Luminescent layer composition, organic electroluminescent device and display panel

Abstract

The invention belongs to the technical field of organic electroluminescence, and particularly relates to a luminescent layer composition, an organic electroluminescent device and a display panel. The light-emitting layer combination comprises a first main body material composed of a hole-type main body material containing a carbazole structure and an electronic main body material containing a triazine structure, a second main body material containing an iridium or platinum phosphorescent material and a light-emitting material containing a boron organic resonance thermal activation delayed fluorescent material. According to the luminescent layer composition disclosed by the invention, the electroluminescent external quantum efficiency of the organic electroluminescent device under the brightness of 5000 cd / m < 2 > can be up to 25% or above while the organic electroluminescent device realizes narrow-band emission, and the service life of the device T90 under the brightness of 1000 cd / m < 2 > is 5000 h or above.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic electroluminescence, and in particular relates to a luminescent layer composition, an organic electroluminescent device and a display panel. Background Art

[0002] Organic optoelectronic materials are a type of organic materials that have the properties of generating, converting and transmitting photons and electrons. At present, the controllable optoelectronic properties of organic optoelectronic materials have been applied to organic light-emitting diodes (OLED), organic solar cells (OPV), organic field effect transistors (OFET), and even organic lasers. In recent years, OLED has become a very popular new type of flat-panel display product at home and abroad. OLED displays have the characteristics of self-luminescence, wide viewing angle, short response time, high luminous efficiency, wide color gamut, low operating voltage, thin panel, large-size flexible panel and low cost, and are known as the star flat-panel display product of the 21st century.

[0003] In 1987, CW Tang et al. of Kodak Company in the United States used ultra-thin film technology to prepare a light-emitting device with aromatic amines with good hole transport effect as the hole transport layer, 8-hydroxyquinoline aluminum complex as the light-emitting layer, indium tin oxide (ITO) film and metal alloy as the anode and cathode respectively. The device achieved a brightness of up to 1000 cd / m at a driving voltage of 10 V. 2The green light emission of the device is 1.5lm / W. This breakthrough has led to a rapid and in-depth development of organic electroluminescence research around the world. Organic electroluminescent materials have a decisive influence on the performance of display devices and terminal products. In 2012, the Adachi research group of Kyushu University reported a highly efficient all-fluorescent OLED device based on the thermally activated delayed fluorescence (TADF) mechanism. The triplet exciton can absorb thermal energy, return to the singlet state through the RISC process, and then emit fluorescence. The internal quantum efficiency (IQE) of the device can theoretically reach 100%, and the external quantum efficiency (EQE) can even reach 30%, which is comparable to the level of phosphorescent devices. As the next generation of luminescent materials, the research on TADF materials is in the ascendant. However, TADF molecules are mainly doped as guest materials in wide bandgap host materials to achieve high-efficiency thermally activated delayed fluorescence. Unlike the localized (LE) state luminescence of traditional fluorescent molecules, TADF emission mainly originates from the transition of the ICT state, so it is easily affected by the vibrational and rotational motion between the donor and the acceptor, resulting in low electroluminescence efficiency and poor stability. In addition, ultra-high-definition display technology has higher requirements for the emission spectrum of TAD F materials. TADF materials based on multiple resonances can achieve narrow spectrum emission characteristics, but due to their unbalanced carrier migration and long excited state lifetime, their electroluminescent devices have low efficiency at high brightness and poor device stability, which cannot meet the needs of industrial applications. Therefore, how to use multiple resonance TADF materials to maintain their narrow spectrum emission while improving their device performance still needs to be further improved. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the prior art. The first aspect of the present invention is to provide a light-emitting layer composition for an organic electroluminescent device, comprising a first host material, a second host material and a light-emitting material. The first host material comprises a host material A and a host material B. The host material A is a hole-type host material containing a carbazole structure, the host material B is an electronic-type host material containing a triazine structure, the second host material is a phosphorescent material containing iridium or platinum, and the light-emitting material is a boron-containing organic resonance thermally activated delayed fluorescent material.

