These host materials preferably do not have an absorption spectrum in the blue region. Specifically, Preferably, the absorption edge of the absorption spectrum is 440 nm or less.

[0108] The light-emitting layer 113 having the above configuration can be co-deposited by vacuum deposition or as a mixed solution. It can be fabricated using methods such as inkjet printing, spin coating, and dip coating. ru.

[0109] 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 xyphenyl)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.

[0110] 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.

[0111] 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).

[0112] 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.

[0113] 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, ITO, Ke Various conductive materials such as indium oxide-tin oxide containing ion or silicon oxide are used in the second These conductive materials can be used as electrodes 102. The film can be deposited using methods such as the stencil method and spin coating method.

[0114] 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. .

[0115] 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].

[0116] 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.

[0117] 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 is extracted from both the first electrode 101 and the second electrode 102.

[0118] 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.

[0119] 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 band gap is contained in the luminescent material that makes up the luminescent layer or in the luminescent layer. The material is composed of a material having a band gap larger than the band gap of the luminescent central material. It is preferable to do so.

[0120] 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.

[0121] Furthermore, this embodiment can be appropriately combined with other embodiments.

[0122] (Embodiment 3) In this embodiment, a light-emitting device using the light-emitting elements described in Embodiment 1 and Embodiment 2 is provided. I will explain this.

[0123] In this embodiment, the light-emitting element described in Embodiment 1 and Embodiment 2 is used to create the element. The light-emitting device will be explained using Figure 4. Figure 4(A) is a top view showing the light-emitting device. Figure 4(B) is a cross-sectional view of Figure 4(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, 625 is the desiccant, and 605 is the sealing material, surrounded by the sealing material 605 The inside of this structure is a space of 607.

[0124] 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.

[0125] Next, the cross-sectional structure will be explained using Figure 4(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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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 and aluminum Lamination with a film mainly composed of aluminum, titanium nitride film and aluminum film and titanium nitride A three-layer structure with a film can be used. Furthermore, a laminated structure can be used as a wiring resistor. It has low noise levels, provides good ohmic contact, and can even function as an anode. .

[0130] 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 Embodiment 1 and Embodiment 2 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). .

[0131] 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.

[0132] The first electrode 613, the EL layer 616, and the second electrode 617 form a light-emitting element. The light-emitting element is the same as the light-emitting element described in Embodiment 1 and Embodiment 2. Oh, the pixel section is made up of multiple light-emitting elements, but the light-emitting device in this embodiment Now, let's look at the light-emitting elements described in Embodiment 1 and Embodiment 2, and the light-emitting elements having other configurations. It is acceptable for both elements to be included.

[0133] 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].

[0134] 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.

[0135] As described above, the light-emitting elements described in Embodiment 1 and Embodiment 2 are used to create the following: A light-emitting device can be obtained.

[0136] The light-emitting device in this embodiment has the light-emitting elements described in Embodiment 1 and Embodiment 2. Because it is used, a light-emitting device with good characteristics can be obtained. Specifically, the implementation The light-emitting element shown in Embodiment 1 and Embodiment 2 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.

[0137] 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 5 shows the application of the present invention. The passive matrix type light-emitting device fabricated by [method] is shown. Figure 5(A) shows the light-emitting device. The perspective view shown, Figure 5(B), is a cross-sectional view obtained by cutting Figure 5(A) along the X and Y lines. In Figure 5, 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 addition, the light-emitting element described in Embodiments 1 and 2 operates at a low driving voltage. This allows for operation with low power consumption. Furthermore, Embodiment 1 and the implementation By having the light-emitting element described in Embodiment 2, it is possible to create a highly reliable light-emitting device. Yes.

[0138] 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 6(A) and (B). Figure 6(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.

[0139] 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 7 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 covers and forms 1022. This third interlayer insulating film 1037 plays a role in planarization. This is also good. The third interlayer insulating film 1037 may be made of the same material as the second interlayer insulating film, as well as other known materials. It can be formed using materials.

[0140] The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting element are positive here. This is referred to as the pole, but it can also be the cathode. Furthermore, top-emission type light emission as shown in Figure 7 is also possible. 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 Embodiment 1 and Embodiment 2, 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 configurations shown in Embodiment 1 and Embodiment 2 are applied, the configuration for obtaining white light emission is this Of course, this is not limited to that.

[0141] 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 6(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 6(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 7, 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 1035 may be covered by an overcoat layer 1036. Furthermore, the sealing substrate 1031 shall be a light-transmitting substrate.

[0142] 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 Embodiment 1 and Embodiment 2, This makes it possible to create light-emitting devices that require little power.

[0143] 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. Also, microcavities Color purity may be improved by introducing a structure. In this case, a microcavity structure The feature may be applied to all pixels, or it may be applied only to blue pixels.

[0144] Furthermore, this embodiment can be freely combined with other embodiments.

[0145] (Embodiment 4) In this embodiment, the light-emitting elements described in Embodiment 1 and Embodiment 2 are used as an illumination device. An example of its use will be explained with reference to Figure 8. Figure 8(B) is a top view of the lighting device, and Figure 8(A) is This is a cross-sectional view of ef in Figure 8(B).

[0146] 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 the first electrode 1 in Embodiment 3. It corresponds to 01.

[0147] 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, reduce reactive current, and improve power efficiency. This is to suppress the decrease in rate. Furthermore, the second electrode 404 is formed simultaneously with the formation of the auxiliary electrode 402. A pad 412 may be formed to supply voltage to it.

[0148] An EL layer 403 is formed on the first electrode 401 and the auxiliary electrode 402. Embodiment 3 has the configuration described in Embodiment 1 and Embodiment 2. 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.

[0149] The EL layer 403 is covered to form the second electrode 404. The second electrode 404 is in Embodiment 3 It corresponds to the second electrode 102 in and has a similar configuration. In this embodiment, Since the light is extracted from the first electrode 401 side, the second electrode 404 is made of a material with high reflectivity. It is preferable that it is formed in this manner. In this embodiment, the second electrode 404 is the pad 4 Voltage will be supplied by connecting to 12.

[0150] 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.

[0151] The light-emitting element having the above configuration is sealed to a substrate 407 using sealing materials 405 and 406. The lighting device is completed by attaching and sealing it. Either sealing material 405 or 406 is used. Either way is fine. Also, a desiccant can be mixed into the inner sealant 406, and this This allows for greater moisture absorption, leading to improved reliability.

[0152] Furthermore, the pad 412, the first electrode 401 and a portion of the auxiliary electrode 402 are sealed with sealing material 405. By extending it outside of 406, it can be used as an external input terminal. An IC chip 420 with a converter or other components may be placed on top of it.

[0153] As described above, the lighting device described in this embodiment has an EL element as described in Embodiment 1 and Embodiment 2. 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.

[0154] (Embodiment 5) This embodiment includes, as a part, the light-emitting elements described in Embodiments 1 and 2. Examples of electronic devices will be described. The light-emitting elements described in Embodiment 1 and Embodiment 2 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 Embodiment 1 and Embodiment 2 are light-emitting elements with a low driving voltage. Therefore, it is possible to use electronic devices with low drive voltage.

[0155] 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, audio 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.

[0156] Figure 9(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 displaying the light-emitting elements described in Embodiment 1 and Embodiment 2. 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.

[0157] 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.

[0158] 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.

[0159] Figure 9(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 Embodiment 2 or Embodiment 3. It is manufactured by arranging optical elements in a matrix and using them in the display unit 7203. Figure 9 ( The computer in B1) may take the form shown in Figure 9(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 light-emitting element emits light. It is possible to create a light-emitting element with good efficiency. Therefore, the table composed of the light-emitting element A computer having the display unit 7203 can be a computer with reduced power consumption. Cut.

[0160] Figure 9(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 Embodiment 1 and Embodiment 2 in a matrix. The 7304 is incorporated, and the display unit 7305 is incorporated into the housing 7302. The portable gaming machine shown in 9(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 Embodiment 1 and Embodiment 2. 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 9(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 a mobile gaming machine. 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.

[0161] Figure 9(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 7400 is as described in Embodiment 1 and The display unit 7402, which is made by arranging the light-emitting elements described in Embodiment 2 in a matrix, It possesses this property. The light-emitting element can be made into a light-emitting element with good luminous efficiency. Furthermore, It is possible to create a light-emitting element with a low driving voltage. Furthermore, it is possible to create a light-emitting element with a long lifespan. This is possible. Therefore, a mobile phone having a display unit 7402 composed of the light-emitting element The device can be a mobile phone with reduced power consumption. Also, a mobile phone with a low operating voltage. It can be used as a telephone. Furthermore, it can be used as a highly reliable mobile phone. .

