Material for light-emitting device and light-emitting device

Abstract

The invention relates to a material for a light-emitting device and a light-emitting device. Provided is a light-emitting device having good characteristics. One embodiment of the present invention is a material for a light-emitting device, which contains an organic compound in which the inner product of a vector (A) connecting two atoms farthest from each other in the lowest excited state in the organic compound and a vector (B) relating to the transition dipole moment of light emission of the organic compound is 2.5 or more, preferably 4.0 or more (notices, notices, notices, notices, notices, notices, notices, notices, notices, notices, notices, notices, notices, notices, notices, notices and notices). The length of the vector A is represented by nm, the size of the vector B is represented by debye, and the direction of the vector A is set so that the angle formed with the vector B is 90 DEG or less.

Description

Technical Field One aspect of the present invention relates to an organic compound, an organic semiconductor device, a light-emitting device, a photodiode sensor, a display module, a lighting module, a display device, an electronic device, a lighting device, and an electronic component. Note that one aspect of the present invention is not limited to the above technical field. One aspect of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. One aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Thus, more specifically, as an example of the technical field of one aspect of the present invention disclosed in this specification, a semiconductor device, a display device, a liquid crystal display device, a lighting device, a power storage device, a storage device, an imaging device, a driving method of these devices, or a manufacturing method of these devices can be cited. Background Art The practical application of a light-emitting device (also referred to as an organic EL element) that uses an organic compound and utilizes electroluminescence (EL) is very active. In the basic structure of these light-emitting devices, an organic compound layer containing a light-emitting center substance is sandwiched between a pair of electrodes. By applying a voltage to this device, carriers are injected, and light emission from the light-emitting center substance can be obtained using the recombination energy of the carriers. Since the light-emitting device is a self-luminous device, a display device using this light-emitting device for pixels has higher visibility than a liquid crystal display device and does not require a backlight. In addition, a display device using such a light-emitting device can be manufactured to be thin and light, which is also a great advantage. Moreover, a very fast response speed is also one of its characteristics. In addition, since the light-emitting layer of such a light-emitting device can be formed continuously in a planar shape, surface light emission can be obtained. Since this is a characteristic that is difficult to obtain in a point light source represented by an incandescent lamp or an LED or a linear light source represented by a fluorescent lamp, the above light-emitting device also has high utility value as a surface light source that can be used for lighting and the like. As described above, although display devices and lighting devices using light-emitting devices are applicable to various electronic devices, research and development of light-emitting devices with better characteristics are increasingly active. Patent Document 1 discloses a light-emitting element that controls the light-emitting direction by depositing in a manner that aligns a light-emitting substance, thereby improving the extraction efficiency. [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-129509 [Non-Patent Document 1] D. Yokoyama, “Journal of Materials Chemistry”, 21, 19187 (2011) [Non-Patent Document 2] P. Liehm et al., “Applied Physics Letters”, 101, 253304 (2012) Summary of the Invention An object of one aspect of the present invention is to provide a light-emitting device having good characteristics. Further, an object of one aspect of the present invention is to provide a light-emitting device having high reliability. Further, an object of one aspect of the present invention is to provide a light-emitting device having a low driving voltage. Further, an object of one aspect of the present invention is to provide a light-emitting device having high reliability and a low driving voltage. Further, an object of one aspect of the present invention is to provide a light-emitting device capable of providing a display device having good characteristics. Further, an object of one aspect of the present invention is to provide a light-emitting device capable of providing a display device having high reliability. Further, an object of one aspect of the present invention is to provide a display device having a low driving voltage. Further, an object of one aspect of the present invention is to provide a light-emitting device capable of providing a display device having a low driving voltage and high reliability. Further, an object of one aspect of the present invention is to provide any one of an organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device having low power consumption. Further, an object of one aspect of the present invention is to provide any one of an electronic device and a lighting device having high reliability. The present invention only needs to achieve any one of the above objects. One aspect of the present invention is a material for a light-emitting device containing an organic compound, wherein the inner product of a vector A connecting two atoms that are farthest apart when the