JP2022014426A - Organic light-emitting element - Google Patents

Abstract

To provide an organic light-emitting element having a long stable emission lifetime.SOLUTION: An organic light-emitting element comprises a light-emitting layer that contains first to fourth organic compounds satisfying the expression below. In the organic light-emitting element, the second organic compound is a delayed fluorescence material, and emission light from the fourth organic compound is the largest in quantity. ES1(1)>ES1(4)>ES1(2)>ES1(3) ET1(1)>ET1(2)>ET1(3)>ET1(4), where ES1 represents a minimum excited singlet energy and ET1 represents a minimum excitation triplet energy.SELECTED DRAWING: None

Description

The present invention relates to an organic light emitting device using a delayed fluorescent material.

Research is being actively conducted to improve the luminous efficiency of organic light emitting elements such as organic electroluminescence elements (organic EL elements). In particular, various studies have been conducted to improve the luminous efficiency by newly developing and combining electron transport materials, hole transport materials, host materials, light emitting materials and the like constituting organic electroluminescence elements. Among them, research on organic light emitting devices using delayed fluorescent materials can be seen.

The delayed fluorescent material is a compound that radiates fluorescence when returning from the excited singlet state to the ground state after an intersystem crossing from the excited triplet state to the excited singlet state occurs in the excited state. Fluorescence by such a pathway is called delayed fluorescence because it is observed later than fluorescence from the excited singlet state directly generated from the ground state (normal fluorescence). Here, for example, when a luminescent compound is excited by injection of a carrier, the probability of occurrence of the excited singlet state and the excited triplet state is statistically 25%: 75%, so that the excited singlet state directly generated is used. There is a limit to the improvement of light emission efficiency only by the fluorescence of. On the other hand, in the delayed fluorescent material, not only the excited singlet state but also the excited triplet state can be used for fluorescence emission by the path via the above-mentioned inverse intersystem crossing, so that it is higher than the ordinary delayed fluorescent material. Luminous efficiency will be obtained.

As such a delayed fluorescent material, a benzene derivative having a heteroaryl group such as a carbazolyl group or a diphenylamino group and at least two cyano groups has been proposed, and high light emission efficiency can be obtained with an organic EL element using the benzene derivative as a light emitting layer. It has been confirmed that this was the case (see Patent Document 1).
Further, in Non-Patent Document 1, the carbazolyl dicyanobenzene derivative (4CzTPN) is a thermally active delayed fluorescent material, and the organic electroluminescence element using this carbazolyl dicyanobenzene derivative has a high internal EL quantum. It has been reported that efficiency has been achieved.

On the other hand, it has also been proposed to use a delayed fluorescent material for the light emitting layer as an assist dopant instead of using it as a light emitting material (see Patent Document 2). Here, it is described that the luminous efficiency is improved by adding a delayed fluorescent material having the lowest excited singlet energy between the host material and the fluorescent light emitting material to the light emitting layer in addition to the host material and the fluorescent light emitting material. ing.

Japanese Unexamined Patent Publication No. 2014-43541 JP-A-2015-179809

H. Uoyama, et al., Nature 492, 234 (2012)

As described above, Patent Document 1, Patent Document 2, and Non-Patent Document 1 report that high luminous efficiency was obtained in an organic electroluminescence device using a delayed fluorescent material. However, when the present inventors have produced an organic electroluminescence element according to the descriptions in Patent Document 1 and Patent Document 2, it has been found that it is not easy to secure a sufficient life.

Under such circumstances, the present inventors have made diligent studies for the purpose of improving the life of the organic light emitting device using the delayed fluorescent material.

As a result of diligent studies to achieve the above object, the present inventors have added a host material, a delayed fluorescent material, a light emitting material, and a modifier that satisfy specific conditions to the light emitting layer to extend the light emitting life. We have found that a long and stable organic light emitting element can be realized. The present invention has been proposed based on such findings, and specifically has the following configuration.

[1] An organic light emitting element having a light emitting layer containing a first organic compound, a second organic compound, a third organic compound, and a fourth organic compound satisfying the following conditions (a) and (b).
The second organic compound is a delayed fluorescent material.
An organic light emitting device, wherein the maximum component of light emission from the organic light emitting device is light emission from the third organic compound.
Conditions (a) E _S1 (1)> E _S1 (4)> E _S1 (2)> E _S1 (3)
Conditions (b) _ET1 (1)> _ET1 (2)> _ET1 (3)> _ET1 (4)
(In the above formula,
_ES1 (1) represents the lowest excited singlet energy of the first organic compound.
_ES1 (2) represents the lowest excited singlet energy of the second organic compound.
_ES1 (3) represents the lowest excited singlet energy of the third organic compound.
_ES1 (4) represents the lowest excited singlet energy of the fourth organic compound.
_ET1 (1) represents the lowest excited triplet energy of the first organic compound.
_ET1 (2) represents the lowest excited triplet energy of the second organic compound.
_ET1 (3) represents the lowest excited triplet energy of the third organic compound.
_ET1 (4) represents the lowest excited triplet energy of the fourth organic compound. )
[2] The organic light emitting device according to [1], which further satisfies the following condition (c).
Conditions (c) Conc (1)> Conc (2)> Conc (4)
(In the above formula,
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 (4) represents the concentration of the fourth organic compound in the light emitting layer. )
[3] The organic light emitting device according to [2], which further satisfies the following condition (c1).
Conditions (c1) Conc (1)> Conc (2)> Conc (4)> Conc (3)
(In the above formula, Conc (3) represents the concentration of the third organic compound in the light emitting layer.)
[4] The organic light emitting device according to [2] or [3], which further satisfies the following condition (d).
Condition (d) Conc (2) / Conc (3)> 5
(In the above formula, Conc (3) represents the concentration of the third organic compound in the light emitting layer.)
[5] The organic light emitting device according to any one of [2] to [4], which further satisfies the following condition (e).
Condition (e) Conc (4) / Conc (3)> 1.5
(In the above formula, Conc (3) represents the concentration of the third organic compound in the light emitting layer.)
[6] The organic light emitting device according to any one of [1] to [5], which further satisfies the following condition (f).
Condition (f) Conc (4) ≤ 5% by weight
(In the above formula, Conc (4) represents the concentration of the fourth organic compound in the light emitting layer.)
[7] The organic light emitting device according to any one of [1] to [6], which further satisfies the following condition (g).
Conditions (g) Conc (3) ≤ 1% by weight
(In the above formula, Conc (3) represents the concentration of the third organic compound in the light emitting layer.)
[8] The second organic compound has an energy difference _ΔEst between the lowest excited singlet state and the lowest excited triplet state of 77K of 0.3 eV or less, any one of [1] to [7]. The organic light emitting element according to.
[9] The third organic compound has an energy difference _ΔEst between the lowest excited singlet state and the lowest excited triplet state of 77K of 0.3 eV or less, any one of [1] to [8]. The organic light emitting element according to.
[10] The light emitting layer according to [1] to [9], wherein the light emitting layer is composed only of a compound composed of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, a boron atom, an oxygen atom and a sulfur atom. The organic light emitting element according to any one item.
[11] The first organic compound, the second organic compound, and the fourth organic compound are compounds each independently composed of an atom selected from the group consisting of a carbon atom, a hydrogen atom, and a nitrogen atom [1]. ] To the organic light emitting element according to any one of [10].
[12] The organic light emitting device according to any one of [1] to [11], wherein the fourth organic compound is a compound composed of only carbon atoms and hydrogen atoms.
[13] The organic light emitting device according to any one of [1] to [12], wherein the second organic compound contains a cyanobenzene structure.
[14] [Step 1] Luminous efficiency of a composition containing a first organic compound, a second organic compound which is a delayed fluorescent material, a third organic compound, and a fourth organic compound, and satisfying the following conditions (a) and (b). And evaluate the lifespan,
[Step 2] At least one of the first organic compound, the second organic compound which is a delayed fluorescent material, the third organic compound, and the fourth organic compound is replaced within the range satisfying the following conditions (a) and (b). Evaluating the emission efficiency and lifetime of the composition was performed at least once.
[Step 3] Select the combination with the best results of the evaluated luminous efficiency and life.
A method for designing a luminescent composition, which comprises each step.
Conditions (a) E _S1 (1)> E _S1 (4)> E _S1 (2)> E _S1 (3)
Conditions (b) _ET1 (1)> _ET1 (2)> _ET1 (3)> _ET1 (4)
(In the above formula,
_ES1 (1) represents the lowest excited singlet energy of the first organic compound.
_ES1 (2) represents the lowest excited singlet energy of the second organic compound.
_ES1 (3) represents the lowest excited singlet energy of the third organic compound.
_ES1 (4) represents the lowest excited singlet energy of the fourth organic compound.
_ET1 (1) represents the lowest excited triplet energy of the first organic compound.
_ET1 (2) represents the lowest excited triplet energy of the second organic compound.
_ET1 (3) represents the lowest excited triplet energy of the third organic compound.
_ET1 (4) represents the lowest excited triplet energy of the fourth organic compound. )
[15] A program that implements the method according to [14].

According to the organic light emitting device of the present invention, long-life light emission can be realized.

It is a schematic cross-sectional view which shows the layer structure example of the organic electroluminescence element.

Hereinafter, the contents of the present invention will be described in detail. The description of the constituent elements described below may be based on typical embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples. In the present application, the numerical range represented by using "-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value. Further, in the present application, "consisting of" means that it consists only of those described before "consisting of" and does not include anything else. Further, the isotope species of hydrogen atoms existing in the molecule of the compound used in the present invention are not particularly limited, and for example, all the hydrogen atoms in the molecule may be ¹ H, and some or all of them may be ² H. (Duterium D) may be used.

(Characteristics of organic light emitting element)
The organic light emitting element of the present invention has a light emitting layer containing a first organic compound, a second organic compound, a third organic compound and a fourth organic compound. Of these, the second organic compound is a delayed fluorescent material. Then, these organic compounds satisfy the following conditions (a) and (b).
Conditions (a) E _S1 (1)> E _S1 (4)> E _S1 (2)> E _S1 (3)
Conditions (b) _ET1 (1)> _ET1 (2)> _ET1 (3)> _ET1 (4)

In the present application, _ES1 (1) represents the lowest excited single term energy of the first organic compound, _ES1 (2) represents the lowest excited single term energy of the second organic compound, and _ES1 (3) represents the above. The lowest excited single term energy of the third organic compound is represented, and _ES1 (4) represents the lowest excited single term energy of the fourth organic compound. In this application, eV is adopted as a unit.
_ET1 (1) represents the lowest excited triplet energy of the first organic compound, _ET1 (2) represents the lowest excited triplet energy of the second organic compound, and _ET1 (3) represents the third organic. The lowest excited triplet energy of the compound is represented, and _ET1 (4) represents the lowest excited triplet energy of the fourth organic compound. In this application, eV is adopted as a unit.
Conc (1) represents the concentration of the first organic compound in the light emitting layer, Conc (2) represents the concentration of the second organic compound in the light emitting layer, and Conc (3) represents the concentration of the third organic compound in the light emitting layer. Conc (4) represents the concentration of the fourth organic compound in the light emitting layer. In this application, weight% is adopted as a unit.

