A compound containing a carbazole ring structure and its application

Abstract

The invention discloses a compound containing a carbazole ring structure and its application, belonging to the field of semiconductor technology. The structure of the compound containing a carbazole ring structure of the invention is shown in the general formula (1), the middle of the compound of the invention is bridged by biphenyl or terphenyl, and the carbazole ring is dispersedly connected to the biphenyl or terphenyl in a specific way, and the density of each carbazole ring connection is higher, so that the compound of the invention has excellent hole migration ability, and the rigidity of the molecule is improved by an asymmetric connection mode, so that this type of structure has a higher glass transition temperature, excellent film phase stability and excellent high temperature weather resistance, and is applied to an organic electroluminescent device, having a strong hole injection and transmission ability and a suitable energy level; it can achieve high-efficiency luminescence of the organic electroluminescent device at a low driving voltage and extend the device life.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, in particular to a compound containing a carbazole ring structure and an organic electroluminescent device containing the compound. Background Art

[0002] The carriers (holes and electrons) in an organic electroluminescent device (OLED) are injected into the device by the two electrodes of the device under the drive of an electric field, and meet in the organic light-emitting layer to recombine and emit light. High-performance organic electroluminescent devices require various organic functional materials to have good photoelectric properties. For example, as a charge transport material, it is required to have good carrier mobility. The injection and transport properties of the hole transport layer and electron blocking layer materials used in existing organic electroluminescent devices are relatively weak, and the hole injection and transport rates do not match the electron injection and transport rates, resulting in a large offset in the recombination area, which is not conducive to the stability of the device. In addition, the reasonable energy level matching of the hole transport layer material and the electron blocking material is an important factor in improving the efficiency and life of the device. Therefore, how to adjust the balance of holes and electrons and adjust the recombination area has always been an important topic in this field.

[0003] Blue organic electroluminescent devices have always been the weak point in the development of full-color OLEDs. Up to now, the efficiency and life of blue light devices have been difficult to be comprehensively improved. Therefore, how to improve the performance of such devices is still a crucial issue and challenge facing this field. Most of the blue light host materials currently used in the market are electron-biased hosts. Therefore, in order to adjust the carrier balance of the light-emitting layer, the electron blocking material needs to have excellent hole transport performance. The better the hole injection and transport, the more the recombination area will be adjusted to shift away from the electron blocking layer, thereby emitting light away from the interface, improving the device performance and increasing the life. Therefore, the electron blocking area material is required to have high hole injectivity, high hole mobility, high electron blocking property and high hole tolerance.

[0004] The heat resistance and amorphous nature of electron blocking materials have a crucial impact on the life of the device. Materials with poor heat resistance are prone to decomposition during the evaporation process, polluting the evaporation cavity and damaging the life of the device; materials with poor film phase stability will crystallize during the use of the device, reducing the service life of the device. Therefore, the electron blocking material is required to have high film phase stability and decomposition temperature during use. In addition, since the triplet energy level of the guest luminescent material in the green organic electroluminescent device is 2.3~2.4eV, the triplet energy level of the hole-type host material matched with it is required to be greater than 2.5eV to effectively prevent the triplet energy from being transmitted back to the host material and dissipated; and the triplet energy level of the matching electron blocking material must be greater than 2.5eV to effectively prevent the triplet energy from diffusing and dissipating.

[0005] The main material of the green organic electroluminescent device adopts a dual main material combination, that is, the first main material and the second main material form a main material in a certain proportion, wherein the first main material is a hole transport material, and the second main material is an electron transport material. The main material formed by the dual main material combination can transmit both holes and electrons, which can effectively reduce the device driving voltage, improve the electron-hole recombination efficiency, and inhibit triplet exciton quenching, thereby effectively improving the device efficiency and life. Furthermore, the main material has both hole tolerance and electron tolerance, so that the main material has good redox stability, effectively improving the device life.