organic compound is in the lowest excited state and a vector B related to the transition dipole moment of the light emission of the organic compound is 2.5 or more (note that the length of the vector A is represented by nm, the magnitude of the vector B is represented by debye, and the direction of the vector A is set so that the angle formed with the vector B is 90° or less). Further, another aspect of the present invention is a material for a light-emitting device containing an organometallic complex, wherein the inner product of a vector A connecting two atoms that are farthest apart when the organometallic complex is in the lowest triplet excited state and a vector B related to the transition dipole moment of the light emission of the organometallic complex is 2.5 or more (note that the length of the vector A is represented by nm, the magnitude of the vector B is represented by debye, and the direction of the vector A is set so that the angle formed with the vector B is 90° or less). Further, another aspect of the present invention is a material for a light-emitting device having the above structure, wherein the organometallic complex is a tetradentate ligand complex. In addition, another aspect of the present invention is a material for a light-emitting device having the above structure, wherein the organometallic complex is a cyclometalated complex. In addition, another aspect of the present invention is a material for a light-emitting device having the above structure, wherein a part of the atoms contained in the metal of the organometallic complex and the atoms contained in the ligand of the organometallic complex form a six-membered ring. In addition, another aspect of the present invention is a material for a light-emitting device having the above structure, wherein a part of the atoms contained in the metal of the organometallic complex and the atoms contained in the ligand of the organometallic complex form a five-membered ring. In addition, another aspect of the present invention is a material for a light-emitting device having the above structure, wherein the organometallic complex includes a plurality of five-membered rings. In addition, another aspect of the present invention is a material for a light-emitting device having the above structure, wherein the ligand of the organometallic complex contains carbazole. In addition, another aspect of the present invention is a material for a light-emitting device having the above structure, wherein the metal contained in the organometallic complex is platinum. In addition, another aspect of the present invention is a material for a light-emitting device having the above structure, wherein the luminescence quantum yield of the organometallic complex is 0.60 or more. In addition, another aspect of the present invention is a material for a light-emitting device having the above structure, wherein the molecular orientation parameter a of the light emitted by a light-emitting device containing the organometallic complex as a luminescent center substance in the light-emitting layer is 0.23 or less. In addition, another aspect of the present invention is a material for a light-emitting device having the above structure, wherein the light-emitting layer contains a host material and a luminescent center substance. In addition, another aspect of the present invention is a light-emitting device including a first electrode, a second electrode, and a light-emitting layer disposed between the first electrode and the second electrode, wherein the light-emitting layer contains an organic compound in which the inner product of the vector A connecting two atoms that are farthest apart in the excited state and the vector B of the transition dipole moment is 2.5 or more (note that the length of the vector A is expressed in nm, the magnitude of the vector B is expressed in debye, and the direction of the vector A is set so that the angle formed with the vector B is 90° or less). Further, another aspect of the present invention is a light-emitting device including a first electrode, a second electrode, and a light-emitting layer disposed between the first electrode and the second electrode, wherein the light-emitting layer contains an organometallic complex having an inner product of a vector A connecting two atoms that are farthest apart in the excited state and a vector B of the transition dipole moment of 2.5 or more (note that the length of the vector A is expressed in nm, the magnitude of the vector B is expressed in debye, and the direction of the vector A is set such that the angle formed with the vector B is 90° or less). Further, another aspect of the present invention is a light-emitting device having the above structure, wherein the organometallic complex is a tetradentate ligand complex. Further, another aspect of the present invention is a light-emitting device having the above structure, wherein the organometallic complex is a cyclometalated complex. Further, another aspect of the present invention is a light-emitting device having the above structure, wherein a part of the atoms contained in the metal included in the organometallic complex and the ligands in the organometallic complex form a six-membered ring. Further, another aspect of the present invention is a light-emitting device having the above structure, wherein a part of the atoms contained in the metal included in the organometallic complex and the ligands in the organometallic complex form a five-membered ring. Further, another aspect of the present invention is a light-emitting device having the above structure, wherein the organometallic complex includes a plurality of five-membered rings. Further, another aspect of the present invention is a light-emitting device having the above