[0162] The mobile phone shown in Figure 9(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.

[0163] 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.

[0164] For example, when making a phone call or composing an email, the display unit 7402 is used for text input. In this case, the primary text input mode should be used, 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.

[0165] 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 set to switch automatically.

[0166] 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.

[0167] Furthermore, in input mode, the signal detected by the optical sensor of the display unit 7402 is detected and displayed If there is no input via touch operation 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 that display mode to a different mode.

[0168] 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.

[0169] The configuration shown in this embodiment is a combination of the configurations shown in Embodiments 1 to 4 as appropriate. They can be used together.

[0170] As described above, the scope of application of the light-emitting device equipped with the light-emitting element described in Embodiment 1 and Embodiment 2 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 Embodiment 1 and Embodiment 2, power consumption can be reduced. You can obtain advanced electronic devices.

[0171] Figure 10 shows the light-emitting elements described in Embodiments 1 and 2 applied to a backlight. This is an example of a liquid crystal display device. The liquid crystal display device shown in Figure 10 consists of a housing 901 and a liquid crystal layer 902 The liquid crystal layer 902 has a backlight unit 903 and a housing 904, and the driver IC 90 It is connected to 5. Also, the backlight unit 903 has the same configuration as in Embodiment 1 and the embodiment. The light-emitting element described in Form 2 is used, and current is supplied via terminal 906.

[0172] The light-emitting elements described in Embodiments 1 and 2 are applied to the backlight of a liquid crystal display device. As a result, a backlight with reduced power consumption can be obtained. Also, in Embodiment 2 By using the described light-emitting element, a surface-emitting illumination device can be fabricated, and it is also possible to scale it up to a large area. This makes it possible to increase the backlight area, and also to increase the liquid crystal display area. Furthermore, the light-emitting device to which the light-emitting element described in Embodiment 2 is applied has a thickness compared to the conventional device. Because it can be made smaller, it also becomes possible to make display devices thinner.

[0173] Figure 11 shows the light-emitting element described in Embodiment 1 and Embodiment 2, which is an electrical lighting device. This is an example of its use in a lamp. The lamp shown in Figure 11 consists of a housing 2001 and a light source 2002 The device has the light-emitting device described in Embodiment 4, and the light-emitting device described in Embodiment 4 is used as the light source 2002.

[0174] Figure 12 shows the light-emitting element described in Embodiment 1 and Embodiment 2 in an indoor lighting device 300. Examples of use as 1 and display device 3002 are described in Embodiments 1 and 2. Because the light-emitting element is a light-emitting element with reduced power consumption, it is a lighting device with reduced power consumption. This can be done. Furthermore, the light-emitting elements described in Embodiments 1 and 2 can be made to have a large area. Because this is possible, it can be used as a large-area lighting device. Also, Embodiment 1 and The light-emitting element described in Embodiment 2 is thin and can be used as a thinned lighting device. This becomes possible.

[0175] The light-emitting elements described in Embodiments 1 and 2 are used in automobile windshields and dashcams. It can also be mounted on a board. Figure 13 shows the light-emitting element described in Embodiment 2 on an automobile. This shows one application to the windshield and dashboard. (Display 5000 to Display 5005) This is a display provided using the light-emitting elements described in Embodiment 1 and Embodiment 2.

[0176] Display 5000 and Display 5001 are provided on the windshield of an automobile in Embodiment 1 and This is a display device equipped with the light-emitting element described in Embodiment 2. Embodiments 1 and 2 The light-emitting element described in 2 is made by fabricating the first electrode and the second electrode with light-transmitting electrodes. Therefore, it can be used as a display device that is transparent, allowing the other side to be seen through, a so-called see-through display device. If the display is see-through, even if it is installed on the windshield of a car, the field of view will be obstructed. It can be installed without obstruction. Furthermore, transistors and other components for driving the device are provided. In such cases, organic transistors made from organic semiconductor materials, or transistors using oxide semiconductors, are used. It is best to use a translucent transistor, such as a sta.

[0177] Display 5002 is a light-emitting element according to Embodiment 1 and Embodiment 2 provided on the pillar portion. This is a display device equipped with a child. Display 5002 shows images from an imaging device installed on the vehicle body. By projecting this image, the view obstructed by the pillar can be compensated for. The display 5003 located on the dashboard shows the view obstructed by the vehicle body, By displaying images from imaging devices located on the outside, blind spots are compensated for, and safety is improved. It can be enhanced. By projecting images in a way that complements the unseen parts, it can be made more natural. Safety checks can be performed without any sense of unease.

[0178] Display 5004 and 5005 show navigation information, speedometer, and tachometer. It provides various information such as mileage, fuel level, gear status, air conditioning settings, and more. This is possible. The display items and layout can be changed as needed to suit the user's preferences. This is possible. Furthermore, this information can also be provided in displays 5000 to 5003. Furthermore, indicators 5000 to 5005 can also be used as lighting devices.

[0179] The light-emitting elements described in Embodiments 1 and 2 are light-emitting elements with high luminous efficiency. This is possible. Furthermore, it allows for the creation of light-emitting elements with low power consumption. Therefore, display 5 Even if you have many large screens like 000 or 5005, it puts a load on the battery. Because it is less likely to cause problems and can be used comfortably, Embodiments 1 and 2 are preferred. The light-emitting device or lighting device using the described light-emitting element is a vehicle-mounted light-emitting device or lighting device. It can be used suitably.

[0180] Figures 14(A) and 14(B) show examples of foldable tablet devices. 4(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 Embodiment 1 and Embodiment 2. By using the light-emitting device in either or both of the display unit 9631a and the display unit 9631b It is made.

[0181] 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.

[0182] 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.

[0183] Furthermore, if you touch the touch panel area 9632a and the touch panel area 9632b simultaneously... You can also input "chi".

[0184] 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. Tablet devices use light. In addition to sensors, other detection devices such as gyroscopes, accelerometers, and other sensors that detect tilt It may be built-in.

[0185] Furthermore, Figure 14(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 display quality may also differ. For example, one display panel can provide a higher-resolution display than the other. You can also use "ru".

[0186] Figure 14(B) shows the closed state, and in this embodiment, the tablet terminal has a housing. 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 14(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.

[0187] 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.

[0188] In addition, the tablet devices shown in Figures 14(A) and 14(B) are also available in various forms. Functions to display information (still images, videos, text images, etc.), calendar, date or time, etc. A function to display 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.

[0189] 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 It can be provided on one or both sides of the housing 9630, and the battery 9635 can be charged efficiently. This configuration can be implemented in this way.

[0190] Furthermore, the configuration and operation of the charge / discharge control circuit 9634 shown in Figure 14(B) are shown in Figure 14( A block diagram is shown and explained in C). Figure 14(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 14(B). This corresponds to circuit 9634.

[0191] 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.

[0192] 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.

[0193] Furthermore, if the above-mentioned display unit 9631 is included, it is a tablet terminal with the shape shown in Figure 14. Not limited to this. [Examples]

[0194] Light-emitting element corresponding to one aspect of the present invention as described in Embodiment 1 and Embodiment 2 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.

[0195] [ka]

[0196] Next, the method for fabricating the light-emitting element of this embodiment is shown.

[0197] First, indium tin oxide (ITSO) containing silicon oxide is sputtered onto a glass substrate. The first electrode 101 was formed by depositing a film using the 3D method. The film thickness was set to 110 nm. The area was set to 2 mm x 2 mm. Here, the first electrode 101 functions as the anode of the light-emitting element. It is an electrode.

[0198] 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.

[0199] 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.

[0200] 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 33 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.

[0201] 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.

[0202] 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 Bis[2-(6-tert-butyl-4-pyrimidinyl-κN3], represented by structural formula (v) )phenyl-κC](2,4-pentanedionato-κ 2O,O') Iridium(III) (Abbreviation: Ir(tBuppm)2(acac)) and, in a weight ratio of 0.8:0.2:0.05 (=2mDBTPDBq-II:PCBA1BP:Ir(tBuppm)2(acac) ) is co-deposited at 20 nm to form the first light-emitting layer 113a, and 2mDBTPDBq-I I and bis(2,3,5-triphenylpyradinate)(dipy) represented by the above structural formula (vi) Valoylmethanato iridium(III) (abbreviation: Ir(tppr)2(dpm)) , weight ratio 1:0.06 (=2mDBTPDBq-II:Ir(tppr)2(dpm)) A second light-emitting layer 113b was formed by co-depositing at a depth of 20 nm in the host material. A certain 2mDBTPDBq-II and PCBA1BP form an excited complex.

