Organic light emitting element

Abstract

The organic light emitting element having a light emitting layer containing the first to fourth organic compounds satisfying the following formulae has a long light emitting life and is stable. The second organic compound is a delayed fluorescence material, and the light emission amount from the fourth organic compound is the largest.E S1 represents the lowest excited singlet state energy, E T1 represents the lowest excited triplet state energy.E S1 (1) > E S1 (4) > E S1 (2) > E S1 (3), E T1 (1) > E T1 (2) > E T1 (3) > E T1 (4).

Description

Technical Field

[0001] This invention relates to an organic light-emitting element that uses delayed fluorescence material. Background Technology

[0002] Research is actively underway to improve the luminous efficiency of organic light-emitting elements (OLEDs) and other organic light-emitting devices. In particular, research is being conducted on various methods to enhance luminous efficiency by developing and combining new electron transport materials, hole transport materials, host materials, and luminescent materials that constitute organic OLEDs. Research has also been found to utilize organic light-emitting elements with delayed fluorescence materials.

[0003] Delayed fluorescence materials are compounds that emit fluorescence upon returning to the ground state after a reverse intersystem crossing from an excited triplet state to an excited singlet state in the excited state. Because fluorescence generated via this pathway is observed later than fluorescence from an excited singlet state directly generated from the ground state (typical fluorescence), it is called delayed fluorescence. Here, for example, when a luminescent compound is excited via carrier injection, since the generation probabilities of the excited singlet state and the excited triplet state are statistically 25%:75%, there is a limit to the improvement in luminescence efficiency if only fluorescence from the directly generated excited singlet state is used. On the other hand, because delayed fluorescence materials can also emit fluorescence from the excited triplet state via the aforementioned reverse intersystem crossing pathway, in addition to the excited singlet state, they can achieve higher luminescence efficiency compared to typical delayed fluorescence materials.

[0004] As such delayed fluorescence materials, benzene derivatives having carbazole or other heteroaryl groups or diphenylamino and at least two cyano groups have been proposed, and it has been confirmed that high luminous efficiency has been obtained in organic EL elements using this benzene derivative as the light-emitting layer (see Patent Document 1).

[0005] Furthermore, Non-Patent Document 1 reports that carbazole dibenzonitrile derivative (4CzTPN) is a thermally active delayed fluorescence material, and reports that high internal EL quantum efficiency is achieved by using an organic electroluminescent element based on this carbazole dibenzonitrile derivative.

[0006] On the other hand, it has been proposed that instead of using delayed fluorescence material as the luminescent material, it is used as an auxiliary dopant in the luminescent layer (see Patent Document 2). Here, it is described that luminescence efficiency is improved by adding a delayed fluorescence material having the lowest excitation singlet energy between the host material and the fluorescent luminescent material to the luminescent layer, in addition to the host material and the fluorescent luminescent material.

[0007] Previous technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2014-43541

[0010] Patent Document 2: Japanese Patent Application Publication No. 2015-179809

[0011] Non-patent literature

[0012] Non-patent literature 1: H. Uoyama, et al., Nature 492, 234 (2012) Summary of the Invention

[0013] The technical problem to be solved by the invention

[0014] As described above, Patent Document 1, Patent Document 2, and Non-Patent Document 1 report the attainment of high luminous efficiency in organic electroluminescent elements using delayed fluorescence materials. However, the inventors have found that when organic electroluminescent elements are fabricated according to the description in Patent Document 1 or Patent Document 2, it is not easy to ensure sufficient lifetime.

[0015] Under these circumstances, the inventors conducted in-depth research with the aim of improving the lifetime of organic light-emitting elements using delayed fluorescence materials.

[0016] means for solving technical problems

[0017] As a result of in-depth research to achieve the aforementioned objectives, the inventors discovered that by adding a host material, a delayed fluorescence material, a luminescent material, and a modifier that meet specific conditions to the luminescent layer, it is possible to achieve an organic light-emitting element with a long and stable luminescence lifetime. This invention is based on this insight and specifically has the following structure.

[0018] [1] An organic light-emitting element having a light-emitting layer comprising a first organic compound, a second organic compound, a third organic compound, and a fourth organic compound satisfying conditions (a) and (b) below, wherein,

[0019] The second organic compound is a delayed fluorescence material.

[0020] The largest component of the light emitted from the organic light-emitting element is the light emitted from the third organic compound.

[0021] Condition(a)E S1 (1) > E S1 (4) > E S1 (2)>E S1 (3)

[0022] Condition (b)E T1 (1) > E T1 (2)>E T1 (3) > ET1 (4)

[0023] (in the above formula,

[0024] E S1 (1) represents the lowest excited singlet energy of the first organic compound.

[0025] E S1 (2) represents the lowest excited singlet energy of the second organic compound.

[0026] E S1 (3) represents the lowest excited singlet energy of the third organic compound.

[0027] E S1 (4) represents the lowest excited singlet energy of the fourth organic compound.

[0028] E T1 (1) represents the lowest excited triplet energy of the first organic compound.

[0029] E T1 (2) represents the lowest excited triplet energy of the second organic compound.

[0030] E T1 (3) represents the lowest excited triplet energy of the third organic compound.

[0031] E T1 (4) represents the lowest excited triplet energy of the fourth organic compound.

[0032] [2] The organic light-emitting element according to [1] further satisfies the following condition (c).

[0033] Condition (c)Conc(1)>Conc(2)>Conc(4)

[0034] (in the above formula,

[0035] Conc(1) represents the concentration of the first organic compound in the light-emitting layer.

[0036] Conc(2) represents the concentration of the second organic compound in the light-emitting layer.

[0037] Conc(4) represents the concentration of the fourth organic compound in the luminescent layer.

[0038] [3] The organic light-emitting element according to [2] further satisfies the following condition (c1).

[0039] Condition (c1)Conc(1)>Conc(2)>Conc(4)>Conc(3)

[0040] (In the above formula, Conc(3) represents the concentration of the third organic compound in the light-emitting layer.)

[0041] [4] The organic light-emitting element according to [2] or [3] further satisfies the following condition (d).

[0042] Condition (d)Conc(2) / Conc(3)>5

[0043] (In the above formula, Conc(3) represents the concentration of the third organic compound in the light-emitting layer.)

[0044] [5] The organic light-emitting element according to any one of [2] to [4] further satisfies the following condition (e).

[0045] Condition (e)Conc(4) / Conc(3)>1.5

[0046] (In the above formula, Conc(3) represents the concentration of the third organic compound in the light-emitting layer.)

[0047] [6] The organic light-emitting element according to any one of [1] to [5] further satisfies the following condition (f).

[0048] Condition (f)Conc(4)≤5% by weight

[0049] (In the above formula, Conc(4) represents the concentration of the fourth organic compound in the light-emitting layer.)

[0050] [7] The organic light-emitting element according to any one of [1] to [6] further satisfies the following condition (g).

[0051] Condition (g)Conc(3)≤1 wt%

[0052] (In the above formula, Conc(3) represents the concentration of the third organic compound in the light-emitting layer.)

[0053] [8] An organic light-emitting element according to any one of [1] to [7], wherein the energy difference ΔE between the lowest excited singlet state and the lowest excited triplet state at 77K of the second organic compound is... st It is below 0.3 eV.

[0054] [9] An organic light-emitting element according to any one of [1] to [8], wherein the energy difference ΔE between the lowest excited singlet state and the lowest excited triplet state at 77K of the third organic compound is... st It is below 0.3 eV.

[0055]

[10] An organic light-emitting element according to any one of [1] to [9], wherein the light-emitting layer is composed only of a compound, the compound being composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, boron atoms, oxygen atoms and sulfur atoms.

[0056]

[11] An organic light-emitting element according to any one of [1] to

[10] , wherein the first organic compound, the second organic compound and the fourth organic compound are each independently a compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms and nitrogen atoms.

[0057]

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

[11] , wherein the fourth organic compound is a compound consisting only of carbon atoms and hydrogen atoms.

[0058]

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

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

[0059]

[14] A method for designing a luminescent composition, comprising the following steps:

[0060] [Step 1] The luminescence efficiency and lifetime of a composition comprising a first organic compound, a second organic compound, a third organic compound, and a fourth organic compound as a delayed fluorescence material, and satisfying the following conditions (a) and (b) are evaluated;

[0061] [Step 2] The luminous efficiency and lifetime of a composition that replaces at least one of the first organic compound, the second organic compound, the third organic compound, and the fourth organic compound as a delayed fluorescence material within the range satisfying conditions (a) and (b) below are evaluated, and the evaluation is performed at least once; and

[0062] [Step 3] Select the best combination of the evaluated luminous efficiency and lifetime results.

[0063] Condition(a)E S1 (1) > E S1 (4) > E S1 (2)>E S1 (3)

[0064] Condition (b)E T1 (1) > E T1 (2)>E T1 (3) > E T1 (4)

[0065] (in the above formula,

[0066] E S1(1) represents the lowest excited singlet energy of the first organic compound.

[0067] E S1 (2) represents the lowest excited singlet energy of the second organic compound.

[0068] E S1 (3) represents the lowest excited singlet energy of the third organic compound.

[0069] E S1 (4) represents the lowest excited singlet energy of the fourth organic compound.

[0070] E T1 (1) represents the lowest excited triplet energy of the first organic compound.

[0071] E T1 (2) represents the lowest excited triplet energy of the second organic compound.

[0072] E T1 (3) represents the lowest excited triplet energy of the third organic compound.

[0073] E T1 (4) represents the lowest excited triplet energy of the fourth organic compound.

[0074]

[15] A procedure that implements the method described in

[14] .

[0075] Invention Effects

[0076] The organic light-emitting element according to the present invention can achieve long-lifetime light emission. Attached Figure Description

[0077] Figure 1 This is a schematic cross-sectional view showing an example of a layered structure of an organic electroluminescent element. Detailed Implementation

[0078] The present invention will now be described in detail. The descriptions of the constituent elements described below are sometimes based on representative embodiments or specific examples of the invention, but the invention is not limited to such embodiments or specific examples. Furthermore, in this document, the numerical range indicated by “~” means a range including the values ​​described before and after “~” as both a lower and upper limit. Also, in this document, “composed of ~” means only the composition described above “composed of ~”, excluding anything else. Furthermore, the types of hydrogen isotopes present within the molecules of the compounds used in the present invention are not particularly limited; for example, all hydrogen atoms within the molecule may be... 1 H can be partly or entirely. 2H(deuterium)D).

[0079] (Characteristics of organic light-emitting elements)

[0080] The organic light-emitting element of the present invention has a light-emitting layer comprising a first organic compound, a second organic compound, a third organic compound, and a fourth organic compound. The second organic compound is a delayed fluorescence material. Furthermore, these organic compounds satisfy the following conditions (a) and (b).

[0081] Condition(a)E S1 (1) > E S1 (4) > E S1 (2)>E S1 (3)

[0082] Condition (b)E T1 (1) > E T1 (2)>E T1 (3) > E T1 (4)

[0083] In this article, E S1 (1) represents the lowest excited singlet energy of the first organic compound, E S1 (2) represents the lowest excited singlet energy of the second organic compound, E. S1 (3) represents the lowest excited singlet energy of the third organic compound, E S1 (4) represents the lowest excited singlet energy of the fourth organic compound. In this document, eV is used as the unit.