[0006] Therefore, the electron blocking material and the hole-type host material are required to have high film phase stability and decomposition temperature, high triplet energy level, good hole tolerance and electron blocking ability during use. However, the development of materials for stable and effective organic material layers for organic electroluminescent devices has not yet been fully realized. Therefore, it is necessary to continuously develop a new material to better meet the performance requirements of organic electroluminescent devices. Summary of the invention

[0007] In view of the above problems existing in the prior art, the applicant of the present invention provides a compound containing a carbazole ring structure, wherein the compound of the present invention is bridged by biphenyl or terphenyl in the middle, and the compound has a higher triplet energy level, excellent hole transport ability, lower evaporation stability, good film phase stability and excellent hole tolerance. By using the compound to form an electron blocking material or a hole-type host material of an organic electroluminescent device, the device can simultaneously obtain the effects of improving efficiency, reducing driving voltage and extending life.

[0008] The technical solution of the present invention is as follows:

[0009] A compound containing a carbazole ring structure, wherein the compound structure is shown in the general formula (1):

[0010]

[0011] In the general formula (1), R1 and R2 are independently hydrogen atoms, phenyl groups or biphenyl groups; L1 is a structure represented by the general formula (3), the general formula (4) or the general formula (5);

[0012] R3 and R4 are independently hydrogen atoms, phenyl groups, biphenyl groups or structures represented by general formula (2); M1 and M2 are respectively cyclically bonded with *1 and *2, *2 and *3, *3 and *4, *5 and *6, *6 and *7 or *7 and *8;

[0013] X1 is represented by one of O, S, CRaRb, and N-Rc, and Ra and Rb are independently represented by C1-C10 Alkyl, substituted or unsubstituted C6-C 30 One of the aromatic groups; Ra and Rb may also be connected to form a ring through a single bond; Rc represents a phenyl group or a biphenyl group;

[0014] When R3 and R4 are not represented by the general formula (2), L1 is represented by the structure shown in the general formula (5);

[0015] When only one of R3 and R4 is represented by the structure shown in the general formula (2), the general formula (2) is cyclically connected with *1 and *2 or *5 and *6, and L1 is represented by the general formula (3), at least one of R1 and R2 is not hydrogen.

[0016] In a preferred embodiment, the compound structure is shown in any one of general formulas (6) to (8):

[0017]

[0018] In the general formulae (6) to (8), R1, R2, R3, and R4 have the same definitions as above.

[0019] More preferably, the compound structure is as shown in any one of general formula (9) to general formula (17):

[0020]

[0021]

[0022] R1, R2, R3, and R4 are independently represented by hydrogen atom, phenyl or biphenyl; X1 is represented by one of O, S, CRaRb, and N-Rc; Ra and Rb are independently represented by C1-C 10 Alkyl, substituted or unsubstituted C6-C 30 One of the aromatic groups; Ra and Rb can also be connected to form a ring through a single bond; Rc represents a phenyl group or a biphenyl group.

[0023] In a preferred embodiment, Ra and Rb are independently represented by methyl, phenyl,

[0024] One of them.

[0025] In a preferred embodiment, the specific structure of the compound containing a carbazole ring structure is any one of the following structures:

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] An organic electroluminescent device, which comprises an anode, a hole transport region, a light emitting layer region, an electron transport region, a cathode and a light extraction layer in sequence, wherein the hole transport region or the light emitting layer region comprises the compound containing a carbazole ring structure;

[0049] In a preferred embodiment, the hole transport region comprises the compound containing a carbazole ring structure.

[0050] In a preferred embodiment, the light-emitting layer region comprises a host material and a guest material, wherein the host material is composed of a first host material and a second host material, the guest material is a phosphorescent material, and the first host material is the compound containing a carbazole ring structure.

[0051] In a preferred embodiment, the light-emitting layer region comprises a host material and a guest material, wherein the host material is composed of a first host material and a second host material, the guest material is a thermally excited delayed fluorescent material, and the first host material is the compound containing a carbazole ring structure.

[0052] A display device comprises the organic electroluminescent device.

[0053] The beneficial technical effects of the present invention are:

[0054] Compared with the carbazole ring structure type bridged by biphenyl or terphenyl, the compound containing the carbazole ring structure of the present invention has improved molecular rigidity as a whole, so that this structure type has a higher glass transition temperature, excellent film phase stability and excellent high-temperature weather resistance, so that the device will not age or crystallize due to the heat generated during the lighting process.