[0203] Subsequently, 2mDBTPDBq-II was deposited on the light-emitting layer 113 to a thickness of 15 nm. Furthermore, bathophenanthroline (abbreviated as BPhen), represented by the above structural formula (vii) A film was deposited to a thickness of 15 nm to form an electron transport layer 114.

[0204] 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.

[0205] 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.

[0206] In the vapor deposition process described above, resistance heating was used for all deposition steps.

[0207] Table 1 shows the element structure of the light-emitting element 1 obtained as described above.

[0208] [Table 1]

[0209] 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.

[0210] In the light-emitting element 1, the first phosphorescent compound 113Da is Ir(tBuppm)2(ac Using Ir(tppr)2(dpm) as the second phosphorescent compound 113Db, (ac) Here, the PL spectrum of Ir(tBuppm)2(acac) and Ir(tp pr)2(dpm)ε(λ)λ 4 The relationship between λ and ε(λ) will be described. Note that λ is the wavelength and ε(λ) is This is the molar extinction coefficient.

[0211] First, Figure 20(a) shows the molar extinction coefficient ε(λ) of Ir(tppr)²(dpm) and ε(λ )λ 4 A graph showing this is shown. The molar extinction coefficient ε(λ) shows a prominent pyramidal region on the longer wavelength side. While -k does not exist, ε(λ)λ 4 In this graph, there is a maximum value at 543 nm. There is a peak (mountain) that is Ir(tppr)2(dpm) triplet ML. This is a CT absorption peak, and the emission peak of the first phosphorescent compound 113Da is superimposed on this peak. By combining these methods, it becomes possible to significantly increase the efficiency of energy transfer.

[0212] Figure 20(b) shows the first phosphorescent compound 113Da, Ir(tBuppm)2(ac The PL spectrum F(λ) of ac) and the second phosphorescent compound 113Db, Ir(tpp) r)²(dpm) ε(λ)λ 4 A graph representing this is shown. From this graph, Ir(tBu The PL spectrum of ppm)2(acac) has a peak F(λ) and Ir(tpp) r)²(dpm) ε(λ)λ 4 The peak with the maximum value on the longest wavelength side largely overlaps with this peak. It appears that this combination allows for very efficient energy transfer. The emission of the first phosphorescent compound 113Da, Ir(tBuppm)2(acac), The 'c' is located at 546 nm and is the second phosphorescent compound, Ir(tppr)2, which is 113Db. (dpm) of ε(λ)λ 4 The long-wavelength maximum in the spectrum representing this is located at 543 nm. Therefore, the difference is 3 nm. 546 nm is 2.27 eV, and 543 nm is 2.28 eV. Since it corresponds to V, the difference is 0.01 eV, which is smaller than 0.2 eV. This suggests that efficient energy transfer can also occur from the peak position.

[0213] Next, Figure 21(a) shows the first phosphorescent compound 113Da, Ir(tBuppm)2 The molar extinction coefficient ε(λ) of (acac) and ε(λ)λ 4 A graph illustrating the relationship between molar absorption is shown. In the graph representing the optical coefficient ε(λ), the peak in the long-wavelength region is relative to the peak in the short-wavelength region. In comparison, its intensity is smaller, while ε(λ)λ 4 In the graph, there is a large There exists a maximum value with a large intensity. The peak (mountain) where this maximum value exists is Ir(tBu This is a triplet MLCT absorption of ppm)2(acac), and this peak contains an energy donor. By overlapping the emission peaks, it becomes possible to significantly increase the efficiency of energy transfer. ru.

[0214] In this embodiment, the light-emitting element 1 uses 2mDBTPDBq-II as the first host material. The first organic compound PCBA1BP and the excited complex 113Ec form the excited complex The structure is such that energy is supplied from body 113Ec to the first phosphorescent compound 113Da. Figure 23 shows 2mDBTPDBq-II, PCBA1BP, and a mixed film thereof. This figure shows the PL spectrum of 2mDBTPDBq (mass ratio 0.8:0.2). -II and the first organic compound PCBA1BP form an excited complex 113Ec. This can be seen. Also, Figure 21(b) shows the PL spectrum F(λ) of the excited complex and the first The phosphorescent compound 113Da, Ir(tBuppm)2(acac), has ε(λ)λ 4 of The graph shown is presented. From this graph, the peak of the PL spectrum F(λ) of the excited complex is present. The mountain and the ε(λ)λ of Ir(tBuppm)2(acac) 4 The maximum value on the longest wavelength side The mountains have overlapping structures, and this combination allows for efficient energy transfer. This can be seen. Also, the peak in the PL spectrum of the excited complex is located at 519 nm, and the first phosphorus The photoactive compound 113Da, Ir(tBuppm)2(acac), has ε(λ)λ 4 Represents In the spectrum, the maximum on the longer wavelength side is at 494 nm, so the difference is 25 nm. Yes. 519nm is equivalent to 2.39eV in energy, and 494nm is equivalent to... Calculating this, it corresponds to 2.51 eV, so the difference is 0.12 eV, which is less than 0.2 eV. The small difference suggests that efficient energy transfer occurs even from the peak position. It will be done.

[0215] Note that, as can be seen from FIG. 23, 2mDBTPDBq which is the first host material 113Ha -II has a PL spectrum peak at 426 nm, which corresponds to 2.91 when converted to energy eV. Further, the peak of the PL spectru m of PCBA1BP which is the first organic compound 113A is 405 nm, which corresponds to 3.06 eV when converted to energy. In Ir (tBuppm)2(acac), ε(λ)λ 4 on the long wavelength side in the spectrum representing the maximum value exists at 494 nm, so it corresponds to 2.51 eV when converted to energy, and the respect ive differences are 0.4 eV (first host material 113Ha: 2mDBTPDBq-II), and 0.55 eV (first organic compound 113A: PCBA1BP), both of which are 0.2 e V or more in energy difference, so it can be seen that energy transfer from 2mDBTPDBq-II and PCBA1BP to Ir(tBuppm)2(acac) is less likely to occur.

[0216] Further, FIG. 22 shows the PL spectrum F(λ) of the exciplex, Ir(tBuppm)2(acac ) PL spectrum F(λ), the PL spectrum F(λ) of Ir(tppr)2(dpm) , ε(λ)λ of Ir(tBuppm)2(acac) 4 , Ir(tppr)2(dpm) ε(λ)λ 4 are shown in a single combined graph. Using the overlap (near maximum value A) between the PL spectrum of the exciplex and the ε(λ)λ of Ir(tB uppm)2(acac) 4 , energy transfer from the exciplex to Ir(tBuppm)2(acac), and the overlap between the PL spectrum of Ir(tBuppm)2(aca c) and ε(λ)λ of Ir(tppr)2(dpm) 4 maximum near the value B) from Ir(tBuppm)2(acac) to Ir(tppr)2(dp m), it can be seen that stepwise energy transfer is possible. Note that energy can also be directly transferred from the excited complex to Ir(tppr)2(dpm), which is the second phosphorescent compound . This is because, as can be seen from FIG. 22, the triplet ML of Ir(tppr)2(dpm) on the short-wavelength side of the CT absorption band (near the maximum value B), both the PL spectrum F(λ) of the excited complex and Ir (tppr)2(dpm)'s ε(λ)λ 4 overlap with each other.

[0217] Measurements were performed on the device characteristics of this light-emitting element. The measurement was carried out at room temperature (in an atmosp here maintained at 25°C).

[0218] The luminance-current efficiency characteristics of Light-Emitting Element 1 are shown in FIG. 15. In FIG. 15, the horizontal axis represents luminance (cd / m 2 ), and the vertical axis represents current efficiency (cd / A). Further, the voltage-luminance characteristics are shown in FIG. 16. In FIG. 16, the horizontal axis represents voltage (V), and the vertical axis represents luminance (cd / m 2 ). Further, the luminance-external quantum efficiency characteristics are shown in FIG. 17. In FIG. 17, the horizontal axis represents luminance (cd / m 2 ), and the vertical axis represents external quantum efficiency (%). Further, the luminance-power efficiency characteristics are shown in FIG. 18. In FIG. 18, the horizontal axis represents luminance (cd / m 2 ), and the vertical axis represents power efficiency (%).

[0219] As described above, it was found that Light-Emitting Element 1 exhibits favorable device characteristics. In particular, from FIG. 15, FIG. 1 7 and FIG. 18, it can be seen that the element has very favorable luminous efficiency, and the external quantum efficiency at practical luminance ( 1000 cd / m 2 ) showed a high value of 20% or more. Similarly, the current efficiency The current output is around 60 cd / A, and the power efficiency is also very good, at around 60 lm / W.