[0084] E T1 (1) represents the lowest excited triplet energy of the first organic compound, E T1 (2) represents the lowest excited triplet energy of the second organic compound, E T1 (3) represents the lowest excited triplet energy of the third organic compound, E T1 (4) represents the lowest excited triplet energy of the fourth organic compound. In this document, eV is used as the unit.

[0085] 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, Conc(3) represents the concentration of the third organic compound in the light-emitting layer, and Conc(4) represents the concentration of the fourth organic compound in the light-emitting layer. In this document, weight percent (%) is used as the unit.

[0086] The organic light-emitting element of the present invention satisfies both conditions (a) and (b) for the lowest excitation singlet state energy. Therefore, the lowest excitation singlet state energy E of the second organic compound is... S1 (2) and the lowest excited triplet energy E T1 (2) and the lowest excited singlet energy E of the third organic compound S1 (3) and the lowest excited triplet energy E T1 (3) All of them are at the lowest excited singlet energy E of the 4th organic compound. S1 (4) and the lowest excited triplet energy E T1 (4) Therefore, the difference ΔE between the lowest excited singlet energy and the lowest excited triplet energy at 77 K for the fourth organic compound is... ST (4) Greater than that of the second and third organic compounds. The ΔE of the fourth organic compound is... ST (4) Preferably, it is 0.5 eV or more, more preferably 0.6 eV or more, and even more preferably 0.7 eV or more. The ΔE of the fourth organic compound. ST (4) For example, it can be set in the range of 1.5eV or below, in the range of 1.2eV or below, or in the range of 0.9eV or below.

[0087] The difference E between the lowest excited singlet state energies of the fourth organic compound and the second compound. S1 (4)-E S1 (2) Preferably, it is 0.05 eV or more, more preferably 0.10 eV or more, and can be 0.15 eV or more. S1 (4)-E S1 (2) For example, it can be set in the range below 0.7eV, the range below 0.5eV, or the range below 0.3eV.

[0088] The energy difference E between the lowest excited triplet states of the third and fourth organic compounds T1 (3)-E T1 (4) Preferably 0.10 eV or more, more preferably 0.30 eV or more, and can be 0.45 eV or more. T1 (3)-E T1 (4) For example, it can be set in the range below 0.9eV, the range below 0.7eV, or the range below 0.5eV.

[0089] The difference E between the lowest excited singlet state energies of the first organic compound and the second compound. S1 (1)-E S1(2) It can be set in a range of 0.3eV or above, 0.5eV or above, or 0.7eV or above, and can be set in a range of 1.6eV or below, 1.3eV or below, or 0.9eV or below.

[0090] The difference E between the lowest excited singlet state energies of organic compound 1 and compound 4 S1 (1)-E S1 (4) It can be set in a range of 0.2eV or above, 0.4eV or above, or 0.6eV or above, and can be set in a range of 1.5eV or below, 1.2eV or below, or 0.8eV or below.

[0091] The lowest excited triplet energy E of the first organic compound T1 (1) It can be greater than the lowest excited singlet energy E of the fourth compound. S1 (4). For example, E T1 (1)-E S1 (4) It can be set in a range of 0.05 eV or higher, 0.10 eV or higher, or 0.15 eV or higher. Furthermore, it can be set in a range of 0.7 eV or lower, 0.5 eV or lower, or 0.3 eV or lower.

[0092] The organic light-emitting element of the present invention preferably has contents of the first compound, the second compound, and the fourth compound satisfying the relationship of condition (c).

[0093] Condition (c)Conc(1)>Conc(2)>Conc(4)

[0094] The organic light-emitting element of the present invention preferably has the contents of the first to fourth compounds satisfying the relationship of condition (c1).

[0095] Condition (c1)Conc(1)>Conc(2)>Conc(4)>Conc(3)

[0096] Conc(1) is preferably 30% by weight or more, and can be set in the range of 50% by weight or more or in the range of 65% by weight or more, and can be set in the range of 99% by weight or less, in the range of 85% by weight or less or in the range of 75% by weight or less.

[0097] Conc(2) is preferably 10% by weight or more, and can be set in the range of 20% by weight or more or in the range of 30% by weight or more, and can be set in the range of 45% by weight or less, or in the range of 40% by weight or less or in the range of 35% by weight or less.

[0098] Conc(3) is preferably 5% by weight or less, more preferably 3% by weight or less. Conc(3) can be set in the range of 1% by weight or less or in the range of 0.5% by weight or less, and can be set in the range of 0.01% by weight or more, in the range of 0.1% by weight or more or in the range of 0.3% by weight or more.

[0099] Conc(4) is preferably 15% by weight or less, more preferably 10% by weight or less, and even more preferably 5% by weight or less. Conc(4) can be set in the range of 0.01% by weight or more, in the range of 1% by weight or more, in the range of 3% by weight or more, or in the range of 4% by weight or more.

[0100] The organic light-emitting element of the present invention preferably further satisfies the following condition (d).

[0101] Condition (d)Conc(2) / Conc(3)>5

[0102] Conc(2) / Conc(3) can be set in a range of 10 or more, in a range of 30 or more, or in a range of 50 or more, and can also be set in a range of 500 or less, in a range of 300 or less, or in a range of 100 or less.

[0103] The organic light-emitting element of the present invention preferably further satisfies the following condition (e).

[0104] Condition (e)Conc(4) / Conc(3)>1.5

[0105] Conc(4) / Conc(3) can be set in a range of 2 or higher, in a range of 5 or higher, or in a range of 10 or higher, and can also be set in a range of 500 or lower, in a range of 100 or lower, or in a range of 50 or lower.

[0106] The second organic compound used in the organic light-emitting element of this invention is a delayed fluorescence material. In this invention, a "delayed fluorescence material" is an organic compound that generates a reverse intersystem crossing from an excited triplet state to an excited singlet state in the excited state, and emits fluorescence (delayed fluorescence) upon returning from the excited singlet state to the ground state. In this invention, when the luminescence lifetime is measured using a fluorescence lifetime measurement system (such as the Hamamatsu Photonics KK stripe camera system), materials with observed fluorescence lifetimes of 100 ns (nanoseconds) or more are referred to as delayed fluorescence materials.

[0107] The difference ΔE between the lowest excited singlet energy and the lowest excited triplet energy at 77 K for the second organic compound.ST (2) Preferably, it is 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 especially preferably 0.01 eV or less.

[0108] If ΔE ST (2) If the temperature is low, the excitation singlet state can easily transition from the excitation triplet state to the excitation triplet state due to the absorption of thermal energy. Therefore, the second organic compound functions as a thermally activated delayed fluorescence material. The thermally activated delayed fluorescence material absorbs the heat emitted by the device and can relatively easily transition from the excitation triplet state to the excitation singlet state, thereby enabling its excitation triplet state to have good energy efficiency and contribute to luminescence.

[0109] The lowest excited singlet energy (E) of the compounds in this article S1 ) and the lowest excited triplet energy (E T1 ΔE is the value obtained through the following steps. ST To calculate E S1 -E T1 The value obtained is...

[0110] (1) Lowest excitation singlet energy (E S1 )

[0111] Prepare a thin film or toluene solution (concentration 10) of the compound to be measured. -5 A sample (mol / L) was used. The fluorescence spectrum of this sample was measured at room temperature (300 K). In the fluorescence spectrum, the vertical axis was set to emission, and the horizontal axis to wavelength. A tangent was drawn relative to the rising short-wavelength side of the emission spectrum, and the wavelength value λedge [nm] at the intersection of this tangent and the horizontal axis was determined. This wavelength value was converted into an energy value using the following conversion formula, which was taken as E. S1 .

[0112] Conversion formula: E S1 [eV] = 1239.85 / λedge

[0113] Regarding the measurement of the emission spectrum in the embodiments described later, an LED light source (M300L4 manufactured by Thorlabs Japan Inc.) was used as the excitation source, and the measurement was performed using a detector (PMA-12 multichannel spectrometer C10027-01 manufactured by Hamamatsu Photonics KK).

[0114] (2) Minimum Excitation Triplet Energy (E) T1 )

[0115] Using liquid nitrogen, the lowest excitation singlet energy (E) will be used to... S1 The same sample used in the phosphorescence measurement was cooled to 77 K, and the sample was irradiated with excitation light (300 nm), and the phosphorescence was measured using a detector. The phosphorescence spectrum was prepared from the emission 100 ms after excitation. A tangent was drawn relative to the rise on the shorter wavelength side of this phosphorescence spectrum, and the wavelength value λedge [nm] at the intersection of this tangent and the horizontal axis was determined. This wavelength value was converted into an energy value using the following conversion formula, which is taken as E. T1 .

[0116] Conversion formula: E T1 [eV] = 1239.85 / λedge

[0117] The rising tangent on the short-wavelength side of the phosphorescence spectrum is drawn as follows. Consider the tangents at various points on the curve towards the long-wavelength side as the spectral curve moves from the short-wavelength side of the phosphorescence spectrum to the maximum value on the shortest wavelength side of the spectrum. As the curve rises (i.e., as the vertical axis increases), the slope of this tangent increases. The tangent drawn at the point where this slope reaches its maximum value is taken as the rising tangent on the short-wavelength side of the phosphorescence spectrum.

[0118] In addition, the maximum point of peak intensity with less than 10% of the maximum peak intensity of the spectrum is not included in the maximum value on the shortest wavelength side. The tangent line drawn at the point closest to the maximum value on the shortest wavelength side and where the slope value is the maximum value is set as the rising tangent line for the short wavelength side of the phosphorescence spectrum.

[0119] (Organic Compound No. 1)

[0120] The first organic compound is an organic compound with a minimum excited singlet energy greater than that of the second, third, and fourth organic compounds, and it functions as a host material responsible for energy transport or as a confining agent for the energy of the third organic compound. Therefore, the third organic compound can efficiently convert the energy generated by the rebonding of intramolecular holes and electrons, as well as the energy received from the first and second organic compounds, into luminescence.

[0121] The first organic compound is preferably an organic compound that has hole transport capability, electron transport capability, prevents luminescence by increasing wavelength, and has a high glass transition temperature. Furthermore, in a preferred aspect of the invention, the first organic compound is selected from compounds that do not emit delayed fluorescence.

[0122] The following include preferred compounds that can be used as the first organic compound.

[0123] [Chemical Formula 1-1]

[0124]

[0125] [Chemical Formula 1-2]

[0126]

[0127] [Chemical Formulas 1-3]

[0128]

[0129] (Second organic compound)

[0130] The second organic compound is a delayed fluorescence material whose lowest excitation singlet state energy is lower than that of the first and fourth organic compounds and higher than that of the third organic compound. Furthermore, the second organic compound is also a delayed fluorescence material whose lowest excitation triplet state energy is lower than that of the first organic compound and higher than that of the third and fourth organic compounds. The second organic compound only needs to be a compound capable of emitting delayed fluorescence under certain conditions; in the organic light-emitting element of the present invention, emitting delayed fluorescence from the second organic compound is not necessary. In the organic light-emitting element of the present invention, the second organic compound receives energy from the first and fourth organic compounds in their excited singlet states and transitions to the excited singlet state. Furthermore, the second organic compound can receive energy from the first organic compound in its excited triplet state and transition to the excited triplet state. Because the ΔE of the second organic compound... ST Because the size of the second organic compound in the excited triplet state is small, it is easy for the second organic compound in the excited singlet state to undergo reverse intersystem crossing. The second organic compound in the excited singlet state generated through these pathways imparts energy to the third organic compound, causing the third organic compound to transition to the excited singlet state.