structure, wherein the ligand in the organometallic complex contains carbazole. Further, another aspect of the present invention is a light-emitting device having the above structure, wherein the metal included in the organometallic complex is platinum. Further, another aspect of the present invention is a light-emitting device having the above structure, wherein the photoluminescence quantum yield of the organometallic complex is 0.60 or more. Further, another aspect of the present invention is a light-emitting device having the above structure, wherein the molecular orientation parameter a of the light emitted by the light-emitting device containing the organometallic complex as a light-emitting center substance in the light-emitting layer is 0.23 or less. Further, another aspect of the present invention is a light-emitting device having the above structure, wherein the light-emitting layer contains a host material and a light-emitting center substance. Further, another aspect of the present invention is a display device including any of the above light-emitting devices. Further, another aspect of the present invention is an electronic device including the above light-emitting device, as well as a sensor, an operation button, a speaker, or a microphone. In addition, another aspect of the present invention is an illumination device, which includes the above-mentioned light-emitting device and a housing. One aspect of the present invention can provide a light-emitting device with high luminous efficiency. In addition, one aspect of the present invention can provide a light-emitting device with high reliability. In addition, any one of a display device, an electronic device, and an illumination device with low power consumption can be provided. In addition, any one of a display device, an electronic device, and an illumination device with high reliability can be provided. Note that the description of these effects does not preclude the existence of other effects. Note that one aspect of the present invention does not need to have all of the above-mentioned effects. Note that effects other than the above can be known and extracted from the descriptions in the specification, drawings, claims, etc. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1A to 1C is a schematic diagram of a light-emitting device according to one aspect of the present invention; Figure 2 is a diagram showing each vector and the formed angle in platinum complex 2 (platinum complex B); Figure 3 is a diagram showing the relationship between the observation direction of the measuring instrument in the measurement of the spatial distribution of luminous intensity and each vector component of the transition dipole moment on the substrate; Figure 4 is a diagram showing the external quantum efficiency-current density characteristics of light-emitting devices 1 to 3; Figure 5A and Figure 5B is a diagram showing a display device according to one aspect of the present invention; Figure 6A and Figure 6B is a diagram showing a display device according to one aspect of the present invention; Figures 7A to 7E is a cross-sectional view showing an example of a manufacturing method of a display device; Figure 8A and Figure 8B is a cross-sectional view showing an example of a manufacturing method of a display device; Figures 9A to 9D is a cross-sectional view showing an example of a manufacturing method of a display device; Figures 10A to 10C is a cross-sectional view showing an example of a manufacturing method of a display device; Figures 11A to 11C is a cross-sectional view showing an example of a manufacturing method of a display device; Figures 12A to 12C is a cross-sectional view showing an example of a manufacturing method of a display device; Figure 13A and Figure 13B is a perspective view showing an example of the structure of a display module; Figure 14A and Figure 14B is a cross-sectional view showing a structural example of a display device; Figure 15 is a perspective view showing a structural example of a display device; Figure 16 is a cross-sectional view showing a structural example of a display device; Figure 17 is a cross-sectional view showing a structural example of a display device; Figure 18A is a cross-sectional view showing a structural example of a display device, Figure 18B is a top layout showing a structural example of a display device, Figure 18C is a top view showing a structural example of a display device; Figure 19 is a cross-sectional view showing a structural example of a display device; Figure 20A is a cross-sectional view showing a structural example of a display device, Figure 20B is a top layout showing a structural example of a display device, Figure 20C is a top view showing a structural example of a display device; Figures 21A to 21D is a diagram showing an example of a wearable device; Figures 22A to 22F is a diagram showing an example of an electronic device; Figures 23A to 23G is a diagram showing an example of an electronic device; Figure 24 is a schematic diagram of the device structure of a light-emitting device for orientation measurement; Figure 25 is a graph showing the luminance-current density characteristics of light-emitting devices 1Aa and 1Ab; Figure 26 is a graph showing the current efficiency-current density characteristics of light-emitting devices 1Aa and 1Ab; Figure 27 is a graph showing the luminance-voltage characteristics of light-emitting devices 1Aa and 1Ab; Figure 28 is a graph showing the current density-voltage characteristics of light-emitting devices 1Aa and 1Ab; Figure 29 is a graph showing the external quantum efficiency-current density characteristics of light-emitting devices 1Aa and 1Ab; Figure 30 is a graph showing the electroluminescence spectra of light-emitting devices 