[0220] Furthermore, Figure 19 shows the emission spectrum when a current of 0.1 mA is passed through the light-emitting element 1. In Figure 19, the horizontal axis represents wavelength (nm), and the vertical axis represents emission intensity (in arbitrary units). From Figure 19, Light-emitting element 1 is bis[2-(6-tert-butyl-4-pyrimidinyl-κN3)phenyl -κC](2,4-pentanedionato-κ 2 O,O') Iridium(III) (Abbreviation: I Green wavelength light originating from r(tBuppm)2(acac) and bis(2,3,5-truffle) Iridium(III) (Abbreviation: Ir(tp) The emission spectrum shows a well-balanced distribution of red wavelength light originating from pr)2(dpm)). It was discovered that...

[0221] Thus, the light-emitting element 1 corresponding to one aspect of the present invention has good luminescence efficiency, 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]

[0222] Light-emitting element corresponding to one aspect of the present invention as described in Embodiment 1 and Embodiment 2 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.

[0223] [ka]

[0224] Next, the method for fabricating the light-emitting element of this embodiment is shown.

[0225] First, indium tin oxide (ITSO) containing silicon oxide is sputtered onto a glass substrate. The first electrode 101 was formed by depositing a film using the 3D method. The film thickness was set to 110 nm. The area was set to 2 mm x 2 mm. Here, the first electrode 101 functions as the anode of the light-emitting element. It is an electrode.

[0226] 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.

[0227] 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.

[0228] 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, the above structural formula (viii) is deposited onto the first electrode 101 by a vapor deposition method using resistance heating. ) represented as 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H- By co-depositing Lubazole (abbreviation: PCPPn) and molybdenum(VI) oxide, holes are formed. An injection layer 111 was formed. Its film thickness was set to 33.3 nm, and it was made of PCPPn and molybdenum oxide. The ratio was adjusted to be 1:0.5 by weight (=PCPPn: molybdenum oxide). Co-evaporation is a vapor deposition method in which vapor deposition is performed simultaneously from multiple evaporation sources within a single processing chamber. be.

[0229] 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.

[0230] Furthermore, on the hole transport layer 112, 2-[3'-(dibenzo represented by the above structural formula (ix) is added. Thiofen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation) :2mDBTBPDBq-II) and the 4,4'-di(1-naph) represented by the above structural formula (x) (Tyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (Abbreviation: PCBNBB) and the screw [2-(6-tert-butyrate) represented by the above structural formula (v) [4-pyrimidinyl-κN3)phenyl-κC](2,4-pentanediona-κ 2 O ,O') Iridium(III) (abbreviation: Ir(tBuppm)2(acac)) and, Amount ratio 0.8:0.2:0.06(=2mDBTBPDBq-II:PCBNBB:Ir( The first light-emitting layer 113a is co-deposited at a density of 20 nm so that it becomes tBuppm)2(acac)). Let 2mDBTBPDBq-II and the bis(2,3,5-) represented by the above structural formula (vi) Triphenylpyrazinate (dipivaloylmethanato) Iridium(III) (abbreviation: Ir (tppr)2(dpm)) and the weight ratio 1:0.06 (=2mDBTBPDBq-II The second light-emitting layer 113 is co-deposited at a density of 20 nm so that it becomes :Ir(tppr)2(dpm)). b was formed. Note that the host material 2mDBTBPDBq-II and PCBNBB are different. It forms an excited complex.

[0231] Subsequently, 2mDBTBPDBq-II is deposited on the light-emitting layer 113 to a thickness of 15 nm. Furthermore, bathophenanthroline (abbreviated as BPhen), represented by the above structural formula (vii), A film was deposited to a thickness of 15 nm to form an electron transport layer 114.

[0232] 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.

[0233] 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.

[0234] In the vapor deposition process described above, resistance heating was used for all deposition steps.

[0235] Table 2 shows the element structure of the light-emitting element 2 obtained as described above.

[0236] [Table 2]

[0237] The light-emitting element 2 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.

[0238] In the light-emitting element 2, similar to the light-emitting element 1, Ir(tB) is used as the first phosphorescent compound 113Da. uppm)2(acac) is used as the second phosphorescent compound 113Db, and Ir(tppr) It uses 2(dpm). Therefore, the PL spec of Ir(tBuppm)2(acac) The clef and the ε(λ)λ of Ir(tppr)2(dpm) 4Regarding the relationship, light-emitting element 1 Since it is the same, we will omit the repetitive explanation. Regarding Figures 20(a) and (b) of Example 1 Please refer to the description. Thus, the first phosphorescent compound 113 in the light-emitting element 2 Energy transfer between Da and the second phosphorescent compound 113Db should occur efficiently. This suggests that...

[0239] 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.

[0240] Figure 24 shows the brightness-current efficiency characteristics of the light-emitting element 2. Figure 25 shows the voltage-brightness characteristics. Furthermore, the luminance-external quantum efficiency characteristics are shown in Figure 26. Also, the luminance-power efficiency characteristics are shown in Figure 27. This will be shown.

[0241] As described above, the light-emitting element 2 was found to exhibit good element characteristics. In particular, Figures 24 and 22 6. As can be seen from Figure 27, it has very good luminous efficiency, and the external quantum efficiency is practical brightness ( 1000 cd / m² 2 It showed high values ​​of over 20% in the vicinity of ). Similarly, current efficiency The current output is around 60 cd / A, and the power efficiency is also around 60 lm / W, showing very good values.

[0242] Furthermore, Figure 28 shows the emission spectrum when a current of 0.1 mA is passed through the light-emitting element 2. From 28, the light-emitting element 2 is bis[2-(6-tert-butyl-4-pyrimidinyl-κN3 )phenyl-κC](2,4-pentanedionato-κ 2 O,O') Iridium(III) (Abbreviation: Ir(tBuppm)2(acac)) Green wavelength light and bis(2,3, 5-Triphenylpyrazinato)(dipivaloylmethanato) Iridium(III) (Abbreviation: The emission spectrum contains a well-balanced amount of red wavelength light originating from Ir(tppr)2(dpm) It was determined that it indicated a cleric.

[0243] Additionally, the initial brightness was set to 5000 cd / m². 2 Assuming a constant current density, the initial brightness is set to 100. Figure 29 shows the results of a reliability test conducted under these conditions. From Figure 29, the light-emitting element 2 has an initial brightness. degree 5000cd / m 2 Despite reliability testing, after 70 hours, the initial brightness was only 96%. It was found to maintain this characteristic and to be a reliable light-emitting element.

[0244] Thus, the light-emitting element 2 corresponding to one aspect of the present invention has good luminescence efficiency, 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. Furthermore, it was found to be a reliable, long-lasting light-emitting element. [Examples]

[0245] Light-emitting element corresponding to one aspect of the present invention as described in Embodiment 1 and Embodiment 2 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.

[0246] [ka]

[0247] Next, the method for fabricating the light-emitting element of this embodiment is shown.

[0248] First, indium tin oxide (ITSO) containing silicon oxide is sputtered onto a glass substrate. The first electrode 101 was formed by depositing a film using the 3D method. The film thickness was set to 110 nm. The area was set to 2 mm x 2 mm. Here, the first electrode 101 functions as the anode of the light-emitting element. It is an electrode.

[0249] 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.

[0250] 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.

[0251] 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, A pore-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 den is adjusted to be 4:2 by weight (=DBT3P-II: molybdenum oxide). The co-evaporation method is a method in which vapor deposition is carried out simultaneously from multiple evaporation sources within a single processing chamber. It is a way of wearing it.

[0252] Next, on the hole injection layer 111, the 4,4',4''-triangulation represented by the above structural formula (xi) is injected. (N-carbazolyl)triphenylamine (abbreviated as TCTA) will form a film thickness of 10 nm. A film was deposited on the surface to form a hole transport layer 112.