[0131] The following include preferred compounds that can be used as a second organic compound. In the structural formulas of the following illustrative compounds, t-Bu represents tert-butyl.

[0132] [Chemical Formula 2-1]

[0133]

[0134] [Chemical Formula 2-2]

[0135]

[0136] [Chemical Formula 2-3]

[0137]

[0138] [Chemical Formula 2-4]

[0139]

[0140] [Chemical Formula 2-5]

[0141]

[0142] Regarding the second organic compound, in addition to the above, known delayed fluorescence materials can also be used in appropriate combinations. Furthermore, unknown delayed fluorescence materials can also be used.

[0143] Preferred delayed fluorescence materials may include segments 0008–0048 and 0095–0133 of WO2013 / 154064, segments 0007–0047 and 0073–0085 of WO2013 / 011954, segments 0007–0033 and 0059–0066 of WO2013 / 011955, and segments 0008–009 ... Paragraphs 71 and 0118–0133, paragraphs 0009–0046 and 0093–0134 of Japanese Patent Application Publication No. 2013-256490, paragraphs 0008–0020 and 0038–0040 of Japanese Patent Application Publication No. 2013-116975, paragraphs 0007–0032 and 0079–0084 of Japanese Patent Application Publication No. WO2013 / 133359, and paragraph 00007–0032 and 0079–0084 of Japanese Patent Application Publication No. WO2013 / 161437. Paragraphs 08 to 0054 and 0101 to 0121, paragraphs 0007 to 0041 and 0060 to 0069 of Japanese Patent Application Publication No. 2014-9352, paragraphs 0008 to 0048 and 0067 to 0076 of Japanese Patent Application Publication No. 2014-9224, paragraphs 0013 to 0025 of Japanese Patent Application Publication No. 2017-119663, and paragraphs 0013 to 0054 of Japanese Patent Application Publication No. 2017-119664. Compounds contained in the general formulas described in paragraphs 26, paragraphs 0012 to 0025 of Japanese Patent Application Publication No. 2017-222623, paragraphs 0010 to 0050 of Japanese Patent Application Publication No. 2017-226838, paragraphs 0012 to 0043 of Japanese Patent Application Publication No. 2018-100411, and paragraphs 0016 to 0044 of WO2018 / 047853, especially exemplary compounds that emit delayed fluorescence.Furthermore, Japanese Patent Application Publication Nos. 2013-253121, WO2013 / 133359, WO2014 / 034535, WO2014 / 115743, WO2014 / 122895, WO2014 / 126200, WO2014 / 136758, and WO2014 / 133121 may be preferred. Communiqués, WO2014 / 136860, WO2014 / 196585, WO2014 / 189122, WO2014 / 168101, WO2015 / 008580, WO2014 / 203840, WO2015 / 002213, WO2015 / 016200, WO201 Japanese Publication No. 5 / 019725, WO2015 / 072470, WO2015 / 108049, WO2015 / 080182, WO2015 / 072537, WO2015 / 080183, Japanese Patent Application Publication No. 2015-129240, WO2015 / 129714, WO2015 / 1297 Materials that emit delayed fluorescence as described in Publications No. 15, WO2015 / 133501, WO2015 / 136880, WO2015 / 137244, WO2015 / 137202, WO2015 / 137136, WO2015 / 146541, and WO2015 / 159541. Furthermore, the aforementioned publications described in this paragraph are incorporated herein by reference as part of this document.

[0144] Compounds represented by the following general formula (1) and emitting delayed fluorescence can preferably 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 (1) can be used as the second organic compound.

[0145] [Chemical Formula 3]

[0146] General formula (1)

[0147]

[0148] In general formula (1), X 1 ~X 5 Represents N or CR. R represents a hydrogen atom or a substituent. When X 1 ~X 5 When there are two or more CRs in a given string, these CRs can be the same or different. Where X... 1 ~X 5At least one of them is a CD (where D represents a donor group). When X 1 ~X 5 When both are CR, Z represents the acceptor group, and in X 1 ~X 5 When at least one of them is N, Z represents a hydrogen atom or a substituent.

[0149] Among the compounds represented by general formula (1), the compounds represented by general formula (2) are particularly preferred.

[0150] [Chemical Formula 4]

[0151] General formula (2)

[0152]

[0153] In general formula (2), X 1 ~X 5 Represents N or CR. R represents a hydrogen atom or a substituent. When X 1 ~X 5 When there are two or more CRs in a given string, these CRs can be the same or different. Where X... 1 ~X 5 At least one of them is CD (where D represents the donor group).

[0154] For an explanation and preferred range of the substituent represented by Z in general formula (1), please refer to the explanation and preferred range of the substituent in 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 relative to the ring bonded to Z, and can be selected, for example, from groups with a positive Hammett σp value. The donor group represented by D in general formulas (1) and (2) is a group that has the property of attracting electrons relative to the ring bonded to D, and can be selected, for example, from groups with a negative Hammett σp value. Hereinafter, the acceptor group is sometimes referred to as A.

[0155] Here, "Hammett's σp value" is a value proposed by L.P. Hammett, which quantifies the effect of substituents on the reaction rate or equilibrium of para-substituted benzene derivatives. Specifically, it is the following equation that holds between the substituents in the para-substituted benzene derivative and the reaction rate constant or equilibrium constant:

[0156] log(k / k0)=ρσp

[0157] or

[0158] log(K / K0)=ρσp

[0159] The constant (σp) is specific to the substituents in the formula. In the above formula, k represents the rate constant of the benzene derivative without substituents, k0 represents the rate constant of the benzene derivative substituted with substituents, K represents the equilibrium constant of the benzene derivative without substituents, K0 represents the equilibrium constant of the benzene derivative substituted with substituents, and ρ represents the reaction constant determined by the type and conditions of the reaction. For a description of the "Hammett's σp value" mentioned in this invention and the numerical values ​​of each substituent, please refer to the description of the σp value mentioned in Hansch, C. et.al., Chem. Rev., 91, 165–195 (1991).

[0160] In general formulas (1) and (2), X 1 ~X 5 It represents N or CR, but at least one is CD. X 1 ~X 5 The number of N values ​​in the expression can be 0 to 4, for example, X can be exemplified. 1 and X 3 and X 5 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 Only X 1 Only X 2 Only X 3 The case where N is the number of elements. X 1 ~X 5 The number of CDs in the CD holder is 1 to 5, preferably 2 to 5. For example, X can be exemplified. 1 and X 2 and X 3 and 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 X1 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 Only X 1 Only X 2 Only X 3 This is the case for CD. X 1 ~X 5 At least one of them can be CA. Here, A represents an acceptor group. X 1 ~X 5 The number of CAs in the formula is preferably 0 to 2, more preferably 0 or 1. The A group of the CAs preferably includes a cyano group and a heterocyclic aromatic group having an unsaturated nitrogen atom. Furthermore, X... 1 ~X 5 They can be CD or CA independently.

[0161] When X 1 ~X 5 When two adjacent Rs represent CR, the two Rs can bond together to form a ring structure. The ring structure formed by these bonds can be an aromatic ring, an aliphatic ring, or a structure containing heteroatoms, and the ring structure can be a fused ring with two or more rings. The heteroatoms mentioned here are preferably atoms selected from the group consisting of nitrogen, oxygen, and sulfur atoms. Examples of the formed ring structures 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, cyclopentene rings, cycloheptanetriene rings, cycloheptadiene rings, cycloheptene rings, furan rings, thiophene rings, naphthidine rings, quinoxaline rings, quinoline rings, etc. For example, rings formed by the fusion of multiple rings can be formed, such as phenanthrene rings or triphenylene rings.

[0162] The donor group D in general formulas (1) and (2) is preferably, for example, the group represented by the following general formula (3).

[0163] [Chemical Formula 5]

[0164] General formula (3)

[0165]

[0166] In general formula (3), R 11 and R 12 Each of these can be independently represented as 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. R 11 and R 12 They can bond together to form a cyclic structure. L represents a single bond, a substituted or unsubstituted arylene, or a substituted or unsubstituted heteroarylene. The substituents that can be introduced into the arylene or heteroarylene of L can 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) can be introduced up to the maximum number of substituents that can be introduced into L. Furthermore, when multiple groups represented by general formulas (1) to (6) are introduced, these substituents can be the same or different from each other. * indicates the bonding position of the carbon atom (C) in general formula (1) or general formula (2) with the carbon atom (C) constituting the ring skeleton.

[0167] The "alkyl" referred to herein can be any of the following: straight-chain, branched, or cyclic. Furthermore, two or more of the straight-chain, cyclic, and branched portions can 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. 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 may include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, 2-ethylhexyl, n-heptyl, isohexyl, n-octyl, isooctyl, n-nonyl, isononyl, n-decyl, isododecyl, cyclopentyl, cyclohexyl, and cycloheptyl. The alkyl group, as a substituent, can be further substituted with an aryl group.

[0168] The "alkenyl" group can be any of the following: linear, branched, or cyclic. Furthermore, two or more of the linear, cyclic, and branched groups can be mixed. The number of carbon atoms in the alkenyl group can be, for example, 2 or more, or 4 or more. The number of carbon atoms can also be 30 or less, 20 or less, 10 or less, 6 or less, or 4 or less. Specific examples of alkenyl groups include vinyl, propenyl, isopropenyl, n-butenyl, isobutenyl, n-pentenyl, isopentenyl, n-hexenyl, isohexenyl, and 2-ethylhexenyl. The alkenyl group, as a substituent, can be further substituted with other substituents.

[0169] "Aryl" and "heteroaryl" can be monocyclic or fused rings composed of two or more rings. When fused rings are used, the number of fused rings is preferably 2 to 6, for example, 2 to 4. Specific examples of rings may include benzene rings, pyridine rings, pyrimidine rings, triazine rings, naphthyl rings, anthracene rings, phenanthrene rings, triphenylene rings, quinoline rings, pyrazine rings, quinoxaline rings, and naphthidine rings. Specific examples of aryl or heteroaryl groups may include phenyl, 1-naphthyl, 2-naphthyl, 1-anthrayl, 2-anthrayl, 9-anthrayl, 2-pyridyl, 3-pyridyl, and 4-pyridyl. "Arylidene" and "heteroaryl" can be used by replacing the valence number in the description of aryl and heteroaryl groups with 2 instead of 1.

[0170] Substituents are defined as monovalent groups that can be replaced by hydrogen atoms, rather than as groups containing fused groups. For a description of substituents and preferred ranges, please refer to the description of substituents and preferred ranges of general formula (7) described below.

[0171] The compound represented by general formula (3) is preferably a compound represented by any one of the following general formulas (4) to (6).