The organic light emitting device of the present invention simultaneously satisfies the condition (a) and the condition (b) for the lowest excited singlet energy. Therefore, the lowest excited singlet energy _ES1 (2) and the lowest excited triplet energy _ET1 (2) of the second organic compound, and the lowest excited singlet energy _ES1 (3) and the lowest excited triplet of the third organic compound. The term energy _ET1 (3) is between the lowest excited singlet energy _ES1 (4) and the lowest excited triplet energy _ET1 (4) of the fourth organic compound. Therefore, the difference _ΔEST (4) between the lowest excited singlet energy and the lowest excited triplet energy of 77K of the fourth organic compound is larger than that of the second organic compound and the third organic compound. The _ΔEST (4) of the fourth organic compound is preferably 0.5 eV or more, more preferably 0.6 eV or more, and even more preferably 0.7 eV or more. The _ΔEST (4) of the fourth organic compound can be, for example, in the range of 1.5 eV or less, in the range of 1.2 eV or less, or in the range of 0.9 eV or less.
The difference between the lowest excited singlet energy of the fourth organic compound and the second compound _ES1 (4) _-ES1 (2) is preferably 0.05 eV or more, more preferably 0.10 eV or more. It can be 0.15 eV or higher. _ES1 (4) _-ES1 (2) can be, for example, in the range of 0.7 eV or less, in the range of 0.5 eV or less, or in the range of 0.3 eV or less.
The difference between the lowest excited triplet energies of the third organic compound and the fourth compound _ET1 (3) _-ET1 (4) is preferably 0.10 eV or more, more preferably 0.30 eV or more. It can be 0.45 eV or higher. _ET1 (3) _-ET1 (4) can be, for example, in the range of 0.9 eV or less, in the range of 0.7 eV or less, or in the range of 0.5 eV or less.
Difference between the lowest excited singlet energy of the first organic compound and the second compound _ES1 (1) _-ES1 (2) should be in the range of 0.3 eV or more, in the range of 0.5 eV or more, or 0. It can be in the range of .7 eV or more, in the range of 1.6 eV or less, in the range of 1.3 eV or less, or in the range of 0.9 eV or less.
Difference between the lowest excited singlet energy of the first organic compound and the fourth compound _ES1 (1) _-ES1 (4) should be in the range of 0.2 eV or more, in the range of 0.4 eV or more, or 0. It can be in the range of .6 eV or more, in the range of 1.5 eV or less, in the range of 1.2 eV or less, or in the range of 0.8 eV or less.
The lowest excited triplet energy _ET1 (1) of the first organic compound may be larger than the lowest excited singlet energy _ES1 (4) of the fourth compound. For example, ET1 ( ₁ ) _-ES1 (4) can be in the range of 0.05 eV or more, in the range of 0.10 eV or more, or in the range of 0.15 eV or more. Further, the range may be 0.7 eV or less, 0.5 eV or less, or 0.3 eV or less.

In the organic light emitting device of the present invention, it is preferable that the contents of the first compound, the second compound, and the fourth compound satisfy the relationship of the condition (c).
Conditions (c) Conc (1)> Conc (2)> Conc (4)
In the organic light emitting device of the present invention, it is preferable that the content of the first to fourth compounds satisfies the relationship of the condition (c1).
Conditions (c1) Conc (1)> Conc (2)> Conc (4)> Conc (3)
Conc (1) is preferably 30% by weight or more, can be in the range of 50% by weight or more, can be in the range of 65% by weight or more, and can be in the range of 99% by weight or less. , 85% by weight or less, or 75% by weight or less.
Conc (2) is preferably 10% by weight or more, can be in the range of 20% by weight or more, can be in the range of 30% by weight or more, and can be in the range of 45% by weight or less. , 40% by weight or less, or 35% by weight or less.
Conc (3) is preferably 5% by weight or less, and more preferably 3% by weight or less. Conc (3) can be in the range of 1% by weight or less, in the range of 0.5% by weight or less, in the range of 0.01% by weight or more, or in the range of 0.1% by weight. It can be within the above range or within the range of 0.3% by weight or more.
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 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. ..

It is preferable that the organic light emitting device of the present invention further satisfies the following condition (d).
Condition (d) Conc (2) / Conc (3)> 5
Conc (2) / Conc (3) can be in the range of 10 or more, in the range of 30 or more, in the range of 50 or more, in the range of 500 or less, or in the range of 300 or less. It can be within the range of 100 or less.
It is preferable that the organic light emitting device of the present invention further satisfies the following condition (e).
Condition (e) Conc (4) / Conc (3)> 1.5
Conc (4) / Conc (3) can be in the range of 2 or more, in the range of 5 or more, in the range of 10 or more, in the range of 500 or less, or in the range of 100 or less. It can be within the range of 50 or less.

The second organic compound used in the organic light emitting device of the present invention is a delayed fluorescent material. The "delayed fluorescence material" in the present invention means that in an excited state, an intersystem crossing from an excited triplet state to an excited singlet state occurs, and fluorescence (delayed fluorescence) occurs when the excited singlet state returns to the ground state. It is an organic compound that emits light. In the present invention, when the emission lifetime is measured by a fluorescence lifetime measurement system (such as a streak camera system manufactured by Hamamatsu Photonics), a material in which fluorescence with a emission lifetime of 100 ns (nanoseconds) or more is observed is referred to as a delayed fluorescence material.
For the second organic compound, the difference _ΔEST (2) between the lowest excited single term energy and the lowest excited triplet energy of 77K is preferably 0.3 eV or less, more preferably 0.25 eV or less, and 0. It is more preferably 2 eV or less, more preferably 0.15 eV or less, further preferably 0.1 eV or less, further preferably 0.07 eV or less, and even more preferably 0.05 eV or less. Is even more preferable, 0.03 eV or less is even more preferable, and 0.01 eV or less is particularly preferable.
If _ΔEST (2) is small, the second organic compound functions as a thermally activated delayed fluorescent material because the excited singlet state is likely to cross the excited triplet state between the inverted states due to the absorption of heat energy. Thermally activated delayed fluorescent material absorbs the heat generated by the device, crosses the excited triplet state from the excited triplet state to the excited singlet relatively easily, and efficiently contributes the excited triplet energy to emission. Can be done.

In the present application, the lowest excited singlet energy ( _ES1 ) and the lowest excited triplet energy ( _ET1 ) of the compound are values obtained by the following procedure. _ΔEST is a value obtained by calculating _ES1 - _ET1 .
(1) Minimum excitation singlet energy ( _ES1 )
A thin film of the compound to be measured or a toluene solution (concentration ^10-5 mol / L) is prepared and used as a sample. The fluorescence spectrum of this sample is measured at room temperature (300K). In the fluorescence spectrum, the vertical axis is light emission and the horizontal axis is wavelength. A tangent line is drawn for the rising edge of the emission spectrum on the short wave side, and the wavelength value λedge [nm] at the intersection of the tangent line and the horizontal axis is obtained. The value obtained by converting this wavelength value into an energy value by the following conversion formula is defined as _ES1 .
Conversion formula: ES1 [eV] = _1239.85 / λedge
The measurement of the emission spectrum in the examples described later was performed by using an LED light source (Thorlabs, M300L4) as an excitation light source and a detector (PMA-12 multi-channel spectroscope C10027-01, Hamamatsu Photonics).
(2) Minimum excited triplet energy ( _ET1 )
The same sample used for the measurement of the lowest excitation singlet energy ( _ES1 ) was cooled to 77 [K] with liquid nitrogen, the sample for phosphorescence measurement was irradiated with excitation light (300 nm), and a detector was used. Measure phosphorescence. The emission spectrum after 100 milliseconds after the irradiation with the excitation light is defined as the phosphorescence spectrum. A tangent line is drawn for the rising edge of the phosphorescence spectrum on the short wavelength side, and the wavelength value λedge [nm] at the intersection of the tangent line and the horizontal axis is obtained. The value obtained by converting this wavelength value into an energy value by the following conversion formula is defined as _ET1 .
Conversion formula: ET1 [eV] = _1239.85 / λedge
The tangent to the rising edge of the phosphorescence spectrum on the short wavelength side is drawn as follows. When moving on the spectrum curve from the short wavelength side of the phosphorescence spectrum to the maximum value on the shortest wavelength side of the maximum values of the spectrum, consider the tangents at each point on the curve toward the long wavelength side. This tangent increases in slope as the curve rises (ie, as the vertical axis increases). The tangent line drawn at the point where the value of the slope reaches the maximum value is defined as the tangent line with respect to the rising edge of the phosphorescence spectrum on the short wavelength side.
The maximum point having a peak intensity of 10% or less of the maximum peak intensity of the spectrum is not included in the above-mentioned maximum value on the shortest wavelength side, and the value of the gradient closest to the maximum value on the shortest wavelength side is the maximum. The tangent line drawn at the point where the value is taken is taken as the tangent line to the rising edge of the phosphorescent spectrum on the short wavelength side.

(First organic compound)
The first organic compound is an organic compound having a higher minimum excitation single term energy than the second organic compound, the third organic compound, and the fourth organic compound, and has a function as a host material responsible for carrier transport and a third organic compound. It has the function of confining energy in the compound. As a result, the third organic compound can efficiently convert the energy generated by the recombination of holes and electrons in the molecule and the energy received from the first organic compound and the second organic compound into light emission. can.
The first organic compound is preferably an organic compound having a hole transporting ability and an electron transporting ability, preventing a long wavelength of light emission, and having a high glass transition temperature. Further, in a preferred embodiment of the present invention, the first organic compound is selected from compounds that do not emit delayed fluorescence.
The following are preferable compounds that can be used as the first organic compound.

(Second organic compound)
The second organic compound is a delayed fluorescent material having a lower minimum excitation singlet energy than the first organic compound and the fourth organic compound and a higher minimum excitation singlet energy than the third organic compound. Further, the second organic compound is a delayed fluorescent material having a smaller minimum excited triplet energy than the first organic compound and a larger minimum excited triplet energy than the third organic compound and the fourth organic compound. The second organic compound may be any compound that can emit delayed fluorescence under some conditions, and it is not essential for the organic light emitting device of the present invention to emit delayed fluorescence derived from the second organic compound. In the organic light emitting element of the present invention, the second organic compound receives energy from the first organic compound and the fourth organic compound in the excited singlet state and transitions to the excited singlet state. Further, the second organic compound may receive energy from the first organic compound in the excited triplet state and transition to the excited triplet state. Since the _ΔEST of the second organic compound is small, the second organic compound in the excited triplet state tends to cross the second organic compound in the excited singlet state. The second organic compound in the excited singlet state generated by these paths applies energy to the third organic compound to make the third organic compound transition to the excited singlet state.

The following are preferable compounds that can be used as the second organic compound. In the structural formulas of the following exemplary compounds, t-Bu represents a tertiary butyl group.