1Aa and 1Ab; Figure 31 is a graph showing the luminance-current density characteristics of light-emitting devices 1Ba and 1Bb; Figure 32 It is a graph showing the current efficiency - current density characteristics of the light - emitting device 1Ba and the light - emitting device 1Bb; Figure 33 It is a graph showing the luminance - voltage characteristics of the light - emitting device 1Ba and the light - emitting device 1Bb; Figure 34 It is a graph showing the current density - voltage characteristics of the light - emitting device 1Ba and the light - emitting device 1Bb; Figure 35 It is a graph showing the external quantum efficiency - current density characteristics of the light - emitting device 1Ba and the light - emitting device 1Bb; Figure 36 It is a graph showing the electroluminescence spectra of the light - emitting device 1Ba and the light - emitting device 1Bb; Figure 37 It is a graph showing the luminance - current density characteristics of the light - emitting device 1Ca and the light - emitting device 1Cb; Figure 38 It is a graph showing the current efficiency - current density characteristics of the light - emitting device 1Ca and the light - emitting device 1Cb; Figure 39 It is a graph showing the luminance - voltage characteristics of the light - emitting device 1Ca and the light - emitting device 1Cb; Figure 40 It is a graph showing the current density - voltage characteristics of the light - emitting device 1Ca and the light - emitting device 1Cb; Figure 41 It is a graph showing the external quantum efficiency - current density characteristics of the light - emitting device 1Ca and the light - emitting device 1Cb; Figure 42 It is a graph showing the electroluminescence spectra of the light - emitting device 1Ca and the light - emitting device 1Cb; Figure 43 It is a graph showing the measurement method of the molecular orientation parameter a; Figure 44 It is a graph showing the area intensity at an angle (θ) of the light - emitting device 1Aa and the angle (θ) of the detector of the substrate; Figure 45 It is a graph showing the area intensity at an angle (θ) of the light - emitting device 1Ba and the angle (θ) of the detector of the substrate; Figure 46 It is a graph showing the area intensity at an angle (θ) of the light - emitting device 1Ca and the angle (θ) of the detector of the substrate; Figure 47 It is a graph showing the luminance - current density characteristics of the light - emitting device 2a, the light - emitting device 2b, and the comparative light - emitting device 2; Figure 48 It is a graph showing the luminance - voltage characteristics of the light - emitting device 2a, the light - emitting device 2b, and the comparative light - emitting device 2; Figure 49 is a graph showing the current efficiency-current density characteristics of the light-emitting device 2a, the light-emitting device 2b, and the comparative light-emitting device 2; Figure 50 is a graph showing the current density-voltage characteristics of the light-emitting device 2a, the light-emitting device 2b, and the comparative light-emitting device 2; Figure 51 is a graph showing the blue index (BI)-current density characteristics of the light-emitting device 2a, the light-emitting device 2b, and the comparative light-emitting device 2; Figure 52 is a graph showing the electroluminescence spectra of the light-emitting device 2a, the light-emitting device 2b, and the comparative light-emitting device 2; Figure 53 is a graph showing the time-varying characteristics of the normalized luminance of the light-emitting device 2a, the light-emitting device 2b, and the comparative light-emitting device 2. Detailed Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following description, and it is easily understood by those of ordinary skill in the art that the manner and details thereof can be changed into various forms without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited only to the content described in the following embodiments. Note that, in this specification and the like, a device manufactured using a metal mask or an FMM (Fine Metal Mask, high-precision metal mask) is sometimes referred to as a device having an MM (Metal Mask) structure. In addition, in this specification and the like, a device manufactured without using a metal mask or an FMM is sometimes referred to as a device having an MML (Metal Mask Less) structure. Embodiment 1 As a factor that has a great influence on the external quantum efficiency, there is the light extraction efficiency (χ). Although it depends on the structure, lamination, etc. of the light-emitting device, the light extraction efficiency (χ) in an organic EL device on a glass substrate is generally 20% to 30%. However, this value is based on the assumption that light emission is isotropic, and if the light emission is anisotropic, this value changes. Here, since the light emission of the light-emitting center substance occurs in the direction perpendicular to the transition dipole of the molecule, the light extraction efficiency (χ) can be improved by controlling the orientation state of the molecule. However, even if the orientation state is controlled, when the luminescence quantum yield of the light-emitting center substance itself is low, it is difficult to obtain a light-emitting device with high luminous efficiency only by controlling the orientation state. Generally speaking, it is known that a highly planar structure such as an organometallic complex represented by platinum complex 1 of the following structural formula is advantageous for molecular orientation. However, platinum complex 2 and platinum complex 3 represented by the following structural formula can achieve a light-emitting device with a higher luminous efficiency although their