[0172] [Chemical Formula 6]

[0173] General formula (4)

[0174]

[0175] General formula (5)

[0176]

[0177] General formula (6)

[0178]

[0179] In general formulas (4) to (6), R 51 ~R 60 R 61 ~R 68 R 71 ~R 78 Each can be represented independently by a hydrogen atom or a substituent. For a description and preferred range of substituents described herein, please refer to the description and preferred range of substituents in general formula (7) described later. R 51 ~R 60 R 61 ~R 68 R 71 ~R 78It is also preferred that each substituent is independently represented by any one of the general formulas (4) to (6) above. There is no particular limitation on the number of substituents in general formulas (4) to (6). It is also preferred that all substituents are unsubstituted (i.e., hydrogen atoms). Furthermore, when there are two or more substituents in each of the general formulas (4) to (6), these substituents may be the same or different. When there are substituents in general formulas (4) to (6), if they are in general formula (4), then the substituent is preferably R. 52 ~R 59 If any of the substituents is in general formula (5), then the substituent is preferably R. 62 ~R 67 If any of the substituents is in general formula (6), then the substituent is preferably R. 72 ~R 77 Any one of them.

[0180] 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 5 6 and R 57 R 57 and R 58 R 58 and R 59 R 59 and R 60 R 61 and R 62 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 78They can bond together to form a ring structure. For an explanation and preferred examples of the ring structure, please refer to X in general formulas (1) and (2) above. 1 ~X 5 Explanation and preferred examples of the ring structure.

[0181] 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, and carbonyl group with a chain length of 1 atom, or a divalent substituted or unsubstituted vinyl group, substituted or unsubstituted vinylidene group, substituted or unsubstituted ortho-arylene group, or substituted or unsubstituted ortho-hetero-arylene group with a bonded chain length of 2 atom. Specific examples and preferred ranges of substituents can be found in the descriptions of substituents in general formulas (1) and (2) above.

[0182] In general formulas (4) to (6), L 12 ~L 14 This indicates a single bond, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group. Regarding L... 12 ~L 14 The description and preferred scope of the arylene or heteroarylene group represented by L can be found by referring to the description and preferred scope of the arylene or heteroarylene group represented by L. 12 ~L 14 Preferably, it is a single bond, a substituted or unsubstituted arylene group. The substituents of the arylene or heteroarylene group described herein can be groups represented by general formulas (1) to (6). The groups represented by general formulas (1) to (6) can be introduced into L... 11 ~L 14 The maximum number of substituents. Furthermore, when multiple groups represented by general formulas (1) to (6) are introduced, these substituents may be the same as each other or different. * indicates the bonding position of the carbon atom (C) in general formula (1) or general formula (2) with the carbon atom (C) constituting the ring skeleton.

[0183] In this invention, compounds represented by the following general formula (7) and emitting delayed fluorescence are particularly preferred as delayed fluorescence materials. In a preferred embodiment of the invention, the compound represented by general formula (7) may be used as the second organic compound.

[0184] [Chemical Formula 7]

[0185] General formula (7)

[0186]

[0187] In general formula (7), R 1 ~R 5 The 0 to 4 groups represent cyano groups, R1 ~R 5 At least one of them represents a substituted amino group, and the remaining R 1 ~R 5 It represents a hydrogen atom or a substituent other than a cyano group or a substituted amino group.

[0188] The substituted amino group described herein is preferably a substituted or unsubstituted diarylamino group, wherein the two aryl groups constituting the substituted or unsubstituted diarylamino group can be linked to each other. Linkage can occur via a single bond (in which case a carbazole ring is formed), or via -O-, -S-, or -N(R) bonds. 6 )-、-C(R 7 (R) 8 )-、-Si(R 9 (R) 10 The linkage group is used. Here, R... 6 ~R 10 R represents a hydrogen atom or substituent. 7 and R 8 R 9 and R 10 They can be connected to each other to form a ring structure.

[0189] The substituted amino group can be R 1 ~R 5 Any one of them, for example, capable of 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 R4 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 Assuming it's a substituted amino group, etc. The cyano group can also be R. 1 ~R 5 Any one of them, for example, capable of R 1 R 2 R 3 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 Let it be cyano, etc.

[0190] R is neither cyano nor substituted amino 1 ~R 5This refers to a hydrogen atom or a substituent. Examples of substituents described herein may include hydroxyl groups, halogen atoms (e.g., fluorine, chlorine, bromine, iodine), alkyl groups (e.g., 1 to 40 carbon atoms), alkoxy groups (e.g., 1 to 40 carbon atoms), alkylthio groups (e.g., 1 to 40 carbon atoms), aryl groups (e.g., 6 to 30 carbon atoms), aryloxy groups (e.g., 6 to 30 carbon atoms), arylthio groups (e.g., 6 to 30 carbon atoms), heteroaryl groups (e.g., 5 to 30 atoms forming the ring skeleton), heteroaryloxy groups (e.g., 5 to 30 atoms forming the ring skeleton), and heteroarylthio groups. The substituent group A comprises groups consisting of groups whose aryl groups (e.g., 5 to 30 atoms in a ring skeleton), acyl groups (e.g., 1 to 40 carbon atoms), alkenyl groups (e.g., 1 to 40 carbon atoms), alkoxycarbonyl groups (e.g., 1 to 40 carbon atoms), aryloxycarbonyl groups (e.g., 1 to 40 carbon atoms), heteroaryloxycarbonyl groups (e.g., 1 to 40 carbon atoms), silyl groups (e.g., trialkylsilyl groups with 1 to 40 carbon atoms), nitro groups, and groups further substituting one or more of the groups listed herein. Preferred examples of substituents when the aryl group of the diarylamino group is substituted may also include substituents from substituent group A, and may also include cyano groups and substituted amino groups.

[0191] For specific examples of the groups of compounds and compounds included in general formula (7), reference can be made to paragraphs 0008 to 0048 of WO2013 / 154064, paragraphs 0009 to 0030 of WO2015 / 080183, paragraphs 0006 to 0019 of WO2015 / 129715, paragraphs 0013 to 0025 of Japanese Patent Application Publication No. 2017-119663, and paragraphs 0013 to 0026 of Japanese Patent Application Publication No. 2017-119664, which are incorporated herein by reference as part of this document.

[0192] Furthermore, compounds represented by the following general formula (8) that emit delayed fluorescence are particularly preferred as the delayed fluorescence material of the present invention. In a preferred embodiment of the present invention, the compound represented by general formula (8) may be used as the second organic compound.

[0193] [Chemical Formula 8]

[0194] General formula (8)

[0195]

[0196] In general formula (8), Y 1 Y 2 and Y 3 Any two of them represent nitrogen atoms, and the remaining one represents either a methine or a Y atom. 1 Y 2and Y 3 Both represent nitrogen atoms. Z 1 and Z 2 Each can be used independently to represent a hydrogen atom or a substituent. R 11 ~R 18 Each can independently represent a hydrogen atom or a substituent, R 11 ~R 18 At least one of them is preferably a substituted or unsubstituted aromatic amino group or a substituted or unsubstituted carbazole group. The benzene ring constituting the aromatic amino group and the benzene ring constituting the carbazole group can be respectively with R 11 ~R 18 Together they form single bonds or linking groups. Furthermore, the compound represented by general formula (8) contains at least two carbazole structures in its molecule. 1 Z 2 Examples of substituents that can be used may include substituents from substituent group A described above. Furthermore, regarding R... 11 ~R 18 Specific examples of substituents that can be used for the aforementioned aromatic amino and carbazole groups include substituents of substituent group A, cyano groups, substituted aromatic amino groups, and substituted alkyl amino groups. Additionally, R... 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 They can bond together to form a ring structure.

[0197] Of the compounds represented by general formula (8), those represented by general formula (9) are particularly useful.

[0198] [Chemical Formula 9]

[0199] General formula (9)

[0200]

[0201] In general formula (9), Y 1 Y 2 and Y 3 Any two of them represent nitrogen atoms, and the remaining one represents either a methine or a Y atom. 1 Y 2 and Y 3 Both represent nitrogen atoms. Z 2 Represents a hydrogen atom or a substituent. R 11 ~R 18 and R 21 ~R28 Each can be used independently to represent a hydrogen atom or a substituent. R 11 ~R 18 At least one of them and / or R 21 ~R 28 At least one of them preferably represents a substituted or unsubstituted aromatic amino group or a substituted or unsubstituted carbazole group. The benzene ring constituting the aromatic amino group and the benzene ring constituting the carbazole group can be respectively associated with R 11 ~R 18 Or R 21 ~R 28 Together they form single bonds or linking groups. Z 2 Examples of substituents that can be used may include substituents from substituent group A described above. Furthermore, regarding R... 11 ~R 18 R 21 ~R 28 Specific examples of substituents that can be used for the aforementioned aromatic amino and carbazole groups include substituents of substituent group A, cyano groups, substituted aromatic amino groups, and substituted alkyl amino groups. Additionally, R... 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 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 can bond together to form a ring structure.

[0202] For specific examples of the groups of compounds and compounds contained in general formula (9), reference can be made to the compounds described in paragraphs 0020 to 0062 of WO2013 / 081088, which are incorporated herein by reference as part of this document, or in Appl. Phys. Let, 98, 083302 (2011).

[0203] Furthermore, compounds represented by the following general formula (10) and emitting delayed fluorescence may be used, particularly preferably, as the delayed fluorescence material of the present invention.

[0204] [Chemical Formula 10]

[0205] General formula (10)

[0206]

[0207] In general formula (10), R 91 ~R 96 Each of the following groups independently represents a hydrogen atom, a donor group, or an acceptor group, wherein at least one is the donor group and at least two are 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 in a meta-relationship with each other. For example, when R... 91 When it is a donor group, at least R can be preferably exemplified. 92 and R 94 The structure of the acceptor group and at least R 92 and R 96 The structure of the acceptor group is as follows. The acceptor groups present in the molecule can be all the same or different from each other, but for example, all the same structure can be selected. The number of acceptor groups is preferably 2 to 3, for example, 2 can be selected. Furthermore, there can be more than 2 donor groups, and the donor groups can be all the same or different from each other. The number of donor groups is preferably 1 to 3, for example, only 1 or 2. In addition, for the description and preferred range of donor groups and acceptor groups, refer to the description and preferred range 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 cyano or the following general formula (11).

[0208] [Chemical Formula 11]

[0209] General formula (11)

[0210]

[0211] In general formula (11), Y 4 ~Y 6 It can represent a nitrogen atom or a methine, but at least one of them is a nitrogen atom, preferably both of which represent nitrogen atoms. R 101 ~R 110 Each can be represented independently by a hydrogen atom or a substituent, but at least one is preferably an alkyl group. For a description and preferred range of substituents described herein, please refer to the description and preferred range of substituents in the foregoing general formula (7). 15 The term L represents a single bond or a linking group, and can be referred to the description and preferred scope of L in the aforementioned general formula (3). In a preferred aspect of the invention, L in general formula (11) 15 It is a single bond. * indicates the bonding position of the carbon atom (C) in the general formula (10) with the carbon skeleton that makes up the ring.

[0212] In another preferred embodiment of the invention, the compound represented by general formula (12) may be used as the second organic compound.

[0213] [Chemical Formula 12]

[0214] General formula (12)

[0215]

[0216] Among the compounds represented by general formula (12), the compounds represented by general formula (13) and general formula (14) are particularly preferred.