[0253] Furthermore, on the hole transport layer 112, TCTA and bis(2,3) represented by the above structural formula (vi) are added. ,5-triphenylpyrazinate)(dipivaloylmethanato) iridium(III) (abbreviation) :Ir(tppr)2(dpm)) and the weight ratio 1:0.1 (=TCTA:Ir(tpp A 10 nm co-deposited layer was formed to create a second light-emitting layer 113b, such that r)2(dpm)) and the above structure 2-[3-(dibenzothiophen-4-yl)phenyl]dibe, represented by formula (iii). Nzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II) and the above structural formula (iv) Represented as 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)tri Phenylamine (abbreviation: PCBA1BP) and bis[2-(6) represented by the above structural formula (v) [-tert-butyl-4-pyrimidinyl-κN3)phenyl-κC](2,4-pentane) Geonath-κ 2 O,O') Iridium(III) (Abbreviation: Ir(tBuppm)2(ac ac)) and the weight ratio is 0.8:0.2:0.05 (=2mDBTPDBq-II:PCB A1BP:Ir(tBuppm)2(acac)) is co-deposited at 5nm to form the first A light-emitting layer 113a was formed. Note that the host material is 2mDBTPDBq-II and PCB A1BP forms an excited complex with it.

[0254] Subsequently, 2mDBTPDBq-II and Ir(tBuppm)2(aca) are placed on the light-emitting layer 113. c) and 1:0.05(=2mDBTPDBq-II:Ir(tBuppm)2(aca c)) Co-deposit 20 nm so that 2 mDBTPDBq-II is deposited as a 10 nm film, Furthermore, bathophenanthroline (abbreviation: BPhen), represented by the above structural formula (vii), is divided into two parts. The electron transport layer 114 was formed by depositing a film with a thickness of 0 nm.

[0255] 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.

[0256] 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 3 of this embodiment was fabricated by depositing the material in such a manner.

[0257] In the vapor deposition process described above, resistance heating was used for all deposition steps.

[0258] Table 3 shows the element structure of the light-emitting element 3 obtained as described above. The light-emitting element 3 is made of a hole transport layer material The material and the second host material were fabricated using materials significantly different from those used for light-emitting elements 1 and 2. This is a light-emitting element. Also, the position of the electrodes of the first and second light-emitting layers, and the electron transport The structure of the transmission layer is also significantly different.

[0259] [Table 3]

[0260] The light-emitting element 3 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.

[0261] In the light-emitting element 3, similar to the light-emitting element 1, Ir(tB) is used as the first phosphorescent compound 113Da. uppm)2(acac) is used as the second phosphorescent compound 113Db, and Ir(tppr) It uses 2(dpm). Therefore, the PL spec of Ir(tBuppm)2(acac) The clef and the ε(λ)λ of Ir(tppr)2(dpm) 4 Regarding the relationship, light-emitting element 1 Since it is the same, we will omit the repetitive explanation. Regarding Figures 20(a) and (b) of Example 1 Please refer to the description. Thus, the first phosphorescent compound 113 in the light-emitting element 3 Energy transfer between Da and the second phosphorescent compound 113Db should occur efficiently. This suggests that...

[0262] 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.

[0263] Figure 30 shows the brightness-current efficiency characteristics of the light-emitting element 3. Figure 31 shows the voltage-brightness characteristics. Furthermore, the luminance-external quantum efficiency characteristics are shown in Figure 32. Also, the luminance-power efficiency characteristics are shown in Figure 33. This will be shown.

[0264] As described above, it was found that the light-emitting element 3 exhibits good element characteristics. In particular, Figures 30 and 3 2. As can be seen from Figure 33, it has very good luminous efficiency, and the external quantum efficiency is the practical brightness ( 1000 cd / m² 2 It showed high values ​​of over 20% in the vicinity of ). Similarly, current efficiency The output power is around 60 cd / A, and the power efficiency is also very good, at around 70 lm / W.

[0265] Furthermore, Figure 34 shows the emission spectrum when a current of 0.1 mA is passed through the light-emitting element 3. From 34, the light-emitting element 3 is bis[2-(6-tert-butyl-4-pyrimidinyl-κN3 )phenyl-κC](2,4-pentanedionato-κ 2 O,O') Iridium(III) (Abbreviation: Ir(tBuppm)2(acac)) Green wavelength light and bis(2,3, 5-Triphenylpyrazinato)(dipivaloylmethanato) Iridium(III) (Abbreviation: The emission spectrum contains a well-balanced amount of red wavelength light originating from Ir(tppr)2(dpm) It was determined that it indicated a cleric.

[0266] Thus, the light-emitting element 3 corresponding to one aspect of the present invention is different from the light-emitting elements 1 and 2. Although it uses a host material, it has good luminescence efficiency and is derived from two types of luminescent central materials. It was found to be a light-emitting element that provides a balanced amount of light. [Examples]

[0267] Light-emitting element corresponding to one aspect of the present invention as described in Embodiment 1 and Embodiment 2 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.

[0268] [ka]

[0269] Next, the method for manufacturing the light-emitting elements (light-emitting element 4, light-emitting element 5) of this embodiment is shown.

[0270] First, indium tin oxide (ITSO) containing silicon oxide is sputtered onto a glass substrate. The first electrode 101 was formed by depositing a film using the 3D method. The film thickness was set to 110 nm. The area was set to 2 mm x 2 mm. Here, the first electrode 101 functions as the anode of the light-emitting element. It is an electrode.

[0271] 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.

[0272] 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.

[0273] 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, the above structural formula (ii) is deposited onto the first electrode 101 by a vapor deposition method using resistance heating. The expression is 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenyl Hole implantation is achieved by co-depositing MIN (abbreviated as BPAFLP) and molybdenum(VI) oxide. Layer 111 was formed. Its film thickness was set to 33.3 nm, and it consisted of BPAFLP and molybdenum oxide. The ratio was adjusted to be 1:0.5 by weight (=BPAFLP: molybdenum oxide). Co-evaporation is a vapor deposition method in which vapor deposition is performed simultaneously from multiple evaporation sources within a single processing chamber. be.

[0274] Next, BPAFLP is deposited on the hole injection layer 111 to a thickness of 20 nm, and hole injection A deposition layer 112 was formed.

[0275] 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 Bis[2-(6-tert-butyl-4-pyrimidinyl-κN3], represented by structural formula (v) )phenyl-κC](2,4-pentanedionato-κ 2 O,O') Iridium(III) (Abbreviation: Ir(tBuppm)2(acac)) and, in a weight ratio of 0.8:0.2:0.06 (=2mDBTPDBq-II:PCBA1BP:Ir(tBuppm)2(acac) ) is co-deposited at 20 nm to form the first light-emitting layer 113a, and 2mDBTPDBq-I I and the bis{4,6-dimethyl-2-[3-(3,5-di} represented by the above structural formula (xii) Methylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6- Dimethyl-3,5-heptanedionato-κ 2 O,O'') Iridium(III) (Abbreviation: [Ir(dmdppr-P)2(dibm)]) and a weight ratio of 1:0.06 (=2mDB) TPDBq-II:[Ir(dmdppr-P)2(dibm)]) 20n A second light-emitting layer 113b was formed by co-deposition of m. The host material was 2mDBTPD. Bq-II and PCBA1BP form an excited complex.

[0276] Subsequently, 2mDBTPDBq-II was deposited on the light-emitting layer 113 to a thickness of 15 nm. Furthermore, bathophenanthroline (abbreviated as BPhen), represented by the above structural formula (vii) A film was deposited to a thickness of 15 nm to form an electron transport layer 114.

[0277] 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.

[0278] 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.

[0279] The light-emitting element 5 has [Ir(tBuppm)2(acac)] in the first light-emitting layer 113a Tris[2-(6-tert-butyl-4-pyrimidium], represented by the above structural formula (xiii). [Ir(tBuppm) (Ir-κN3)phenyl-κC]iridium(III) Except for the part fabricated in place of (3)), the light-emitting element 4 was fabricated in the same manner as the other element.

[0280] In the vapor deposition process described above, resistance heating was used for all deposition steps.

[0281] The element structure of the light-emitting element 4 obtained as described above is shown in Table 4, and the element structure of the light-emitting element 5 is shown in Table 5.

[0282] [Table 4]

[0283] [Table 5]

[0284] The light-emitting elements 4 and 5 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.

[0285] In the light-emitting element 4, the first phosphorescent compound 113Da is Ir(tBuppm)2(ac [Ir(dmdppr-P)2(di) ac) is used as the second phosphorescent compound 113Db The bm) is used here. Here, the PL spectrum of Ir(tBuppm)2(acac) is used. And, ε(λ)λ of [Ir(dmdppr-P)2(dibm)] 4 This section will discuss the relationship between these relationships. Note that λ is the wavelength and ε(λ) is the molar extinction coefficient.