[0055] The compound of the present invention has a relatively high triplet energy level. When used as an electron blocking layer material, it can also effectively block high-energy triplet excitons, inhibit the diffusion and energy back-transfer of triplet excitons, and improve the electron-hole recombination efficiency, thereby improving the device efficiency.

[0056] Furthermore, the compound of the present invention has good hole mobility and thus excellent hole transport performance, and when used as a host material, it can reduce the device driving voltage.

[0057] Furthermore, the compounds of the present invention have good hole transport ability, hole tolerance and high triplet energy level. When used as the main material of the light-emitting layer, they are combined with the electronic main material to form a dual main combination. This combination can effectively transport holes, improve the electron-hole recombination efficiency, and inhibit the energy return of triplet excitons and the exciton quenching effect, thereby effectively reducing the device driving voltage and improving the device luminescence efficiency and device service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a cross-sectional schematic diagram of the organic electroluminescent device of the present invention.

[0059] In the figure: 1 is a transparent substrate layer, 2 is an anode layer, 3 is a hole injection layer, 4 is a hole transport layer, 5 is an electron blocking layer, 6 is a light-emitting layer, 7 is a hole blocking layer, 8 is an electron transport layer, 9 is an electron injection layer, 10 is a cathode layer, and 11 is a light extraction layer (CPL layer). DETAILED DESCRIPTION

[0060] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0061] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0062] In the present invention, unless otherwise stated, all operations are carried out at room temperature and normal pressure.

[0063] In the present invention, unless otherwise specified, HOMO means the highest occupied orbital of a molecule, and LUMO means the lowest unoccupied orbital of a molecule. In addition, the "difference in HOMO energy levels" and "difference in LUMO energy levels" referred to in this specification mean the difference in the absolute value of each energy value. In addition, in the present invention, HOMO and LUMO energy levels are expressed in absolute values, and the comparison between energy levels is also a comparison of the absolute values ​​thereof. Those skilled in the art know that the greater the absolute value of an energy level, the lower the energy of the energy level.

[0064] In the present invention, when a layer or element is referred to as being "on" another layer or substrate, the layer or element may be directly on the other layer or substrate, or there may be intervening layers. In addition, it will be understood that when a layer is referred to as being "between" two layers, the layer may be the only layer between the two layers, or there may be one or more intervening layers. The same reference numerals throughout the text represent the same elements.

[0065] In the present invention, when describing electrodes and organic electroluminescent devices, as well as other structures, the words "upper", "lower", "top" and "bottom" used to indicate orientation only indicate the orientation in a certain state, and do not mean that the related structure can only exist in the orientation described; on the contrary, if the structure can change its position, such as inverted, the orientation of the structure will be changed accordingly. Specifically, in the present invention, the "bottom" or "lower" side of the electrode refers to the side of the electrode close to the substrate during the preparation process, and the opposite side away from the substrate is the "top" or "upper" side.

[0066] Preferably, the functional layer includes a light-emitting layer, the light-emitting layer contains a light-emitting host material, the light-emitting host material is a mixture of any one of the first host material and the second host material containing a carbazole ring structure, and the mass ratio of the first host material to the second host material is 30:70 to 70:30; more preferably, the mass ratio of the first host material to the second host material is 40:60 to 60:40;

[0067] In the preferred organic electroluminescent device of the present invention, the second host material is a triazine compound represented by the following general formula (a):

[0068]

[0069] In the general formula (a), Ar1, Ar2, and Ar3 are independently substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C5-C 30 One of the heterocyclic groups;

[0070] L1 is selected from a single bond, a substituted or unsubstituted C6-C 30 Arylene, substituted or unsubstituted C5-C 30 A heterocyclylene group;

[0071] The heteroatoms are each independently selected from N, O or S;

[0072] Preferably, the second host material is selected from one of GHE-1 to GHE-12, and the specific structure of the second organic compound is

[0073]

[0074] Hereinafter, an organic electroluminescent device according to an embodiment of the present invention is described.

