Organic light-emitting diodes

Abstract

To provide an organic light-emitting element having a long luminous life and high luminous efficiency.SOLUTION: An organic light-emitting element includes a light-emitting layer containing a first organic compound (1), a second organic compound (2) which is a delayed fluorescence material, and a third organic compound (3), and an adjacent layer containing the first organic compound (1) adjacent to the light-emitting layer, and satisfies the following formula. ES1 represents the lowest excited singlet energy. ES1(1)>ES1(2)>ES1(3)SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to an organic light-emitting device using a delayed fluorescence material. [Background technology]

[0002] Research is actively being conducted to improve the luminescence efficiency of organic light-emitting devices, such as organic electroluminescent devices (OLEDs). In particular, various studies are being conducted to improve luminescence efficiency by newly developing and combining electron transport materials, hole transport materials, host materials, and light-emitting materials that constitute organic electroluminescent devices. Among these studies, there are also studies on organic light-emitting devices that utilize delayed fluorescence materials.

[0003] Delayed fluorescence materials are compounds that, in their excited state, emit fluorescence when they return from the excited singlet state to the ground state after undergoing a reverse intersystem crossover from the excited triplet state to the excited singlet state. This fluorescence is called delayed fluorescence because it is observed later than fluorescence directly generated from the excited singlet state (normal fluorescence) from the ground state. For example, when a luminescent compound is excited by carrier injection, the probability of generating the excited singlet state and the excited triplet state is statistically 25%:75%, so there is a limit to improving the luminescence efficiency if only fluorescence from the directly generated excited singlet state is used. On the other hand, with delayed fluorescence materials, not only the excited singlet state but also the excited triplet state can be used for fluorescence emission via the reverse intersystem crossover pathway described above, resulting in higher luminescence efficiency compared to ordinary delayed fluorescence materials.

[0004] As such delayed fluorescence materials, benzene derivatives having a heteroaryl group such as a carbazolyl group or a diphenylamino group and at least two cyano groups have been proposed, and it has been confirmed that high luminescence efficiency can be obtained in organic EL devices using these benzene derivatives in the light-emitting layer (see Patent Document 1). Furthermore, Non-Patent Document 1 reports that the carbazolyl dicyanobenzene derivative (4CzTPN) is a thermally activated delayed fluorescence material, and that a high internal EL quantum efficiency was achieved in an organic electroluminescent device using this carbazolyl dicyanobenzene derivative.

[0005] On the other hand, it has also been proposed to use delayed fluorescence materials not as light-emitting materials, but as assist dopants in the light-emitting layer (see Patent Document 2). This document describes how to improve luminescence efficiency by adding a delayed fluorescence material having the lowest excitation singlet energy intermediate between the host material and the fluorescent light-emitting material to the light-emitting layer, in addition to the host material and the fluorescent light-emitting material. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-43541 [Patent Document 2] Japanese Patent Publication No. 2015-179809 [Non-patent literature]

[0007] [Non-Patent Document 1] H. Uoyama, et al., Nature 492, 234 (2012) [Overview of the project] [Problems that the invention aims to solve]

[0008] As described above, Patent Documents 1, 2, and Non-Patent Document 1 report that high luminescence efficiency has been achieved in organic electroluminescent elements using delayed fluorescence materials. On the other hand, in order to provide organic electroluminescent elements with high practicality, it is necessary to further increase the luminescence efficiency and extend the lifespan of the elements. However, further improving luminescence efficiency and element lifespan is not easy, and the direction for doing so has not been clarified.

[0009] Under these circumstances, the inventors diligently pursued research aimed at improving the luminescence efficiency and device lifetime of organic light-emitting devices using delayed fluorescence materials. [Means for solving the problem]

[0010] As a result of diligent research to achieve the above objectives, the inventors have found that by using materials that satisfy specific conditions for the light-emitting layer and its adjacent layer, it is possible to realize an organic light-emitting element with high luminous efficiency and a long device life. The present invention is proposed based on this finding and specifically has the following configuration.

[0011] [1] An organic light-emitting element comprising a light-emitting layer containing a first organic compound, a second organic compound, and a third organic compound that satisfy the following condition (a), and an adjacent layer adjacent to the light-emitting layer, The second organic compound is a delayed fluorescence material, An organic light-emitting element comprising the adjacent layer containing the first organic compound. Condition (a) E S1 (1)>E S1 (2)>E S1 (3) (In the above equation, E S1 (1) represents the lowest singlet excitation energy of the first organic compound. E S1 (2) represents the lowest singlet excitation energy of the second organic compound. E S1 (3) represents the lowest singlet excitation energy of the third organic compound. [2] The organic light-emitting element according to [1], wherein the adjacent layer is composed solely of the first organic compound. [3] The organic light-emitting element according to [1] or [2], wherein the light-emitting layer is located between the anode and the cathode, and the adjacent layer is adjacent to the anode side of the light-emitting layer. [4] The organic light-emitting element according to any one of [1] to [3], wherein the thickness of the adjacent layer is less than 10 nm. The organic light-emitting device according to any one of [1] to [4], wherein the thickness of the adjacent layer is less than one-sixth of the thickness of the light-emitting layer. [6] In the organic light-emitting device according to any one of [1] to [5], the difference in energy ΔE between the lowest excited singlet state and the lowest excited triplet state at 77K of the second organic compound st is 0.3 eV or less. [7] In the organic light-emitting device according to any one of [1] to [6], the difference in energy ΔE between the lowest excited singlet state and the lowest excited triplet state at 77K of the third organic compound st is 0.3 eV or less. [8] The organic light-emitting device according to any one of [1] to [7], wherein the first organic compound, the second organic compound, and the third organic compound satisfy the following condition (b). Condition (b) E T1 (1) > E T1 (2) > E T1 (3) (In the above formula, E T1 (1) represents the lowest excited triplet energy of the first organic compound at 77K. E T1 (2) represents the lowest excited triplet energy of the second organic compound at 77K. E T1 (3) represents the lowest excited triplet energy of the third organic compound at 77K.) [9] The organic light-emitting device according to any one of [1] to [8], wherein the light-emitting layer is composed only of a compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, oxygen atoms, and sulfur atoms.

[10] The organic light-emitting device according to any one of [1] to [9], wherein the first organic compound is a compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, and oxygen atoms.

[11] The organic light-emitting device according to any one of [1] to

[10] , wherein the second organic compound is a compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, oxygen atoms, and sulfur atoms.

[12] The organic light-emitting element according to any one of [1] to

[11] , wherein the third organic compound is a compound comprising an atom selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, oxygen atoms and sulfur atoms.

[13] The organic light-emitting element according to any one of [1] to

[12] , wherein the second organic compound comprises a cyanobenzene structure.

[14] The process includes forming a light-emitting layer containing a first organic compound and a second and third organic compound which are delayed fluorescence materials, and forming an adjacent layer containing the first organic compound adjacent to the light-emitting layer, or The process includes forming an adjacent layer containing a first organic compound, and forming a light-emitting layer adjacent to the adjacent layer, containing the first organic compound and a second and third organic compound which are delayed fluorescence materials. A method for manufacturing an organic light-emitting element, wherein the first organic compound, the second organic compound, and the third organic compound satisfy the following condition (a). Condition (a) E S1 (1)>E S1 (2)>E S1 (3) (In the above equation, E S1 (1) represents the lowest singlet excitation energy of the first organic compound. E S1 (2) represents the lowest singlet excitation energy of the second organic compound. E S1 (3) represents the lowest singlet excitation energy of the third organic compound. [Effects of the Invention]

[0012] The organic light-emitting element of the present invention has a long device life and high luminous efficiency. Furthermore, by using the manufacturing method of the present invention, an organic light-emitting element with a long device life and high luminous efficiency can be easily manufactured. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic cross-sectional view showing an example of the layer structure of an organic electroluminescent element. [Figure 2] This is a flowchart showing the steps for manufacturing an organic light-emitting element. [Modes for carrying out the invention]

[0014] The contents of the present invention will be described in detail below. The descriptions of the constituent elements described below may be based on representative embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples. In this application, numerical ranges expressed using "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits. Also, in this application, "consists of" means consisting only of what is written before "consists of" and does not include anything else. Furthermore, some or all of the hydrogen atoms present in the molecule of the compound used in the present invention are deuterium atoms ( 2 It can be substituted with H (deuterium D). In the chemical structural formulas herein, hydrogen atoms are either represented as H or omitted. For example, when the representation of an atom bonded to a carbon atom in the ring skeleton of a benzene ring is omitted, it is assumed that H is bonded to the carbon atom in the omitted portion. In this specification, the term "substituent" means an atom or group of atoms other than hydrogen and deuterium atoms. On the other hand, the term "substituted or unsubstituted" means that the hydrogen atom may be substituted with a deuterium atom or a substituent.

[0015] (Characteristics of organic light-emitting devices) The organic light-emitting element of the present invention comprises a light-emitting layer containing a first organic compound, a second organic compound, and a third organic compound, and an adjacent layer adjacent to the light-emitting layer. The adjacent layer contains the same first organic compound as that contained in the light-emitting layer. The second organic compound is a delayed fluorescence material, and the first, second, and third organic compounds satisfy the following condition (a). Condition (a) E S1 (1)>E S1 (2)>E S1 (3) In this application, E S1(1) represents the lowest singlet excitation energy of the first organic compound, E S1 (2) represents the lowest singlet excitation energy of the second organic compound, E S1 (3) represents the lowest singlet excitation energy of the third organic compound. In this application, eV is used as the unit.

[0016] The difference E between the lowest excitation singlet energies of the first organic compound and the second compound. S1 (1)-E S1 (2) can be set to a range of 0.3 eV or more, 0.5 eV or more, 0.7 eV or more, and also to a range of 1.6 eV or less, 1.3 eV or less, or 0.9 eV or less. The difference E between the lowest excitation singlet energies of the second organic compound and the third organic compound. S1 (2)-E S1 (3) can be set to a range of 0.03 eV or more, or a range of 0.06 eV or more, or a range of 0.6 eV or less, or a range of 0.3 eV or less, or a range of 0.1 eV or less.

[0017] In a preferred embodiment of the present invention, the first organic compound, the second organic compound, and the third organic compound also satisfy the following condition (b). Condition (b) E T1 (1)>E T1 (2)>E T1 (3) E T1 (1) represents the lowest excited triplet energy of the first organic compound at 77 K (Kelvin), E T1 (2) represents the lowest excited triplet energy of the second organic compound at 77K, E T1 (3) represents the lowest excited triplet energy of the third organic compound at 77K, E T1 (Q) represents the lowest excited triplet energy at 77K of the third organic compound. In this application, eV is used as the unit.

[0018] The difference E between the lowest excitation singlet energies of the first and second organic compounds.S1 (1)-E S1 (2) can be set to a range of 0.3 eV or more, 0.5 eV or more, 0.7 eV or more, and also to a range of 1.6 eV or less, 1.3 eV or less, or 0.9 eV or less. The difference E between the lowest excitation singlet energies of the second and third organic compounds. S1 (2)-E S1 (3) can be set to a range of 0.03 eV or more, or a range of 0.06 eV or more, or a range of 0.6 eV or less, or a range of 0.3 eV or less, or a range of 0.1 eV or less.