[0005] The present invention realizes that the electroluminescent device maintains a high electroluminescent external quantum efficiency and a long device life at high brightness through the above scheme. Wherein the main body A is a main material with strong hole transport performance, and the main body B has a main material with strong electron transport performance. By doping the main body A with the main body B in any proportion, the balance of carrier migration in the light-emitting layer can be maximized, thereby improving the exciton utilization efficiency and improving the device performance. In addition, in addition to the strong electron transport performance of the triazine structure, its LUMO energy level is equivalent to the work function of the traditional cathode material (LiQ / Al), which is conducive to the injection of electrons, which is of great significance for balancing carrier transport, reducing the driving voltage, and improving the device efficiency and device stability. The terminal luminescent material boron-containing organic resonance thermal activation delayed fluorescent material is easy to cause the exciton quenching effect under the high driving current density of the device due to its long excited state life, thereby increasing the efficiency roll-off, which is not conducive to the realization of the long life of the device. In the present invention, by introducing a phosphorescent material containing iridium or platinum as the second host material, when triplet excitons are transferred to the luminescent material (boron-containing organic resonance thermally activated delayed fluorescence material) through the second host material, the singlet exciton density in the device is increased, the proportion of delayed fluorescence is increased, and the quenching effect of high-density triplet excitons on the luminescent material is avoided, thereby reducing the efficiency roll-off of the device under high driving current and improving the device stability.

[0006] Wherein, the structure of the main material A is shown in Formula I:

[0007]

[0008] R1 and R2 are independently selected from one of aryl, heteroaryl, biaryl, aromatic amine substituted aryl, aromatic amine substituted heteroaryl, and aromatic amine substituted biaryl; R2 can form a ring with the connected structure. Preferably, the host material A is one of compounds A1-A80;

[0009]

[0010]

[0011]

[0012]

[0013] Wherein, the structure of the main material B is shown in Formula II:

[0014]

[0015] R3, R4 and R5 are independently selected from one of aryl, heteroaryl, biaryl, aromatic amine substituted aryl, aromatic amine substituted heteroaryl, and aromatic amine substituted biaryl. Preferably, the host material B is one of compounds B1-B258;

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025] The structure of the second host material is shown in Formula III, Formula IV or Formula V:

[0026]

[0027] Among them, R ri (i=1-30) is independently selected from hydrogen, deuterium, C1-C18 alkyl, C6-C18 aryl; X is one of O, S, N-Ph. Preferably, the second host material is one of compounds Ir-1 to Ir-16, Pt-1 to Pt-16;

[0028]

[0029]

[0030] The structure of the luminescent material is shown in Formula VI:

[0031]

[0032] Among them, R r31 and R r32 is independently selected from one of hydrogen, deuterium, C1-C18 alkyl, C6-C18 aryl, and C6-C18 arylamine; Cy1 and Cy2 are independently selected from C6-C30 aromatic groups; R r31 and R r32can independently form a ring with the connected benzene ring. Preferably, the luminescent material is one of compounds BN-1 to BN-28;

[0033]

[0034]

[0035]

[0036] In the above-mentioned light-emitting layer composition, the mass ratio of the host material A to the host material B is (1-10): (1-10). The mass ratio of the first host material, the second host material and the light-emitting material is (60-96.9): (3-30): (0.1-10).

[0037] The second aspect of the present invention provides an organic electroluminescent device, which includes the above-mentioned luminescent layer composition. The organic electroluminescent device specifically includes an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a luminescent layer, a hole blocking layer, an electron transport layer, an electron input layer and a cathode; the luminescent layer includes the above-mentioned luminescent layer composition. The organic electroluminescent device can be prepared by vacuum evaporation or solution method (spin coating or inkjet printing, etc.).

[0038] A third aspect of the present invention provides a display panel (or lighting) panel, comprising the above-mentioned light-emitting layer composition, or comprising the above-mentioned organic electroluminescent device.