[0075] In addition, it should be noted that the materials used to form each layer described in the present invention can be formed into a film alone and used as a single layer, or can be mixed with other materials to form a film and used as a single layer. It can also be a stacked structure between layers formed into films alone, a stacked structure between layers formed into films after mixing, or a stacked structure of layers formed into films alone and layers formed into films after mixing.

[0076] The present invention also relates to a full-color display device having three pixels of red, green and blue, including the organic electroluminescent device of the present invention, in particular a flat panel display device. The display device may also include at least one thin film transistor. The thin film transistor may include a gate electrode, a source electrode and a drain electrode, a gate insulating layer and an active layer, wherein one of the source electrode and the drain electrode may be electrically connected to the anode of the organic electroluminescent device. The active layer may include crystalline silicon, amorphous silicon, an organic semiconductor or an oxide semiconductor, but is not limited thereto.

[0077] Exemplary embodiments have been disclosed herein, and although specific terms are used therein, these terms are used and interpreted only as general and descriptive meanings, and not for limiting purposes. In some cases, as will be apparent to those of ordinary skill in the art with the filing of this application, unless specifically indicated, the features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with the features, characteristics, and / or elements described in conjunction with other embodiments. Accordingly, it will be understood by those skilled in the art that various changes may be made in form and detail without departing from the spirit and scope of the invention.

[0078] The following examples are intended to better explain the present invention, but the scope of the present invention is not limited thereto. DETAILED DESCRIPTION

[0080] The raw materials involved in the synthesis examples of the present invention can all be purchased from the market.

[0081] Key intermediate synthesis: Intermediate C-1

[0082]

[0083] Add 0.01 mol of raw material A-1, 0.012 mol of raw material B-1, and 100 ml of toluene, stir and mix, add 0.02 mol of sodium tert-butoxide, 5×10 -5 mol Pd2(dba)3,5×10 -5 mol tri-tert-butylphosphine, stirred and heated to 115°C, refluxed for 11 hours, sampled and plated, showing no residual raw material B-1, the reaction was complete; cooled naturally to room temperature, filtered, the filtrate was evaporated under reduced pressure until no fraction was left, and passed through a neutral silica gel column to obtain intermediate C-1; LC-MS: theoretical value: 429.13; measured value: 430.28 ([M+H] + ).

[0084] The following intermediate C was synthesized by referring to the preparation process of intermediate C-1; the reaction conditions were similar, except that the raw materials and standard data listed in the following Table 1 were used.

[0085] Table 1

[0086]

[0087]

[0088] Example 1: Synthesis of Compound 13:

[0089]

[0090] Add 0.01 mol of intermediate C-1, 0.013 mol of raw material B-6, and 100 ml of toluene, stir and mix, add 0.04 mol of sodium tert-butoxide, 5×10 -4 mol Pd2(dba)3,1×10 -4 mol tri-tert-butylphosphine, stirred and heated to 115°C, refluxed for 20 hours, sampled and plated, showing no intermediate C-1 remaining, the reaction was complete; cooled naturally to room temperature, filtered, the filtrate was vacuum evaporated until there was no fraction, passed through a neutral silica gel column, and compound 13 was obtained; elemental analysis molecular formula (C48H30N2O), theoretical value: C, 88.59; H, 4.65; N, 4.30; test value: C, 88.61; H, 4.67; N, 4.34. LC-MS: theoretical value: 650.24; measured value ([M+H]+): 651.18.

[0091] The following target compounds were synthesized by referring to the preparation process in Example 1; the reaction conditions were the same, except that the intermediate C and raw materials B / D listed in Table 2 were used; detailed characterization data are shown in Table 2.

[0092] Table 2

[0093]

[0094]

[0095]

[0096] The compounds of the present invention are used in light-emitting devices and can be used as light-emitting layer materials. The compounds prepared in the above embodiments of the present invention were tested for their physicochemical and photoelectric properties, and the test results are shown in Table 3:

[0097] Table 3

[0098]

[0099]

[0100] Note: The triplet energy level T1 is tested by Horiba's Fluorolog-3 series fluorescence spectrometer, and the material test sample is 2*10 -5mol / L toluene solution; the glass transition temperature Tg was measured by differential scanning calorimetry (DSC, DSC204F1 differential scanning calorimeter of NETZSCH, Germany), with a heating rate of 10℃ / min; the highest occupied molecular orbital HOMO energy level was tested by ionization energy test system (IPS-3), and the test was in atmospheric environment. The hole mobility was tested by time of flight (TOF), and the test equipment was CMM-250 of JASCO Corporation.