[0019] The content of the first organic compound, the second organic compound, and the third organic compound in the light-emitting layer of the organic light-emitting element of the present invention preferably satisfies the following condition (c). Condition (c) Conc(1)>Conc(2)>Conc(3) Conc(1) represents the concentration of the first organic compound in the light-emitting layer, Conc(2) represents the concentration of the second organic compound in the light-emitting layer, and Conc(3) represents the concentration of the third organic compound in the light-emitting layer. In this application, the unit used is weight percent.

[0020] The organic light-emitting element of the present invention preferably has a Conc(1) content of 30% by weight or more, but can be in the range of 50% by weight or more, or 65% by weight or more, or can be in the range of 99% by weight or less, 85% by weight or less, or 75% by weight or less. The organic light-emitting element of the present invention preferably has a Conc(2) content of 10% by weight or more, and can be in the range of 20% by weight or more, or 30% by weight or more, or in the range of 45% by weight or less, or 40% by weight or less, or 35% by weight or less.

[0021] In the organic light-emitting element of the present invention, Conc(3) is preferably 5% by weight or less, and more preferably 3% by weight or less. Conc(3) can be in the range of 1% by weight or less, or 0.5% by weight or less, or in the range of 0.01% by weight or more, or 0.1% by weight or more, or 0.3% by weight or more. Furthermore, it is preferable to satisfy the following condition (d). Condition (d) Conc(2) / Conc(3)>5 Conc(2) / Conc(3) can be in the range of 10 or more, 30 or more, 50 or more, and also in the range of 500 or less, 300 or less, or 100 or less.

[0022] The organic light-emitting element of the present invention contains a first organic compound in an adjacent layer adjacent to the light-emitting layer. Here, "adjacent" means that the light-emitting layer and the adjacent layer are stacked, and that the surface of the light-emitting layer and the surface of the adjacent layer are in direct contact. The adjacent layer may be stacked on the light-emitting layer, or the light-emitting layer may be stacked on the adjacent layer. In a preferred embodiment of the present invention, the organic light-emitting element has a structure in which an organic layer containing a light-emitting layer is located between the anode and the cathode, and an adjacent layer containing the first organic compound is formed to be in contact with the anode side of the light-emitting layer. In this case, the layer in contact with the cathode side of the light-emitting layer does not contain the first organic compound. The adjacent layer is preferably composed only of the first organic compound, but may mainly contain the first organic compound and have the lowest excitation singlet energy (E) of the first organic compound. S1 ) and the lowest excited triplet energy (E T1The layer may also contain a compound having the lowest excited singlet energy and the lowest excited triplet energy close to the first organic compound. Here, "close in energy" means that the energy difference is less than 0.1 eV, preferably less than 0.05 eV, more preferably less than 0.03 eV, and even more preferably less than 0.01 eV. The concentration of the first organic compound in the adjacent layer is preferably 90% by weight or more, more preferably 99% by weight or more, for example, 99.9% by weight or more, or 99.99% by weight or more.

[0023] The thickness of the adjacent layer is preferably 1 nm or more, more preferably 3 nm or more, and can be, for example, 5 nm or more. The thickness of the adjacent layer is preferably less than 20 nm, more preferably less than 10 nm, and can be, for example, less than 7 nm. The thickness of the adjacent layer is preferably less than the thickness of the light-emitting layer. The thickness of the adjacent layer is preferably half or less of the thickness of the light-emitting layer, more preferably one-quarter or less, and can be, for example, one-sixth or less. It is also preferably one-twentieth or more, and can be, for example, one-tenth or more.

[0024] (first organic compound) The first organic compound is an organic compound whose lowest excitation singlet energy is greater than that of the second and third organic compounds. The first organic compound functions as a host material responsible for carrier transport and also has the function of confining the energy of the second and third organic compounds within itself. This allows the energy generated by the recombination of holes and electrons within the molecule to be efficiently converted into light emission. The HOMO (Highest Occupied Molecular Orbital) level of the first organic compound is preferably deeper (lower in energy) than the HOMO level of the charge transfer material contained in the adjacent organic layer on the opposite side of the luminescent layer. For example, the HOMO level of the first organic compound is preferably 0.1 eV or more deeper than the HOMO level of the charge transfer material contained in the adjacent organic layer, and can be, for example, 0.2 eV or more, or 0.25 eV or more. The upper limit can be, for example, less than 0.5 eV or less than 0.3 eV. The HOMO level of the first organic compound is preferably close to the HOMO level of the second organic compound. The difference is preferably less than 0.3 eV, more preferably less than 0.2 eV, and can be, for example, less than 0.1 eV or less than 0.05 eV. In a preferred embodiment of the present invention, the HOMO level of the first organic compound is deeper than the HOMO level of the second organic compound.

[0025] The first organic compound is preferably an organic compound that has hole transport ability and electron transport ability, prevents the emission from becoming longer wavelengths, and has a high glass transition temperature. In a preferred embodiment of the present invention, the first organic compound is selected from compounds that do not emit delayed fluorescence. The first organic compound is preferably a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, oxygen atoms, and sulfur atoms. For example, the first organic compound may be a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, and oxygen atoms. For example, the first organic compound may be a compound consisting only of carbon atoms, hydrogen atoms, nitrogen atoms, and oxygen atoms. Alternatively, the first organic compound may be a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, and sulfur atoms. Alternatively, the first organic compound may be a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, and nitrogen atoms. The first organic compound may be a compound that does not have a cyano group. The first organic compound may be a compound that has only one carbazole ring. The first organic compound may be a compound that contains only one metaphenylene group. The first organic compound may be a compound that contains a dibenzofuran structure or a dibenzothiophene structure. The first organic compound may be a compound other than 3,3'-di(9H-carbazole-9-yl)biphenyl (mCBP). The following are some preferred compounds that can be used as the first organic compound.

[0026] [ka] JPEG0007838780000002.jpg198170JPEG0007838780000003.jpg250168

[0027] (Second organic compound) The second organic compound used in the organic light-emitting device of the present invention is a delayed fluorescence material. In the present invention, a "delayed fluorescence material" is an organic compound that, in its excited state, undergoes a reverse intersystem crossover from an excited triplet state to an excited singlet state, and emits fluorescence (delayed fluorescence) when returning from the excited singlet state to the ground state. In the present invention, a delayed fluorescence material is defined as one in which fluorescence with an emission lifetime of 100 ns (nanoseconds) or more is observed when the emission lifetime is measured using a fluorescence lifetime measurement system (such as the Hamamatsu Photonics Streak Camera System). The second organic compound is the difference ΔE between the lowest excited singlet energy and the lowest excited triplet energy at 77K. ST (2) is preferably 0.3 eV or less, more preferably 0.25 eV or less, more preferably 0.2 eV or less, more preferably 0.15 eV or less, even more preferably 0.1 eV or less, even more preferably 0.07 eV or less, even more preferably 0.05 eV or less, even more preferably 0.03 eV or less, and particularly preferably 0.01 eV or less. ΔE ST If (2) is small, the second organic compound can easily reverse intersystem cross from the excited singlet state to the excited triplet state by absorbing thermal energy, and thus function as a thermally activated delayed fluorescence material. Thermally activated delayed fluorescence materials can absorb the heat emitted by the device and reverse intersystem cross from the excited triplet state to the excited singlet state relatively easily, and can efficiently contribute the excited triplet energy to luminescence.

[0028] In this application, the lowest excited singlet energy (E) of the compound S1 ) and the lowest excited triplet energy (E T1 ) is the value obtained by the following procedure: ΔE ST is E S1 -E T1 This value was obtained by calculation. (1) Lowest excitation singlet energy (E S1 ) A thin film or toluene solution of the compound to be measured (concentration 10%) -5Prepare a sample (mol / L). Measure the fluorescence spectrum of this sample at room temperature (300K). The fluorescence spectrum has emission on the vertical axis and wavelength on the horizontal axis. Draw a tangent to the rising edge of the short-wave side of the emission spectrum, and determine the wavelength value λedge [nm] at the intersection of this tangent and the horizontal axis. Convert this wavelength value to an energy value using the following conversion formula: E S1 Let's assume that. Conversion formula: E S1 [eV]=1239.85 / λedge In the examples described below, the emission spectra were measured using an LED light source (Thorlabs, M300L4) as the excitation light source and a detector (Hamamatsu Photonics, PMA-12 multi-channel spectrometer C10027-01). (2) Lowest excited triplet energy (E T1 ) Lowest excitation singlet energy (E S1 The same sample used in the measurement of phosphorescence is cooled to 77[K] with liquid nitrogen, and excitation light (300 nm) is irradiated onto the sample for phosphorescence measurement. The phosphorescence is measured using a detector. The emission from 100 milliseconds after the excitation light irradiation is taken as the phosphorescence spectrum. A tangent line is drawn to the rising edge of the short wavelength side of this phosphorescence spectrum, and the wavelength value λedge[nm] at the intersection of this tangent line and the horizontal axis is determined. This wavelength value is converted to an energy value using the following conversion formula, and the value E is obtained. T1 Let's assume that. Conversion formula: E T1 [eV]=1239.85 / λedge The tangent to the rise of the short-wavelength side of the phosphorescence spectrum is drawn as follows: When moving along the spectral curve from the short-wavelength side of the phosphorescence spectrum to the shortest wavelength maximum value of the spectrum, consider the tangent at each point on the curve toward the long-wavelength side. The slope of this tangent increases as the curve rises (i.e., as the vertical axis increases). The tangent drawn at the point where this slope value is maximum is taken as the tangent to the rise of the short-wavelength side of the phosphorescence spectrum. Furthermore, local maxima with a peak intensity of 10% or less of the maximum peak intensity of the spectrum are not included in the shortest wavelength local maxima mentioned above. Instead, the tangent line drawn at the point closest to the shortest wavelength local maxima, where the slope value is at its maximum, is considered the tangent line to the rising edge of the phosphorescence spectrum on the short wavelength side.

[0029] The second organic compound is a delayed fluorescence material having a lower minimum excited singlet energy than the first organic compound and a higher minimum excited singlet energy than the third organic compound. The second organic compound can be any compound capable of emitting delayed fluorescence under certain conditions. In the organic light-emitting device of the present invention, it is not essential for the second organic compound to emit delayed fluorescence, and the emission from the third organic compound is the main emission. In the organic light-emitting device of the present invention, the second organic compound transitions to the excited singlet state by receiving energy from the first organic compound in the excited singlet state. Alternatively, the second organic compound may transition to the excited triplet state by receiving energy from the first organic compound in the excited triplet state. The second organic compound is ΔE ST Because the energy is small, the second organic compound in the excited triplet state readily crosses back into the excited singlet state of the second organic compound. The second organic compound in the excited singlet state, generated by these pathways, transfers energy to the third organic compound, causing the third organic compound to transition to the excited singlet state.