[0039] The beneficial effects of the present invention are as follows: the luminescent layer composition of the present invention can enable the organic electroluminescent device to achieve narrow-band emission while enabling the device to have a brightness of 5000 cd / m 2 The external quantum efficiency of electroluminescence at brightness is as high as 25%, 1000cd / m 2 Device T under brightness 90 The service life is more than 5000h. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The figure shows a schematic diagram of the structure of an organic electroluminescent device; wherein 1 is an ITO anode, 2 is a first hole transport layer, 3 is a second hole transport layer, 4 is a light-emitting layer, 5 is a first electron transport layer, 6 is a second electron transport layer, 7 is an electron injection layer, and 8 is a metal cathode;

[0041] Figure 2 Shown is the electroluminescence spectrum of device embodiment 1-1;

[0042] Figure 3 Shown is a brightness-electroluminescence external quantum efficiency curve of device embodiment 1-1. DETAILED DESCRIPTION

[0043] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention, so as to fully understand the purpose, scheme and effect of the present invention. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0044] The compounds of the present invention may contain non-natural ratios of atomic isotopes on one or more atoms constituting the compounds. For example, radioactive isotope labeled compounds may be used, such as deuterium (2H). The conversion of all isotopic compositions of the compounds of the present invention, whether radioactive or not, is included within the scope of the present invention.

[0045] In the present invention, unless otherwise specified, the number of "substituted" can be one or more; when it is multiple, it means more than two, for example, it can be 2, 3 or 4. In addition, when the number of "substituted" is multiple, the "substituted" can be the same or different. In the present invention, the position of "substituted" can be any position unless otherwise specified.

[0046] In the present invention, as a group or part of other groups (for example, in groups such as halogen-substituted alkyl), the term "alkyl" means a saturated aliphatic hydrocarbon group including branched and straight chains with a specified number of carbon atoms. For example, C1-C20 alkyl includes straight or branched alkyl groups with 1-20 carbon atoms. As defined in "C1-C20 alkyl", groups including 1, 2, 3, 4, 5, or 6 carbon atoms in a straight or branched structure are included. For example, in the present invention, the C1-C20 alkyl groups are each independently methyl, ethyl, propyl, butyl, pentyl or hexyl; wherein the propyl group is a C3 alkyl group (including isomers, such as n-propyl or isopropyl); the butyl group is a C4 alkyl group (including isomers, such as n-butyl, sec-butyl, isobutyl or tert-butyl); the pentyl group is a C5 alkyl group (including isomers, such as n-pentyl, 1-methyl-butyl, 1-ethyl-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, isopentyl, tert-pentyl or neopentyl); and the hexyl group is a C6 alkyl group (including isomers, such as n-hexyl or isohexyl).

[0047] In the present invention, as a group or part of other groups, the term "Cn-m aryl" refers to a monocyclic or polycyclic aromatic group having n to m ring carbon atoms (ring atoms are only carbon atoms), which has at least one carbon ring with a conjugated π electron system. Examples of the above-mentioned aryl units include phenyl, naphthyl, indenyl, azulenyl, fluorenyl, phenanthrenyl, or anthracenyl. In one embodiment, the aryl is preferably a C6-14 aryl, such as phenyl and naphthyl, more preferably phenyl.

[0048] In the present invention, as a group or part of other groups, the term "nm-membered heteroaryl" refers to an aromatic group whose ring atoms contain one or more (e.g., 1, 2, 3, and 4) heteroatoms selected from nitrogen, oxygen, and sulfur, and whose ring atoms are n to m, and the heteroaryl is a monocyclic, bicyclic, tricyclic, or tetracyclic ring system, wherein at least one ring is an aromatic ring. The heteroaryl groups within the scope of this definition include, but are not limited to, acridinyl, carbazolyl, cinnolinyl, quinoxalinyl, pyrazolyl, indolyl, benzotriazolyl, furanyl, thienyl, benzothienyl, benzofuranyl, quinolyl, isoquinolyl, oxazolyl, isoxazolyl, pyrazinyl, pyridazinyl, pyridinyl, pyrimidinyl, pyrrolyl, tetrahydroquinoline, imidazolyl, triazolyl, tetrazolyl, thiazolyl, isothiazolyl, furazanyl, thiadiazolyl, oxadiazolyl, pyridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, triazinyl, purinyl, pteridinyl, naphthyridinyl, quinazolinyl, phthalazinyl, imidazopyridinyl, imidazothiazolyl, imidazooxazolyl, benzothiazolyl, benzoxazolyl, benzimidazolyl, isoindolyl, indazolyl, pyrrolopyridinyl, thienopyridinyl, furopyridinyl, benzothiadiazolyl, benzoxadiazolyl, pyrrolopyrimidinyl, thienofuranyl. In one embodiment, as preferred examples of the “5-18 membered heteroaryl”, furanyl, thienyl, pyrrolyl, imidazolyl, thiazolyl, pyrazolyl, oxazolyl, isoxazolyl, isothiazolyl, pyridinyl, pyrimidinyl and carbazolyl can be cited, and carbazolyl is more preferred.