In addition to the above, known delayed fluorescent materials can be appropriately combined and used as the second organic compound. In addition, even unknown delayed fluorescent materials can be used.
Preferred delayed fluorescent materials include paragraphs 0008 to 0048 and 0995 to 0133 of WO2013 / 154064, paragraphs 0007 to 0047 and 0073 to 985 of WO2013 / 011954, and paragraphs 0007 to 0033 and 0059 to 0066 of WO2013 / 01955. , WO 2013/081088, paragraphs 0008 to 0071 and 0118 to 0133, Japanese Patent Laid-Open No. 2013-256490, paragraphs 0009 to 0046 and 093 to 0134, Japanese Patent Application Laid-Open No. 2013-116975, paragraphs 0008 to 0020 and 0038 to 0040. Paragraphs 0007 to 0032 and 0079 to 0084 of WO2013 / 133359A, paragraphs 0008 to 0054 and 0101 to 0121 of WO2013 / 161437, paragraphs 0007 to 0041 and 0060 to 0069 of JP-A-2014-9352, JP-A-2014. -Paragraphs 0008 to 0048 and 0067 to 0076 of JP-A-9224, paragraphs 0013-0025 of JP-A-2017-119663, paragraphs 0013-0026-0026 of JP-A-2017-119664, paragraphs 0012 of JP-A-2017-226233. -0025, paragraphs 0010 to 0050 of JP-A-2017-226838, paragraphs 0012-0043 of JP-A-2018-1441, paragraphs 0016-0044 of JP-A-2018 / 047853, compounds included in the general formula. In particular, examples of compounds that emit delayed fluorescence can be mentioned. In addition, JP-A-2013-253121, WO2013 / 133359, WO2014 / 034535, WO2014 / 115743, WO2014 / 122895, WO2014 / 126200, WO2014 / 136758, WO2014 / 133121. WO2014 / 136860, WO2014 / 196585, WO2014 / 189122, WO2014 / 168101, WO2015 / 008580, WO2014 / 203840, WO2015 / 002213, WO2015 / 016200, WO2015 / 019725, WO2015 / 072470, WO2015 / 108049, WO2015 / 080182, WO2015 / 072537, WO2015 / 080183, JP2015-129240, WO2015 / 129714, Described in WO2015 / 129715, WO2015 / 133501, WO2015 / 136880, WO2015 / 137244, WO2015 / 137202, WO2015 / 137136, WO2015 / 146541, WO2015 / 159541. A light emitting material that emits delayed fluorescence can be preferably adopted. It should be noted that the above publications described in this paragraph are cited herein as part of this specification.

A compound represented by the following general formula (1) and emitting delayed fluorescence can be preferably used as the delayed fluorescent material of the present invention. In a preferred embodiment of the present invention, the compound represented by the general formula (1) can be adopted as the second organic compound.

In the general formula (1), X ¹ to X ⁵ represent N or CR. R represents a hydrogen atom or a substituent. When two or more of X ¹ to X ⁵ represent CR, they may be the same or different from each other. However, at least one of X ¹ to X ⁵ is CD (where D represents a donor group). When all of X ¹ to X ⁵ are CR, Z represents an acceptor group, and when at least one of X ¹ to X ⁵ is N, Z represents a hydrogen atom or substituent.
Among the compounds represented by the general formula (1), a particularly preferable compound is a compound represented by the following general formula (2).

In the general formula (2), X ¹ to X ⁵ represent N or CR. R represents a hydrogen atom or a substituent. When two or more of X ¹ to X ⁵ represent CR, they may be the same or different from each other. However, at least one of X ¹ to X ⁵ is CD (where D represents a donor group).

For the description and preferred range of the substituent represented by Z in the general formula (1), the description and preferred range of the substituent in the general formula (7) described later can be referred to. The acceptor group represented by Z in the general formula (1) is a group having a property of donating an electron to the ring to which Z is bonded. Can be done. The donor group represented by D in the general formula (1) and the general formula (2) is a group having a property of attracting an electron to the ring to which D is bonded, for example, a group having a negative σp value of Hammett. You can choose from. In the following, the acceptor group may be referred to as A.
Here, the “hammet σp value” is L. P. Proposed by Hammett, it quantifies the effect of substituents on the reaction rate or equilibrium of para-substituted benzene derivatives. Specifically, the following equation holds between the substituent in the para-substituted benzene derivative and the reaction rate constant or the equilibrium constant:
log (k / k ₀ ) = ρσp
or
log (K / K ₀ ) = ρσp
It is a constant (σp) peculiar to the substituent in. In the above equation, k is the rate constant of the benzene derivative having no substituent, k ₀ is the rate constant of the benzene derivative substituted with the substituent, K is the equilibrium constant of the benzene derivative having no substituent, and K ₀ is the substituent. The equilibrium constant of the benzene derivative substituted with, ρ represents the reaction constant determined by the type and conditions of the reaction. For the description of "Hammet's σp value" and the numerical value of each substituent in the present invention, refer to the description of σp value in Hansch, C.et.al., Chem.Rev., 91,165-195 (1991). can.

In the general formula (1) and the general formula (2), X ¹ to X ⁵ represent N or CR, but at least one is CD. The number of N among X ¹ to X ⁵ is 0 to 4, for example, X ¹ and X ³ and X ⁵ , X ¹ and X ³ , X ¹ and X ⁴ , X ² and X ³ , and X ¹ . And X ⁵ , X ² and X ⁴ , only X ¹ , only X ² , and only X ³ are N. Of X ¹ to X ⁵ , the number of CDs is 1 to 5, preferably 2 to 5. For example, X 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 X ⁵ , X ¹ and X ³ and X ⁵ , X ¹ and X ² and X ⁵ , X ¹ and X ² and X ⁴ , X ¹ and X ³ and X ⁴ , X ¹ and X ³ , X ¹ and X ⁴ , X ² and X ³ , X ¹ and X ⁵ , X ² and X ⁴ , X ¹ only, X ² only, and X ³ only CD. At least one of X ¹ to X ⁵ may be CA. Here, A represents an acceptor group. Of X ¹ to X ⁵ , the number of CAs is preferably 0 to 2, and more preferably 0 or 1. A of CA is preferably a heterocyclic aromatic group having a cyano group and an unsaturated nitrogen atom. Further, X ¹ to X ⁵ may be CD or CA independently.
When two adjacent two of X ¹ to X ⁵ represent CR, the two Rs may be coupled to each other to form a cyclic structure. The cyclic structure formed by bonding with each other may be an aromatic ring or an alicyclic ring, may contain a hetero atom, and the cyclic structure may be a fused ring having two or more rings. .. The hetero atom referred to here is preferably selected from the group consisting of a nitrogen atom, an oxygen atom and a sulfur atom. Examples of the cyclic structure formed include a benzene ring, a naphthalene ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a pyrrol ring, an imidazole ring, a pyrazole ring, an imidazoline ring, an oxazole ring, an isooxazole ring, a thiazole ring, and an iso. Examples thereof include thiazole ring, cyclohexadiene ring, cyclohexene ring, cyclopentadiene ring, cycloheptatriene ring, cycloheptadiene ring, cycloheptaene ring, furan ring, thiophene ring, naphthylidine ring, quinoxalin ring, quinoline ring and the like. .. For example, a ring in which a large number of rings are condensed, such as a phenanthrene ring or a triphenylene ring, may be formed.

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

In the general formula (3), R ¹¹ and R ¹² are independently substituted or unsubstituted alkyl groups, substituted or unsubstituted alkenyl groups, substituted or unsubstituted aryl groups, or substituted or unsubstituted heteroaryl groups, respectively. Represents. R ¹¹ and R ¹² may be combined with each other to form an annular structure. L represents a single bond, substituted or unsubstituted arylene group, or substituted or unsubstituted heteroarylene group. The substituent that can be introduced into the arylene group or heteroarylene group of L may be a group represented by the general formula (1) or the general formula (2), or may be a group represented by the general formula (1) to (6) described later. It may be a group represented by. The groups represented by these (1) to (6) may be introduced up to the maximum number of substituents that can be introduced into L. Further, when a plurality of groups represented by the general formulas (1) to (6) are introduced, the substituents thereof may be the same or different from each other. * Represents the bond position to the carbon atom (C) constituting the ring skeleton of the ring in the general formula (1) or the general formula (2).
The "alkyl group" referred to here may be linear, branched or cyclic. Further, two or more of the linear portion, the annular portion and the branched portion may be mixed. The number of carbon atoms of the alkyl group can be, for example, 1 or more, 2 or more, and 4 or more. Further, the number of carbon atoms can be 30 or less, 20 or less, 10 or less, 6 or less, and 4 or less. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, n-hexyl group and isohexyl group. 2-Ethylhexyl group, n-heptyl group, isoheptyl group, n-octyl group, isooctyl group, n-nonyl group, isononyl group, n-decanyl group, isodecanyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group can be mentioned. can. The alkyl group as a substituent may be further substituted with an aryl group.
The "alkenyl group" may be linear, branched or cyclic. Further, two or more of the linear portion, the annular portion and the branched portion may be mixed. The carbon number of the alkenyl group can be, for example, 2 or more and 4 or more. Further, the number of carbon atoms can be 30 or less, 20 or less, 10 or less, 6 or less, and 4 or less. Specific examples of the alkenyl group include ethenyl group, n-propenyl group, isopropenyl group, n-butenyl group, isobutenyl group, n-pentenyl group, isopentenyl group, n-hexenyl group, isohexenyl group and 2-ethylhexenyl group. Can be mentioned. The alkenyl group as a substituent may be further substituted with a substituent.
The "aryl group" and the "heteroaryl group" may be a monocyclic ring or a condensed ring in which two or more rings are condensed. In the case of fused rings, the number of fused rings is preferably 2 to 6, and can be selected from, for example, 2 to 4. Specific examples of the ring include a benzene ring, a pyridine ring, a pyrimidine ring, a triazine ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a triphenylene ring, a quinoline ring, a pyrazine ring, a quinoxaline ring, and a naphthylidine ring. Specific examples of the aryl group or heteroaryl group include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthrasenyl group, a 2-anthrasenyl group, a 9-anthrasenyl group, a 2-pyridyl group, a 3-pyridyl group, and 4 -Pyridyl groups can be mentioned. The "arylene group" and "heteroaryl group" can be read as the valences in the description of the aryl group and the heteroaryl group from 1 to 2.
Substituent means a monovalent group that can be substituted with a hydrogen atom, and is not a concept including those that condense. For the description of the substituent and the preferable range, the description of the substituent of the general formula (7) described later and the preferable range can be referred to.

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

In the general formulas (4) to (6), R ⁵¹ to R ⁶⁰ , R ⁶¹ to R ⁶⁸ , and R ⁷¹ to R ⁷⁸ each independently represent a hydrogen atom or a substituent. For the description and preferred range of the substituents referred to here, the description and preferred range of the substituents in the general formula (7) described later can be referred to. It is also preferable that R ⁵¹ to R ⁶⁰ , R ⁶¹ to R ⁶⁸ , and R ⁷¹ to R ⁷⁸ are groups represented by any of the above general formulas (4) to (6) independently. The number of substituents in the general formulas (4) to (6) is not particularly limited. It is also preferable that all are unsubstituted (that is, hydrogen atoms). Further, when there are two or more substituents in each of the general formulas (4) to (6), the substituents may be the same or different. When a substituent is present in the general formulas (4) to (6), the substituent is preferably any one of R ⁵² to R ⁵⁹ in the case of the general formula (4), and the general formula (5). If this is the case, it is preferably any of R ⁶² to R ⁶⁷ , and if it is the general formula (6), it is preferably any of R ⁷² to R ⁷⁷ .