[0030] In a preferred embodiment of the present invention, each compound is selected and combined such that there is an overlap between the emission wavelength region of the first organic compound and the absorption wavelength region of the second organic compound. In particular, it is preferable that the short-wavelength edge of the emission spectrum of the first organic compound and the long-wavelength edge of the absorption spectrum of the second organic compound overlap (intersect).

[0031] The second organic compound is preferably a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, oxygen atoms, and sulfur atoms. For example, the second organic compound may be a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, and oxygen atoms. For example, the second organic compound may be a compound consisting only of carbon atoms, hydrogen atoms, nitrogen atoms, and oxygen atoms. Alternatively, the second organic compound may be a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, and sulfur atoms. Alternatively, the second organic compound may be a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, and nitrogen atoms. The second organic compound may be a compound having one cyano group. The second organic compound may be a compound having two cyano groups. Alternatively, the second organic compound may be a compound without cyano groups. The second organic compound may be a compound having a carbazole ring. The second organic compound may be a compound having a substituted carbazolyl group and an unsubstituted carbazolyl group. The second organic compound may be a compound containing a dibenzofuran structure or a dibenzothiophene structure. The second organic compound may be a compound having a triazine ring. The following are preferred compounds that can be used as the second organic compound. In the structural formulas of the following example compounds, t-Bu represents a tert-butyl group. [ka] JPEG0007838780000005.jpg236170JPEG0007838780000006.jpg234170JPEG0007838780000007.j pg249170JPEG0007838780000008.jpg247170JPEG0007838780000009.jpg210170JPEG0007838780 000010.jpg210169JPEG0007838780000011.jpg228163JPEG0007838780000012.jpg191169JPEG00 07838780000013.jpg235170JPEG0007838780000014.jpg231170JPEG0007838780000015.jpg48170

[0032] In addition to the above, other known delayed fluorescence materials can be used in combination with the second organic compound as appropriate. Furthermore, even unknown delayed fluorescence materials can be used. Preferred delayed fluorescence materials include paragraphs 0008-0048 and 0095-0133 of WO2013 / 154064, paragraphs 0007-0047 and 0073-0085 of WO2013 / 011954, paragraphs 0007-0033 and 0059-0066 of WO2013 / 011955, and paragraph 0008- of WO2013 / 081088. Paragraphs 0071 and 0118-0133, paragraphs 0009-0046 and 0093-0134 of Japanese Patent Publication No. 2013-256490, paragraphs 0008-0020 and 0038-0040 of Japanese Patent Publication No. 2013-116975, paragraphs 0007-0032 and 0079-0084 of WO2013 / 133359, paragraph 000 of WO2013 / 161437 Paragraphs 8-0054 and 0101-0121, paragraphs 0007-0041 and 0060-0069 of JP 2014-9352, paragraphs 0008-0048 and 0067-0076 of JP 2014-9224, paragraphs 0013-0025 of JP 2017-119663, paragraphs 0013-0026 of JP 2017-119664, JP 2017 Examples include compounds included in the general formulas described in paragraphs 0012-0025 of Japanese Patent Publication No. 222623, paragraphs 0010-0050 of Japanese Patent Application Publication No. 2017-226838, paragraphs 0012-0043 of Japanese Patent Application Publication No. 2018-100411, and paragraphs 0016-0044 of Japanese Patent Application Publication No. WO2018 / 047853, particularly exemplary compounds that emit delayed fluorescence.Also, Japanese Patent Publication No. 2013-253121, WO2013 / 133359, WO2014 / 034535, WO2014 / 115743, WO2014 / 122895, WO2014 / 126200, WO2014 / 136758, WO2014 / 133121, WO2014 / 1 36860, WO2014 / 196585, WO2014 / 189122, WO2014 / 168101, WO2015 / 008580 No. Publication, WO2014 / 203840 Publication, WO2015 / 002213 Publication, WO2015 / 016200 Publication, WO2015 / 019725 Publication, WO Japanese Patent Publication No. 2015 / 072470, WO2015 / 108049, WO2015 / 080182, WO2015 / 072537, WO2015 / 080183, Japanese Patent Publication No. 2015-129240, WO2015 / 129714, WO2015 / 129715, WO2015 / 133501 Light-emitting materials described in Publication No. 136880, WO2015 / 137244, WO2015 / 137202, WO2015 / 137136, WO2015 / 146541, and WO2015 / 159541 that emit delayed fluorescence can be preferably used. The above publications described in this paragraph are incorporated herein by reference as part of this specification.

[0033] Compounds represented by the following general formula (1) that emit delayed fluorescence can preferably be used as the delayed fluorescence material of the present invention. In a preferred embodiment of the present invention, a compound represented by general formula (1) can be used as the second organic compound. [ka]

[0034] In general formula (1), X 1 ~X 5 represents N or CR. R represents a hydrogen atom, deuterium atom, or substituent. X 1 ~X 5When two or more of these represent CR, those CRs may be identical or different. However, X 1 ~X 5 At least one of them is CD (where D represents the donor group). 1 ~X 5 When all of them are CR, Z represents an acceptor group, and X 1 ~X 5 When at least one of them is N, Z represents a hydrogen atom, a deuterium atom, or a substituent. Among the compounds represented by general formula (1), the compounds represented by general formula (2) below are particularly preferred. [ka]

[0035] In general formula (2), X 1 ~X 5 represents N or CR. R represents a hydrogen atom, deuterium atom, or substituent. X 1 ~X 5 When two or more of these represent CR, those CRs may be identical or different. However, X 1 ~X 5 At least one of them is a CD (where D represents the donor group).

[0036] For a description of the substituent represented by Z in general formula (1) and its preferred range, refer to the description of the substituent and its preferred range for general formula (7) described later. The acceptor group represented by Z in general formula (1) is a group that has the property of donating electrons to the ring to which Z is bonded, and can be selected from groups with a positive Hammett σp value, for example. The donor group represented by D in general formulas (1) and (2) is a group that has the property of withdrawing electrons to the ring to which D is bonded, and can be selected from groups with a negative Hammett σp value, for example. Hereinafter, the acceptor group may be referred to as A. Here, the "Hammett's σp value" was proposed by L.P. Hammett and quantifies the influence of substituents on the reaction rate or equilibrium of para-substituted benzene derivatives. Specifically, the following equation that holds between the substituent in a para-substituted benzene derivative and the reaction rate constant or equilibrium constant: log(k / k0) = ρσp or log(K / K0) = ρσp is the constant (σp) specific to the substituent in the above formula. In the above formula, k is the rate constant of a benzene derivative without a substituent, k0 is the rate constant of a benzene derivative substituted with a substituent, K is the equilibrium constant of a benzene derivative without a substituent, K0 is the equilibrium constant of a benzene derivative substituted with a substituent, and ρ represents a reaction constant determined by the type and conditions of the reaction. For the description of the "Hammett's σp value" in the present invention and the numerical values of each substituent, reference can be made to the description of the σp value in Hansch, C. et al., Chem. Rev., 91, 165 - 195 (1991).

[0037] In General Formula (1) and General Formula (2), X 1 ~X 5 represents N or C-R, but at least one is C-D. The number of N among X 1 ~X 5 is 0 to 4. For example, the cases where only X 1 and X 3 and X 5 , only X 1 and X 3 , only X 1 and X 4 , only X 2 and X 3 , only X 1 and X 5 , only X 2 and X 4 , only X 1 , only X 2 , only X 3 are N can be exemplified. The number of C-D among X 1 ~X 5 is 1 to 5, and preferably 2 to 5. For example, X 1 and X 2 and X 3and X 4 and X 5 , X 1 and X 2 and X 4 and X 5 , X 1 and X 2 and X 3 and X 4 , X 1 and X 3 and X 4 and X 5 , X 1 and X 3 and X 5 , X 1 and X 2 and X 5 , X 1 and X 2 and X 4 , X 1 and X 3 and X 4 , X 1 and X 3 , X 1 and X 4 , X 2 and X 3 , X 1 and X 5 , X 2 and X 4 , X 1 Only, X 2 Only, X 3 An example can be given where only the CD is X. 1 ~X 5 At least one of them may be a CA. Here, A represents an acceptor group. 1 ~X 5 The number of CAs is preferably 0 to 2, and more preferably 0 or 1. As A in CA, a heterocyclic aromatic group having a cyano group and an unsaturated nitrogen atom is a preferred example. Also, X 1 ~X 5 Each of these can be independently a CD or CA. X 1 ~X 5When two adjacent R atoms represent CR, the two R atoms may bond to each other to form a cyclic structure. The cyclic structure formed by the bonding may be an aromatic ring or an antilipid ring, and may contain a heteroatom. Furthermore, the cyclic structure may be a fused ring of two or more rings. The heteroatom here is preferably selected from the group consisting of nitrogen, oxygen, and sulfur atoms. Examples of the cyclic structures formed include benzene rings, naphthalene rings, pyridine rings, pyridazine rings, pyrimidine rings, pyrazine rings, pyrrole rings, imidazole rings, pyrazole rings, imidazoline rings, oxazole rings, isoxazole rings, thiazole rings, isothiazole rings, cyclohexadiene rings, cyclohexene rings, cyclopentaene rings, cycloheptatriene rings, cycloheptadiene rings, cycloheptaene rings, furan rings, thiophene rings, naphthyridine rings, quinoxaline rings, and quinoline rings. For example, multiple rings may be fused together to form a ring, such as a phenanthrene ring or a triphenylene ring.