planarity is not high. The inventors of the present invention have found that estimating the contribution of the transition dipole moment to the improvement of the luminous efficiency from a viewpoint different from planarity can provide a light-emitting device with a high luminous efficiency. One aspect of the present invention provides a material for a light-emitting device or a material for a light-emitting device including an organic compound or an organometallic complex, in which the inner product of a vector A connecting two atoms that are farthest apart in the lowest excited state and a vector B that is a transition dipole moment related to light emission in the organic compound or the organometallic complex is 2.5 or more, preferably 4.0 or more. Note that the direction of the vector A is set so as to form an angle of 90° or less with the vector B. The unit of the vector B is debye, and in order to make the number of digits of the vector magnitude consistent, the unit of the vector A is nm. In the case of using a platinum complex, the lowest excited state is the lowest triplet excited state, and a transition dipole moment that is large in magnitude in the lowest excited state and affects the shape of the emission spectrum is adopted. The direction of the vector A connecting two atoms that are farthest apart in the lowest excited state is parallel to the direction of the longest side of the molecule (also referred to as the long side direction). When the angle formed by the vector A and the vector B of the transition dipole moment is small, it is advantageous for molecular orientation. In addition, a large transition dipole moment is advantageous for improving the light-emission quantum yield. Therefore, in the above-mentioned organic compound or organometallic complex having these characteristics, the inner product of the vector A connecting two atoms that are farthest apart in the lowest excited state and the vector B of the transition dipole moment is large. When this value in the organic compound or the organometallic complex is 2.5 or more, preferably 4.0 or more, a light-emitting device or a light-emitting device using the material for a light-emitting device or the material for a light-emitting device including the organic compound or the organometallic complex can have a high luminous efficiency. In addition, a light-emitting device or a light-emitting device with high reliability can be achieved. As described above, the light emission of the organic compound or the organometallic complex occurs in a direction perpendicular to the transition dipole of the molecule. Probabilistically, in a certain molecule, the direction in which the vector connecting two atoms that are farthest apart extends (long side direction) tends to be arranged in a horizontal direction with respect to the deposition surface compared to other directions when the molecule is deposited. Therefore, the angle formed by the vector B, which is the vector of the transition dipole moment, and the vector A is preferably small. Note that although the vector connecting the two atoms that are farthest apart in the ground state and the vector A connecting the two atoms that are farthest apart in the lowest excited state are different vectors, the directions are not likely to differ greatly. Therefore, vector A can be used as an index of the easy horizontal orientation with respect to the deposition surface. In addition, the transition dipole moment represents the easy transition between two electronic states. The larger its value, the easier the transition, which is therefore beneficial to the improvement of the luminescence quantum yield. The value of vector B is preferably large. Therefore, the inner product of vector A and vector B is preferably large. By using a luminescent device material or a light-emitting device material containing an organic compound or an organometallic complex with an inner product of 2.5 or more, preferably 4.0 or more, luminescence can be extracted more efficiently. Note that when there are multiple vectors connecting the two atoms that are farthest apart in the lowest excited state in an organic compound or an organometallic complex, the vector with a smaller angle formed with vector B is regarded as vector A. In addition, the organic compound or organometallic complex contained in the luminescent device material or the light-emitting device material has the function of presenting light in the luminescent device or the light-emitting device. As materials with the function of presenting light, there are luminescent center substances, color conversion materials, etc. The luminescence quantum yield of the organic compound or organometallic complex is preferably 0.60 or more, more preferably 0.70 or more. Preferably, the luminescence quantum yield of the PMMA film obtained by the following steps is measured: using deoxygenated dichloromethane as a solvent, depositing a solution in which each material is dispersed in PMMA (polymethyl methacrylate) at an appropriate concentration (for example, 4.8 wt%) on a quartz substrate by the drop-casting method, and drying it in a glove box under a nitrogen stream (for example, at room temperature for 30 minutes). In addition, the luminescent device material or the light-emitting device material can be composed only of the above-mentioned organic compound or organometallic complex, or can contain other substances. Figure 1A FIG. shows a light-emitting device according to one embodiment of the present invention. The light-emitting device according to one embodiment of the present invention includes a first electrode 101, a second electrode 102, and an organic compound layer 103 on an insulating layer 1000. The organic compound layer 103 includes a light-emitting