In the general formulas (4) to (6), R ⁵¹ and R ⁵² , R ⁵² and R ⁵³ , R ⁵³ and R ⁵⁴ , R ⁵⁴ and R ⁵⁵ , R ⁵⁵ and R ⁵⁶ , R ⁵⁶ and R ⁵⁷ , and R ⁵⁷ . 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 , and R ⁷⁷ and R ⁷⁸ , even if they are connected to each other to form an annular structure. good. For the description and preferred examples of the annular structure, the description and preferred examples of the annular structure in X ¹ to X ⁵ of the general formula (1) and the general formula (2) can be referred to.

In the general formula (6), X is a divalent oxygen atom having a chain length of 1 atom, a sulfur atom, a substituted or unsubstituted nitrogen atom, a substituted or unsubstituted carbon atom, a substituted or unsubstituted silicon atom, and a carbonyl. A group or a divalent substituted or unsubstituted ethylene group having a bond chain length of 2 atoms, a substituted or unsubstituted vinylene group, a substituted or unsubstituted o-arylene group, or a substituted or unsubstituted o-hetero Represents an arylene group. For specific examples and preferable ranges of the substituents, the description of the substituents in the above general formulas (1) and (2) can be referred to.

In the general formulas (4) to (6), L ¹² to L ¹⁴ represent a single-bonded, substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group. For the description and preferred range of the arylene or heteroarylene group represented by L ¹² to L ¹⁴ , the description and preferred range of the arylene or heteroarylene group represented by L can be referred to. L ¹² to L ¹⁴ are preferably single-bonded, substituted or unsubstituted arylene groups. The substituent of the arylene group or the heteroarylene group referred to here may be a group represented by the general formulas (1) to (6). The groups represented by the general formulas (1) to (6) may be introduced up to the maximum number of substituents that can be introduced into L ¹¹ to L ¹⁴ . Further, when a plurality of groups represented by the general formulas (1) to (6) are introduced, the substituents thereof may be the same or different from each other. * Represents the bond position to the carbon atom (C) constituting the ring skeleton of the ring in the general formula (1) or the general formula (2).

In the present invention, a compound represented by the following general formula (7) and emitting delayed fluorescence can be particularly preferably used as a delayed fluorescent material. In a preferred embodiment of the present invention, the compound represented by the general formula (7) can be adopted as the second organic compound.

In the general formula (7), 0 to 4 of R ¹ to R ⁵ represent a cyano group, at least one of R ¹ to R ⁵ represents a substituted amino group, and the remaining R ¹ to R ⁵ represent hydrogen atoms. Alternatively, it represents a substituent other than a cyano group and a substituted amino group.
The substituted amino group referred to here is preferably a substituted or unsubstituted diarylamino group, and the two aryl groups constituting the substituted or unsubstituted diarylamino group may be linked to each other. The linkage may be a single bond (in which case a carbazol ring is formed), -O-, -S-, -N (R ⁶ )-, -C (R ⁷ ) (R ⁸ ). )-, -Si (R ⁹ ) (R ¹⁰ )-may be made of a linking group. Here, R ⁶ to R ¹⁰ represent hydrogen atoms or substituents, and R ⁷ and R ⁸ and R ⁹ and R ¹⁰ may be connected to each other to form a cyclic structure.
The substituted amino group may be any of R ¹ to R ⁵ , for example, R ¹ and R ² , R ¹ and R ³ , R ¹ and R ⁴ , R ¹ and R ⁵ , R ² and R ³ , R ² . And R ⁴ , R ¹ and R ² and R ³ , R ¹ and R ² and R ⁴ , R ¹ and R ² and R ⁵ , R ¹ and R ³ and R ⁴ , R ¹ and R ³ and R ⁵ , R ² and R ³ and R ⁴ , R ¹ and R ² and R ³ and R ⁴ , R ¹ and R ² and R ³ and R ⁵ , R ¹ and R ² and R ⁴ and R ⁵ , R ¹ and R ² . R ³ and R ⁴ and R ⁵ can be substituted amino groups and the like. The cyano group may also be any of R ¹ to R ⁵ , for example 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 can be cyano groups and the like.
R ¹ to R ⁵ which are neither a cyano group nor a substituted amino group represent a hydrogen atom or a substituent. Examples of the substituent here include a hydroxyl group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), an alkyl group (for example, 1 to 40 carbon atoms), and an alkoxy group (for example, 1 to 40 carbon atoms). , Alkylthio group (for example, 1 to 40 carbon atoms), aryl group (for example, 6 to 30 carbon atoms), aryloxy group (for example, 6 to 30 carbon atoms), arylthio group (for example, 6 to 30 carbon atoms), heteroaryl group (for example, 6 to 30 carbon atoms). For example, a ring skeleton constituent atom number 5 to 30), a heteroaryloxy group (for example, a ring skeleton constituent atom number 5 to 30), a heteroarylthio group (for example, a ring skeleton constituent atom number 5 to 30), an acyl group (for example, a ring skeleton constituent atom number 1). ~ 40), alkenyl group (for example, 1 to 40 carbon atoms), alkynyl group (for example, 1 to 40 carbon atoms), alkoxycarbonyl group (for example, 1 to 40 carbon atoms), aryloxycarbonyl group (for example, 1 to 40 carbon atoms) , Heteroaryloxycarbonyl groups (eg, 1-40 carbon atoms), silyl groups (eg, trialkylsilyl groups with 1-40 carbon atoms), nitro groups, the groups listed here are further one or more groups listed here. A group of substituents A consisting of substituted groups can be mentioned. As a preferable example of the substituent when the aryl group of the diarylamino group is substituted, the substituent of the above-mentioned substituent group A can be mentioned, and further, a cyano group and a substituted amino group can also be mentioned.
For the compound group included in the general formula (7) and specific examples of the compounds, paragraphs 0008 to 0048 of WO2013 / 154064 and paragraphs 0009 to WO2015 / 080183, which are referred to herein as a part of the present specification. 0030, paragraphs 0006 to 0019 of WO2015 / 129715, paragraphs 0013 to 0025 of JP2017-119663, and paragraphs 0013 to 0026 of JP2017-119664 can be referred to.

Further, a compound represented by the following general formula (8) and emitting delayed fluorescence can also be particularly preferably used as the delayed fluorescent material of the present invention. In a preferred embodiment of the present invention, the compound represented by the general formula (8) can be adopted as the second organic compound.

In the general formula (8), Y ¹ , Y ² and Y ³ either represent a nitrogen atom and the remaining one represents a methine group, or all of Y ¹ , Y ² and Y ³ represent a nitrogen atom. show. Z ¹ and Z ² each independently represent a hydrogen atom or substituent. R ¹¹ to R ¹⁸ each independently represent a hydrogen atom or a substituent, and at least one of R ¹¹ to R ¹⁸ may be a substituted or unsubstituted arylamino group or a substituted or unsubstituted carbazolyl group. preferable. The benzene ring constituting the arylamino group and the benzene ring constituting the carbazolyl group may be combined with R ¹¹ to R ¹⁸ to form a single bond or a linking group, respectively. Further, the compound represented by the general formula (8) contains at least two carbazole structures in the molecule. Examples of the substituents that Z ¹ and Z ² can take include the above-mentioned substituents of the substituent group A. Specific examples of the substituents that can be taken from R ¹¹ to R ¹⁸ , the above-mentioned arylamino group and carbazolyl group include the above-mentioned substituent, cyano group, substituted arylamino group and substituted alkylamino group of the substituent group A. be able to. It should be noted that 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 , and R ¹⁷ and R ¹⁸ are coupled to each other to form an annular structure. May be good.
Among the compounds represented by the general formula (8), the compound represented by the general formula (9) is particularly useful.

In the general formula (9), Y ¹ , Y ² and Y ³ either represent a nitrogen atom and the remaining one represents a methine group, or all of Y ¹ , Y ² and Y ³ represent a nitrogen atom. show. Z ² represents a hydrogen atom or a substituent. R ¹¹ to R ¹⁸ and R ²¹ to R ²⁸ each independently represent a hydrogen atom or a substituent. At least one of R ¹¹ to R ¹⁸ and / or at least one of R ²¹ to R ²⁸ preferably represent a substituted or unsubstituted arylamino group or a substituted or unsubstituted carbazolyl group. The benzene ring constituting the arylamino group and the benzene ring constituting the carbazolyl group may be combined with R ¹¹ to R ¹⁸ or R ²¹ to R ²⁸ to form a single bond or a linking group, respectively. Examples of the substituents that Z ² can take include the above-mentioned substituents of the substituent group A. Further, for specific examples of the substituents that can be taken from R ¹¹ to R ¹⁸ , R ²¹ to R ²⁸ , the above arylamino group and the carbazolyl group, the substituent, the cyano group and the substituted arylamino group of the above-mentioned substituent group A are used. Substituted alkylamino groups can be mentioned. In addition, 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 , and R ²⁷ and R ²⁸ may be coupled to each other to form an annular structure.
For a group of compounds and specific examples of the compounds included in the general formula (9), paragraphs 0020 to 0062 of WO2013 / 081088, which are cited herein as a part of the present specification, and Appl. Phys. The compounds described in Let, 98,083302 (2011) can be referred to.

Further, a compound represented by the following general formula (10) and emitting delayed fluorescence can also be particularly preferably used as the delayed fluorescent material of the present invention.

In the general formula (10), R ⁹¹ to R ⁹⁶ each independently represent a hydrogen atom, a donor group, or an acceptor group, at least one of which is the donor group and at least two of which are the donor group. It is an acceptor group. The substitution position of at least two acceptor groups is not particularly limited, but it is preferable to include two acceptor groups having a meta-position relationship with each other. For example, when R ⁹¹ is a donor group, a structure in which at least R ⁹² and R ⁹⁴ are acceptor groups and a structure in which at least R ⁹² and R ⁹⁶ are acceptor groups can be preferably exemplified. The acceptor groups present in the molecule may be all the same or different from each other, but it is possible to select, for example, structures that are all the same. The number of acceptor groups is preferably 2-3, for example 2 can be selected. Further, two or more donor groups may be present, and in that case, the donor groups may all be the same or different from each other. The number of donor groups is preferably 1 to 3, and may be, for example, only one or two. For the description and preferred range of the donor group and the acceptor group, the description and preferred range of D and Z in the general formula (1) can be referred to. In particular, in the general formula (10), the donor group is preferably represented by the general formula (3), and the acceptor group is preferably represented by the cyano group or the following general formula (11).