[0038] In general formulas (1) and (2), the donor group D is preferably a group represented by the following general formula (3). [ka]

[0039] In general formula (3), R 11 and R 12 Each of these independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group. 11 and R 12These groups may bond to each other to form a cyclic structure. L represents a single bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group. Substituents that can be introduced to the arylene group or heteroarylene group of L may be groups represented by general formula (1) or general formula (2), or groups represented by general formulas (3) to (6) described later. These groups represented by (1) to (6) may be introduced up to the maximum number of substituents that can be introduced to L. Also, if multiple groups represented by general formulas (1) to (6) are introduced, their substituents may be the same or different from each other. * represents the bond position to the carbon atoms (C) that constitute the ring skeleton of the ring in general formula (1) or general formula (2). The "alkyl group" referred to here may be linear, branched, or cyclic. Furthermore, two or more of the linear, cyclic, and branched portions may be mixed. The number of carbon atoms in the alkyl group can be, for example, 1 or more, 2 or more, or 4 or more. Also, the number of carbon atoms can be 30 or less, 20 or less, 10 or less, 6 or less, or 4 or less. Specific examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, 2-ethylhexyl, n-heptyl, isoheptyl, n-octyl, isooctyl, n-nonyl, isononyl, n-decanyl, isodecanyl, cyclopentyl, cyclohexyl, and cycloheptyl groups. The alkyl group substituent may be further substituted with an aryl group. The "alkenyl group" may be linear, branched, or cyclic. Furthermore, two or more of these linear, cyclic, and branched portions may be mixed. The number of carbon atoms in the alkenyl group can be, for example, 2 or more, 4 or more, or 30 or less, 20 or less, 10 or less, 6 or less, or 4 or less. Specific examples of alkenyl groups include ethenyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl, n-pentenyl, isopentenyl, n-hexenyl, isohexenyl, and 2-ethylhexenyl. The substituted alkenyl group may be further substituted with other substituents. The "aryl group" and "heteroaryl group" may be monocyclic or fused rings formed by the fusion of two or more rings. In the case of a fused ring, the number of fused rings is preferably 2 to 6, and can be selected from, for example, 2 to 4. Specific examples of rings include benzene rings, pyridine rings, pyrimidine rings, triazine rings, naphthalene rings, anthracene rings, phenanthrene rings, triphenylene rings, quinoline rings, pyrazine rings, quinoxaline rings, and naphthyridine rings. Specific examples of aryl or heteroaryl groups include phenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthracenyl group, 2-anthracenyl group, 9-anthracenyl group, 2-pyridyl group, 3-pyridyl group, and 4-pyridyl group. The "arylene group" and "heteroaryl group" may be defined by changing the valency from 1 to 2 in the descriptions of the aryl group and heteroaryl group. Substituents refer to monovalent groups that can be substituted for hydrogen or deuterium atoms, and do not include condensed groups. For a description of substituents and preferred ranges, refer to the description of substituents and preferred ranges for general formula (7) below.

[0040] The compound represented by general formula (3) is preferably a compound represented by any of the following general formulas (4) to (6). [ka]

[0041] In general formulas (4) to (6), R 51 ~R 60 , R 61 ~R 68 , R 71 ~R 78 Each of these independently represents a hydrogen atom, a deuterium atom, or a substituent. For a description of the substituents and preferred ranges, refer to the description of the substituents and preferred ranges in general formula (7) described later. 51 ~R 60 , R 61 ~R 68 , R 71 ~R 78 It is also preferable that each of these groups be independently represented by one of the general formulas (4) to (6) above. The number of substituents in general formulas (4) to (6) is not particularly limited. It is also preferable that all of them be unsubstituted (i.e., hydrogen atoms or deuterium atoms). Furthermore, if there are two or more substituents in each of general formulas (4) to (6), those substituents may be the same or different. If substituents exist in general formulas (4) to (6), the substituent is R if it is general formula (4). 52 ~R 59 It is preferable that it be one of the following, and if it is general formula (5), then R 62 ~R 67 It is preferable that it be one of the following, and if it is general formula (6), then R 72 ~R 77 It is preferable that it be one of the following.

[0042] In general formulas (4) to (6), R 51 and R 52 , R 52 and R 53 , R 53 and R 54 , R 54 and R 55 , R 55 and R 56 , R 56 and R 57 , R 57 and R 58 , R 58 and R 59 , R 59 and R 60 , R 61 and R62 , R 62 and R 63 , R 63 and R 64 , R 65 and R 66 , R 66 and R 67 , R 67 and R 68 , R 71 and R 72 , R 72 and R 73 , R 73 and R 74 , R 75 and R 76 , R 76 and R 77 , R 77 and R 78 These may be joined together to form a ring structure. For a description of the ring structure and preferred examples, see X in general formulas (1) and (2) above. 1 ~X 5 You can refer to the description and preferred examples of the annular structure in this context.

[0043] In general formula (6), X represents a divalent oxygen atom, sulfur atom, substituted or unsubstituted nitrogen atom, substituted or unsubstituted carbon atom, substituted or unsubstituted silicon atom, or carbonyl group with a linkage length of 1 atom, or a divalent substituted or unsubstituted ethylene group, substituted or unsubstituted vinylene group, substituted or unsubstituted o-arylene group, or substituted or unsubstituted o-heteroarylene group with a linkage length of 2 atoms. For specific examples and preferred ranges of substituents, refer to the descriptions of substituents in general formulas (1) and (2) above.

[0044] In general formulas (4) to (6), L 12 ~L 14 L represents a single bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group. 12 ~L 14 For a description and preferred range of the arylene group or heteroarylene group represented by L, refer to the description and preferred range of the arylene group or heteroarylene group represented by L. 12~L 14 It is preferable that the substituent is a single bond, substituted or unsubstituted arylene group. The substituent of the arylene group or heteroarylene group referred to here may be a group represented by general formulas (1) to (6). The group represented by general formulas (1) to (6) is L 11 ~L 14 The maximum number of substituents that can be introduced may be introduced. Also, if multiple groups represented by general formulas (1) to (6) are introduced, their substituents may be the same or different from each other. * represents the bond position to the carbon atoms (C) that constitute the ring skeleton of the ring in general formula (1) or general formula (2).

[0045] In the present invention, a compound represented by the following general formula (7) that emits delayed fluorescence can be particularly preferably used as a delayed fluorescence material. In a preferred embodiment of the present invention, a compound represented by general formula (7) can be used as the second organic compound. [ka]

[0046] In general formula (7), R 1 ~R 5 0 to 4 of these represent cyano groups, R 1 ~R 5 At least one of them represents a substituted amino group, and the remaining R 1 ~R 5 * represents a hydrogen atom, a deuterium atom, or a substituent other than a cyano group and a substituted amino group. The substituted amino group referred to here is preferably a substituted or unsubstituted diarylamino group, and the two aryl groups constituting the substituted or unsubstituted diarylamino group may be linked to each other. The linkage may be a single bond (in which case a carbazole ring is formed), -O-, -S-, -N(R 6 )-,-C(R 7 )(R 8 )-,-Si(R 9 )(R 10 )- may be linked by linking groups such as R. 6 ~R 10R represents a hydrogen atom, a deuterium atom, or a substituent. 7 and R 8 , R 9 and R 10 These elements may be connected to each other to form a ring-shaped structure. The substituted amino group is R 1 ~R 5 It can be any of the following, for example R 1 and R 2 , R 1 and R 3 , R 1 and R 4 , R 1 and R 5 , R 2 and R 3 , R 2 and R 4 , R 1 and R 2 and R 3 , R 1 and R 2 and R 4 , R 1 and R 2 and R 5 , R 1 and R 3 and R 4 , R 1 and R 3 and R 5 , R 2 and R 3 and R 4 , R 1 and R 2 and R 3 and R 4 , R 1 and R 2 and R 3 and R 5 , R 1 and R 2 and R 4 and R 5 , R 1 and R 2 and R 3 and R 4 and R 5 It is possible to use a substituted amino group, etc. A cyano group can also be R 1 ~R 5 It can be any of the following, for example R 1 , R 2 , R 3 , R 1and R 2 , R 1 and R 3 , R 1 and R 4 , R 1 and R 5 , R 2 and R 3 , R 2 and R 4 , R 1 and R 2 and R 3 , R 1 and R 2 and R 4 , R 1 and R 2 and R 5 , R 1 and R 3 and R 4 , R 1 and R 3 and R 5 , R 2 and R 3 and R 4 It is possible to use a cyano group, etc. R is neither a cyano group nor a substituted amino group. 1 ~R 5represents a hydrogen atom, a deuterium atom, or a substituent. Examples of substituents here include hydroxyl groups, halogen atoms (e.g., fluorine, chlorine, bromine, iodine), alkyl groups (e.g., 1-40 carbon atoms), alkoxy groups (e.g., 1-40 carbon atoms), alkylthio groups (e.g., 1-40 carbon atoms), aryl groups (e.g., 6-30 carbon atoms), aryloxy groups (e.g., 6-30 carbon atoms), arylthio groups (e.g., 6-30 carbon atoms), heteroaryl groups (e.g., 5-30 atoms in the ring skeleton), heteroaryloxy groups (e.g., 5-30 atoms in the ring skeleton), and heteroarylthio groups. Examples of substituents include (for example, groups with 5 to 30 atoms in the ring skeleton), acyl groups (for example, groups with 1 to 40 carbon atoms), alkenyl groups (for example, groups with 1 to 40 carbon atoms), alkynyl groups (for example, groups with 1 to 40 carbon atoms), alkoxycarbonyl groups (for example, groups with 1 to 40 carbon atoms), aryloxycarbonyl groups (for example, groups with 1 to 40 carbon atoms), heteroaryloxycarbonyl groups (for example, groups with 1 to 40 carbon atoms), silyl groups (for example, trialkylsilyl groups with 1 to 40 carbon atoms), nitro groups, and substituent group A consisting of groups in which any of the groups listed above are further substituted with one or more of the groups listed above. Preferred examples of substituents when the aryl group of the diarylamino group is substituted include substituents from substituent group A, and also cyano groups and substituted amino groups. For the group of compounds included in general formula (7) and specific examples of compounds, refer to paragraphs 0008-0048 of WO2013 / 154064, paragraphs 0009-0030 of WO2015 / 080183, paragraphs 0006-0019 of WO2015 / 129715, paragraphs 0013-0025 of JP 2017-119663, and paragraphs 0013-0026 of JP 2017-119664, which are cited herein as part of this specification.

[0047] Furthermore, compounds represented by the following general formula (8) that emit delayed fluorescence can also be used as the delayed fluorescence material of the present invention. In a preferred embodiment of the present invention, the compound represented by general formula (8) can be used as the second organic compound. [ka]

[0048] In general formula (8), Y 1 , Y 2 and Y 3 Either two of them represent nitrogen atoms and the remaining one represents a methine group, or Y 1 , Y 2 and Y 3 All of these represent nitrogen atoms. 1 and Z 2 Each of these independently represents a hydrogen atom, a deuterium atom, or a substituent. 11 ~R 18 Each of these independently represents a hydrogen atom, a deuterium atom, or a substituent, and R 11 ~R 18 At least one of them is preferably a substituted or unsubstituted arylamino group, or a substituted or unsubstituted carbazolyl group. The benzene ring constituting the arylamino group and the benzene ring constituting the carbazolyl group are each R 11 ~R 18 They may form single bonds or linking groups together. Furthermore, compounds represented by general formula (8) contain at least two carbazole structures in their molecule. 1 , Z 2 Examples of substituents that can be adopted include the substituents of the above substituent group A. Also, R 11 ~R 18 Specific examples of substituents that the above-mentioned arylamino group and carbazolyl group can take include substituents from the above-mentioned substituent group A, cyano groups, substituted arylamino groups, and substituted alkylamino groups. 11 and R 12 , R 12 and R 13 , R 13 and R 14 , R 15 and R 16 , R 16 and R 17 , R 17 and R 18 These elements may be bonded to each other to form a ring structure. Among the compounds represented by general formula (8), those represented by general formula (9) are particularly useful. [ka]

[0049] In general formula (9), Y 1 , Y 2 and Y 3 Either two of them represent nitrogen atoms and the remaining one represents a methine group, or Y 1 , Y 2 and Y 3 All of these represent nitrogen atoms. 2 R represents a hydrogen atom, a deuterium atom, or a substituent. 11 ~R 18 and R 21 ~R 28 Each of these independently represents a hydrogen atom, a deuterium atom, or a substituent. 11 ~R 18 At least one of the following, and / or R 21 ~R 28 Preferably, at least one of them represents a substituted or unsubstituted arylamino group, or a substituted or unsubstituted carbazolyl group. The benzene ring constituting the arylamino group and the benzene ring constituting the carbazolyl group are each R 11 ~R 18 or R 21 ~R 28 They may form a single bond or a linking group together. 2 Examples of substituents that can be adopted include the substituents of the above substituent group A. Also, R 11 ~R 18 , R 21 ~R 28 Specific examples of substituents that the above-mentioned arylamino group and carbazolyl group can take include substituents from the above-mentioned substituent group A, cyano groups, substituted arylamino groups, and substituted alkylamino groups. 11 and R 12 , R 12 and R 13 , R 13 and R 14 , R 15 and R16 , R 16 and R 17 , R 17 and R 18 , R 21 and R 22 , R 22 and R 23 , R 23 and R 24 , R 25 and R 26 , R 26 and R 27 , R 27 and R 28 They may be joined together to form a ring structure. For the group of compounds included in general formula (9) and specific examples of such compounds, refer to paragraphs 0020-0062 of Publication WO2013 / 081088, which is cited herein as part of this specification, and to the compounds described in Appl. Phys. Let, 98, 083302 (2011).