[0286] First, Figure 45(a) shows the phosphorescent compound 113Db of the second light-emitting element 4, [Ir(dmd The molar extinction coefficient ε(λ) of ppr-P)2(dibm) and ε(λ)λ 4 A graph representing the This was shown. The molar extinction coefficient ε(λ) does not have a prominent peak in the long-wavelength region. In contrast, ε(λ)λ 4 In the graph, the maximum value is at 509nm, and also at 550nm and 605nm. There is a peak (mountain) with a shoulder near m. This peak is [Ir(dmdppr-P) This is a triplet MLCT absorption of 2(dibm)), and the first phosphorescent compound 11 is located at this peak. By overlapping the emission peaks of 3Da, the efficiency of energy transfer is greatly increased. This becomes possible.

[0287] Figure 45(b) shows the first phosphorescent compound 113Da of the light-emitting element 4, Ir(tBupp The PL spectrum F(λ) of m)2(acac) and the second phosphorescent compound 113Db. ε(λ)λ of [Ir(dmdppr-P)2(dibm)] 4 A graph representing this was shown. From the graph, the peak of the PL spectrum F(λ) of Ir(tBuppm)2(acac) The mountain where [Ir(dmdppr-P)2(dibm)] ε(λ)λ 4 The longest wave The peak with the maximum value on the long side largely overlaps with this peak, and energy transfer occurs very efficiently. It can be seen that this is a combination. Also, the first phosphorescent compound 113Da is Ir The emission peak of (tBuppm)2(acac) is located at 546 nm, indicating a second phosphorescence. The ε(λ)λ of compound 113Db [Ir(dmdppr-P)2(dibm)] 4of The maximum on the longer wavelength side of the represented spectrum is at 509 nm, so the difference is 37 nm. Therefore, 546nm corresponds to 2.27eV and 509nm corresponds to 2.44eV, so the difference is... The value is 0.17 eV, which is smaller than the difference of 0.2 eV, indicating that the efficiency is low even from the peak position. This suggests that a specific energy transfer is taking place. (dibm)] of ε(λ)λ 4 The long-wavelength maximum (maximum value C) in the spectrum representing and The emission spectra F(λ) of Ir(tBuppm)2(acac) hardly overlap. However, ε(λ)λ of [Ir(dmdppr-P)2(dibm)] 4 The spectrum representing The peak with a maximum value C has a broad shape on the longer wavelength side, and this long wavelength side spectrum The spectra F(λ) of the emission of Torr and Ir(tBuppm)2(acac) show a large overlap. It possesses this feature. Therefore, very good energy transfer is achieved.

[0288] In the light-emitting element 4, the first host material is 2mDBTPDBq-II and the first organic compound PCBA1BP forms an excited complex with the first phosphorescent compound 113Da, Ir Energy transfer is efficiently occurring in (tBuppm)2(acac). The relationship is the same as that of the light-emitting element 1, and is explained in detail in Example 1, so please refer to the previous example. The relevant description is omitted. Please refer to the corresponding description in Example 1.

[0289] Furthermore, Figure 46 shows the PL spectrum F(λ) of the excited complex, Ir(tBuppm)2(acac PL spectrum F(λ), PL spectrum of [Ir(dmdppr-P)2(dibm)] vector F(λ), ε(λ)λ of Ir(tBuppm)2(acac)4 [Ir(dmd ppr-P)2(dibm)] ε(λ)λ 4 A graph showing all of them together is displayed. Excited complex PL spectrum and ε(λ)λ of Ir(tBuppm)2(acac) 4 Overlap with (extreme) Using a large value (around A), the excited complex is converted to Ir(tBuppm)2(acac), and then I PL spectrum of r(tBuppm)2(acac) and [Ir(dmdppr-P)2( dibm)] ε(λ)λ 4 Using the overlap with (from the maximum value C to around 650 nm), Ir( From tBuppm)2(acac) to [Ir(dmdppr-P)2(dibm)], step It can be seen that energy transfer is possible in stages. Furthermore, from the excited complex, a second phosphorescence is observed. Direct energy transfer to the compound [Ir(dmdppr-P)2(dibm)] This can also be done. As can be seen from Figure 46, [Ir(dmdppr-P)2(dib In the triplet MLCT absorption band (near the maximum value C) of m), the PL spectrum F(λ) of the excited complex is ε(λ)λ of [Ir(dmdppr-P)2(dibm)] 4 Because they overlap. be.

[0290] In the light-emitting element 5, Ir(tBuppm)3 is used as the first phosphorescent compound 113Da, [Ir(dmdppr-P)2(dibm)] was used as the phosphorescent compound 113Db in step 2. Here, the PL spectrum of Ir(tBuppm)3 and [Ir(dmdppr -P)2(dibm)] of ε(λ)λ 4 The relationship between these two will be described. Note that λ is the wavelength, and ε(λ) ) is the molar extinction coefficient.

[0291] First, Figure 47(a) shows the phosphorescent compound 113Db of the second light-emitting element 4, [Ir(dmd The molar extinction coefficient ε(λ) of ppr-P)2(dibm) and ε(λ)λ 4 A graph representing the This was shown. The molar extinction coefficient ε(λ) does not have a prominent peak in the long-wavelength region. In contrast, ε(λ)λ 4 In the graph, the maximum value is at 509nm, and also at 550nm and 605nm. There is a peak (mountain) with a shoulder near m. This peak is [Ir(dmdppr-P) This is a triplet MLCT absorption of 2(dibm)), and the first phosphorescent compound 11 is located at this peak. By overlapping the emission peaks of 3Da, the efficiency of energy transfer is greatly increased. This becomes possible.

[0292] Figure 47(b) shows the first phosphorescent compound 113Da of the light-emitting element 5, Ir(tBupp PL spectrum F(λ) of m)3 and the second phosphorescent compound 113Db [Ir(dm dppr-P)2(dibm)] ε(λ)λ 4 A graph illustrating this is shown. The peak of the PL spectrum F(λ) of Ir(tBuppm)3 is located at the mountain [Ir(dm dppr-P)2(dibm)] ε(λ)λ 4 The peak with the longest wavelength maximum is They overlap significantly, and this combination allows for very efficient energy transfer. I understand. Also, the emission of the first phosphorescent compound 113Da, Ir(tBuppm)3 The peak is located at 540 nm and is the second phosphorescent compound 113Db [Ir(dmdp pr-P)2(dibm)] ε(λ)λ 4 The maximum on the long-wavelength side of the spectrum representing is Since it exists at 509nm, the difference is 31nm. 540nm is 2.30eV, 50 Since 9nm corresponds to 2.44eV, the difference is 0.14eV, which is less than 0.2eV. The small difference suggests that efficient energy transfer occurs even from the peak position. It is done. Furthermore, ε(λ)λ of [Ir(dmdppr-P)2(dibm)] 4 The spell representing Spectrum of the long-wavelength maximal (maximum value C) in the kettle and the emission spectrum of Ir(tBuppm)3 Although the λ F(λ) hardly overlaps, the ε of [Ir(dmdppr-P)2(dibm)] (λ)λ 4 The peak with a maximum value C in the spectrum representing this has a broad shape on the longer wavelength side. The spectrum on the longer wavelength side and the emission spectrum F( of Ir(tBuppm)3) λ) has a large overlap. Therefore, very good energy transfer is achieved.

[0293] Next, Figure 48(a) shows the first phosphorescent compound 113Da of the light-emitting element 5, Ir(tB The molar extinction coefficient ε(λ) of uppm)3 and ε(λ)λ 4 A graph representing this is shown. ε(λ )λ 4 In the graph, there are maximum values ​​with high intensity at 409 and 465 nm, and 49 A peak with a shoulder exists at 4nm. This peak is Ir(tBuppm)3. This is a triplet MLCT absorption peak, and the emission peak of the energy donor is superimposed on this peak. This makes it possible to significantly improve the efficiency of energy transfer.

[0294] In this embodiment, the light-emitting element 5 uses 2mDBTPDBq-II as the first host material. The first organic compound PCBA1BP and the excited complex 113Ec form the excited complex The structure is such that energy is supplied from body 113Ec to the first phosphorescent compound 113Da. Figure 23 shows 2mDBTPDBq-II, PCBA1BP, and a mixed film thereof. This figure shows the PL spectrum of 2mDBTPDBq (mass ratio 0.8:0.2). -II and the first organic compound PCBA1BP form an excited complex 113Ec. This can be seen. Also, Figure 48(b) shows the PL spectrum F(λ) of the excited complex and the first The phosphorescent compound 113Da, Ir(tBuppm)3, has ε(λ)λ 4 A graph representing As shown, from this graph, the peak of the PL spectrum F(λ) of the excited complex is located on the halfway point of the curve. A portion of the wavelength range with intensity of 1 / 2 and ε(λ)λ of Ir(tBuppm)3 4 The longest wavelength The peak with the maximum value on the side overlaps with a portion of the wavelength range that has half the intensity, This combination is clearly efficient for energy transfer.