[0049] Example

[0050] Compounds A1-A80 are shown below:

[0051]

[0052]

[0053]

[0054] Compounds B1-B258 are shown below:

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064] Compounds Ir-1 to Ir-16, Pt-1 to Pt-16 are shown below:

[0065]

[0066]

[0067] Compounds BN-1 to BN-28 are shown below:

[0068]

[0069]

[0070] Some compounds A1-A80 are selected as the main material A, some compounds B1-B220 are selected as the main material B, some compounds Ir-1 to Ir-16 and Pt-1 to Pt-16 are selected as the second main material, and some BN-1 to BN-28 are selected as luminescent materials to form a luminescent layer composition (the main material is doped with the luminescent material, and the doping concentration is 1wt%), and its specific composition is shown in Table 1.

[0071] The above-mentioned light-emitting layer composition is then used as a light-emitting layer of an organic electroluminescent device. Figure 1 As shown, it includes: an ITO anode 1, a first hole transport layer 2, a second hole transport layer 3, a light-emitting layer 4 formed by the light-emitting layer composition shown in Table 1, a first electron transport layer 5, a second electron transport layer 6, an electron injection layer 7, and a metal cathode 8.

[0072] The preparation process of the above device is as follows:

[0073] (1) Substrate treatment: Transparent ITO glass is used as the substrate material for the preparation of the device. It is first ultrasonically treated with 5% ITO washing solution for 30 minutes, then ultrasonically washed with distilled water (2 times), acetone (2 times), and isopropanol (2 times) in sequence, and finally the ITO glass is stored in isopropanol. Before each use, the surface of the ITO glass is carefully wiped with acetone cotton balls and isopropanol cotton balls, rinsed with isopropanol and dried, and then treated with plasma for 5 minutes for use. The preparation of the device is completed by combining spin coating and vacuum evaporation process.

[0074] (2) Preparation of hole injection layer and hole transport layer: The hole transport layer was prepared by evaporation process. When the vacuum degree of the vacuum evaporation system reached 5×10 -4When the temperature is below Pa, the evaporation begins. The deposition rate is measured by the CENS film thickness instrument. The organic hole transport layer is deposited on the surface of the ITO electrode in sequence using a vacuum evaporation process. The deposition rate of the hole transport material is

[0075] (3) Preparation of the luminescent layer: The luminescent layer was prepared by evaporation process. When the vacuum degree of the vacuum evaporation system reached 5×10 - 4 Pa, the deposition rate was measured by the CENS film thickness instrument. The light-emitting layer was deposited on the hole transport layer in sequence using a vacuum evaporation process. The deposition rate of the light-emitting layer material was

[0076] (4) Preparation of electron transport layer, electron injection layer and metal electrode: The electron transport layer, electron injection layer and metal electrode are prepared by evaporation process. When the vacuum degree of vacuum evaporation system reaches 5×10 -4 When the thickness is below 100 Pa, the deposition rate is measured by a film thickness meter. The organic electron transport layer, the LiF electron injection layer and the metal Al electrode are sequentially deposited on the light-emitting layer using a vacuum deposition process (see the following effect example for the specific device structure). The deposition rate of the organic material is The deposition rate of LiF is The deposition rate of Al is

[0077] Among them, HTL-1 doped with HATCN is used as the first hole transport layer, HTL-2 is used as the second hole transport layer, ETL-1 is used as the first electron transport layer, ETL-2 is used as the second electron transport layer, LiF is used as the electron injection layer, and Al is used as the metal cathode. The structure of the organic electroluminescent device of the effect embodiment is [ITO / 15wt%HATCN+85wt%HTL-1(100nm) / HTL-2(10nm) / 47wt%first host material A+47wt%first host material B+5wt%second host material+1wt%luminescent material(30nm) / ETL-1(10nm) / ETL-2(30nm)LiF(1nm) / Al(100nm)].