[0050] Furthermore, compounds represented by the following general formula (10) that emit delayed fluorescence can also be particularly preferably used as delayed fluorescence materials in the present invention. [ka]

[0051] In general formula (10), R 91 ~R 96 Each of these independently represents a hydrogen atom, a deuterium atom, a donor group, or an acceptor group, with at least one being the donor group and at least two being the acceptor groups. The substitution positions of the at least two acceptor groups are not particularly limited, but it is preferable to include two acceptor groups that are in a meta relationship with each other. For example, R 91 If is a donor group, then at least R 92 and R 94 Structures in which is an acceptor group, or at least R 92 and R 96Structures in which are acceptor groups can be preferably exemplified. The acceptor groups present in the molecule may all be the same or different from each other, but for example, it is possible to select a structure in which they are all the same. The number of acceptor groups is preferably 2 to 3, for example, 2 can be selected. In addition, there may be two or more donor groups, and in that case, the donor groups may all be the same or different from each other. The number of donor groups is preferably 1 to 3, for example, there may be just one or two. For explanations and preferred ranges of donor groups and acceptor groups, refer to the explanations and preferred ranges of D and Z in general formula (1). In particular, in general formula (10), the donor group is preferably represented by general formula (3), and the acceptor group is preferably represented by a cyano group or the general formula (11) below. [ka]

[0052] In general formula (11), Y 4 ~Y 6 R represents either a nitrogen atom or a methine group, but at least one is a nitrogen atom, and preferably all of them represent nitrogen atoms. 101 ~R 110 Each of these independently represents a hydrogen atom, a deuterium atom, or a substituent, but it is preferable that at least one is an alkyl group. For a description of the substituents and preferred ranges, refer to the description of the substituents and preferred ranges in general formula (7) above. 15 represents a single bond or linking group, and can be referred to in the description and preferred range of L in the general formula (3) above. In one preferred embodiment of the present invention, L in general formula (11) 15 This is a single bond. * indicates the bond position to the carbon atoms (C) that make up the ring skeleton of the ring in general formula (10).

[0053] In another preferred embodiment of the present invention, the second organic compound can be a compound represented by general formula (12). [ka]

[0054] Among the compounds represented by general formula (12), particularly preferred compounds are those represented by general formula (13) and general formula (14). [ka]

[0055] In general formulas (12) to (14), D represents a donor group, A represents an acceptor group, and R represents a hydrogen atom, a deuterium atom, or a substituent. For descriptions and preferred ranges of the donor and acceptor groups, refer to the corresponding descriptions and preferred ranges of general formula (1) above. Examples of substituents for R include alkyl groups, or aryl groups which may be substituted with one or more groups selected from the group consisting of alkyl groups and aryl groups. The following are specific examples of preferred donor groups for D in general formulas (12) to (14). In the following examples, * indicates the bond position, and "D" represents deuterium. [ka] JPEG0007838780000028.jpg83167

[0056] The following are specific examples of preferred acceptor groups for A in general formulas (12) to (14). In the following examples, * represents the bond position, and "D" represents a deuterium. [ka] JPEG0007838780000030.jpg121170

[0057] The following are preferred examples of R in general formulas (12) to (14). In the following specific examples, * represents the bond position and "D" represents the deuterium. [ka]

[0058] (Third organic compound) The third organic compound is a compound with a lower minimum excited singlet energy than the first and second organic compounds. The organic light-emitting device of the present invention emits fluorescence originating from the third organic compound. The emission from the third organic compound usually includes delayed fluorescence. The largest component of the emission from the organic light-emitting device of the present invention is the emission from the third organic compound. That is, the amount of emission from the third organic compound is the largest of the emission from the organic light-emitting device of the present invention. The third organic compound transitions to an excited singlet state by receiving energy from the first organic compound in an excited singlet state, the second organic compound in an excited singlet state, and the second organic compound which has transitioned from an excited triplet state to an excited singlet state through reverse intersystem crossing. In a preferred embodiment of the present invention, the third organic compound also transitions to an excited singlet state by receiving energy from the second organic compound in an excited singlet state and the second organic compound which has transitioned from an excited triplet state to an excited singlet state through reverse intersystem crossing. The excited singlet state of the resulting third organic compound emits fluorescence when it subsequently returns to the ground state. The fluorescent material used as the third organic compound is not particularly limited as long as it can receive energy from the first and second organic compounds and emit light, and the emission may include fluorescence, delayed fluorescence, or phosphorescence. Preferably, the emission includes fluorescence or delayed fluorescence, and more preferably, the largest component of the emission from the third organic compound is fluorescence. Two or more third organic compounds may be used, provided they satisfy the conditions of the present invention. For example, by using two or more third organic compounds with different emission colors in combination, it becomes possible to emit a desired color. Alternatively, monochromatic emission may be produced from a single third organic compound. In this invention, the maximum emission wavelength of the compound that can be used as the third organic compound is not particularly limited. Therefore, it is possible to appropriately select and use luminescent materials having a maximum emission wavelength in the visible region (380 to 780 nm) or luminescent materials having a maximum emission wavelength in the infrared region (780 nm to 1 mm). Preferably, fluorescent materials having a maximum emission wavelength in the visible region are used. For example, a luminescent material whose maximum emission wavelength within the 380 to 780 nm region is in the range of 380 to 570 nm may be selected and used, or a luminescent material whose maximum emission wavelength is in the range of 380 to 500 nm may be selected and used, or a luminescent material whose maximum emission wavelength is in the range of 380 to 480 nm may be selected and used. In a preferred embodiment of the present invention, each compound is selected and combined such that there is an overlap between the emission wavelength region of the second organic compound and the absorption wavelength region of the third organic compound. In particular, it is preferable that the short-wavelength edge of the emission spectrum of the second organic compound and the long-wavelength edge of the absorption spectrum of the third organic compound overlap (intersect).

[0059] The third organic compound is preferably a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, oxygen atoms, and sulfur atoms. For example, the third organic compound may be a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, and oxygen atoms. The third organic compound may be a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, and sulfur atoms. The third organic compound may be a compound composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, and boron atoms. For example, the third organic compound may be a compound consisting only of carbon atoms, hydrogen atoms, nitrogen atoms, and boron atoms. The third organic compound may be a compound that does not have a cyano group. The third organic compound may be a compound having multiple resonance effects, for example, a compound having multiple resonance effects between boron atoms and nitrogen atoms. The third organic compound may be a compound having a diarylamino group. The following are preferred compounds that can be used as the third organic compound. In the structural formulas of the following example compounds, Et represents an ethyl group.

[0060] [ka] JPEG0007838780000033.jpg228160JPEG0007838780000034.jpg228169

[0061] Preferred compounds include compounds E1 to E5 and derivatives having their skeletons. Derivatives include compounds substituted with alkyl groups, aryl groups, heteroaryl groups, and diarylamino groups.

[0062] Furthermore, the compounds described in paragraphs 0220-0239 of Publication No. WO2015 / 022974 can also be used as the third organic compound of the present invention, and are particularly preferred.

[0063] (Emitting layer) The light-emitting layer of the organic light-emitting device of the present invention comprises a first organic compound, a second organic compound, and a third organic compound that satisfy condition (a). The light-emitting layer may be composed of no compounds or metal elements other than the first, second, and third organic compounds that transfer charge or energy. Furthermore, the light-emitting layer may be composed solely of compounds consisting of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, oxygen atoms, and sulfur atoms. For example, the light-emitting layer may be composed solely of compounds consisting of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, and oxygen atoms. For example, the light-emitting layer may be composed solely of compounds consisting of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, and sulfur atoms. For example, the light-emitting layer may be composed solely of compounds consisting of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, and boron atoms. For example, the light-emitting layer may be composed solely of compounds consisting of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, oxygen atoms, and sulfur atoms. For example, the light-emitting layer may consist only of compounds composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, and nitrogen atoms. The light-emitting layer may also include a first organic compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, and oxygen atoms; a second organic compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, oxygen atoms, and sulfur atoms; and a third organic compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, oxygen atoms, and sulfur atoms. Furthermore, the light-emitting layer may also include a first organic compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, and oxygen atoms; a second organic compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, and nitrogen atoms; and a third organic compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, and boron atoms. The light-emitting layer may be formed by co-depositing the first organic compound, the second organic compound, and the third organic compound, or by a coating method using a solution in which the first organic compound, the second organic compound, and the third organic compound are dissolved. When forming the light-emitting layer by co-depositing, two or more of the first organic compound, the second organic compound, and the third organic compound may be pre-mixed and placed in a vessel or the like to serve as a deposition source, and the light-emitting layer may be formed by co-depositing using this deposition source. For example, the first organic compound and the second organic compound may be pre-mixed to create one deposition source, and the light-emitting layer may be formed by co-depositing using this deposition source and a deposition source for the third organic compound.