layer 113. Note that the organic compound layer 103 may also include other functional layers such as a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer. The light-emitting device according to one embodiment of the present invention includes the above-described material for a light-emitting device or a material for a light-emitting element in the light-emitting layer 113. Preferably, the light-emitting layer 113 further includes a host material, and the material for a light-emitting device or a material for a light-emitting element is dispersed in the host material. In addition, the host material may be composed of a plurality of organic compounds. Further, the material for a light-emitting device or a material for a light-emitting element may include an organic compound serving as a host material. The light-emitting device according to one embodiment of the present invention having the above structure can have high luminous efficiency because it includes an organic compound or an organometallic complex as a light-emitting center substance, and the inner product of the vector A connecting the two atoms farthest apart in the lowest excited state and the vector B related to the transition dipole moment for light emission in the organic compound or the organometallic complex is 2.5 or more, preferably 4.0 or more. In addition, a light-emitting device with high reliability can be realized. Moreover, when the molecular orientation parameter a of the light emitted from the light-emitting device is 0.25 or less, preferably 0.23 or less, since the light-emitting device has good orientation characteristics, light can be easily extracted to realize a light-emitting device with higher efficiency. That is to say, a more preferable light-emitting device is as follows: it includes an organic compound or an organometallic complex in which the inner product of the vector A and the vector B is 2.5 or more, preferably 4.0 or more, as a light-emitting center substance in the light-emitting layer, and the molecular orientation parameter a of the light emitted from the light-emitting device is 0.25 or less, preferably 0.23 or less. In addition, a more preferable material for a light-emitting device or a material for a light-emitting element including an organic compound or an organometallic complex is as follows: when it is used in the light-emitting layer, it can provide a light-emitting device in which the molecular orientation parameter a of light is 0.25 or less, preferably 0.23 or less, and the inner product of the vector A and the vector B is 2.5 or more, preferably 4.0 or more. The molecular orientation parameter a is a value obtained by estimating the molecular orientation based on the light-emitting state of the device. The angular dependence of the luminous intensity of the light-emitting device (spatial light-emitting mode) reflects the spatial distribution of the transition dipoles of the light-emitting center substance. By analyzing this spatial distribution, the orientation state of the light-emitting device can be investigated. In this method, since the light emission of the light-emitting device itself is observed and analyzed, even when the light-emitting center substance is dispersed in the host material at a low concentration, the orientation state of the light-emitting center substance in the light-emitting layer in the relationship between the light-emitting surface and the transition dipole moment can be investigated as long as the light-emitting center substance emits light. Therefore, a light-emitting device using the above-described material for a light-emitting device or a material for a light-emitting element in the light-emitting layer and having a molecular orientation parameter a of 0.25 or less, preferably 0.23 or less, can have high efficiency. <Calculation method of the inner product of vector A and vector B> Taking a platinum complex of an organic compound or an organometallic complex contained in a material for a light-emitting device or a material for a light-emitting element as an example, the calculation method of the inner product of vector A connecting two atoms farthest apart in the atomic configuration of the lowest triplet excited state and vector B related to the transition dipole moment for luminescence is described. Here, an example of calculating the inner product of vector A and vector B of these three platinum complexes, platinum complex 1, platinum complex 2, and platinum complex 3, is shown. As the structure for performing quantum chemical calculations, use Maestro GUI manufactured by the company, and perform conformational analysis using Macro Model for sampling. Using the quantum chemical calculation software Jaguar, based on density functional theory (DFT), calculate the most stable structure in the singlet ground state to determine the most stable conformational structure. In this structure, use DYALL-2ZCVP_ZORA-J-PT-GEN++ as the basis function for the Pt atom, use LACVP** as the basis function for other atoms, use ωB97X-D (ω = 0.1) as the functional, and based on time-dependent density functional theory (TD-DFT) using the spin-free ZORA relativistic Hamiltonian, calculate using the lowest triplet excited state as the excited state to obtain the most stable structure. In this structure, perform a single-point energy calculation of the excited state using the spin-orbit ZORA relativistic Hamiltonian to visualize vector B related to the transition dipole moment for luminescence. In this structure, set vector A connecting two atoms farthest apart so that the angle formed with vector B is 90° or less, and calculate the angle formed with vector B. As an example, Figure 2 vectors in platinum complex 2 and the formed angles are shown. Table 1 shows the results.