[0078]

[0079] The performance data of the organic electroluminescent devices of various effect examples are shown in Table 1.

[0080] Table 1

[0081]

[0082]

[0083] The device's current, voltage, brightness, luminescence spectrum and other characteristics were tested synchronously using a Photo Research PR 655 spectral scanning luminance meter and a Keithley K 2400 digital source meter system. The device performance test was carried out at room temperature and in ambient atmosphere. The device's external quantum efficiency (EQE) was calculated from the current density, brightness and electroluminescent spectrum combined with the visual function under the condition of Lambertian luminescence distribution. The device lifetime (T 90 , hours) refers to the initial brightness of 1000cd / m 2 The time required for the device's brightness to drop to 90% of its initial brightness in constant current drive mode.

[0084] Figure 2 Shown is the electroluminescence spectrum of device embodiment 1-1, with an emission peak at 522 nm and a half-peak width of 44 nm.

[0085] Figure 3 The figure shows the brightness-electroluminescence external quantum efficiency curve of device embodiment 1-1. The maximum external quantum efficiency is 27.6% at 5000 cd / m 2 The external quantum efficiency at brightness is 26.5%.

[0086] Comparative Example

[0087] The material structure used for comparison is shown in the figure below:

[0088]

[0089] The electroluminescent device was prepared by the same method as in the embodiment, wherein HTL-1 doped with HATCN was used as the first hole transport layer, HTL-2 was used as the second hole transport layer, ETL-2 was used as the first electron transport layer, ETL-1 was used as the second electron transport layer, LiF was used as the electron injection layer, and Al was used as the metal cathode. The structure of the organic electroluminescent device in the effect embodiment is [ITO / 15wt%HATCN+85wt%HTL-1(100nm) / HTL-2(10nm) / luminescent layer(30nm) / ETL-2(10nm) / ETL-1(30nm)LiF(1nm) / Al(100nm)].

[0090] The composition of the D-1 light-emitting layer is: 99% first host A1: 1% BN-1.

[0091] The composition of the D-2 light-emitting layer is: 99% first host B2: 1% BN-2.

[0092] The composition of the D-3 light-emitting layer is: 49.5% first host A1: 49.5% first host B3: 1% BN-3.

[0093] The composition of the D-4 light-emitting layer is: 94% first host A4: 5% Ir-4: 1% BN-4.

[0094] The composition of the D-5 light-emitting layer is: 94% first host B1: 5% Ir-5: 1% BN-5.

[0095] The composition of the D-6 light-emitting layer is: 94% first host A6: 5% Pt-6: 1% BN-6.

[0096] The composition of the D-7 light-emitting layer is: 94% first host B3: 5% Pt-8: 1% BN-7.

[0097] The composition of the D-8 light-emitting layer is: 49.5% first host A8: 49.5% first host B4: 1% BN-8.

[0098] The composition of the D-9 light-emitting layer is: 49.5% first host A9: 49.5% first host B5: 1% BN-9.

[0099] The composition of the D-10 light-emitting layer is: 49.5% first host A10: 49.5% first host B6: 1% BN-10.

[0100] The composition of the D-11 light-emitting layer is: 47.0% first host A1: 47.0% TPBi: 5% Ir-4: 1% BN-3.

[0101] The composition of the light-emitting layer of D-12 is: 47.0% first host A1: 47.0% TmPyPb: 5% Ir-4: 1% BN-3.

[0102] The composition of the light-emitting layer of D-13 is: 47.0% first host A1: 47.0% T2T: 5% Ir-4: 1% BN-3.

[0103] The composition of the light-emitting layer of D-14 is: 47.0% first host A1: 47.0% B3PyMPM: 5% Ir-4: 1% BN-3.

[0104] The composition of the light-emitting layer of D-15 is: 47.0% first host A1: 47.0% B3PyCzPm: 5% Ir-4: 1% BN-3.

[0105] The performance data of the organic electroluminescent devices of various comparative examples are shown in Table 2.