[0217] [Chemical Formula 13]

[0218]

[0219] In general formulas (12) to (14), D represents a donor group, A represents an acceptor group, and R represents a hydrogen atom or a substituent. For descriptions and preferred ranges of the donor and acceptor groups, please refer to the descriptions and preferred ranges corresponding to the aforementioned general formula (1). Substituents of R may be alkyl groups or aryl groups that can be replaced by one or more groups selected from the group consisting of alkyl and aryl groups.

[0220] The following are specific examples of donor groups for which D is preferred in general formulas (12) to (14). In the following specific examples, * indicates the bonding position and "D" indicates deuterium.

[0221] [Chemical Formula 14-1]

[0222]

[0223] [Chemical Formula 14-2]

[0224]

[0225] The following are specific examples of the preferred acceptor group A in general formulas (12) to (14). In the following specific examples, * indicates the bonding position and "D" indicates deuterium.

[0226] [Chemical Formula 15-1]

[0227]

[0228] [Chemical Formula 15-2]

[0229]

[0230] The following are examples of preferred R in general formulas (12) to (14). In the following specific examples, * indicates the bonding position and "D" indicates deuterium.

[0231] [Chemical Formula 16]

[0232]

[0233] (The third organic compound)

[0234] The third organic compound is a compound whose lowest excited singlet state energy is lower than that of the first, second, and fourth organic compounds. The third organic compound is a compound whose lowest excited triplet state energy is lower than that of the first and second organic compounds and higher than that of the fourth organic compound. In the organic light-emitting element of the present invention, fluorescence is emitted from the third organic compound. The fluorescence emitted from the third organic compound typically includes delayed fluorescence. The largest component of the fluorescence emitted from the organic light-emitting element of the present invention is the fluorescence emitted from the third organic compound. That is, the amount of fluorescence emitted from the third organic compound is the largest in the fluorescence emitted from the organic light-emitting element of the present invention. The third organic compound receives energy from the first organic compound in the excited singlet state, the second organic compound in the excited singlet state, the fourth organic compound in the excited singlet state, and the second organic compound in the excited singlet state through a reverse intersystem crossing from the excited triplet state, and transitions to the excited singlet state. Furthermore, in a preferred aspect of the invention, the third organic compound receives energy from the second organic compound in its excited singlet state and from the second organic compound in its excited triplet state through a reverse intersystem crossing, thus becoming the excited singlet state, and transitions to the excited singlet state. The resulting excited singlet state of the third organic compound then emits fluorescence upon returning to its ground state.

[0235] As a fluorescent material used as the third organic compound, there are no particular limitations as long as it can receive energy from the first, second, and fourth organic compounds and emit light in this way. The emission can include any one of fluorescence, delayed fluorescence, and phosphorescence. It is preferable that the emission includes fluorescence or delayed fluorescence, and more preferably that the largest component of the emission from the third organic compound is fluorescence.

[0236] If the conditions of this invention are met, then two or more third organic compounds can be used. For example, a desired color of emission can be achieved by simultaneously using two or more third organic compounds with different emission colors. Furthermore, monochromatic emission can be achieved from a single third compound.

[0237] In this invention, there is no particular limitation on the maximum emission wavelength of the compound that can be used as the third organic compound. Therefore, it is possible to appropriately select luminescent materials that have a maximum emission wavelength in the visible region (380–780 nm) or in the infrared region (780 nm–1 mm). Preferably, a fluorescent material has a maximum emission wavelength in the visible region. For example, a luminescent material with a maximum emission wavelength in the 380–780 nm region within the range of 380–570 nm can be selected, a luminescent material with a maximum emission wavelength in the range of 380–500 nm can be selected, a luminescent material with a maximum emission wavelength in the range of 380–480 nm can be selected, or a luminescent material with a maximum emission wavelength in the range of 420–480 nm can be selected.

[0238] In a preferred aspect of the invention, the compounds are 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 edge of the short-wavelength side of the emission spectrum of the second organic compound overlaps with the edge of the long-wavelength side of the absorption spectrum of the third organic compound.

[0239] The following include preferred compounds that can be used as the third organic compound. Additionally, in the structural formulas of the illustrative compounds below, Et represents the ethyl group.

[0240] [Chemical Formula 17]

[0241]

[0242] The preferred group of compounds may include compounds E1 to E5 and derivatives having these skeletons. Derivatives may include compounds substituted with alkyl, aryl, heteroaryl, or diarylamino groups.

[0243] Furthermore, the compound described in paragraphs 0220 to 0239 of WO2015 / 022974 may be used, in particular, as the third organic compound of the present invention.

[0244] (Organic Compound #4)

[0245] The fourth organic compound is a compound whose lowest excited singlet state energy is lower than that of the first organic compound and higher than that of the second and third organic compounds. Furthermore, the fourth organic compound is a compound whose lowest excited triplet state energy is lower than that of the first, second, and third organic compounds. In the organic light-emitting element of the present invention, the fourth organic compound receives energy from the first, second, and third organic compounds in their excited triplet states and transitions to the excited triplet state. In particular, because energy can be received from the second and third organic compounds in their excited triplet states to deactivate these triplet excitons, the effects of triplet-triplet interactions and triplet-charge interactions in these organic compounds can be suppressed to improve element durability.

[0246] The fourth organic compound may be any compound that satisfies conditions (a) and (b). In a preferred aspect of the invention, the fourth organic compound is a compound represented by the following general formula (15).

[0247] [Chemical Formula 18]

[0248] General formula (15)

[0249]

[0250] In general formula (15), R a and R b Each aryl group can be independently represented as either substituted or unsubstituted. R c and R d Each of the following can independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted amino group, a halogen atom, a cyano group, or a substituted or unsubstituted silyl group. R c and R d Preferably, it contains hydrogen atoms or aryl groups that are substituted or unsubstituted.

[0251] The alkyl, alkoxy, aryl, aryloxy, and silyl groups in general formula (15) can be replaced by substituents including alkyl, alkoxy, aryl, aryloxy, halogen atoms, cyano, and silyl groups. Preferred substituents are alkyl and aryl groups.

[0252] Regarding the aryl, alkyl, aryloxy, and alkyl moiety of the alkoxy group described herein, reference can be made to the description and specific examples of the aryl and alkyl groups in general formula (3). Halogen atoms may be fluorine, chlorine, bromine, and iodine atoms. The silyl group is preferably a substituted or unsubstituted trialkylsilyl group; regarding the alkyl moiety constituting the trialkylsilyl group, reference can be made to the description and specific examples of the alkyl group in general formula (3). A ring containing a heteroatom may be fused into the aryl group. Heteroatoms may be nitrogen, oxygen, and sulfur atoms.

[0253] In a preferred aspect of the invention, R a and R b Same, R c and R d It is a hydrogen atom. In another preferred aspect of the invention, R a and R b Different, R c and R d It is a hydrogen atom.

[0254] In a preferred aspect of the invention, R c and R d At least one of them is a hydrogen atom.

[0255] In a preferred aspect of the invention, R a R b and R c Each is an aryl group, either substituted or unsubstituted, independently. In this case, R... d It can be set to a hydrogen atom. Or, R d It can also be set as either a substituted or unsubstituted aryl group.

[0256] Furthermore, in a preferred aspect of the present invention, the fourth organic compound is a compound represented by the following general formula (16).

[0257] [Chemical Formula 19]

[0258] General formula (16)

[0259]

[0260] In general formula (16), R e R f R g and R hEach of these substituents independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted amino group, a halogen atom, a cyano group, or a substituted or unsubstituted silyl group. For a description and preferred range of these substituents, refer to the description and preferred range of the corresponding substituents in general formula (15). In a preferred aspect of the invention, R e and R g Each of these independently represents a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted amino group, a halogen atom, a cyano group, or a substituted or unsubstituted silyl group, and R f and R h Represents a hydrogen atom. In another preferred aspect of the invention, R e and R g R represents the substituted or unsubstituted amino groups independently. f and R h Represents a hydrogen atom. R e R f R g and R h Both can be hydrogen atoms.

[0261] Furthermore, in another preferred aspect of the invention, the fourth organic compound is a compound represented by the following general formula (17).

[0262] General formula (17)

[0263] HetAr 1 -L 21 -HetAr 2

[0264] In general formula (17), HetAr 1 and HetAr 2 Each group is independently represented by a group represented by general formula (18), at least one of which is a group represented by general formula (18) that is replaced by general formula (19). L 21 The term "linking group" can be referenced to the description and preferred scope of L in the aforementioned general formula (3). In a preferred aspect of the invention, L in general formula (17) 21 It is an unsubstituted aryl group (6 to 16 carbon atoms).

[0265] [Chemical Formula 20]

[0266] General formula (18)

[0267] In general formula (18), X' represents an oxygen atom, a sulfur atom, or NR.89 R 81 ~R 89 One of them is bonded to L, and the remaining R 81 ~R 89 Each can be represented independently by a hydrogen atom or a substituent. For a description and preferred range of the substituents described herein, please refer to the description and preferred range of the substituents in the aforementioned general formula (7). Furthermore, for a description and preferred range of the substituents described herein, please also refer to R in the aforementioned general formula (15). c and R d The description and preferred range (except for the case of hydrogen atoms). Additionally, R 81 and R 82 R 82 and R 83 R 83 and R 84 R 85 and R 86 R 86 and R 87 R 87 and R 88 They can bond together to form a ring structure.

[0268] [Chemical Formula 21]

[0269] General formula (19)

[0270]

[0271] In general formula (19), n represents an integer greater than or equal to 0, and R 91 ~R 96 Each can be represented independently by a hydrogen atom or a substituent. For a description and preferred range of the substituents described herein, please refer to the description and preferred range of the substituents in the aforementioned general formula (7). Furthermore, for a description and preferred range of the substituents described herein, please also refer to R in the aforementioned general formula (15). c and R d The description and preferred range (except for the case of hydrogen atoms). n is preferably 0 to 3, for example, it can be set to 0 or 1. * indicates the bonding position of the carbon atom in the general formula (18) with the carbon atom constituting the ring skeleton.

[0272] Among the compounds represented by general formula (17), compounds represented by general formula (20) are particularly preferred.

[0273] [Chemical Formula 22]

[0274] General formula (20)

[0275]

[0276] In general formula (20), X represents an oxygen atom, a sulfur atom, or NR. p R i R j R k R m R n and R p Substituents are represented independently. For a description and preferred range of substituents described herein, refer to the description and preferred range of substituents in the aforementioned general formula (18). In general formula (20), i, k, m, and n each independently represent any integer from 0 to 4. j represents any integer from 0 to 3. i, j, k, m, and n can each be independently selected from, for example, a range of 0 to 2, a range of 0 to 1, or all of 0. In a preferred aspect of the invention, X represents an oxygen atom. In another preferred aspect of the invention, X represents an oxygen atom or a sulfur atom, and is bonded at position 2 of the dibenzofuran ring or dibenzothiophene ring containing X to the central benzene ring of general formula (20). In another preferred aspect of the invention, the 3-ring structure containing X is bonded at the meta position of the 9-carbazole group to the central benzene ring.

[0277] In a preferred aspect of the invention, the fourth organic compound is a symmetrical compound.

[0278] If conditions (a) and (b) are met, then two or more fourth organic compounds may be used.

[0279] The following include preferred compounds that can be used as the fourth organic compound.