In the general formula (11), Y ⁴ to Y ⁶ represent a nitrogen atom or a methine group, but at least one represents a nitrogen atom, and preferably all represent a nitrogen atom. Each of R ¹⁰¹ to R ¹¹⁰ independently represents a hydrogen atom or a substituent, but at least one is preferably an alkyl group. For the description of the substituent and the preferable range referred to here, the description of the substituent and the preferable range in the above-mentioned general formula (7) can be referred to. L ¹⁵ represents a single bond or a linking group, and the description and preferred range of L in the above general formula (3) can be referred to. In a preferred embodiment of the present invention, L15 in the general formula ⁽ 11) is a single bond. * Represents the bond position to the carbon atom (C) constituting the ring skeleton of the ring in the general formula (10).

In another preferred embodiment of the present invention, the compound represented by the general formula (12) can be adopted as the second organic compound.

Among the compounds represented by the general formula (12), a particularly preferable compound is a compound represented by the following general formula (13) or a compound represented by the general formula (14).

In the 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 the description and preferred range of the donor and acceptor groups, the corresponding description and preferred range of the general formula (1) above can be referred to. Examples of the substituent of R include an alkyl group and an aryl group which may be substituted with one group selected from the group consisting of an alkyl group and an aryl group or a group in which two or more are combined.
Specific examples of the preferred donor group as D in the general formulas (12) to (14) are given below. In the following specific examples, * represents a bond position and "D" represents deuterium.

Specific examples of acceptor groups preferred as A in the general formulas (12) to (14) are given below. In the following specific examples, * represents a bond position and "D" represents deuterium.

Preferred examples of R in the general formulas (12) to (14) are given below. In the following specific examples, * represents a bond position and "D" represents deuterium.

(Third organic compound)
The third organic compound is a compound having a lower minimum excitation single term energy than the first organic compound, the second organic compound, and the fourth organic compound. The third organic compound is a compound having a lower minimum excitation triplet energy than the first organic compound and the second organic compound and a higher minimum excitation triplet energy than the fourth organic compound. The organic light emitting device of the present invention emits fluorescence derived from the third organic compound. Emissions from the third organic compound usually include delayed fluorescence. The maximum component of light emission from the organic light emitting device of the present invention is light emission from the third organic compound. That is, among the light emitted from the organic light emitting device of the present invention, the amount of light emitted from the third organic compound is the largest. The third organic compound is an excited singlet state, a first organic compound in an excited singlet state, a second organic compound in an excited singlet state, and a fourth organic compound in an excited singlet state. It receives energy from the second organic compound in the term state and transitions to the excited singlet state. Further, in a preferred embodiment of the present invention, the third organic compound receives energy from the second organic compound in the excited singlet state and the second organic compound which crosses between the excited triplet states and becomes the excited singlet state. Receives and transitions to the excited singlet state. The excited singlet state of the resulting tertiary organic compound then radiates fluorescence as it returns to the ground state.
The fluorescent material used as the third organic compound is not particularly limited as long as it can receive energy from the first organic compound, the second organic compound, and the fourth organic compound and emit light, and the light emission is fluorescent. Either delayed fluorescence or phosphorescence may be included. It is preferable that the emission contains fluorescence or delayed fluorescence, and more preferably, the maximum component of the emission from the third organic compound is fluorescence.
As the third organic compound, two or more kinds may be used as long as they satisfy the conditions of the present invention. For example, by using two or more kinds of tertiary organic compounds having different emission colors in combination, it becomes possible to emit a desired color. Further, one kind of the third compound may be used to emit a single color from the third compound.
In the present invention, the maximum emission wavelength of the compound that can be used as the third organic compound is not particularly limited. Therefore, it is possible to appropriately select and use a light emitting material having a maximum emission wavelength in the visible region (380 to 780 nm), a light emitting material having a maximum emission wavelength in the infrared region (780 nm to 1 mm), and the like. Preferred is a fluorescent material having a maximum emission wavelength in the visible region. For example, a light emitting material having a maximum emission wavelength in the range of 380 to 570 nm in the region of 380 to 780 nm may be selected and used, or a light emitting material having a maximum emission wavelength in the range of 380 to 500 nm may be selected and used. , A light emitting material having a maximum emission wavelength in the range of 380 to 480 nm may be selected and used, or a light emitting material having a maximum emission wavelength in the range of 420 to 480 nm may be selected and used.
In a preferred embodiment of the present invention, the compounds are selected and combined so 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 on the short wavelength side of the emission spectrum of the second organic compound and the edge on the long wave side of the absorption spectrum of the third organic compound overlap.
The following are preferable compounds that can be used as the third organic compound. In the structural formulas of the following exemplary compounds, Et represents an ethyl group.

Preferred compound groups include compounds E1 to E5 and derivatives having a skeleton thereof. Examples of the derivative include compounds substituted with an alkyl group, an aryl group, a heteroaryl group, and a diarylamino group.

Further, the compounds described in paragraphs 0220 to 0239 of WO2015 / 022974 can also be particularly preferably used as the third organic compound of the present invention.

(4th organic compound)
The fourth organic compound is a compound having a lower minimum excitation single-term energy than the first organic compound and a higher minimum excitation single-term energy than the second organic compound and the third organic compound. Further, the fourth organic compound is a compound having a lower minimum excitation triplet energy than the first organic compound, the second organic compound and the third organic compound. In the organic light emitting element of the present invention, the fourth organic compound receives energy from the first organic compound, the second organic compound and the third organic compound in the excited triplet state and transitions to the excited triplet state. In particular, triplet-triplet interactions and triplets in these organic compounds can be deactivated by receiving energy from the second and third organic compounds in the excited triplet state. -The influence of charge interaction can be suppressed and the durability of the element can be improved.

The fourth organic compound may be any compound that satisfies the condition (a) and the condition (b). In a preferred embodiment of the present invention, the fourth organic compound is a compound represented by the following general formula (15).

In the general formula (15 ^{), Ra and R b represent} independently substituted or unsubstituted aryl groups, respectively. R ^c and R ^d are independently hydrogen atoms, substituted or unsubstituted alkyl groups, substituted or unsubstituted alkoxy groups, substituted or unsubstituted aryl groups, substituted or unsubstituted aryloxy groups, substituted or unsubstituted, respectively. Represents an amino group, a halogen atom, a cyano group, or a substituted or unsubstituted silyl group. R ^c and R ^d are preferably hydrogen atoms or substituted or unsubstituted aryl groups.
Examples of the substituents that the alkyl group, alkoxy group, aryl group, aryloxy group and silyl group in the general formula (15) can take include an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a halogen atom, a cyano group and a silyl group. Can be mentioned. Preferred substituents are alkyl and aryl groups.
Regarding the aryl group, the alkyl group, the aryl portion of the aryloxy group, and the alkyl portion of the alkoxy group, the description and specific examples of the aryl group and the alkyl group in the general formula (3) can be referred to. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. The silyl group is preferably a substituted or unsubstituted trialkylsilyl group, and for the alkyl moiety constituting the trialkylsilyl group, the description and specific examples of the alkyl group in the general formula (3) can be referred to. .. A ring containing a heteroatom may be condensed on the aryl group. Examples of the hetero atom include a nitrogen atom, an oxygen atom and a sulfur atom.

In a preferred embodiment of the present invention, Ra and R ^b are the same, and R ^c and R ^d are hydrogen atoms ^. In another preferred embodiment of the invention, Ra and R ^b are different, with R ^c and R ^d being hydrogen atoms ^.
In a preferred embodiment of the invention, at least one of R ^c and R ^d is a hydrogen atom.
In a preferred embodiment of the invention, ^{Ra, R b and R c are independently} substituted or unsubstituted aryl groups, respectively. At this time, R ^d can be a hydrogen atom. Alternatively, R ^d can be a substituted or unsubstituted aryl group.

Further, in a preferred embodiment of the present invention, the fourth organic compound is a compound represented by the following general formula (16).

In the general formula (16), R ^e , R ^f , R ^g and R ^h are independently hydrogen atoms, substituted or unsubstituted alkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted alkoxy groups, respectively. Represents 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 the description and preferred range of these substituents, the description and preferred range of the corresponding substituents in the general formula (15) can be referred to. In a preferred embodiment of the invention, ^Re and R ^g are independently substituted or unsubstituted aryl groups, substituted or unsubstituted alkoxy groups, substituted or unsubstituted aryloxy groups, substituted or unsubstituted amino groups, respectively. , Halogen atom, cyano group, or substituted or unsubstituted silyl group, and R ^f and R ^h represent hydrogen atom. In another preferred embodiment of the invention, R ^e and R ^g represent independently substituted or unsubstituted amino groups, respectively, and R ^f and R ^h represent hydrogen atoms. R ^e , R ^f , R ^g and R ^h may all be hydrogen atoms.

Further, in another preferred embodiment of the present invention, the fourth organic compound is a compound represented by the following general formula (17).
General formula (17)
HetAr ¹ -L ²¹ -HetAr ²

In the general formula (17), HetAr ¹ and HetAr ² each independently represent a group represented by the general formula (18), and at least one of them is the general formula (18) substituted by the general formula (19). It is the group represented. L ²¹ represents a linking group, and the description and preferred range of L in the above-mentioned general formula (3) can be referred to. In a preferred embodiment of the present invention, L21 in the general formula ⁽ 17) is an unsubstituted arylene group (6 to 16 carbon atoms).

In the general formula (18), X'represents an oxygen atom, a sulfur atom, or NR ⁸⁹ . One of R ⁸¹ to R ⁸⁹ is bonded to L, and the remaining R ⁸¹ to R ⁸⁹ each independently represent a hydrogen atom or a substituent. For the description of the substituent and the preferable range referred to here, the description of the substituent and the preferable range in the above-mentioned general formula (7) can be referred to. Further, for the description and the preferable range of the substituent referred to here, the description and the preferable range of R ^c and R ^d in the above-mentioned general formula (15) can also be referred to (except when it is a hydrogen atom). Even if 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 , and R ⁸⁷ and R ⁸⁸ are coupled to each other to form an annular structure. good.

In the general formula (19), n represents an integer of 0 or more, and R ⁹¹ to R ⁹⁶ each independently represent a hydrogen atom or a substituent. For the description of the substituent and the preferable range referred to here, the description of the substituent and the preferable range in the above-mentioned general formula (7) can be referred to. Further, for the description and the preferable range of the substituent referred to here, the description and the preferable range of R ^c and R ^d in the above-mentioned general formula (15) can also be referred to (except when it is a hydrogen atom). n is preferably 0 to 3, and can be, for example, 0 or 1. * Represents the bond position to the carbon atom constituting the ring skeleton of the ring in the general formula (18).

Among the compounds represented by the general formula (17), the compound represented by the following general formula (20) can be particularly preferably adopted.