[0106] Table 2

[0107]

[0108] The device's current, voltage, brightness, luminescence spectrum and other characteristics were tested synchronously using a Photo Research PR 655 spectral scanning luminance meter and a Keithley K 2400 digital source meter system. The device performance test was carried out at room temperature and in ambient atmosphere. The device's external quantum efficiency (EQE) was calculated from the current density, brightness and electroluminescent spectrum combined with the visual function under the condition of Lambertian luminescence distribution. The device lifetime (T 90 , hours) refers to the initial brightness of 1000cd / m 2 The time required for the device's brightness to drop to 90% of its initial brightness under constant current drive mode.

[0109] Based on Table 1 and Table 2, it can be seen that the organic electroluminescent device of the present invention exhibits obvious technical advantages, namely high brightness (5000 cd / m 2 ) maintains an external quantum efficiency of more than 25% and at 1000cd / m 2 The device lifespan under the constant current test at the initial brightness is more than 5000 hours, especially device embodiments 1-18, 1-24, 1-28, 1-47, 1-61, and 1-80, which are all more than 5600 hours.

[0110] The above is only a preferred embodiment of the present invention. The present invention is not limited to the above implementation. As long as the technical effect of the present invention is achieved by the same means, it should belong to the protection scope of the present invention. Within the protection scope of the present invention, its technical scheme and / or implementation method can have various modifications and changes.

Claims

1. A light-emitting layer composition, characterized in that: It includes a first host material, a second host material and a luminescent material, wherein the first host material includes a host material A and a host material B, wherein the host material A is a hole-type host material containing a carbazole structure, and the host material B is an electronic-type host material containing a triazine structure, and the second host material is a phosphorescent material containing iridium or platinum, and the luminescent material is a boron-containing organic resonance thermally activated delayed fluorescent material.

2. The light-emitting layer composition according to claim 1, characterized in that The structure of the main material A is shown in Formula I: R1 and R2 are independently selected from one of aryl, heteroaryl, biaryl, aromatic amine substituted aryl, aromatic amine substituted heteroaryl, and aromatic amine substituted biaryl; preferably, the host material A is one of compounds A1-A80; 3. The light-emitting layer composition according to claim 1, characterized in that The structure of the main material B is shown in Formula II: R3, R4 and R5 are independently selected from one of aryl, heteroaryl, biaryl, aromatic amine substituted aryl, aromatic amine substituted heteroaryl, and aromatic amine substituted biaryl; preferably, the host material B is one of compounds B1-B258; 4. The light-emitting layer composition according to claim 1, characterized in that The structure of the second host material is shown in Formula III, Formula IV or Formula V: Among them, R ri (i=1-30) is independently selected from one of hydrogen, deuterium, C1-C18 alkyl, and C6-C18 aryl; X is one of O, S, and N-Ph; preferably, the second host material is one of compounds Ir-1 to Ir-16 and Pt-1 to Pt-16; 5. The light-emitting layer composition according to claim 1, characterized in that The structure of the luminescent material is shown in Formula VI: Among them, R r31 and R r32 is independently selected from one of hydrogen, deuterium, C1-C18 alkyl, C6-C18 aryl, and C6-C18 arylamine; Cy1 and Cy2 are independently selected from aromatic groups of C6-C30; preferably, the luminescent material is one of compounds BN-1 to BN-28; 6. The light-emitting layer composition according to any one of claims 1 to 5, characterized in that: The mass ratio of the main material A to the main material B is (1-10): (1-10).

7. The light-emitting layer composition according to any one of claims 1 to 5, characterized in that: The mass ratio of the first host material, the second host material and the luminescent material is (60-96.9): (3-30): (0.1-10).

8. An organic electroluminescent device, characterized in that: The light-emitting layer composition comprises the light-emitting layer composition according to any one of claims 1 to 7.

9. The organic electroluminescent device according to claim 8, characterized in that: The invention comprises an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron input layer and a cathode; the light-emitting layer comprises the light-emitting layer composition according to any one of claims 1 to 7.

10. A display panel, characterized in that: The light-emitting layer composition according to any one of claims 1 to 7, or the organic electroluminescent device according to claim 8 or 9.

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