[0101] From the data in the above table, it can be seen that the organic compound of the present invention has a high glass transition temperature (Tg>150°C), which can improve the phase stability and high temperature stability of the material film. In particular, when the device works at high temperature, the higher Tg can effectively inhibit the film phase change of the material and improve the device life; the organic compound of the present invention has a suitable HOMO energy level, which can reduce the injection barrier of carriers, reduce the device voltage and improve the device efficiency. The organic compound of the present invention has a higher T1 energy level (T1>2.80eV), and can be used as a host material to ensure the energy transfer efficiency between the host and the guest and inhibit energy loss.

[0102] Furthermore, compared with the comparative compounds GH-1 to GH-4, the evaporation temperature of the compound of the present invention is lower (≤340°C). The lower evaporation temperature can effectively ensure the evaporation stability of the material, improve the heat resistance of the material evaporation, inhibit the evaporation decomposition of the material, and increase the life of the device.

[0103] Surprisingly, the organic compounds of the present invention have high hole mobility, which helps to improve the device voltage, especially the turn-on voltage and current efficiency.

[0104] The following describes in detail the application effect of the OLED material synthesized by the present invention in the device through device examples 1-19 and device comparative examples 1-4. The device manufacturing process of the device embodiments 2-19 and device comparative examples 1-4 of the present invention is exactly the same as that of device embodiment 1, and the same substrate material and electrode material are used, and the film thickness of the electrode material is also the same. The difference is that the light-emitting layer in the device is replaced.

[0105] Device Example 1

[0106] like Figure 1As shown, the transparent substrate layer 1 is a transparent PI film, and the anode layer 2 (ITO (15nm) / Ag (150nm) / ITO (15nm)) is washed, that is, washed with a detergent (SemiClean M-L20), washed with pure water, dried, and then washed with ultraviolet-ozone to remove organic residues on the surface of the anode layer. On the anode layer 2 after the above washing, HT-1 and P-1 are evaporated on the anode layer 2 using a vacuum evaporation device as a hole injection layer 3, with a film thickness of 10nm, and a mass ratio of HT-1 to P-1 of 97:3. Then HT-1 is evaporated as a hole transport layer 4 with a thickness of 130nm. Subsequently, EB-1 is evaporated as an electron blocking layer 5 with a thickness of 40nm. After the above-mentioned electron blocking layer material is evaporated, the light-emitting layer 6 of the OLED light-emitting device is prepared, and its structure includes the compound 13 and GHE-1 used in the OLED light-emitting layer 6 as the main material, GD-1 as the guest material, the mass ratio of compound 13, GHE-1, and GD-1 is 47:47:6, and the thickness of the light-emitting layer is 40nm. After the above-mentioned light-emitting layer 6, HB-1 is vacuum evaporated and used as a hole blocking layer 7 with a film thickness of 5nm; then ET-1 and Liq are evaporated, the mass ratio of ET-1 and Liq is 1:1, the film thickness is 30nm, and this layer is the electron transport layer 8. On the electron transport layer 8, a Yb layer with a film thickness of 1nm is prepared by a vacuum evaporation device, and this layer is the electron injection layer 9. On the electron injection layer 9, a Mg:Ag electrode layer with a film thickness of 15nm is prepared by a vacuum evaporation device, and the mass ratio of Mg and Ag is 1:9, and this layer is the cathode layer 10. On the cathode layer 10, CP-1 was vacuum-evaporated to form a CPL layer 11 with a thickness of 70 nm to obtain an organic electroluminescent device 1.

[0107] The molecular structure formula of the relevant materials is shown below:

[0108]

[0109] After the OLED light-emitting device is completed as described above, the anode and cathode are connected with a known driving circuit, and the voltage, current efficiency, luminescence spectrum and device life of the device are measured. The device examples and comparative examples prepared by the same method are shown in Table 4; the voltage, current efficiency and 20 mA / cm 2 The test results of LT95 life under the conditions are shown in Table 5.