In the general formula (20), X represents an oxygen atom, a sulfur atom, or N- ^Rp . R ⁱ , R ^j , R ^k , R ^m , R ⁿ and R ^p each independently represent a substituent. For the description of the substituent and the preferable range referred to here, the description of the substituent and the preferable range in the above-mentioned general formula (18) can be referred to. In the general formula (20), i, k, m and n each independently represent an integer of 0 to 4. j represents an integer of 0 to 3. i, j, k, m and n may be independently selected, for example, within the range of 0 to 2, may be selected within the range of 0 to 1, and all may be 0. In a preferred embodiment of the invention, X represents an oxygen atom. In another preferred embodiment of the invention, X represents an oxygen atom or a sulfur atom and is attached to the central benzene ring of the general formula (20) at the 2-position of the dibenzofuran ring or dibenzothiophene ring containing X. In another preferred embodiment of the invention, the X-containing tricyclic structure is attached to the central benzene ring at the meta position of the 9-carbazolyl group.

In a preferred embodiment of the invention, the fourth organic compound is a symmetric compound.
As the fourth organic compound, two or more kinds may be used as long as they satisfy the condition (a) and the condition (b).

The following are preferable compounds that can be used as the fourth organic compound.

(Light emitting layer)
The light emitting layer of the organic light emitting element of the present invention contains a first organic compound, a second organic compound, a third organic compound, and a fourth organic compound that satisfy the conditions (a) and (b). The light emitting layer can be configured to contain no compound or metal element that transfers charge or energy, in addition to the first organic compound, the second organic compound, the third organic compound, and the fourth organic compound. Further, the light emitting layer may be composed of only the first organic compound, the second organic compound, the third organic compound and the fourth organic compound. Further, the light emitting layer may be composed of only a compound consisting of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, a boron atom, an oxygen atom and a sulfur atom. For example, the light emitting layer can be composed only of a compound consisting of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, a boron atom and an oxygen atom. For example, the light emitting layer can be composed only of a compound consisting of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, a boron atom and a sulfur atom. For example, the light emitting layer can be composed only of a compound consisting of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom and a boron atom. For example, the light emitting layer can be composed only of a compound consisting of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom and a sulfur atom. For example, the light emitting layer can be composed only of a compound consisting of an atom selected from the group consisting of a carbon atom, a hydrogen atom and a nitrogen atom. Alternatively, the first organic compound, the second organic compound, and the fourth organic compound contained in the light emitting layer are independently selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, and a sulfur atom. It can also be a compound. For example, the first organic compound, the second organic compound, and the fourth organic compound can each independently be a compound composed of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, and an oxygen atom. For example, the first organic compound, the second organic compound, and the fourth organic compound can each independently be a compound composed of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, and a sulfur atom. For example, the first organic compound, the second organic compound, and the fourth organic compound can each independently be a compound composed of an atom selected from the group consisting of a carbon atom, a hydrogen atom, and a nitrogen atom.
The light emitting layer may be formed by co-depositing the first organic compound, the second organic compound, the third organic compound and the fourth organic compound, or the first organic compound, the second organic compound and the third organic compound. And may be formed by a coating method using a solution in which a fourth organic compound is dissolved. When forming a light emitting layer by co-deposited, two or more of the first organic compound, the second organic compound, the third organic compound and the fourth organic compound are mixed in advance and put into a pot or the like to be used as a vapor deposition source. A light emitting layer may be formed by co-depositing using a vapor deposition source. For example, by mixing the second organic compound, the third organic compound, and the fourth organic compound in advance to prepare one vapor deposition source, and co-depositing using the vapor deposition source and the vapor deposition source of the first organic compound. A light emitting layer may be formed.

(Layer structure of organic light emitting element)
By forming a light emitting layer containing the first organic compound, the second organic compound, the third organic compound and the fourth organic compound satisfying the conditions (a) and (b), an organic photoluminescence element (organic PL element) or It is possible to provide an excellent organic light emitting element such as an organic electroluminescence element (organic EL element).
The thickness of the light emitting layer can be, for example, 1 to 15 nm, 2 to 10 nm, or 3 to 7 nm.
The organic photoluminescence device has a structure in which at least a light emitting layer is formed on a base material. Further, the organic electroluminescence device has at least an anode, a cathode, and a structure in which an organic layer is formed between the anode and the cathode. The organic layer includes at least a light emitting layer, and may be composed of only a light emitting layer, or may have one or more organic layers in addition to the light emitting layer. Examples of such other organic layers include a hole transport layer, a hole injection layer, an electron barrier layer, a hole barrier layer, an electron injection layer, an electron transport layer, an exciton barrier layer, and the like. The hole transport layer may be a hole injection transport layer having a hole injection function, and the electron transport layer may be an electron injection transport layer having an electron injection function. FIG. 1 shows a specific structural example of the organic electroluminescence device. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 is a light emitting layer, 6 is an electron transport layer, and 7 is a cathode.
When the organic light emitting element of the present invention is a multi-wavelength light emitting element, the shortest wavelength light emission can include delayed fluorescence. It is also possible that the shortest wavelength emission does not include delayed fluorescence.

Hereinafter, each member of the organic electroluminescence device and each layer other than the light emitting layer will be described.

Base material:
In some embodiments, the organic electroluminescence device of the present invention is held by a substrate, the substrate is not particularly limited and is commonly used in organic electroluminescence devices, such as glass, clear plastic, quartz and silicon. Any material formed by the above may be used.

anode:
In some embodiments, the anode of an organic electroluminescence device is manufactured from a metal, alloy, conductive compound or a combination thereof. In some embodiments, the metal, alloy or conductive compound has a high work function (4 eV or higher). In some embodiments, the metal is Au. In some embodiments, the conductive transparent material is selected from CuI, indium tin oxide (ITO), SnO ₂ and ZnO. In some embodiments, an amorphous material capable of forming a transparent conductive film, such as IDIXO (In ₂ O ₃ -ZnO), is used. In some embodiments, the anode is a thin film. In some embodiments, the thin film is made by vapor deposition or sputtering. In some embodiments, the film is patterned by a photolithography method. In some embodiments, if the pattern does not need to be highly accurate (eg, about 100 μm or larger), the pattern may be formed using a mask having a shape suitable for vapor deposition or sputtering on the electrode material. In some embodiments, when a coating material such as an organic conductive compound can be applied, a wet film forming method such as a printing method or a coating method is used. In some embodiments, when synchrotron radiation passes through the anode, the anode has a transmittance of greater than 10% and the anode has a sheet resistance of no more than a few hundred ohms per unit area. 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 will vary depending on the material used.

cathode:
In some embodiments, the cathode is made of an electrode material such as a metal with a low work function (4 eV or less) (referred to as an electron-injected metal), an alloy, a conductive compound or a combination thereof. In some embodiments, the electrode material is sodium, sodium-potassium alloy, magnesium, lithium, magnesium-copper mixture, magnesium-silver mixture, magnesium-aluminum mixture, magnesium-indium mixture, aluminum-aluminum oxide (Al ₂ ). O ₃ ) Selected from mixtures, indium, lithium-aluminum mixtures and rare earth elements. In some embodiments, a mixture of the electron-injected metal and a second metal, which is a stable metal with a higher work function than the electron-injected metal, is used. In some embodiments, the mixture is selected from a magnesium-silver mixture, a magnesium-aluminum mixture, a magnesium-indium mixture, an aluminum-aluminum oxide (Al ₂ O ₃ ) mixture, a lithium-aluminum mixture and aluminum. In some embodiments, the mixture improves electron injection properties and resistance to oxidation. In some embodiments, the cathode is manufactured by forming the electrode material as a thin film by vapor deposition or sputtering. In some embodiments, the cathode has a sheet resistance of tens of ohms or less per unit area. In some embodiments, the cathode has a thickness of 10 nm to 5 μm. In some embodiments, the thickness of the cathode is 50-200 nm. In some embodiments, any one of the anode and cathode of the organic electroluminescence element is transparent or translucent in order to transmit synchrotron radiation. In some embodiments, the transparent or translucent electroluminescent device improves the light radiance.
In some embodiments, the cathode is formed of the conductive transparent material described above with respect to the anode to form a transparent or translucent cathode. In some embodiments, the device comprises an anode and a cathode, both of which are transparent or translucent.

Injection layer:
The injection layer is the layer between the electrode and the organic layer. In some embodiments, the injection layer reduces the drive voltage and enhances the light radiance. In some embodiments, the injection layer comprises a hole injection layer and an electron injection layer. The injection layer can be arranged between the anode and the light emitting layer or the hole transport layer, and between the cathode and the light emitting layer or the electron transport layer. In some embodiments, an injection layer is present. In some embodiments, there is no injection layer.
The following are examples of preferable compounds that can be used as hole injection materials.

Next, examples of preferable compounds that can be used as electron injection materials are given.

Barrier layer:
The barrier layer is a layer capable of preventing charges (electrons or holes) and / or excitons present in the light emitting layer from diffusing outside the light emitting layer. In some embodiments, the electron barrier layer resides between the light emitting layer and the hole transport layer, preventing electrons from passing through the light emitting layer to the hole transport layer. In some embodiments, the hole barrier layer exists between the light emitting layer and the electron transport layer to prevent holes from passing through the light emitting layer to the electron transport layer. In some embodiments, the barrier layer prevents excitons from diffusing outside the light emitting layer. In some embodiments, the electron barrier layer and the hole barrier layer constitute an exciton barrier layer. As used herein, the term "electron barrier layer" or "exciton barrier layer" includes both an electron barrier layer and a layer having both the functions of an exciton barrier layer.

Hole barrier layer:
The hole barrier layer functions as an electron transport layer. In some embodiments, the hole barrier layer prevents holes from reaching the electron transport layer during electron transport. In some embodiments, the hole barrier layer increases the probability of electron-hole recombination in the light emitting layer. The material used for the hole barrier layer may be the same material as described above for the electron transport layer.
The following are examples of preferable compounds that can be used for the hole barrier layer.

Electronic barrier layer:
The electron barrier layer transports holes. In some embodiments, the electron barrier layer blocks electrons from reaching the hole transport layer during hole transport. In some embodiments, the electron barrier layer increases the probability of electron-hole recombination in the light emitting layer. The material used for the electron barrier layer may be the same material as described above for the hole transport layer.
Specific examples of preferable compounds that can be used as an electron barrier material are given below.

Exciton barrier layer:
The exciton barrier layer prevents excitons generated through recombination of holes and electrons in the light emitting layer from diffusing to the charge transport layer. In some embodiments, the exciton barrier layer allows for effective exciton confinement in the light emitting layer. In some embodiments, the light emission efficiency of the device is improved. In some embodiments, the exciton barrier layer is adjacent to the light emitting layers on either the anode side and the cathode side, and on either side of the anode side. In some embodiments, when the exciton barrier layer is present on the anode side, the layer may be present between the hole transport layer and the light emitting layer and adjacent to the light emitting layer. In some embodiments, when the exciton barrier layer is present on the cathode side, the layer may be present between the light emitting layer and the cathode and adjacent to the light emitting layer. In some embodiments, a hole injection layer, an electron barrier layer or a similar layer resides between the anode and the exciton barrier layer adjacent to the light emitting layer on the anode side. In some embodiments, the hole injection layer, electron barrier layer, hole barrier layer or similar layer is present between the cathode and the exciton barrier layer adjacent to the light emitting layer on the cathode side. In some embodiments, the excited element barrier layer comprises an excited singlet energy and an excited triplet energy, at least one of which is higher than the excited singlet energy and the excited triplet energy of the light emitting material, respectively.