[0295] Furthermore, Figure 49 shows the PL spectra of the excited complex F(λ) and Ir(tBuppm)3. PL spectrum of clef F(λ), [Ir(dmdppr-P)2(dibm)] F(λ ), Ir(tBuppm)3's ε(λ)λ 4 [Ir(dmdppr-P)2(dibm ) of ε(λ)λ 4 A graph showing the combined PL spectrum and Ir( tBuppm)3's ε(λ)λ 4 Using the overlap (near the maximum value A), Ir is released from the excited complex. (tBuppm)3, and the PL spectrum of Ir(tBuppm)3 and [Ir(d mdppr-P)2(dibm)] ε(λ)λ 4 Overlap with (650nm from the maximum value C) Using (nearby), from Ir(tBuppm)3 to [Ir(dmdppr-P)2(dibm) It can be seen that energy transfer is possible in steps from the excited complex to the second The phosphorescent compound [Ir(dmdppr-P)2(dibm)] is directly transferred to the phosphorescent compound [Ir(dmdppr-P)2(dibm)]. It can also be moved. This can be seen from Figure 49, [Ir(dmdppr-P)2 The PL spectrum of the excited complex is shown in the triplet MLCT absorption band (near the maximum value C) of (dibm). F(λ) is also ε(λ)λ of [Ir(dmdppr-P)2(dibm)] 4 They overlap Therefore.

[0296] The element characteristics of these light-emitting devices were measured. The measurements were taken at room temperature (maintained at 25°C). I went there with a certain atmosphere.

[0297] Figure 35 shows the brightness-current efficiency characteristics of the light-emitting element 4. Figure 36 shows the voltage-brightness characteristics. Furthermore, the luminance-external quantum efficiency characteristics are shown in Figure 37. Also, the luminance-power efficiency characteristics are shown in Figure 38. This will be shown.

[0298] As described above, it was found that the light-emitting element 4 exhibits good element characteristics. In particular, Figures 35 and 3 7. As can be seen from Figure 38, it has very good luminous efficiency, and the external quantum efficiency is practical brightness ( 1000 cd / m² 2 It showed high values ​​of over 20% in the vicinity of ). Similarly, current efficiency The current output is around 50 cd / A, and the power efficiency is also very good, at around 50 lm / W.

[0299] Furthermore, Figure 39 shows the emission spectrum when a current of 0.1 mA is passed through the light-emitting element 4. In Figure 39, the horizontal axis represents wavelength (nm), and the vertical axis represents emission intensity (in arbitrary units). From Figure 39, The light-emitting element 4 emits green wavelength light originating from [Ir(tBuppm)2(acac)] and [Ir( Emission containing a balanced amount of red wavelength light originating from dmdppr-P)2(dibm) It was found to exhibit a spectrum.

[0300] Figure 40 shows the brightness-current efficiency characteristics of the light-emitting element 5. Figure 41 shows the voltage-brightness characteristics. Furthermore, the luminance-external quantum efficiency characteristics are shown in Figure 42. Also, the luminance-power efficiency characteristics are shown in Figure 43. This will be shown.

[0301] As described above, the light-emitting element 5 was found to exhibit good element characteristics. In particular, Figures 40 and 4 2. As can be seen from Figure 43, it has very good luminous efficiency, and the external quantum efficiency is practical brightness ( 1000 cd / m² 2 In the vicinity of ), it showed a high value of around 25%. Similarly, current efficiency The current output is around 65 cd / A, and the power efficiency is also very good, at around 70 lm / W.

[0302] Furthermore, the emission spectrum when a current of 0.1 mA is passed through the light-emitting element 5 is shown in Figure 44. In Figure 44, the horizontal axis represents wavelength (nm), and the vertical axis represents emission intensity (in arbitrary units). From Figure 44, The light-emitting element 5 emits green wavelength light originating from [Ir(tBuppm)2(acac)] and [Ir( Emission containing a balanced amount of red wavelength light originating from dmdppr-P)2(dibm) It was found to exhibit a spectrum.

[0303] Thus, the light-emitting element 4 and light-emitting element 5 corresponding to one aspect of the present invention have good luminous efficiency. Furthermore, it was found to be a light-emitting element that obtains light from two types of light-emitting central materials in a well-balanced manner. It was.

[0304] (Reference example 1) The organometallic complex used in the above embodiment, bis[2-(6-tert-butyl-4-pyrim [Dinyl-κN3)phenyl-κC](2,4-pentanedionato-κ 2 O,O') Iriji This shows an example of the synthesis of um(III) (abbreviation: [Ir(tBuppm)2(acac)]). The structure of [Ir(tBuppm)2(acac)] is shown below.

[0305] [ka]

[0306] 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. m was obtained (colorless oil, yield 14%). The synthesis scheme for Step 1 is shown below.

[0307] [ka]

[0308] 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. m1.49g, iridium chloride hydrate (IrCl3·H2O) 1.04g, attached to a reflux tube. 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.

[0309] [ka]

[0310] 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.

[0311] [ka]

[0312] 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...

[0313] 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).

[0314] (Reference example 2) In this reference example, the organometallic iridium complex used in the example, bis{4,6-dimethyl-2 -[3-(3,5-dimethylphenyl)-5-phenyl-2-pyradinyl-κN]phenyl ∫-κC}(2,6-dimethyl-3,5-heptanedionato-κ) 2 O,O'') Irijiu Regarding the synthesis method of m(III) (abbreviation: [Ir(dmdppr-P)2(dibm)]) I will explain it below. The structure of [Ir(dmdppr-P)2(dibm)] (abbreviation) is as follows: This will be shown.

[0315] [ka]

[0316] Step 1: 2,3-Bis(3,5-dimethylphenyl)pyrazine (abbreviation: Hdmdp) pr) synthesis > First, 5.00 g of 2,3-dichloropyrazine and 10 g of 3,5-dimethylphenylboronic acid. 0.23g, sodium carbonate 7.19g, bis(triphenylphosphine)palladium(I I) Dichloride (abbreviation: Pd(PPh3)2Cl2) 0.29 g, water 20 mL, aceton 20 mL of toll was placed in a round-bottom flask fitted with a reflux tubing, and the inside was purged with argon. The reaction vessel was heated by irradiating it with microwaves (2.45 GHz, 100 W) for 60 minutes. Here, we add 2.55g of 3,5-dimethylphenylboronic acid and 1.80g of sodium carbonate. Pd(PPh3)2Cl2 0.070g, water 5mL, acetonitrile 5mL, frustrated Place it in the container and heat it again by irradiating it with microwaves (2.45GHz 100W) for 60 minutes. did.

[0317] Subsequently, water was added to this solution, and the organic layer was extracted with dichloromethane. The resulting organic layer Wash with saturated sodium bicarbonate solution, water, and saturated saline solution, then dry with magnesium sulfate. The solution was filtered after drying. After removing the solvent from this solution, the resulting residue was... Flash column chromatography using xane:ethyl acetate = 5:1 (volume ratio) as the developing solvent. Purified with a ferrite. The solvent was removed by distillation, and the resulting solid was collected as dichloromethane:ethyl acetate = 10: Purification is performed by flash column chromatography using 1 (volume ratio) of the developing solvent, and the objective is achieved. A pyrazine derivative, Hdmdppr (abbreviated), was obtained (white powder, yield 44%). Kuro wave irradiation was performed using a microwave synthesizer (CEM Discover). The synthesis scheme for P1 is shown below (a-1).