[0280] [Chemical Formula 23-1]

[0281]

[0282] [Chemical Formula 23-2]

[0283]

[0284] (Emitting layer)

[0285] The light-emitting layer of the organic light-emitting element of the present invention comprises a first organic compound, a second organic compound, a third organic compound, and a fourth organic compound satisfying conditions (a) and (b). The light-emitting layer can be configured such that, apart from the first, second, third, and fourth organic compounds, it does not contain any compounds or metal elements capable of charging or accepting charge or energy. Furthermore, the light-emitting layer can also be composed solely of the first, second, third, and fourth organic compounds. Moreover, the light-emitting layer can also be composed solely of compounds, wherein the compounds are composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, boron atoms, oxygen atoms, and sulfur atoms. For example, the light-emitting layer can be composed solely of compounds, wherein the compounds are composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, boron atoms, and oxygen atoms. For example, the light-emitting layer can be composed solely of compounds, wherein the compounds are composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, boron atoms, and sulfur atoms. For example, the light-emitting layer can be composed solely of a compound, which is composed of atoms selected from the group consisting of carbon, hydrogen, nitrogen, and boron atoms. Alternatively, the first, second, and fourth organic compounds included in the light-emitting layer can also be independently composed of compounds selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, and sulfur atoms. For example, the first organic compound, the second organic compound, and the fourth organic compound can each be independently defined as a compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, and nitrogen atoms.

[0286] Regarding the luminescent layer, it can be formed by co-deposition of the first, second, third, and fourth organic compounds, or by using a solution obtained by dissolving the first, second, third, and fourth organic compounds and forming it through a coating method. When forming the luminescent layer by co-deposition, two or more of the first, second, third, and fourth organic compounds can be pre-mixed and added to a crucible or similar container as a deposition source. Co-deposition is then performed using this deposition source to form the luminescent layer. For example, a deposition source can be prepared by pre-mixing the second, third, and fourth organic compounds, and co-deposition is performed using this deposition source and a deposition source containing the first organic compound to form the luminescent layer.

[0287] (Layer structure of organic light-emitting elements)

[0288] By forming a light-emitting layer comprising a first organic compound, a second organic compound, a third organic compound, and a fourth organic compound that satisfy conditions (a) and (b), it is possible to provide an excellent organic light-emitting element, such as an organic photoluminescent element (organic PL element) or an organic electroluminescent element (organic EL element).

[0289] The thickness of the light-emitting layer can be set to, for example, 1–15 nm, 2–10 nm, or 3–7 nm.

[0290] Organic photoluminescent devices have a structure in which at least one light-emitting layer is formed on a substrate. Furthermore, organic electroluminescent devices have at least an anode, a cathode, and an organic layer formed between the anode and cathode. The organic layer at least includes the light-emitting layer, and may be formed solely of the light-emitting layer, or may have one or more organic layers in addition to the light-emitting layer. Such other organic layers may include hole transport layers, hole injection layers, electron blocking layers, hole blocking layers, electron injection layers, electron transport layers, exciton blocking layers, etc. The hole transport layer may be a hole injection and transport layer with hole injection function, and the electron transport layer may be an electron injection and transport layer with electron injection function. A specific structure of an organic electroluminescent device is shown below. Figure 1 In. Figure 1 In the diagram, 1 represents the substrate, 2 represents the anode, 3 represents the hole injection layer, 4 represents the hole transport layer, 5 represents the light-emitting layer, 6 represents the electron transport layer, and 7 represents the cathode.

[0291] When the organic light-emitting element of the present invention is a multi-wavelength light-emitting organic light-emitting element, the shortest wavelength light emission can be configured to include delayed fluorescence. Furthermore, the shortest wavelength light emission can also be configured to not include delayed fluorescence.

[0292] The following describes the components of an organic electroluminescent element and its layers other than the light-emitting layer.

[0293] Substrate:

[0294] In some embodiments, the organic electroluminescent element of the present invention is supported by a substrate, wherein the substrate is not particularly limited and may be any of those substrates commonly used in organic electroluminescent elements, such as those formed of glass, transparent plastic, quartz and silicon.

[0295] anode:

[0296] In some embodiments, the anode of the organic electroluminescent device is made of a metal, alloy, conductive compound, or a combination thereof. In some embodiments, the metal, alloy, or conductive compound has a large work function (above 4 eV). 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 fabricated by vapor deposition or sputtering. In some embodiments, the film is patterned by photolithography. In some embodiments, when high precision (e.g., above about 100 μm) may not be required for the pattern, the pattern can be formed by vapor deposition or sputtering of the electrode material using a mask with the desired shape. In some embodiments, when a coating material (such as an organic conductive compound) can be applied, wet film formation methods, such as printing and coating, are used. In some embodiments, when emitted light passes through the anode, the transmittance of the anode is greater than 10%, and the sheet resistance of the anode is less than several hundred ohms per square meter. In some embodiments, the thickness of the anode is 10–1,000 nm. In some embodiments, the thickness of the anode is 10–200 nm. In some embodiments, the thickness of the anode varies depending on the material used.

[0297] cathode:

[0298] In some embodiments, the cathode is made of a metal (below 4 eV) (referred to as an electron-injecting metal), alloy, conductive compound, or combination thereof, with an electrode material having a low work function. In some embodiments, the electrode material is selected from sodium, sodium-potassium alloy, magnesium, lithium, magnesium-copper mixtures, magnesium-silver mixtures, magnesium-aluminum mixtures, magnesium-indium mixtures, aluminum-alumina (Al2O3) mixtures, indium, lithium-aluminum mixtures, and rare earth metals. In some embodiments, a mixture of the electron-injecting metal and a second metal is used, the second metal being a stable metal with a work function greater than that of the electron-injecting metal. In some embodiments, the mixture is selected from magnesium-silver mixtures, magnesium-aluminum mixtures, magnesium-indium mixtures, aluminum-alumina (Al2O3) mixtures, lithium-aluminum mixtures, and aluminum. In some embodiments, the mixture increases electron-injection characteristics and durability against oxidation. In some embodiments, the cathode is manufactured by forming the electrode material into a thin film using vapor deposition or sputtering. In some embodiments, the film resistivity of the cathode is below several hundred ohms per square meter. In some embodiments, the thickness of the cathode is in the range of 10 nm to 5 μm. In some embodiments, the thickness of the cathode is in the range of 50–200 nm. In some embodiments, either the anode or the cathode of the organic electroluminescent element is transparent or translucent in order to transmit the emitted light. In some embodiments, transparent or translucent electroluminescent elements enhance the luminous brightness.

[0299] In some embodiments, the cathode is formed using a conductive transparent material as described for the anode to form a transparent or translucent cathode. In some embodiments, the element comprises a uniformly transparent or translucent anode and cathode.

[0300] Injection layer:

[0301] The injection layer is a layer located between the electrode and the organic layer. In some embodiments, the injection layer reduces the driving voltage and enhances the luminous intensity. In some embodiments, the injection layer includes a hole injection layer and an electron injection layer. The injection layer may be disposed between the anode and the luminescent layer or hole transport layer, and between the cathode and the luminescent layer or electron transport layer. In some embodiments, an injection layer is present. In some embodiments, an injection layer is not present.

[0302] The following are examples of preferred compounds that can be used as hole injection materials.

[0303] [Chemical Formula 24]

[0304] MoO3,

[0305]

[0306] Next, preferred examples of compounds that can be used as electron injection materials are included.

[0307] [Chemical Formula 25]

[0308] LiF, CsF,

[0309] Barrier layer:

[0310] A blocking layer is a layer capable of suppressing the diffusion of charges (electrons or holes) and / or excitons in the light-emitting layer to the outside of the light-emitting layer. In some embodiments, an electron blocking layer is located between the light-emitting layer and the hole transport layer, and suppresses electrons from passing through the light-emitting layer toward the hole transport layer. In some embodiments, a hole blocking layer is located between the light-emitting layer and the electron transport layer, and suppresses holes from passing through the light-emitting layer toward the electron transport layer. In some embodiments, the blocking layer suppresses exciton diffusion to the outside of the light-emitting layer. In some embodiments, the electron blocking layer and the hole blocking layer constitute an exciton blocking layer. As used herein, the terms "electron blocking layer" or "exciton blocking layer" include layers that function as both electron blocking layers and exciton blocking layers.

[0311] Cavity blocking layer:

[0312] The hole blocking layer functions as an electron transport layer. In some embodiments, the hole blocking layer suppresses holes from reaching the electron transport layer while transporting electrons. In some embodiments, the hole blocking layer enhances the probability of rebonding between electrons and holes in the light-emitting layer. The material used for the hole blocking layer can be the same material described for the electron transport layer.

[0313] The following are examples of preferred compounds that can be used in hole-blocking layers.

[0314] [Chemical Formula 26]

[0315]

[0316] [Chemical Formula 27]

[0317]

[0318] Electron blocking layer:

[0319] Holes are transported by an electron blocking layer. In some embodiments, the electron blocking layer suppresses electrons from reaching the hole transport layer while transporting holes. In some embodiments, the electron blocking layer enhances the probability of rebonding between electrons and holes in the light-emitting layer. The material used for the electron blocking layer can be the same material described for the hole transport layer.

[0320] The following are specific examples of preferred compounds that can be used as electron blocking materials.

[0321] [Chemical Formula 28]

[0322]

[0323] Exciton blocking layer:

[0324] An exciton blocking layer suppresses the diffusion of excitons generated via the rebonding of holes and electrons in the light-emitting layer into the charge transport layer. In some embodiments, the exciton blocking layer enables effective confinement of excitons within the light-emitting layer. In some embodiments, it enhances the luminous efficiency of the device. In some embodiments, the exciton blocking layer is adjacent to the light-emitting layer on either the anode side or the cathode side, and on both sides. In some embodiments, when the exciton blocking layer is on the anode side, the layer may be located between and adjacent to the hole transport layer and the light-emitting layer. In some embodiments, when the exciton blocking layer is on the cathode side, the layer may be located between and adjacent to the light-emitting layer and the cathode. In some embodiments, a hole injection layer, an electron blocking layer, or a similar layer is located between the anode and the exciton blocking layer, with the exciton blocking layer adjacent to the light-emitting layer on the anode side. In some embodiments, a hole injection layer, an electron blocking layer, a hole blocking layer, or a similar layer is located between the cathode and the exciton blocking layer, with the exciton blocking layer adjacent to the light-emitting layer on the cathode side. In some embodiments, the exciton blocking 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 luminescent material, respectively.

[0325] Hole transport layer:

[0326] 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.

[0327] In some embodiments, the hole transport material has one of hole injection or transport properties and electron blocking 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 this invention include (but are not limited to) triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkyl derivatives, pyrazoline derivatives, dihydropyrazolone derivatives, phenylenediamine derivatives, aromatic amine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrene-anthracene 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 amines, and styrene amine 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 included below.

[0328] [Chemical Formula 29]

[0329]

[0330] [Chemical Formula 30]

[0331]

[0332] [Chemical Formula 31]

[0333]

[0334] Electron transport layer:

[0335] 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.