[0064] (Layer structure of organic light-emitting element) By forming a light-emitting layer containing a first organic compound, a second organic compound, and a third organic compound that satisfy condition (a), and an adjacent layer containing the first organic compound adjacent thereto, it is possible to provide excellent organic light-emitting elements such as organic photoluminescent elements (organic PL elements) and organic electroluminescent elements (organic EL elements). The thickness of the light-emitting layer can be, for example, 5 nm or more, 10 nm or more, 20 nm or more, 40 nm or more, or 80 nm or less, or 60 nm or less. Organic photoluminescent elements have a structure in which at least an emissive layer and adjacent layers are formed on a substrate. Organic electroluminescent elements have a structure in which at least an anode, a cathode, and an organic layer are formed between the anode and the cathode. The organic layer includes at least an emissive layer and adjacent layers, and may consist only of the emissive layer and adjacent layers, or it may have one or more organic layers in addition to the emissive layer and adjacent layers. Examples of organic layers other than the emissive layer include hole transport layers, hole injection layers, electron barrier layers, electron injection layers, electron transport layers, and exciton barrier layers. The hole transport layer may be a hole injection transport layer with hole injection function, and the electron transport layer may be an electron injection transport layer with electron injection function. A specific structural example of an organic electroluminescent element is shown in Figure 1. In Figure 1, 1 represents the glass substrate, 2 the anode, 3 the hole injection layer, 4 the hole transport layer, 5 the electron barrier layer, 6 the adjacent layer, 7 the light-emitting layer, 8 the hole barrier layer, 9 the electron transport layer, 10 the electron injection layer, and 11 the cathode. When the organic light-emitting element of the present invention is a multi-wavelength emitting organic light-emitting element, the shortest wavelength emission may include delayed fluorescence. Alternatively, the shortest wavelength emission may not include delayed fluorescence.

[0065] (Method for manufacturing organic light-emitting diodes) The organic light-emitting element of the present invention may be manufactured by any method. A preferred manufacturing method includes the step of forming an adjacent layer containing a first organic compound, and then forming a light-emitting layer adjacent to that adjacent layer, containing the first organic compound and a second and third organic compound which are delayed fluorescence materials. For example, when manufacturing an organic electroluminescent element by laminating an organic layer on an anode, an adjacent layer containing a first organic compound can be formed, and then a light-emitting layer containing the first organic compound, the second organic compound, and the third organic compound can be formed on top of that adjacent layer. Another preferred manufacturing method is one that includes the step of forming an emissive layer containing a first organic compound and a second and third organic compound which are delayed fluorescence materials, and forming an adjacent layer containing the first organic compound adjacent to the emissive layer. For example, when manufacturing an organic electroluminescent element by laminating an organic layer on a cathode, an emissive layer containing the first organic compound, a second organic compound and a third organic compound may be formed, and an adjacent layer containing the first organic compound may be formed on top of the emissive layer.

[0066] In the manufacturing method of the present invention, the first organic compound, the second organic compound, and the third organic compound are selected so as to satisfy the above condition (a). The means for forming the light-emitting layer and the barrier layer are not particularly limited. A preferred method for formation is vapor deposition. Alternatively, they may be formed by coating. The adjacent light-emitting layer and barrier layer may be formed continuously or intermittently. Continuous formation is preferred. The manufacturing method of the present invention can be easily implemented using a conventional organic light-emitting element manufacturing line (manufacturing equipment). In other words, the manufacturing method of the present invention can be easily implemented by simply changing the materials used to form the light-emitting layer and adjacent layers in a conventional manufacturing line to satisfy the above condition (a). For this reason, the manufacturing method of the present invention has the advantage of being able to be implemented without changing or constructing a new manufacturing line. Furthermore, after implementing the manufacturing method of the present invention, it is possible to revert to a manufacturing line for organic light-emitting elements other than the present invention by changing the materials used. For this reason, the manufacturing method of the present invention is highly practical in that it can be implemented and adapted economically in a short time.

[0067] In the manufacturing method of the present invention, as long as the light-emitting layer and the adjacent layer are formed adjacent to each other using a material that satisfies the above condition (a), the method of forming other layers or structures is not particularly limited. For example, the method may further include a step of forming electrodes such as an anode and a cathode, or a step of forming layers other than the light-emitting layer and the adjacent layer. When the manufacturing method of the present invention is used, for example, in the manufacture of an organic electroluminescent element, the steps of forming one or more organic layers sequentially on the anode, forming an adjacent layer thereon, forming a light-emitting layer thereon, forming one or more organic layers thereon, and forming a cathode thereon can be carried out. Alternatively, the steps of forming one or more organic layers sequentially on the cathode, forming a light-emitting layer thereon, forming an adjacent layer thereon, forming one or more organic layers thereon, and forming an anode thereon can be carried out. Furthermore, modifications and additions that are obvious to those skilled in the art may be made.

[0068] Figure 2 is a flowchart showing the steps for manufacturing an organic light-emitting element. When manufacturing an organic electroluminescent element, electrodes are prepared (S1), and an organic layer is formed on the electrodes (S2). Next, an adjacent layer is formed on the formed organic layer (S3), and then a light-emitting layer is formed on top of that (S4). Another organic layer, different from the one formed in S2, is formed on the formed light-emitting layer (S5). Finally, electrodes are formed on the organic layer (S6), thereby manufacturing an organic electroluminescent element. In manufacturing, one or both of the organic layer formation steps S2 and S5 may be omitted. Also, when manufacturing an organic photoluminescent element, the electrode preparation step S1 and the electrode formation step S6 may be omitted. In the manufacturing method of the present invention, it is necessary to select materials for the adjacent layer formation step S3 and the light-emitting layer formation step S4 so that they satisfy the above condition (a) when forming the layers.

[0069] The following describes each component of the organic electroluminescent element and each layer other than the light-emitting layer.

[0070] Base material: In some embodiments, the organic electroluminescent element of the present invention is held by a substrate, which is not particularly limited and may be any of the materials commonly used in organic electroluminescent elements, such as glass, transparent plastic, quartz, and silicon.

[0071] anode: In some embodiments, the anode of an organic electroluminescent apparatus is manufactured from a metal, alloy, conductive compound, or a combination thereof. In some embodiments, the metal, alloy, or conductive compound has a high work function (4 eV or more). In some embodiments, the metal is Au. In some embodiments, the conductive transparent material is selected from CuI, indium tin oxide (ITO), SnO2, and ZnO. In some embodiments, an amorphous material capable of forming a transparent conductive film, such as IDIXO (In2O3-ZnO), is used. In some embodiments, the anode is a thin film. In some embodiments, the thin film is manufactured by vapor deposition or sputtering. In some embodiments, the film is patterned by photolithography. In some embodiments, if the pattern does not need to be highly precise (e.g., about 100 μm or more), the pattern may be formed using a mask with a shape suitable for vapor deposition or sputtering onto the electrode material. In some embodiments, when a coating material such as an organic conductive compound can be applied, wet film formation methods such as printing or coating methods are used. In some embodiments, when synchrotron radiation passes through the anode, the anode has a transmittance of more than 10%, and the anode has a sheet resistance of several hundred ohms or less per unit area. In some embodiments, the thickness of the anode is 10 to 1,000 nm. In some embodiments, the thickness of the anode is 10 to 200 nm. In some embodiments, the thickness of the anode varies depending on the material used.

[0072] cathode: In some embodiments, the cathode is made of an electrode material such as a metal with a low work function (4 eV or less) (referred to as an electron-injection metal), an alloy, a conductive compound, or a combination thereof. In some embodiments, the electrode material is selected from sodium, sodium-potassium alloy, magnesium, lithium, magnesium-copper mixture, magnesium-silver mixture, magnesium-aluminum mixture, magnesium-indium mixture, aluminum-aluminum oxide (Al2O3) mixture, indium, lithium-aluminum mixture, and rare earth elements. In some embodiments, a mixture of the electron-injection metal and a second metal that is a stable metal having a higher work function than the electron-injection metal is used. In some embodiments, the mixture is selected from magnesium-silver mixture, magnesium-aluminum mixture, magnesium-indium mixture, aluminum-aluminum oxide (Al2O3) mixture, lithium-aluminum mixture, and aluminum. In some embodiments, the mixture improves electron-injection properties and resistance to oxidation. In some embodiments, the cathode is manufactured by forming the electrode material as a thin film by vapor deposition or sputtering. In some embodiments, the cathode has a sheet resistance of several hundred ohms or less per unit area. In some embodiments, the thickness of the cathode is 10 nm to 5 μm. In some embodiments, the thickness of the cathode is 50 to 200 nm. In some embodiments, either the anode or cathode of the organic electroluminescent element is transparent or translucent in order to transmit synchrotron radiation. In some embodiments, a transparent or translucent electroluminescent element enhances the light radiance. In some embodiments, a transparent or translucent cathode is formed by forming the cathode with respect to the conductive transparent material described above. In some embodiments, the element includes an anode and a cathode, both of which are transparent or translucent.

[0073] Injection layer: The injection layer is a layer between the electrode and the organic layer. In some embodiments, the injection layer reduces the driving voltage and enhances the light radiance. In some embodiments, the injection layer includes a hole injection layer and an electron injection layer. The injection layer can be located between the anode and the light-emitting layer or hole transport layer, and between the cathode and the light-emitting layer or electron transport layer. In some embodiments, an injection layer is present. In some embodiments, an injection layer is absent. The following are examples of preferred compounds that can be used as hole injection materials.

[0074] [ka]

[0075] Next, we will list some examples of preferred compounds that can be used as electron injection materials. [ka]

[0076] Barrier layer: A barrier layer is a layer that can prevent charges (electrons or holes) and / or excitons present in the light-emitting layer from diffusing to the outside of the light-emitting layer. In some embodiments, an electron barrier layer exists between the light-emitting layer and the hole transport layer, preventing electrons from passing through the light-emitting layer to the hole transport layer. In some embodiments, a hole barrier layer exists between the light-emitting layer and the electron transport layer, preventing holes from passing through the light-emitting layer to the electron transport layer. In some embodiments, a barrier layer prevents excitons from diffusing to the outside of the light-emitting layer. In some embodiments, the electron barrier layer and the hole barrier layer constitute an exciton barrier layer. As used herein, the terms “electron barrier layer” or “exciton barrier layer” include layers that have both the functions of an electron barrier layer and an exciton barrier layer.

[0077] Hole barrier layer: The positive hole blocking layer functions as an electron transport layer. In some embodiments, during the transport of electrons, the positive hole blocking layer prevents holes from reaching the electron transport layer. In some embodiments, the positive hole blocking layer increases the probability of recombination of electrons and holes in the light-emitting layer. The material used for the positive hole blocking layer may be the same as the material described above for the electron transport layer. Examples of preferred compounds that can be used for the positive hole blocking layer are given below.

[0078]

Chemical formula

[0079] Electron blocking layer: The electron blocking layer transports holes. In some embodiments, during the transport of holes, the electron blocking layer prevents electrons from reaching the hole transport layer. In some embodiments, the electron blocking layer increases the probability of recombination of electrons and holes in the light-emitting layer. The material used for the electron blocking layer may be the same as the material described above for the hole transport layer. Specific examples of compounds that can be used as electron blocking materials are given below.