Hole transport layer:
The hole transport layer contains a hole transport material. In some embodiments, the hole transport layer is a single layer. In some embodiments, the hole transport layer has multiple layers.
In some embodiments, the hole transport material has one of the hole injection or transport properties and the electron barrier properties. In some embodiments, the hole transport material is an organic material. In some embodiments, the hole transport material is an inorganic material. Examples of known hole transport materials that can be used in the present invention are, but are not limited to, triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane inducers, pyrazoline derivatives, pyrazolones. Derivatives, phenylenediamine derivatives, allylamine derivatives, amino-substituted calcon derivatives, oxazole derivatives, styrylanthracene inducers, fluorenone derivatives, hydrazone derivatives, stilben derivatives, silazane derivatives, aniline copolymers and conductive polymer oligomers (particularly thiophene oligomers), or combinations thereof. Can be mentioned. In some embodiments, the hole transport material is selected from porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds. In some embodiments, the hole transport material is an aromatic tertiary amine compound. Specific examples of preferable compounds that can be used as hole transport materials are given below.

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

Further, examples of compounds preferable as materials that can be added to each organic layer are given. For example, it may be added as a stabilizing material.

Although preferred materials that can be used for organic electroluminescence devices have been specifically exemplified, the materials that can be used in the present invention are not limitedly interpreted by the following exemplified compounds. Further, even a compound exemplified as a material having a specific function can be diverted as a material having another function.

device:
In some embodiments, the light emitting layer is incorporated into the device. For example, devices include, but are not limited to, OLED valves, OLED lamps, television displays, computer monitors, mobile phones and tablets.
In some embodiments, the electronic device comprises an OLED having an anode, a cathode, and at least one organic layer comprising a light emitting layer between the anode and the cathode.
In some embodiments, the components described herein can be incorporated into a variety of photosensitive or photoactivating devices, such as OLEDs or optoelectronic devices. In some embodiments, the construct may be useful for facilitating charge transfer or energy transfer within the device and / or as a hole transport material. Examples of the device include an organic light emitting diode (OLED), an organic integrated line (OIC), an organic field effect transistor (O-FET), an organic thin film (O-TFT), an organic light emitting transistor (O-LET), and an organic solar cell. (O-SC), organic optical detectors, organic photoreceivers, organic field-quench devices (O-FQD), light emitting fuel cells (LECs) or organic laser diodes (O-lasers).

Bulb or lamp:
In some embodiments, the electronic device comprises an OLED comprising an anode, a cathode, and at least one organic layer comprising a light emitting layer between the anode and the cathode.
In some embodiments, the device comprises an OLED of different colors. In some embodiments, the device comprises an array containing a combination of OLEDs. In some embodiments, the combination of OLEDs is a combination of three colors (eg RGB). In some embodiments, the combination of OLEDs is a combination of colors that are neither red nor green nor blue (eg, orange and yellow-green). In some embodiments, the combination of OLEDs is a combination of two colors, four colors or more.
In some embodiments, the device is
A circuit board having a first surface with a mounting surface and a second surface opposite the mounting surface and defining at least one opening.
A configuration in which at least one OLED on the mounting surface, wherein the at least one OLED comprises an anode, a cathode, and at least one organic layer including a light emitting layer between the anode and the cathode. With at least one OLED that has
The housing for the circuit board and
An OLED light comprising at least one connector located at the end of the housing, wherein the housing and the connector define a package suitable for mounting in lighting equipment.
In some embodiments, the OLED light has a plurality of OLEDs mounted on a circuit board such that light is emitted in multiple directions. In some embodiments, some light emitted in the first direction is polarized and emitted in the second direction. In some embodiments, a reflector is used to polarize the light emitted in the first direction.

Display or screen:
In some embodiments, the light emitting layer of the present invention can be used in a screen or display. In some embodiments, the compounds according to the invention are deposited onto a substrate using steps such as, but not limited to, vacuum evaporation, deposition, vapor deposition or chemical vapor deposition (CVD). In some embodiments, the substrate is a photoplate structure useful in two-sided etching that provides pixels with a unique aspect ratio. The screen (also referred to as a mask) is used in the manufacturing process of an OLED display. The design of the corresponding artwork pattern allows the placement of very steep, narrow tie bars between pixels in the vertical direction, as well as large, wide-ranging bevel openings in the horizontal direction. This enables the fine pattern composition of pixels required for high resolution displays while optimizing chemical vapor deposition on the TFT backplane.
Pixel internal patterning makes it possible to construct 3D pixel openings with different aspect ratios in the horizontal and vertical directions. In addition, the use of imaged "stripe" or halftone circles in the pixel area protects the etching in the particular area until these particular patterns are undercut and removed from the substrate. At that time, all the pixel regions are processed at the same etching rate, but the depth varies depending on the halftone pattern. By changing the size and spacing of the halftone patterns, it is possible to etch with different protection rates within the pixel, allowing for the deep localized etching required to form steep vertical bevels. ..
The preferred material for the vapor deposition mask is Invar. Invar is a metal alloy that is cold-rolled in the form of a long thin sheet at a steel mill. Invar cannot be electrodeposited onto the spin mandrel as a nickel mask. A suitable and low-cost method for forming an opening region in a vapor deposition mask is a wet chemical etching method.
In some embodiments, the screen or display pattern is a pixel matrix on a substrate. In some embodiments, the screen or display pattern is processed using lithography (eg, photolithography and e-beam lithography). In some embodiments, the screen or display pattern is processed using wet chemical etching. In a further embodiment, the screen or display pattern is processed using plasma etching.

Device manufacturing method:
The OLED display is generally manufactured by forming a large mother panel and then cutting the mother panel in cell panel units. Normally, each cell panel on the mother panel forms a thin film transistor (TFT) having an active layer and a source / drain electrode on a base substrate, a flattening film is applied to the TFT, and a pixel electrode and a light emitting layer are applied. , The counter electrode and the encapsulating layer are formed in order over time, and are formed by cutting from the mother panel.
The OLED display is generally manufactured by forming a large mother panel and then cutting the mother panel in cell panel units. Normally, each cell panel on the mother panel forms a thin film transistor (TFT) having an active layer and a source / drain electrode on a base substrate, a flattening film is applied to the TFT, and a pixel electrode and a light emitting layer are applied. , The counter electrode and the encapsulating layer are formed in order over time, and are formed by cutting from the mother panel.

In another aspect of the invention, a method of manufacturing an organic light emitting diode (OLED) display is provided, wherein the method is:
The process of forming a barrier layer on the base substrate of the mother panel,
A step of forming a plurality of display units on a cell panel unit on the barrier layer,
A step of forming an encapsulation layer on each of the display units of the cell panel,
A step of applying an organic film to the interface portion between the cell panels is included.
In some embodiments, the barrier layer is, for example, an inorganic film formed of SiNx, the ends of the barrier layer being coated with an organic film formed of polyimide or acrylic. In some embodiments, the organic film helps the mother panel to be softly cut in cell panel units.
In some embodiments, the thin film transistor (TFT) layer comprises a light emitting layer, a gate electrode, and a source / drain electrode. Each of the plurality of display units may have a thin film transistor (TFT) layer, a flattening film formed on the TFT layer, and a light emitting unit formed on the flattened film, and the interface portion may have a light emitting unit. The applied organic film is formed of the same material as the flattening film, and is formed at the same time as the flattening film is formed. In some embodiments, the light emitting unit is coupled to the TFT layer by a passivation layer, a flattening film in between, and an encapsulating layer that coats and protects the light emitting unit. In some embodiments of the manufacturing method, the organic film is not coupled to either the display unit or the encapsulation layer.

Each of the organic film and the flattening film may contain either polyimide or acrylic. In some embodiments, the barrier layer may be an inorganic film. In some embodiments, the base substrate may be made of polyimide. The method further comprises a step of attaching a carrier substrate made of a glass material to the other surface of the base substrate before forming a barrier layer on one surface of the base substrate made of polyimide. It may include a step of separating the carrier substrate from the base substrate prior to cutting along the interface portion. In some embodiments, the OLED display is a flexible display.
In some embodiments, the passivation layer is an organic film placed on the TFT layer for coating the TFT layer. In some embodiments, the flattening film is an organic film formed on the passivation layer. In some embodiments, the flattening film is made of polyimide or acrylic, similar to the organic film formed at the ends of the barrier layer. In some embodiments, the flattening film and the organic film are formed simultaneously during the manufacture of the OLED display. In some embodiments, the organic film may be formed at the edges of the barrier layer, whereby a portion of the organic film is in direct contact with the base substrate and the rest of the organic film is removed. , Surrounding the edge of the barrier layer and in contact with the barrier layer.

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 a source / drain electrode in the TFT layer.
In some embodiments, when a voltage is applied to the pixel electrode through the TFT layer, an appropriate voltage is formed between the pixel electrode and the counter electrode so that the organic light emitting layer emits light, thereby the image. Is formed. Hereinafter, the image forming unit having the TFT layer and the light emitting unit will be referred to as a display unit.
In some embodiments, the encapsulation layer that covers the display unit and prevents the penetration of external moisture may be formed in a thin film encapsulation structure in which organic films and inorganic films are alternately laminated. In some embodiments, the encapsulation layer has a thin film encapsulation structure in which a plurality of thin films are laminated. In some embodiments, the organic film applied to the interface section is spaced apart from each of the plurality of display units. In some embodiments, the organic film is formed in such a manner that some of the organic films are in direct contact with the base substrate and the rest of the organic film surrounds the edges of the barrier layer while in contact with the barrier layer. Will be done.

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

In some embodiments, the manufacturing method further comprises the step of cutting along an interface portion, where a groove is formed in the barrier layer, at least a portion of the organic film is formed in the groove, and the groove is formed. Does not penetrate the base substrate. In some embodiments, a TFT layer of each cell panel is formed, and a passivation layer, which is an inorganic film, and a flattening film, which is an organic film, are placed on the TFT layer to cover the TFT layer. At the same time that a polyimide or acrylic flattening film is formed, for example, the groove of the interface portion is covered with an organic film made of polyimide or acrylic, for example. This prevents cracking by allowing the organic film to absorb the impact generated when each cell panel is cut along the groove at the interface section. That is, if all barrier layers are completely exposed without an organic film, there is a risk that when each cell panel is cut along the groove at the interface, the generated impact will be transmitted to the barrier layer, which will cause cracks. Will increase. However, in one embodiment, the groove of the interface portion between the barrier layers is covered with an organic film to absorb the impact that can be transmitted to the barrier layer without the organic film, so that each cell panel is softly cut and the barrier layer is used. It may be prevented from cracking. In one embodiment, the organic film and the flattening film covering the grooves of the interface portion are arranged at intervals from each other. For example, when the organic film and the flattening film are interconnected as one layer, external moisture may infiltrate into the display unit through the flattening film and the portion where the organic film remains. The organic film and the flattening film are spaced apart from each other so that the organic film is spaced apart from the display unit.