[0336] In some embodiments, the electron transport material only needs to have the function of transporting electrons injected from the cathode into the light-emitting layer. In some embodiments, the electron transport material also functions as a hole-blocking material. Examples that can be used in the electron transport layer of the present invention include (but are not limited to) nitro-substituted fluorene derivatives, dibenzoquinone derivatives, thiopiperanoxide derivatives, carbodiimide, fluorenemethane derivatives, anthraquinone dimethane, anthrone derivatives, oxadiazole derivatives, azole derivatives, aziridine derivatives, or combinations thereof, or polymers thereof. In some embodiments, the electron transport material is a thiadiazole derivatizer 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 included below.

[0337] [Chemical Formula 32]

[0338]

[0339] [Chemical Formula 33]

[0340]

[0341] [Chemical Formula 34]

[0342]

[0343] [Chemical Formula 35]

[0344]

[0345] Furthermore, compounds that are preferred as materials that can be added to each organic layer are included. For example, they can be considered as stabilizing materials.

[0346] [Chemical Formula 36]

[0347]

[0348] Preferred materials that can be used in organic electroluminescent elements are specifically exemplified, but the materials that can be used in this invention are not limited to the compounds exemplified below. Furthermore, even compounds exemplified as materials with specific functions can be used as materials with other functions.

[0349] Device:

[0350] In some embodiments, the light-emitting layer is incorporated into the device. Examples of devices include, but are not limited to, OLED bulbs, OLED lights, television screens, computer monitors, mobile phones, and tablet computers.

[0351] In some embodiments, the electronic device includes an OLED having an anode, a cathode, and at least one organic layer containing a light-emitting layer between the anode and the cathode.

[0352] In some embodiments, the compositions described herein can be incorporated into various photosensitive or photoactivated devices, such as OLEDs or photovoltaic devices. In some embodiments, the compositions can be suitable for facilitating charge transfer or energy transfer within the device and / or for use as hole transport materials. Such devices include, for example, organic light-emitting diodes (OLEDs), organic integrated circuits (O-ICs), organic field-effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic light-emitting transistors (O-LETs), organic solar cells (O-SCs), organic photodetectors, organic photosensors, organic field-quench devices (O-FQDs), light-emitting electrochemical cells (LECs), or organic laser diodes (O-lasers).

[0353] Light bulb or lamp:

[0354] In some embodiments, the electronic device includes an OLED, the OLED including an anode, a cathode and at least one organic layer containing a light-emitting layer between the anode and the cathode.

[0355] 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 that are not red, green, or blue (e.g., orange and yellow-green). In some embodiments, the combination of OLEDs is a combination of two, four, or more colors.

[0356] In some embodiments, the device is an OLED light, the OLED light comprising:

[0357] The circuit board has a first surface having a mounting surface and a second surface opposite thereto, and at least one opening is defined thereon;

[0358] At least one OLED is disposed on the mounting surface and has a structure in which the at least one OLED includes an anode, a cathode and at least one organic layer containing a light-emitting layer between the anode and the cathode and emits light.

[0359] Housing, used for circuit board; and

[0360] At least one connector is disposed at an end of the housing, and the housing and the connector define an encapsulation suitable for mounting to a lighting device.

[0361] In some embodiments, the OLED lamp includes a plurality of OLEDs mounted on a circuit board to emit light in multiple directions. In some embodiments, a portion of the light emitted in a first direction is deflected to be emitted in a second direction. In some embodiments, a reflector is used to deflect the light emitted in the first direction.

[0362] Monitor or screen:

[0363] In some embodiments, the light-emitting layer of the present invention can be used in a screen or display. In some embodiments, the compound involved in the present invention is deposited onto a substrate using methods including (but not limited to) vacuum evaporation, deposition, vapor deposition, or chemical vapor deposition (CVD). In some embodiments, the substrate is a photographic plate structure suitable for double-sided etching, providing pixels with a unique aspect ratio. The screen (which may also be referred to as a mask) is used in methods for manufacturing OLED displays. The corresponding artwork pattern design promotes extremely steep and narrow tie-bars between pixels in the vertical direction and promotes large swept-bevel openings in the horizontal direction. This allows for tight patterning of pixels required for high-definition displays while optimizing chemical vapor deposition onto the TFT substrate.

[0364] Internal patterning of pixels allows for the construction of 3D pixel openings with varying aspect ratios in both the horizontal and vertical directions. Furthermore, imaging "strips" or halftone circles within the pixel region suppress etching in specific areas until these specific patterns are undercut and leave the substrate. At this point, all pixel regions are processed at the same etching rate, but the depth varies depending on the halftone pattern. Varying the size and spacing of the halftone patterns allows etching to be suppressed at different rates within the pixel, enabling locally deeper etching to create steep vertical bevels.

[0365] The preferred material for vapor deposition masks is invar steel. Invar steel is a metal alloy that is cold-rolled into long thin sheets in a steel mill. Invar steel cannot be used as a nickel mask for electrodeposition onto a spin mandrel. A suitable and low-cost method for forming opening regions within a vapor deposition mask is a wet chemical etching method.

[0366] In some embodiments, the screen or display pattern is a pixel matrix on a substrate. In some embodiments, the screen or display pattern is fabricated using lithography (e.g., photolithography and e-beam lithography). In some embodiments, the screen or display pattern is fabricated using wet chemical etching. In other embodiments, the screen or display pattern is fabricated using plasma etching.

[0367] Method for manufacturing the device:

[0368] OLED displays are typically manufactured by forming a large motherboard and then cutting the motherboard into unit cells. Generally, each unit cell on the motherboard is formed by: forming a thin-film transistor (TFT) including an active layer and source / drain electrodes on a substrate, applying a planarization film onto the TFT, and sequentially forming a pixel electrode, a light-emitting layer, a counter electrode, and an encapsulation layer, and then cutting it from the motherboard.

[0369] OLED displays are typically manufactured by forming a large motherboard and then cutting the motherboard into unit cells. Generally, each unit cell on the motherboard is formed by: forming a thin-film transistor (TFT) including an active layer and source / drain electrodes on a substrate, applying a planarization film onto the TFT, and sequentially forming a pixel electrode, a light-emitting layer, a counter electrode, and an encapsulation layer, and then cutting it from the motherboard.

[0370] In another aspect of the present invention, a method for manufacturing an organic light-emitting diode (OLED) display is provided, the method comprising:

[0371] The process of forming a barrier layer on the substrate of the motherboard;

[0372] The process of forming multiple display units from unit board units on the barrier layer;

[0373] The process of forming an encapsulation layer on each of the display units of the unit board; and

[0374] The process of coating an organic film on the interface portion between the unit plates.

[0375] In some embodiments, the barrier layer is an inorganic film formed of, for example, SiNx, and the edge portions of the barrier layer are covered with an organic film formed of polyimide or acryloyl groups. In some embodiments, the organic film facilitates the gentle cutting of the motherboard into unit panels.

[0376] In some embodiments, the thin-film transistor (TFT) layer has a light-emitting layer, a gate electrode, and a source / drain electrode. Each of the plurality of display units may include a thin-film transistor (TFT), a planarization film formed on the TFT layer, and a light-emitting unit formed on the planarization film, wherein an organic film coated on the interface portion is formed of the same material as the planarization film and is formed at the same time as the planarization film is formed. In some embodiments, the light-emitting unit is connected to the TFT layer, with a passivation layer, a planarization film, and an encapsulation layer therebetween, and the encapsulation layer covers and protects the light-emitting unit. In some embodiments of the manufacturing method, the organic film neither contacts the display unit nor the encapsulation layer.

[0377] Each of the organic film and the planarization film may comprise either polyimide or acryloyl groups. In some embodiments, the barrier layer may be an inorganic film. In some embodiments, the substrate may be formed of polyimide. The method may further include mounting a carrier substrate formed of a glass material onto another surface of the substrate before forming the barrier layer on one surface of the substrate formed of polyimide, and separating the carrier substrate from the substrate before cutting along the interface portion. In some embodiments, the OLED display is a flexible display.

[0378] In some embodiments, the passivation layer is an organic film disposed on the TFT layer to cover 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 formed of polyimide or acrylamide, as in the case of an organic film formed on the edge portion of the barrier layer. In some embodiments, the planarization film and the organic film are formed simultaneously when manufacturing an OLED display. In some embodiments, the organic film may be formed on the edge portion of the barrier layer such that a portion of the organic film directly contacts the substrate, and the remaining portion of the organic film contacts the barrier layer while surrounding the edge portion of the barrier layer.

[0379] In some embodiments, the light-emitting layer has 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 electrode of the TFT layer.

[0380] In some embodiments, when a voltage is applied to the pixel electrode via the TFT layer, an appropriate voltage is formed between the pixel electrode and the opposite electrode, thereby causing the organic light-emitting layer to emit light and thus forming an image. Hereinafter, the image forming unit having a TFT layer and light-emitting units will be referred to as a display unit.

[0381] In some embodiments, the encapsulation layer covering the display units and preventing external moisture penetration can be formed as a thin-film encapsulation structure having organic and inorganic films alternately stacked. In some embodiments, the encapsulation layer has a thin-film encapsulation structure having multiple thin films stacked. In some embodiments, the organic film coated on 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 directly contacts the substrate, and the remaining portion of the organic film contacts the barrier layer while surrounding the edge portion of the barrier layer.

[0382] In one embodiment, the OLED display is flexible and uses a soft substrate formed of polyimide. In some embodiments, the substrate is formed on a carrier substrate formed of a glass material, and then the carrier substrate is separated.

[0383] In some embodiments, a barrier layer is formed on the surface of the substrate opposite to the carrier substrate. In one embodiment, the barrier layer is patterned according to the size of each unit plate. For example, while forming the substrate over the entire surface of the motherboard, the barrier layer is formed according to the size of each unit plate, thereby forming a groove at the interface portion between the unit plate barrier layers. Each unit plate can be cut along the groove.

[0384] In some embodiments, the manufacturing method further includes a step of cutting along the interface portion, wherein a groove is formed in the barrier layer, at least a portion of an organic film is formed in the groove, and the groove does not penetrate into the substrate. In some embodiments, a TFT layer is formed for each unit panel, and a passivation layer (i.e., an inorganic film) and a planarization film (i.e., an organic film) are disposed on the TFT layer to cover the TFT layer. The groove at the interface portion is covered with an organic film, such as a polyimide or acrylamide, while a planarization film formed of, for example, polyimide or acrylamide is formed. This is to prevent cracking by allowing the organic film to absorb shocks generated when each unit panel is cut along the groove at the interface portion. That is, if the entire barrier layer is completely exposed without the organic film, the shock generated when each unit panel is cut along the groove at the interface portion is transferred to the barrier layer, thereby increasing the risk of cracking. However, in one embodiment, because the grooves at the interface portions between the barrier layers are covered with an organic film, and this organic film absorbs impacts that would otherwise be transferred to the barrier layers, each unit panel can be cut gently, and cracking in the barrier layers can be prevented. In one embodiment, the organic film covering the grooves at the interface portions is spaced apart from the planarization film. For example, if the organic film and the planarization film are connected to each other as a single layer, then because external moisture may penetrate into the display unit through the planarization film and a portion of the residual organic film, the organic film and the planarization film are spaced apart from each other so that the organic film is separated from the display unit.

[0385] In some embodiments, a display unit is formed by forming light-emitting units, and an encapsulation layer is disposed on the display unit to cover it. Thus, after the motherboard is fully manufactured, a carrier substrate supporting the substrate is separated from the substrate. In some embodiments, when a laser beam is emitted toward the carrier substrate, the carrier substrate separates from the substrate due to the difference in thermal expansion coefficients between the carrier substrate and the substrate.