[0080]

Chemical formula

[0081] Exciton blocking layer: The exciton barrier layer prevents excitons generated through the recombination of holes and electrons in the light-emitting layer from diffusing to the charge transport layer. In some embodiments, the exciton barrier layer enables effective confinement of excitons in the light-emitting layer. In some embodiments, the optical emission efficiency of the device is improved. In some embodiments, the exciton barrier layer is located on either the anode side or the cathode side and adjacent to the light-emitting layers on both sides. In some embodiments, when the exciton barrier layer is located on the anode side, it may be located between the hole transport layer and the light-emitting layer and adjacent to the light-emitting layer. In some embodiments, when the exciton barrier layer is located on the cathode side, it may be located between the light-emitting layer and the cathode and adjacent to the light-emitting layer. In some embodiments, a hole injection layer, electron barrier layer, or similar layer is located between the anode and the exciton barrier layer adjacent to the light-emitting layer on the anode side. In some embodiments, a hole injection layer, electron barrier layer, hole barrier layer, or similar layer is located between the cathode and the exciton barrier layer adjacent to the light-emitting layer on the cathode side. In some embodiments, the exciton barrier layer includes an excitation singlet energy and an excitation triplet energy, at least one of which is higher than the excitation singlet energy and excitation triplet energy of the light-emitting material, respectively.

[0082] Hole transport layer: The hole transport layer comprises a hole transport material. In some embodiments, the hole transport layer is a single layer. In some embodiments, the hole transport layer has multiple layers. In some embodiments, the hole transport material has one of the following properties: hole injection or transport properties and electron barrier properties. In some embodiments, the hole transport material is an organic material. In some embodiments, the hole transport material is an inorganic material. Examples of known hole transport materials that can be used in the present invention include, but are not limited to, triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indrocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, allylamine derivatives, aminosubstituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers and conductive polymer oligomers (especially thiophene oligomers), or combinations thereof. In some embodiments, the hole transport material is selected from porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds. In some embodiments, the hole transport material is an aromatic tertiary amine compound. Specific examples of preferred compounds that can be used as hole transport materials are given below.

[0083] [ka]

[0084] Electron transport layer: The electron transport layer comprises an electron transport material. In some embodiments, the electron transport layer is a single layer. In some embodiments, the electron transport layer has multiple layers. In some embodiments, the electron transport material only needs to have the function of transporting electrons injected from the cathode to the light-emitting layer. In some embodiments, the electron transport material also functions as a hole barrier material. Examples of electron transport layers that can be used in the present invention include, but are not limited to, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimides, fluorenylidene methane derivatives, anthraquinodimethane, anthrone derivatives, oxadiazole derivatives, azole derivatives, azine derivatives or combinations thereof, or polymers thereof. In some embodiments, the electron transport material is a thiadiazole inducer or a quinoxaline derivative. In some embodiments, the electron transport material is a polymer material. Specific examples of preferred compounds that can be used as electron transport materials are listed below.

[0085] [ka]

[0086] Furthermore, examples of preferred compounds that can be added to each organic layer are given. For example, they can be added as stabilizing materials.

[0087] [ka]

[0088] While specific examples of preferred materials that can be used in organic electroluminescent elements have been provided, the materials that can be used in the present invention are not limited to the following exemplary compounds. Furthermore, even compounds exemplified as materials with specific functions can be repurposed as materials with other functions.

[0089] device: In some embodiments, the light-emitting layer is incorporated into the device. For example, devices include, but are not limited to, OLED bulbs, OLED lamps, television displays, computer monitors, mobile phones, and tablets. In some embodiments, the electronic device includes an OLED having an anode, a cathode, and at least one organic layer including a light-emitting layer between the anode and the cathode. In some embodiments, the components described herein can be incorporated into various photosensitive or photoactivated devices, such as OLEDs or optoelectronic devices. In some embodiments, the components may be useful for facilitating charge transfer or energy transfer within the device and / or as hole transport materials. Examples of such devices include organic light-emitting diodes (OLEDs), organic integrated circuits (OICs), organic field-effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic light-emitting transistors (O-LETs), organic solar cells (O-SCs), organic optical detectors, organic photoreceptors, organic field-quench devices (O-FQDs), light-emitting fuel cells (LECs), or organic laser diodes (O-lasers).

[0090] Bulb or lamp: In some embodiments, the electronic device includes an OLED comprising an anode, a cathode, and at least one organic layer including a light-emitting layer between the anode and the cathode. In some embodiments, the device includes OLEDs of different colors. In some embodiments, the device includes an array comprising combinations of OLEDs. In some embodiments, the combination of OLEDs is a combination of three colors (e.g., RGB). In some embodiments, the combination of OLEDs is a combination of colors other than red, green, and blue (e.g., orange and yellow-green). In some embodiments, the combination of OLEDs is a combination of two, four, or more colors. In some embodiments, the device is A circuit board having a first surface with a mounting surface and a second surface opposite to it, defining at least one opening, The mounting surface comprises at least one OLED having a light-emitting configuration, wherein the at least one OLED includes an anode, a cathode, and at least one organic layer comprising a light-emitting layer between the anode and the cathode, A housing for a circuit board, An OLED light comprising at least one connector located at the end of the housing, wherein the housing and the connector define a package suitable for mounting to a lighting fixture. In some embodiments, the OLED light has multiple OLEDs mounted on a circuit board such that light is emitted in multiple directions. In some embodiments, some of the light emitted in the first direction is polarized and emitted in a second direction. In some embodiments, a reflector is used to polarize the light emitted in the first direction.

[0091] Display or screen: In some embodiments, the light-emitting layer of the present invention can be used in a screen or display. In some embodiments, the compound according to the present invention is deposited on a substrate using a process such as vacuum evaporation, deposition, vapor deposition, or chemical vapor deposition (CVD), but is not limited. In some embodiments, the substrate is a photoplate structure useful in two-sided etching, providing pixels with a unique aspect ratio. The screen (also called a mask) is used in the manufacturing process of an OLED display. The design of the corresponding artwork pattern allows for the arrangement of very steep, narrow tie bars between pixels in the vertical direction, as well as large, wide oblique apertures in the horizontal direction. This enables the fine pattern configuration of pixels required for high-resolution displays, while optimizing chemical vapor deposition on a TFT backplane. Internal patterning of pixels enables the formation of three-dimensional pixel apertures with various aspect ratios in the horizontal and vertical directions. Further, the use of imaged "stripes" or halftone circles in the pixel region protects the etching in specific regions until these specific patterns are undercut and removed from the substrate. At that time, all pixel regions are processed at a similar etching rate, but the depth varies according to the halftone pattern. By changing the size and spacing of the halftone pattern, etching with various different protection rates within the pixel becomes possible, enabling localized deep etching necessary to form a sharp vertical bevel. A preferred material for the evaporation mask is Invar. Invar is a metal alloy cold-rolled in a long thin sheet form at a steel mill. Invar cannot be electrodeposited onto a spin mandrel as a nickel mask. A suitable and low-cost method for forming an opening region in the evaporation mask is a method by wet chemical etching. In some embodiments, the screen or display pattern is a pixel matrix on a substrate. In some embodiments, the screen or display pattern is processed using lithography (e.g., photolithography and e-beam lithography). In some embodiments, the screen or display pattern is processed using wet chemical etching. In further embodiments, the screen or display pattern is processed using plasma etching.

[0092] Method for manufacturing a device: An OLED display is generally manufactured by forming a large mother panel and then cutting the mother panel into cell panel units. Usually, each cell panel on the mother panel forms a thin film transistor (TFT) having an active layer and source / drain electrodes on a base substrate, applying a planarization film to the TFT, and sequentially forming a pixel electrode, a light-emitting layer, a counter electrode, and a encapsulation layer over time, and forming by cutting from the mother panel. OLED displays are generally manufactured by forming a large mother panel and then cutting the mother panel into cell panels. Typically, each cell panel on the mother panel is formed by forming a thin-film transistor (TFT) having an active layer and source / drain electrodes on a base substrate, coating the TFT with a planarization film, sequentially forming pixel electrodes, an emissive layer, a counter electrode, and an encapsulation layer over time, and then cutting it from the mother panel.

[0093] In another aspect of the present invention, a method for manufacturing an organic light-emitting diode (OLED) display is provided, the method being A process of forming a barrier layer on the base substrate of the mother panel, The process of forming multiple display units on the barrier layer in cell panel units, The process of forming an encapsulation layer on each of the display units of the cell panel, The process includes the step of applying an organic film to the interface portion between the cell panels. In some embodiments, the barrier layer is an inorganic film formed of, for example, SiNx, and the edges of the barrier layer are covered with an organic film formed of polyimide or acrylic. In some embodiments, the organic film assists in the soft cutting of the mother panel into cell panel units. In some embodiments, the thin-film transistor (TFT) layer includes a light-emitting layer, a gate electrode, and source / drain electrodes. Each of a plurality of display units may include a thin-film transistor (TFT) layer, a planarization film formed on the TFT layer, and a light-emitting unit formed on the planarization film, wherein the organic film coated on the interface portion is formed of the same material as the planarization film and is formed simultaneously with the formation of the planarization film. In some embodiments, the light-emitting unit is connected to the TFT layer by a passivation layer, a planarization film between them, and an encapsulation layer that covers and protects the light-emitting unit. In some embodiments of the manufacturing method, the organic film is not connected to the display unit or the encapsulation layer.

[0094] Each of the organic film and the planarization film may contain either polyimide or acrylic. In some embodiments, the barrier layer may be an inorganic film. In some embodiments, the base substrate may be formed of polyimide. The method may further include the steps of attaching a carrier substrate made of glass material to another surface of the base substrate before forming a barrier layer on one surface of the polyimide base substrate, and separating the carrier substrate from the base substrate before cutting along the interface. In some embodiments, the OLED display is a flexible display. In some embodiments, the passivation layer is an organic film placed on the TFT layer for coating the TFT layer. In some embodiments, the planarization film is an organic film formed on the passivation layer. In some embodiments, the planarization film is made of polyimide or acrylic, as is the organic film formed at the edges of the barrier layer. In some embodiments, the planarization film and the organic film are formed simultaneously during the manufacture of the OLED display. In some embodiments, the organic film may be formed at the edges of the barrier layer, so that a portion of the organic film is in direct contact with the base substrate, and the remaining portion of the organic film is in contact with the barrier layer while surrounding the edges of the barrier layer.

[0095] In some embodiments, the light-emitting layer includes a pixel electrode, a counter electrode, and an organic light-emitting layer disposed between the pixel electrode and the counter electrode. In some embodiments, the pixel electrode is connected to the source / drain electrodes of the TFT layer. In some embodiments, when a voltage is applied to the pixel electrode through the TFT layer, an appropriate voltage is formed between the pixel electrode and the counter electrode, causing the organic light-emitting layer to emit light, thereby forming an image. Hereinafter, an image forming unit having a TFT layer and a light-emitting unit will be referred to as a display unit. In some embodiments, the encapsulation layer covering the display unit and preventing the penetration of external moisture may be formed as a thin-film encapsulation structure in which organic films and inorganic films are alternately laminated. In some embodiments, the encapsulation layer has a thin-film encapsulation structure in which a plurality of thin films are laminated. In some embodiments, the organic film applied to the interface portion is spaced apart from each of the plurality of display units. In some embodiments, the organic film is formed such that a portion of the organic film is in direct contact with the base substrate, while the remaining portion of the organic film surrounds the edges of the barrier layer while also being in contact with the barrier layer.