[0318] [ka]

[0319] <Step 2: 2,3-bis(3,5-dimethylphenyl)-5-phenylpyrazine (abbreviated) Synthesis of (name: Hdmdppr-P) First, use 4.28g of Hdmdppr (abbreviated) and dryTHF80m obtained in step 1 above. L was placed in a three-necked flask and the inside was purged with nitrogen. After the flask was cooled with ice, phenyllithium ( 9.5 mL of 1.9 M butyl ether solution was added dropwise, and the mixture was stirred at room temperature for 23.5 hours. The liquid was poured into water and extracted with chloroform. The resulting organic layer was washed with water and saturated saline solution, and then sulfurized. It was dried with magnesium oxide. Manganese oxide was added to the resulting mixture and stirred for 30 minutes. Afterward, the solution was filtered and the solvent was removed by distillation. The resulting residue was then prepared using dichloromethane as the developing solvent. The desired pyrazine derivative Hdmdppr was purified by silica gel column chromatography. -P (abbreviation) was obtained (orange oil, yield 26%). The synthesis scheme for Step 2 is shown below (a (See -2)

[0320] [ka]

[0321] <Step 3: Di-μ-chlorotetrakis{4,6-dimethyl-2-[3-(3,5- Dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}diidine Synthesis of um(III) (abbreviation: [Ir(dmdppr-P)2Cl]2) Next, 15 mL of 2-ethoxyethanol and 5 mL of water, and the Hdmdp obtained in step 2 above. pr-P (abbreviation) 1.40g, Iridium chloride hydrate (IrCl3·H2O) (Sigm Place 0.51g (Aldrich) into a round-bottom flask fitted with a reflux tubing, and then... The interior was purged with argon. Then, microwaves (2.45 GHz, 100 W) were irradiated for 1 hour. The reaction was carried out. After removing the solvent by distillation, the resulting residue was washed by suction filtration with ethanol, and multiple The nuclear complex [Ir(dmdppr-P)2Cl]2 (abbreviated) was obtained (reddish-brown powder, yield 58%). The synthesis scheme for Step 3 is shown below (a-3).

[0322] [ka]

[0323] <Step 4: Bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5 -phenyl-2-pyradinyl-κN]phenyl-κC}(2,6-dimethyl-3,5- Ptanzionato-κ 2 O,O'') Iridium(III) (Abbreviation: [Ir(dmdppr -P)2(dibm)] synthesis> Furthermore, 30 mL of 2-ethoxyethanol and the dinuclear complex [Ir(d) obtained in step 3 above are added. [mdppr-P)2Cl]20.94g, diisobutyrylmethane (abbreviation: Hdibm) Place 0.23g and 0.52g of sodium carbonate into a round-bottom flask fitted with a reflux condenser, and pour into the flask. The inside was purged with argon. Then, microwaves (2.45 GHz, 120 W) were applied for 60 minutes. The material was heated by irradiation. The solvent was removed by distillation, and the resulting residue was filtered by suction with ethanol. The solid was washed with water and ethanol, and then recomposed in a mixed solvent of dichloromethane and ethanol. By crystallization, the organometallic complex [Ir(dmdppr-P)2(dibm)] of the present invention is obtained. (Abbreviation) was obtained as a dark red powder (yield 75%). The synthesis scheme for step 4 is shown below (a As shown in -4).

[0324] [ka]

[0325] Furthermore, nuclear magnetic resonance spectroscopy of the dark red powder obtained by the above synthesis method ( 1 (H-NMR) The analysis results are shown below. From these results, it can be seen that in this synthesis example, the organometallic complex [Ir(dmdp It was found that pr-P)2(dibm)] (abbreviation) was obtained.

[0326] 1 H-NMR.δ(CDCl3):0.79(d,6H),0.96(d,6H),1 .41(s,6H),1.96(s,6H),2.24-2.28(m,2H),2.4 1(s,12H),5.08(s,1H),6.46(s,2H),6.82(s,2H ),7.18(s,2H),7.39-7.50(m,10H),8.03(d,4H) ,8.76(s,2H). [Explanation of Symbols]

[0327] 10 electrodes 11 electrodes 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 113Ha First host material 113b Second light-emitting layer 113Db Second phosphorescent compound 113Hb Second host material 113A First Organic Compound 113Ec excited complex 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 406 Sealant 407 Sealing substrate 412 pads 420 IC chips 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 3002 Display device 5000 display 5001 display 5002 display 5003 display 5004 display 5005 display 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 7400 mobile phones 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

1. It comprises a first electrode, a second electrode, a first light-emitting layer, and a second light-emitting layer. The first light-emitting layer is provided between the first electrode and the second light-emitting layer. The second light-emitting layer is provided between the first light-emitting layer and the second electrode. The first light-emitting layer comprises a first compound, a second compound that forms an excitation complex with the first compound, and a first phosphorescent compound. The second light-emitting layer comprises a host material and a second phosphorescent compound that exhibits light emission at a longer wavelength than the first phosphorescent compound. The ε(λ)λ of the first phosphorescent compound ４ The wavelength of the longest wavelength maximum of the function represented by overlaps with the emission spectrum of the excited complex. The energy value of the emission peak wavelength F(λ) of the PL spectrum of the first phosphorescent compound and the ε(λ)λ of the second phosphorescent compound ４ A light-emitting element in which the difference between the energy value of the wavelength of the maximum value on the longest wavelength side of the function represented by and the energy value of the longest wavelength side is 0.2 eV or less. (However, ε(λ) represents the molar extinction coefficient and is a function of the wavelength λ.)

2. It comprises a first electrode, a second electrode, a first light-emitting layer, and a second light-emitting layer. The first light-emitting layer is provided between the first electrode and the second light-emitting layer. The second light-emitting layer is provided between the first light-emitting layer and the second electrode. The first light-emitting layer comprises a first compound having one of an aromatic amine skeleton, a carbazole skeleton, a thiophene skeleton, and a furan skeleton, a second compound that forms an excitation complex with the first compound, and a first phosphorescent compound. The second light-emitting layer comprises a host material and a second phosphorescent compound that exhibits light emission at a longer wavelength than the first phosphorescent compound. The ε(λ)λ of the first phosphorescent compound ４ The wavelength of the longest wavelength maximum of the function represented by overlaps with the emission spectrum of the excited complex. The energy value of the emission peak wavelength F(λ) of the PL spectrum of the first phosphorescent compound and the ε(λ)λ of the second phosphorescent compound ４ A light-emitting element in which the difference between the energy value of the wavelength of the maximum value on the longest wavelength side of the function represented by and the energy value of the longest wavelength side is 0.2 eV or less. (However, ε(λ) represents the molar extinction coefficient and is a function of the wavelength λ.)

3. It comprises a first electrode, a second electrode, a first light-emitting layer, and a second light-emitting layer. The first light-emitting layer is provided between the first electrode and the second light-emitting layer. The second light-emitting layer is provided between the first light-emitting layer and the second electrode. The first light-emitting layer comprises a first compound, a second compound that forms an excitation complex with the first compound, and a first iridium complex. The second light-emitting layer comprises a host material and a second iridium complex that emits light at a longer wavelength than the first iridium complex. The ε(λ)λ of the first iridium complex ４ The wavelength of the longest wavelength maximum of the function represented by overlaps with the emission spectrum of the excited complex. The energy value of the emission peak wavelength of the PL spectrum F(λ) of the first iridium complex and the ε(λ)λ of the second iridium complex ４ A light-emitting element in which the difference between the energy value of the wavelength of the maximum value on the longest wavelength side of the function represented by and the energy value of the longest wavelength side is 0.2 eV or less. (However, ε(λ) represents the molar extinction coefficient and is a function of the wavelength λ.)

4. It comprises a first electrode, a second electrode, a first light-emitting layer, and a second light-emitting layer. The first light-emitting layer is provided between the first electrode and the second light-emitting layer. The second light-emitting layer is provided between the first light-emitting layer and the second electrode. The first light-emitting layer comprises a first compound having one of an aromatic amine skeleton, a carbazole skeleton, a thiophene skeleton, and a furan skeleton, a second compound that forms an excitation complex with the first compound, and a first iridium complex. The second light-emitting layer comprises a host material and a second iridium complex that emits light at a longer wavelength than the first iridium complex. The ε(λ)λ of the first iridium complex ４ The wavelength of the longest wavelength maximum of the function represented by overlaps with the emission spectrum of the excited complex. The energy value of the emission peak wavelength of the PL spectrum F(λ) of the first iridium complex and the ε(λ)λ of the second iridium complex ４ A light-emitting element in which the difference between the energy value of the wavelength of the maximum value on the longest wavelength side of the function represented by and the energy value of the longest wavelength side is 0.2 eV or less. (However, ε(λ) represents the molar extinction coefficient and is a function of the wavelength λ.)

5. In claim 3 or claim 4, A light-emitting element in which two of the three ligands of the first iridium complex are the same ligand and one ligand is different.

6. In any one of claims 3 to 5, A light-emitting element in which two of the three ligands of the second iridium complex are the same ligand and one is a different ligand.

7. In any one of claims 1 to 6, A light-emitting element in which the first light-emitting layer and the second light-emitting layer are in contact with each other.

8. A lighting device having a light-emitting element according to any one of claims 1 to 7.

9. A light-emitting device having a light-emitting element according to any one of claims 1 to 7, and means for controlling the light-emitting element.

10. A display device having an light-emitting element according to any one of claims 1 to 7 in its display unit, and having means for controlling the light-emitting element.

11. An electronic device having a light-emitting element according to any one of claims 1 to 7.

Images