[0386] In some embodiments, the motherboard is cut into unit panels. In some embodiments, the motherboard is cut along the interface portion between the unit panels using a cutting machine. In some embodiments, because the grooves at the interface portion along which the motherboard is cut are covered with an organic film, the organic film absorbs impact during cutting. In some embodiments, cracking can be prevented from occurring in the barrier layer during cutting.

[0387] In some embodiments, the method reduces the defect rate of the product and stabilizes its quality.

[0388] On the other hand, there is an OLED display having: a barrier layer formed on a substrate; a display unit formed on the barrier layer; an encapsulation layer formed on the display unit; and an organic film coated on the edge portion of the barrier layer.

[0389] (Design method of luminescent compositions)

[0390] This article also provides a method for designing compositions of the present invention that have long luminescence lifetime and excellent stability.

[0391] The design method of the luminescent composition of the present invention includes the following steps 1 to 3.

[0392] [Step 1] The luminous efficiency and lifetime of a composition comprising a first organic compound, a second organic compound, a third organic compound, and a fourth organic compound as a delayed fluorescence material, and satisfying conditions (a) and (b), are evaluated.

[0393] [Step 2] The luminous efficiency and lifetime of the composition comprising replacing at least one of the first organic compound, the second organic compound, the third organic compound, and the fourth organic compound as a delayed fluorescence material within the range satisfying conditions (a) and (b) are evaluated, and the evaluation is performed at least once.

[0394] [Step 3] Select the best combination of the evaluated luminous efficiency and lifetime results.

[0395] The evaluation of luminescent efficiency and lifetime can be performed by actually causing the luminescent composition to emit light, or by calculation. Alternatively, the evaluation can be performed by actually causing the luminescent composition to emit light and using calculation. The evaluation is preferably based on the degree of practicality and should be conducted from a comprehensive perspective. In the design method of the luminescent composition of the present invention, the first organic compound, the second organic compound, the third organic compound, and the fourth organic compound need to be selected and substituted within the range of satisfying conditions (a) and (b). Furthermore, the second organic compound needs to be selected and substituted from delayed fluorescence materials. Regarding the substitution of compounds in step 2, it is preferable to substitute compounds with a higher probability of obtaining superior evaluation. Step 2 can be performed, for example, more than 10 times, more than 100 times, more than 1000 times, or more than 10000 times.

[0396] The design method for the luminescent composition of the present invention can be saved and used as a program. The program can be stored in a recording medium and can also be transmitted and received electronically.

[0397] Example

[0398] The following includes examples and further detailed descriptions of the features of the present invention. The materials, processing contents, and processing steps shown below can be appropriately modified without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limited by the specific examples shown below. Furthermore, the evaluation of luminescence properties was performed using a source meter (Keithley 2400 series), a semiconductor parameter analyzer (Agilent Technologies Japan, Ltd. E5273A), an optical power meter (Newport Corporation 1930C), a spectrometer (Ocean Optics USB2000), a spectroradiometer (TOPCON CORPORATION SR-3), and a streak camera (Hamamatsu Photonics KK C4334). Furthermore, the lowest excited singlet state energy E of the compounds used in the following examples and comparative examples is... S1 and the lowest excited triplet energy E T1 As shown in the table below.

[0399] [Table 1]

[0400]

[0401] (Example 1)

[0402] Vacuum deposition was performed using a vacuum evaporation method with a vacuum degree of 1×10⁻⁶. -6 Pa stacked the thin films on a glass substrate with an anode consisting of an indium / tin oxide (ITO) layer with a thickness of 100 nm. First, a 10 nm thick HATCN layer was formed on the ITO, followed by a 30 nm thick NPD layer, and then a 10 nm thick TrisPCz layer. Next, a 5 nm thick compound H1 was formed. Then, compound H1 (68.5 wt%), compound T13 (30 wt%), compound E1 (0.5 wt%), and compound Z1 (1 wt%) were co-deposited from different evaporation sources to form a 30 nm thick light-emitting layer. Next, SF3TRZ was formed as a 10 nm thick hole-blocking layer. Then, SF3TRZ and Liq were co-deposited from different evaporation sources to form a 30 nm thick electron transport layer. The SF3TRZ:Liq weight ratio was set to 7:3. Furthermore, Liq was formed to a thickness of 2 nm, followed by aluminum (Al) deposition to a thickness of 100 nm, thereby forming the cathode. Thus, the organic electroluminescent element of Example 1 was fabricated.

[0403] (Example 2)

[0404] The organic electroluminescent element of Example 2 was fabricated using the same steps as in Example 1, except that the concentrations of the light-emitting layer were changed to those of compound H1 (64.5 wt%), compound T13 (30 wt%), compound E1 (0.5 wt%), and compound Z1 (5 wt%).

[0405] (Example 2, Comparative Examples 1-2)

[0406] The only change was to alter the concentration of the light-emitting layer as shown in Table 2 below. Otherwise, the organic electroluminescent elements of Example 2, Comparative Example 1, and Comparative Example 2 were fabricated using the same steps as in Example 1.

[0407] [Table 2]

[0408]

[0409] When each of the manufactured organic electroluminescent elements was energized, delayed fluorescence emission from the third organic compound E1 was observed (all with a maximum emission wavelength of 471 nm). Because the organic electroluminescent element of Comparative Example 1 had a low external quantum efficiency, other performance characteristics were not evaluated. On the other hand, at 2 mA / cm²... 2 The LT95 of Comparative Example 2, Example 1, and Example 2, which showed significantly higher external quantum efficiency than Comparative Example 1, was measured. The results confirmed that Example 1 had a lifetime 2.83 times longer than Comparative Example 2, and Example 2 had a lifetime 12.4 times longer than Comparative Example 2. Furthermore, it was confirmed that increasing the concentration of compound Z1 further extended the lifetime.

[0410] [Chemical Formula 37]

[0411]

[0412] Industrial availability

[0413] According to the present invention, a long-life and stable organic light-emitting element can be provided. Therefore, the present invention has high industrial applicability.

[0414] Symbol Explanation

[0415] 1-Substrate, 2-Anode, 3-Hole injection layer, 4-Hole transport layer, 5-Light emission layer, 6-Electron transport layer, 7-Cathode.

Claims

1. An organic light-emitting element having a light-emitting layer comprising a first organic compound, a second organic compound, a third organic compound, and a fourth organic compound satisfying conditions (a), (b), and (c1) below, wherein, The second organic compound is a delayed fluorescence material. The largest component of the light emitted from the organic light-emitting element is the light emitted from the third organic compound. Condition (a) E S1 (1) > E S1 (4) > E S1 (2) > E S1 (3), Condition (b) E T1 (1) > E T1 (2) > E T1 (3) > E T1 (4), Condition (c1) Conc(1)>Conc(2)>Conc(4)>Conc(3), In the above formula, E S1 (1) represents the lowest excited singlet energy of the first organic compound, in eV; E S1 (2) represents the lowest excited singlet energy of the second organic compound, in eV; E S1 (3) represents the lowest excited singlet energy of the third organic compound, in eV; E S1 (4) represents the lowest excited singlet energy of the fourth organic compound, in eV; E T1 (1) represents the lowest excited triplet energy of the first organic compound, in eV; E T1 (2) represents the lowest excited triplet energy of the second organic compound, in eV; E T1 (3) represents the lowest excited triplet energy of the third organic compound, in eV; E T1 (4) represents the lowest excited triplet energy of the fourth organic compound, in eV; Conc(1) represents the concentration of the first organic compound in the luminescent layer, in weight % . Conc(2) represents the concentration of the second organic compound in the luminescent layer, in weight % . Conc(3) represents the concentration of the third organic compound in the light-emitting layer, in weight% %. Conc(4) represents the concentration of the fourth organic compound in the luminescent layer, in weight.

2. The organic light-emitting element according to claim 1, further satisfying the following condition (d). Condition (d) Conc(2) / Conc(3) > 5.

3. The organic light-emitting element according to claim 1, further satisfying the following condition (e). Condition (e) Conc(4) / Conc(3) > 1.

5.

4. The organic light-emitting element according to claim 1, further satisfying the following condition (f). Condition (f) Conc (4) ≤ 5% weight.

5. The organic light-emitting element according to claim 1, further satisfying the following condition (g). Condition (g) Conc (3) ≤ 1 weight.

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

7. The organic light-emitting element according to any one of claims 1 to 5, wherein, The energy difference ΔE between the lowest excited singlet state and the lowest excited triplet state at 77 K of the third organic compound. st It is below 0.3 eV.

8. The organic light-emitting element according to any one of claims 1 to 5, wherein, The light-emitting layer is composed solely of compounds, which are composed of atoms selected from the group consisting of carbon, hydrogen, nitrogen, boron, oxygen, and sulfur atoms.

9. The organic light-emitting element according to any one of claims 1 to 5, wherein, The first organic compound, the second organic compound, and the fourth organic compound are each independently a compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, and nitrogen atoms.

10. The organic light-emitting element according to any one of claims 1 to 5, wherein, The fourth organic compound is a compound consisting only of carbon and hydrogen atoms.

11. The organic light-emitting element according to any one of claims 1 to 5, wherein, The second organic compound contains a benzonitrile structure.

12. A method for designing a luminescent composition, comprising the following steps: Step 1: Evaluate the luminescence efficiency and lifetime of a composition comprising a first organic compound, a second organic compound, a third organic compound, and a fourth organic compound as a delayed fluorescence material, and satisfying the following conditions (a), (b), and (c1); Step 2 involves evaluating the luminous efficiency and lifetime of a composition that replaces at least one of the first organic compound, the second organic compound, the third organic compound, and the fourth organic compound as a delayed fluorescence material within the ranges satisfying conditions (a), (b), and (c1) below, wherein the evaluation is performed at least once; and Step 3: Select the optimal combination of the evaluated luminous efficiency and lifetime results. Condition (a) E S1 (1) > E S1 (4) > E S1 (2) > E S1 (3), Condition (b) E T1 (1) > E T1 (2) > E T1 (3) > E T1 (4), Condition (c1) Conc(1)>Conc(2)>Conc(4)>Conc(3), In the above formula, E S1 (1) represents the lowest excited singlet energy of the first organic compound, in eV; E S1 (2) represents the lowest excited singlet energy of the second organic compound, in eV; E S1 (3) represents the lowest excited singlet energy of the third organic compound, in eV; E S1 (4) represents the lowest excited singlet energy of the fourth organic compound, in eV; E T1 (1) represents the lowest excited triplet energy of the first organic compound, in eV; E T1 (2) represents the lowest excited triplet energy of the second organic compound, in eV; E T1 (3) represents the lowest excited triplet energy of the third organic compound, in eV; E T1 (4) represents the lowest excited triplet energy of the fourth organic compound, in eV; Conc(1) represents the concentration of the first organic compound in the composition, in weight % Conc(2) represents the concentration of the second organic compound in the composition, in weight% %. Conc(3) represents the concentration of the third organic compound in the composition, in weight% %. Conc(4) represents the concentration of the fourth organic compound in the composition, in units of weight.

13. A program product that implements the method of claim 12.

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