In some embodiments, the display unit is formed by the formation of a light emitting unit and the encapsulation layer is placed on the display unit to cover the display unit. As a result, after the mother panel is completely manufactured, the carrier base material that supports the base base material is separated from the base base material. In some embodiments, when the laser beam is radiated to the carrier substrate, the carrier substrate is separated from the base substrate due to the difference in thermal expansion rate between the carrier substrate and the base substrate.
In some embodiments, the mother panel is cut in cell panel units. In some embodiments, the mother panel is cut along the interface between the cell panels using a cutter. In some embodiments, the grooves in the interface section where the mother panel is cut are covered with an organic film so that the organic film absorbs the impact during cutting. In some embodiments, the barrier layer can be prevented from cracking during cutting.
In some embodiments, the method reduces the defective rate of the product and stabilizes its quality.
Another embodiment is a barrier layer formed on a base substrate, a display unit formed on the barrier layer, an encapsulating layer formed on the display unit, and an organic coating applied to the ends of the barrier layer. An OLED display with a film.

(Design method of luminescent composition)
The present application also provides a method for designing the composition of the present invention, which has a long emission life and excellent stability.
The method for designing a luminescent composition of the present invention includes the following steps 1 to 3.
[Step 1] Evaluation of luminous efficiency and lifetime of a composition containing a first organic compound, a second organic compound which is a delayed fluorescent material, a third organic compound, and a fourth organic compound and satisfying the conditions (a) and (b). death,
[Step 2] At least one of the first organic compound, the second organic compound which is a delayed fluorescent material, the third organic compound, and the fourth organic compound was replaced within the range satisfying the conditions (a) and (b). Evaluating the emission efficiency and lifetime of the composition was performed at least once.
[Step 3] Select the combination with the best result of the evaluated luminous efficiency and life.

The evaluation of the luminous efficiency and the lifetime may be made by actually causing the luminous composition to emit light, or may be evaluated by calculation. Further, the luminescent composition may be actually made to emit light and evaluated by using a calculation method. The evaluation is preferably performed from a comprehensive viewpoint using the high degree of practicality as an index. In the method for designing a luminescent composition of the present invention, the first organic compound, the second organic compound, the third organic compound and the fourth organic compound are selected and replaced within the range satisfying the conditions (a) and (b). Is required. Secondly, the organic compound needs to be selected from delayed fluorescent materials and substituted. Substitution of the compound in step 2 is preferably replaced with a compound that is likely to give a better evaluation. Step 2 may be performed, for example, 10 times or more, 100 times or more, 1000 times or more, and 10000 times or more.
The method for designing a luminescent composition of the present invention can be stored and used as a program. The program can be stored in a recording medium and can be transmitted and received by electronic means.

Hereinafter, the features of the present invention will be described in more detail with reference to examples. The materials, treatment contents, treatment procedures, etc. shown below can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limiting by the specific examples shown below. The emission characteristics are evaluated by a source meter (Caseley: 2400 series), a semiconductor parameter analyzer (Agilent Technology: E5273A), an optical power meter measuring device (Newport: 1930C), and an optical spectroscope. (Ocean Optics Co., Ltd .: USB2000), spectroradiometer (Topcon Co., Ltd .: SR-3) and streak camera (Hamamatsu Photonics Co., Ltd. C4334 type) were used. The lowest excited singlet energy _ES1 and the lowest excited triplet energy ET1 of the compounds used in the following Examples and Comparative Examples are as shown in the _table below.

(Example 1)
Each thin film was laminated with a vacuum degree of 1 × ^10-6 Pa on a glass substrate having an anode made of indium tin oxide (ITO) having a film thickness of 100 nm formed by a vacuum vapor deposition method. First, HATCN was formed on ITO to a thickness of 10 nm, NPD was formed on it to a thickness of 30 nm, and TrisPCz was further formed on it to a thickness of 10 nm. Next, compound H1 was formed to a thickness of 5 nm. Further, compound H1 (68.5% by weight), compound T13 (30% by weight), compound E1 (0.5% by weight) and compound Z1 (1% by weight) were co-deposited from different vapor deposition sources to a thickness of 30 nm. A light emitting layer was formed. Next, SF3TRZ was formed as a hole barrier layer having a thickness of 10 nm. Subsequently, SF3TRZ and Liq were co-deposited from different vapor deposition sources to form an electron transport layer having a thickness of 30 nm. At this time, SF3TRZ: Liq (weight ratio) was set to 7: 3. Further, Liq was formed to a thickness of 2 nm, and then aluminum (Al) was deposited to a thickness of 100 nm to form a cathode. As a result, the organic electroluminescence device of Example 1 was produced.

(Example 2)
Only the point that the concentration of the light emitting layer was changed to compound H1 (64.5% by weight), compound T13 (30% by weight), compound E1 (0.5% by weight) and compound Z1 (5% by weight) was changed. Made the organic electroluminescence element of Example 2 by the same procedure as in Example 1.

(Example 2, Comparative Examples 1 and 2)
The organic electroluminescence devices of Example 2, Comparative Example 1, and Comparative Example 2 were produced by the same procedure as in Example 1 except that the concentration of the light emitting layer was changed as shown in Table 2 below. ..

When each of the manufactured organic electroluminescence devices was energized, delayed fluorescent radiation derived from the third organic compound E1 was observed (both had a maximum emission wavelength of 471 nm). Since the organic electroluminescence device of Comparative Example 1 had low external quantum efficiency, other performances were not evaluated. On the other hand, LT95 of Comparative Example 2, Example 1 and Example 2 which showed significantly higher external quantum efficiency than Comparative Example 1 was measured at 2 mA / cm ² . As a result, it was confirmed that Example 1 had a life of 2.83 times longer than that of Comparative Example 2, and Example 2 had a life of 12.4 times longer than that of Comparative Example 2. It was also confirmed that increasing the concentration of compound Z1 further prolongs the life.

According to the present invention, it is possible to provide a stable organic light emitting device having a long life. Therefore, the present invention has high industrial applicability.

1 Base material 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Electron transport layer 7 Cathode

Claims (15)

An organic light emitting element having a light emitting layer containing a first organic compound, a second organic compound, a third organic compound, and a fourth organic compound satisfying the following conditions (a) and (b).
The second organic compound is a delayed fluorescent material.
An organic light emitting device, wherein the maximum component of light emission from the organic light emitting device is light emission from the third organic compound.
Conditions (a) E _S1 (1)> E _S1 (4)> E _S1 (2)> E _S1 (3)
Conditions (b) _ET1 (1)> _ET1 (2)> _ET1 (3)> _ET1 (4)
(In the above formula,
_ES1 (1) represents the lowest excited singlet energy of the first organic compound.
_ES1 (2) represents the lowest excited singlet energy of the second organic compound.
_ES1 (3) represents the lowest excited singlet energy of the third organic compound.
_ES1 (4) represents the lowest excited singlet energy of the fourth organic compound.
_ET1 (1) represents the lowest excited triplet energy of the first organic compound.
_ET1 (2) represents the lowest excited triplet energy of the second organic compound.
_ET1 (3) represents the lowest excited triplet energy of the third organic compound.
_ET1 (4) represents the lowest excited triplet energy of the fourth organic compound. ) The organic light emitting device according to claim 1, further satisfying the following condition (c).
Conditions (c) Conc (1)> Conc (2)> Conc (4)
(In the above formula,
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 (4) represents the concentration of the fourth organic compound in the light emitting layer. ) The organic light emitting device according to claim 2, further satisfying the following condition (c1).
Conditions (c1) Conc (1)> Conc (2)> Conc (4)> Conc (3)
(In the above formula, Conc (3) represents the concentration of the third organic compound in the light emitting layer.) The organic light emitting device according to claim 2 or 3, further satisfying the following condition (d).
Condition (d) Conc (2) / Conc (3)> 5
(In the above formula, Conc (3) represents the concentration of the third organic compound in the light emitting layer.) The organic light emitting device according to any one of claims 2 to 4, further satisfying the following condition (e).
Condition (e) Conc (4) / Conc (3)> 1.5
(In the above formula, Conc (3) represents the concentration of the third organic compound in the light emitting layer.) The organic light emitting device according to any one of claims 1 to 5, further satisfying the following condition (f).
Condition (f) Conc (4) ≤ 5% by weight
(In the above formula, Conc (4) represents the concentration of the fourth organic compound in the light emitting layer.) The organic light emitting device according to any one of claims 1 to 6, further satisfying the following condition (g).
Conditions (g) Conc (3) ≤ 1% by weight
(In the above formula, Conc (3) represents the concentration of the third organic compound in the light emitting layer.) The organic emission according to any one of claims 1 to 7, wherein the second organic compound has an energy difference _ΔEst between the lowest excited singlet state and the lowest excited triplet state of 77K of 0.3 eV or less. element. The organic emission according to any one of claims 1 to 8, wherein the third organic compound has an energy difference _ΔEst between the lowest excited singlet state and the lowest excited triplet state of 77K of 0.3 eV or less. element. The invention according to any one of claims 1 to 9, wherein the light emitting layer is composed only of a compound consisting of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, a boron atom, an oxygen atom and a sulfur atom. The organic light emitting element described. Claims 1 to 10 wherein the first organic compound, the second organic compound, and the fourth organic compound are each independently composed of an atom selected from the group consisting of a carbon atom, a hydrogen atom, and a nitrogen atom. The organic light emitting element according to any one of the above items. The organic light emitting device according to any one of claims 1 to 11, wherein the fourth organic compound is a compound composed of only a carbon atom and a hydrogen atom. The organic light emitting device according to any one of claims 1 to 12, wherein the second organic compound contains a cyanobenzene structure. [Step 1] Luminous efficiency and lifetime of a composition containing a first organic compound, a second organic compound which is a delayed fluorescent material, a third organic compound, and a fourth organic compound and satisfying the following conditions (a) and (b). Evaluate and
[Step 2] At least one of the first organic compound, the second organic compound which is a delayed fluorescent material, the third organic compound, and the fourth organic compound is replaced within the range satisfying the following conditions (a) and (b). Evaluating the emission efficiency and lifetime of the composition was performed at least once.
[Step 3] Select the combination with the best results of the evaluated luminous efficiency and life.
A method for designing a luminescent composition, which comprises each step.
Conditions (a) E _S1 (1)> E _S1 (4)> E _S1 (2)> E _S1 (3)
Conditions (b) _ET1 (1)> _ET1 (2)> _ET1 (3)> _ET1 (4)
(In the above formula,
_ES1 (1) represents the lowest excited singlet energy of the first organic compound.
_ES1 (2) represents the lowest excited singlet energy of the second organic compound.
_ES1 (3) represents the lowest excited singlet energy of the third organic compound.
_ES1 (4) represents the lowest excited singlet energy of the fourth organic compound.
_ET1 (1) represents the lowest excited triplet energy of the first organic compound.
_ET1 (2) represents the lowest excited triplet energy of the second organic compound.
_ET1 (3) represents the lowest excited triplet energy of the third organic compound.
_ET1 (4) represents the lowest excited triplet energy of the fourth organic compound. ) A program that implements the method of claim 14.

Images