[0001]

Chemical 01

[0002]

Chemical Formula 02

Claims

1. A material for a light-emitting device, comprising: Organic compounds, wherein the inner product of a vector A connecting two atoms that are farthest apart when the organic compound is in the lowest excited state and a vector B related to the transition dipole moment of the luminescence of the organic compound is greater than 2.5, The length of the vector A is denoted by nm, The magnitude of the vector B is expressed in debye, Furthermore, the direction of the vector A is set so that the angle formed by the vector A and the vector B is less than or equal to 90°.

2. A material for a light-emitting device, comprising: Organometallic complexes, wherein the inner product of a vector A connecting two atoms that are farthest apart when the organometallic complex is in the lowest triplet excited state and a vector B related to the transition dipole moment of the luminescence of the organometallic complex is greater than 2.5, The length of the vector A is denoted by nm, The magnitude of the vector B is expressed in debye, Furthermore, the direction of the vector A is set so that the angle formed by the vector A and the vector B is less than or equal to 90°. The material for a light-emitting device according to claim 2 , wherein the organometallic complex comprises a tetradentate ligand. The material for a light-emitting device according to claim 2 , wherein the organometallic complex is a cyclometallic complex. 5 . The light-emitting device material according to claim 2 , wherein the metal in the organic metal complex and a part of atoms included in the ligand in the organic metal complex form a six-membered ring. 6 . The light-emitting device material according to claim 2 , wherein the metal in the organic metal complex and a part of atoms included in the ligand in the organic metal complex form a five-membered ring. The material for a light-emitting device according to claim 6 , further comprising a plurality of the five-membered rings. 8 . The material for a light-emitting device according to claim 2 , wherein the organometallic complex includes a ligand containing carbazole. 9 . The material for a light-emitting device according to claim 2 , wherein the metal in the organic metal complex is platinum. 10 . The material for a light-emitting device according to claim 2 , wherein the light-emitting quantum yield of the organic metal complex is 0.60 or more. 11 . The material for a light-emitting device according to claim 1 , wherein a light-emitting device including the organic compound as a light-emitting center substance in a light-emitting layer emits light having a molecular orientation parameter a of 0.23 or less. 12 . The material for a light-emitting device according to claim 2 , wherein a light-emitting device including the organic metal complex as a light-emitting center substance in a light-emitting layer emits light having a molecular orientation parameter a of 0.23 or less.

13. A light emitting device, comprising: The material for a light-emitting device according to claim 1.

14. A light emitting device, comprising: a first electrode; a second electrode; as well as The light-emitting layer between the first electrode and the second electrode, Wherein, the light-emitting layer comprises an organic metal complex, The inner product of a vector A connecting two atoms that are farthest apart when the organometallic complex is in the lowest triplet excited state and a vector B related to the transition dipole moment of the luminescence of the organometallic complex is greater than 2.5, The length of the vector A is denoted by nm, The magnitude of the vector B is expressed in debye, Furthermore, the direction of the vector A is set so that the angle formed by the vector A and the vector B is less than or equal to 90°. The light emitting device according to claim 14 , wherein the organometallic complex comprises a tetradentate ligand. The light emitting device according to claim 14 , wherein the organometallic complex comprises a ligand including carbazole. The light emitting device according to claim 14 , wherein the metal in the organic metal complex is platinum. The light-emitting device according to claim 14 , wherein the light-emitting quantum yield of the organic metal complex is 0.60 or more.

19. The light-emitting device according to claim 14, wherein a molecular orientation parameter a of light emitted by the light-emitting device including the organic metal complex as a light-emitting center substance in the light-emitting layer is 0.23 or less.

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