[0096] In one embodiment, the OLED display is flexible and uses a flexible base substrate made of polyimide. In some embodiments, the base substrate is formed on a carrier substrate made of glass material, and then the carrier substrate is separated. In some embodiments, the barrier layer is formed on the surface of the base substrate opposite the carrier substrate. In one embodiment, the barrier layer is patterned according to the size of each cell panel. For example, while the base substrate is formed on all surfaces of the mother panel, the barrier layer is formed according to the size of each cell panel, thereby forming grooves at the interface between the barrier layers of the cell panels. Each cell panel can be cut along the grooves.

[0097] In some embodiments, the manufacturing method further includes a step of cutting along the interface portion, where a groove is formed in the barrier layer, and at least a portion of the organic film is formed in the groove, and the groove does not penetrate the base substrate. In some embodiments, a TFT layer is formed for each cell panel, and a passivation layer, which is an inorganic film, and a planarization film, which is an organic film, are placed on the TFT layer and cover the TFT layer. At the same time that a planarization film made of, for example, polyimide or acrylic is formed, the groove in the interface portion is covered with an organic film made of, for example, polyimide or acrylic. This prevents cracking by allowing the organic film to absorb the impact generated when each cell panel is cut along the groove at the interface portion. That is, if all barrier layers are completely exposed without an organic film, when each cell panel is cut along the groove at the interface portion, the impact generated is transmitted to the barrier layer, thereby increasing the risk of cracking. However, in one embodiment, the groove in the interface portion between barrier layers may be covered with an organic film to absorb the impact that would otherwise be transmitted to the barrier layer, so that each cell panel is cut softly and cracking in the barrier layer is prevented. In one embodiment, the organic film and the planarizing film covering the grooves of the interface portion are arranged with a gap between them. For example, if the organic film and the planarizing film are connected to each other as a single layer, there is a risk that external moisture may penetrate the display unit through the remaining parts of the planarizing film and organic film. Therefore, the organic film and the planarizing film are arranged with a gap between them so that the organic film is spaced away from the display unit.

[0098] In some embodiments, the display unit is formed by the formation of a light-emitting unit, and an encapsulation layer is placed on the display unit to cover it. This separates the carrier substrate supporting the base substrate from the base substrate after the mother panel is completely manufactured. In some embodiments, when a laser beam is emitted onto the carrier substrate, the carrier substrate is separated from the base substrate due to the difference in thermal expansion coefficients between the carrier substrate and the base substrate. In some embodiments, the mother panel is cut into cell panel units. In some embodiments, the mother panel is cut along the interface between cell panels using a cutter. In some embodiments, the grooves of the interface along which the mother panel is cut are covered with an organic film so that the organic film absorbs the impact during cutting. In some embodiments, cracking can be prevented in the barrier layer during cutting. In some embodiments, the method reduces the defect rate of the product and stabilizes its quality. Another embodiment is an OLED display having a barrier layer formed on a base substrate, a display unit formed on the barrier layer, an encapsulation layer formed on the display unit, and an organic film coated on the edges of the barrier layer. [Examples]

[0099] The features of the present invention will be further described in detail below with reference to examples. The materials, processing content, processing procedures, etc. shown below can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below. The luminescence characteristics were evaluated using a source meter (Keithley Corporation: 2400 series), a semiconductor parameter analyzer (Agilent Technologies: E5273A), an optical power meter measuring device (Newport Corporation: 1930C), an optical spectrometer (Ocean Optics Corporation: USB2000), a spectroradiometer (Topcon Corporation: SR-3), and a streak camera (Hamamatsu Photonics K.K.: C4334). In addition, the lowest excited singlet energy E of the compounds used in the following examples and comparative examples was also determined. S1 and the lowest excited triplet energy E T1 This is as shown in the table below. [Table 1]

[0100] (Example 1) Each thin film is deposited onto a glass substrate with an anode made of indium tin oxide (ITO) with a thickness of 100 nm using a vacuum deposition method at a vacuum level of 1 × 10⁻⁶. -6 The layers were stacked using Pa. First, HATCN was formed to a thickness of 10 nm on ITO, then NPD was formed to a thickness of 35 nm on top of it, and then EB1 was formed to a thickness of 10 nm on top of that. Next, compound H4 was formed to a thickness of 5 nm to form an adjacent layer. Furthermore, compound H4 (69.5 wt%), compound T13 (30.0 wt%), and compound E1 (0.5 wt%) were co-deposited from different deposition sources to form a light-emitting layer with a thickness of 40 nm. Next, HB1 was formed to a thickness of 13 nm, followed by ET1 to a thickness of 20 nm. Furthermore, Liq was formed to a thickness of 2 nm, and then aluminum (Al) was deposited to a thickness of 100 nm to form the cathode. In this way, an organic electroluminescent device of Example 1 having the layer configuration shown in Figure 1 was fabricated.

[0101] (Comparative Example 1) By performing the manufacturing method of Example 1, with the only modification being the absence of an adjacent layer, an organic electroluminescent element of Comparative Example 1 was fabricated.

[0102] (Comparative Example 2) By performing the manufacturing method of Example 1, with the only change being the use of compound T13 instead of compound H4 in the adjacent layer, an organic electroluminescent element of Comparative Example 2 was fabricated.

[0103] (evaluation) When current was passed through each of the fabricated organic electroluminescent elements, delayed fluorescence emission originating from the third organic compound E1 was observed (all with a maximum emission wavelength of 472 nm). The external quantum efficiency (EQE) of the three organic electroluminescent elements was measured. 2 The time (LT95) required to reduce the luminescence intensity to 95% of the initial level after continuous energization was measured, and the relative values ​​are shown in Table 2, with the LT95 of the Comparative Example 1 element set to 1. As shown in Table 2, the element of Example 1, which had an adjacent layer made of the first organic compound, was found to have higher luminous efficiency and a longer element life than the element of Comparative Example 1, which did not have an adjacent layer, and the element of Comparative Example 2, which had an adjacent layer made of a compound other than the first organic compound. In particular, the element of Example 1 of the present invention achieved a high EQE of 23.6%, a 3.5% improvement in luminous efficiency compared to the element of Comparative Example 1, which did not have an adjacent layer, and its element life was 1.52 times longer.

[0104] [Table 2]

[0105] (Example 2) The organic electroluminescent element of Example 2 was fabricated by following the manufacturing method of Example 1, with the only change being that the composition of the light-emitting layer consisted of compound H4 (69.7 wt%), compound T13 (30.0 wt%), and compound E1 (0.3 wt%). When the LT95 was measured, it was confirmed that the element lifespan was 1.2 times longer than that of the element of Example 1.

[0106] [ka] [Industrial applicability]

[0107] According to the present invention, it is possible to provide an organic light-emitting element with a long lifespan and high luminous efficiency. Therefore, the present invention has high potential for industrial application. [Explanation of Symbols]

[0108] 1. Glass substrate 2 Anode 3. Hole injection layer 4. Hole transport layer 5. Electron barrier layer 6 Adjacent Layers 7. Emitting layer 8. Hole barrier layer 9 Electron transport layer 10 Electron injection layer 11 Cathode

Claims

1. An organic light-emitting element comprising a light-emitting layer containing a first organic compound, a second organic compound, and a third organic compound that satisfy the following condition (a), and an adjacent layer adjacent to the light-emitting layer, The first organic compound is selected from compounds having only one carbazole ring, further comprising a dibenzofuran structure or a dibenzothiophene structure, and further comprising only one metaphenylene group between the carbazole ring and the dibenzofuran structure or dibenzothiophene structure. The second organic compound is a delayed fluorescence material, An organic light-emitting element comprising the adjacent layer containing the first organic compound. Condition (a) E Ｓ１ (1) > E Ｓ１ (2) > E Ｓ１ (3) (In the above equation, E Ｓ１ (1) represents the lowest singlet excitation energy of the first organic compound. E Ｓ１ (2) represents the lowest singlet excitation energy of the second organic compound. E Ｓ１ (3) represents the lowest singlet excitation energy of the third organic compound.

2. The organic light-emitting element according to claim 1, wherein the adjacent layer is composed solely of the first organic compound.

3. The organic light-emitting element according to claim 1 or 2, wherein the light-emitting layer is located between the anode and the cathode, and the adjacent layer is adjacent to the anode side of the light-emitting layer.

4. The organic light-emitting element according to any one of claims 1 to 3, wherein the thickness of the adjacent layer is less than 10 nm.

5. The organic light-emitting element according to any one of claims 1 to 4, wherein the thickness of the adjacent layer is less than one-sixth of the thickness of the light-emitting layer.

6. The second organic compound is defined by the energy difference ΔE between its lowest excited singlet state and its lowest excited triplet state at 77K. ｓｔ The organic light-emitting element according to any one of claims 1 to 5, wherein the voltage is 0.3 eV or less.

7. The third organic compound is defined by the energy difference ΔE between its lowest excited singlet state and its lowest excited triplet state at 77K. ｓｔ The organic light-emitting element according to any one of claims 1 to 6, wherein the voltage is 0.3 eV or less.

8. The organic light-emitting element according to any one of claims 1 to 7, wherein the first organic compound, the second organic compound, and the third organic compound satisfy the following condition (b). Condition (b) E Ｔ１ (1) > E Ｔ１ (2) > E Ｔ１ (3) (In the above equation, E Ｔ１ (1) represents the lowest excited triplet energy at 77 K of the first organic compound. E Ｔ１ (2) represents the lowest excited triplet energy at 77 K of the second organic compound. E Ｔ１ (3) represents the lowest excited triplet energy at 77 K of the third organic compound.

9. The organic light-emitting element according to any one of claims 1 to 8, wherein the light-emitting layer is composed only of a compound consisting of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, oxygen atoms, and sulfur atoms.

10. The organic light-emitting element according to any one of claims 1 to 9, wherein the first organic compound is a compound comprising atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, and oxygen atoms.

11. An organic light-emitting element comprising a light-emitting layer containing a first organic compound, a second organic compound, and a third organic compound that satisfy the following condition (a), and an adjacent layer adjacent to the light-emitting layer, The first organic compound is a compound having one of the following structures: The second organic compound is a delayed fluorescence material, An organic light-emitting element comprising the adjacent layer containing the first organic compound. Condition (a) E S1 (1)>E S1 (2)>E S1 (3) (In the above equation, E S1 (1) represents the lowest singlet excitation energy of the first organic compound. E S1 (2) represents the lowest singlet excitation energy of the second organic compound. E S1 (3) represents the lowest singlet excitation energy of the third organic compound. 【Chemistry 1】 【change】 【change】

12. The organic light-emitting element according to any one of claims 1 to 11, wherein the second organic compound is a compound comprising an atom selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, oxygen atoms, and sulfur atoms.

13. The organic light-emitting element according to any one of claims 1 to 12, wherein the third organic compound is a compound comprising an atom selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, oxygen atoms, and sulfur atoms.

14. The organic light-emitting element according to any one of claims 1 to 13, wherein the second organic compound comprises a cyanobenzene structure.

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