[0110] Table 4

[0111]

[0112]

[0113] Table 5

[0114]

[0115]

[0116] Note: Voltage, current efficiency and color coordinates are obtained at a current density of 10 mA / cm 2 The test was conducted under the following conditions: IVL (current-voltage-luminance) test system (Suzhou Fushida Scientific Instrument Co., Ltd.); the life test system was EAS-62C OLED device life tester from Japan System Technology Co., Ltd.; the device life LT95 refers to the device life under the condition of current density of 20mA / cm 2 The device brightness decays to 95% of the initial brightness when the current density is 20mA / cm 2 And when the temperature is 85°C, the time it takes for the device brightness to decay to 95% of the initial brightness.

[0117] It can be seen from the device data results in Table 6 that, compared with the device comparison example, the organic light-emitting device of the present invention is improved in terms of device voltage, device efficiency and device life relative to OLED devices of known materials, especially the device's turn-on voltage and high-temperature life are significantly improved.

[0118] In order to compare the efficiency attenuation of different devices at high current density, the efficiency attenuation coefficient of each device is defined where μ m Expressed as the maximum current efficiency of the device, μ 50 Indicates that the driving current is 50mA / cm 2 The current efficiency of the device. The larger the value, the more serious the efficiency roll-off of the device. Conversely, it means that the problem of rapid attenuation of the device at high current density has been controlled. The present invention measured the efficiency attenuation coefficient φ of the device obtained in device examples 5, 6, 7, 8, 9, 14, 17 and 19, and device comparison examples 1-4. The results are shown in Table 6:

[0119] Table 6

[0120]

[0121]

[0122] It can be seen from the data in Table 6 that the organic light-emitting device prepared using the compound of the present invention has a smaller efficiency attenuation coefficient than that of the comparative example, indicating that the organic electroluminescent device prepared using the compound of the present invention can effectively reduce the efficiency roll-off of the device at high current density.

[0123] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A compound containing a carbazole ring structure, characterized in that: The compound structure is shown in general formula (1): In the general formula (1), R1 and R2 are independently a hydrogen atom or a phenyl group; L1 is a structure represented by the general formula (3), the general formula (4) or the general formula (5); R3 represents a hydrogen atom, a phenyl group or a structure represented by the general formula (2); R4 is represented by the structure shown in general formula (2); M1 and M2 form a ring bond with *2 and *3, *3 and *4, *6 and *7 or *7 and *8 respectively; X1 is represented by O.

2. The compound containing a carbazole ring structure according to claim 1, characterized in that: The structure of the compound is shown in any one of the general formulas (6) to (8): In general formulae (6) to (8), the definitions of R1, R2, R3, and R4 are the same as those in claim 1.

3. The compound containing a carbazole ring structure according to claim 1, characterized in that: The structure of the compound is shown in any one of the general formulas (9) to (17): R1, R2, R3, and R4 are independently hydrogen atoms or phenyl groups; X1 is O.

4. The compound containing a carbazole ring structure according to claim 1, characterized in that: The specific structure of the compound is any one of the following structures:

5. An organic electroluminescent device, which comprises an anode, a hole transport region, a light emitting layer region, an electron transport region, a cathode and a light extraction layer in sequence, characterized in that: The light-emitting layer region comprises the compound containing a carbazole ring structure according to any one of claims 1 to 4.

6. The organic electroluminescent device according to claim 5, characterized in that: The light-emitting layer region comprises a host material and a guest material, wherein the host material is composed of a first host material and a second host material, the guest material is a phosphorescent material, and the first host material is the compound containing a carbazole ring structure according to any one of claims 1 to 4.

7. The organic electroluminescent device according to claim 5, characterized in that: The light-emitting layer region comprises a host material and a guest material, wherein the host material is composed of a first host material and a second host material, the guest material is a thermally excited delayed fluorescent material, and the first host material is the compound containing a carbazole ring structure as claimed in any one of claims 1 to 4.

8. A display device, characterized in that: The device comprises the organic electroluminescent device according to any one of claims 5 to 7.

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