Organic electroluminescent device, display substrate and display device

Abstract

The embodiment of the invention provides an organic light-emitting device, a display substrate and a display device. The organic light-emitting device comprises an anode, a first functional layer, a light-emitting layer, a second functional layer, a cathode and a covering layer which are sequentially arranged in a stacked mode, and the material of the covering layer comprises a compound with the structure shown in the formula (I) or a compound with the structure shown in the formula (II); # imgabs0 #

Description

Technical Field

[0001] The embodiments of the present disclosure relate to, but are not limited to, the field of display technology, and in particular to an organic electroluminescent device, a display substrate, and a display apparatus. Background Art

[0002] Organic Light Emitting Device (OLED) is an active light-emitting device with the advantages of luminescence, ultra-thinness, wide viewing angle, high brightness, high contrast, low power consumption, and extremely high response speed. It has gradually become a promising next-generation display technology. The device generally includes an anode, a cathode, a light-emitting material located between the two electrodes, and a cover layer located on the side of the cathode away from the anode. How to make OLED achieve better luminous efficiency and long life, the design of the cover layer is relatively important. Summary of the invention

[0003] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0004] In a first aspect, an embodiment of the present disclosure provides an organic electroluminescent device, comprising: an anode, a first functional layer, a light-emitting layer, a second functional layer, a cathode and a covering layer stacked in sequence, wherein the material of the covering layer comprises: a compound having a structure as shown in formula (I) or a compound having a structure as shown in formula (II);

[0005]

[0006] In formula (I) and formula (II), L3, L4 and L5 are each independently selected from any one of the following groups: a single bond, a substituted or unsubstituted alkyl group having 2 to 30 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a substituted or unsubstituted fused aryl group having 6 to 20 carbon atoms, and a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms; at least one of Ar3 and Ar4 is selected from any one of the groups having structures shown in formula (2-1) to formula (2-7);

[0007]

[0008] in, represents a chemical bond; X is selected from CR, NR, oxygen or sulfur; CR is a carbon atom connected to hydrogen or an alkyl group; NR is a nitrogen atom connected to hydrogen or an alkyl group; Y, Y1, Y2, Y3 and Y4 are each independently CR or nitrogen, and only one of Y1 to Y4 is nitrogen; Z is CR or NR; R is selected from any one of the following: hydrogen, deuterium, an alkyl group having 2 to 30 carbon atoms, an arylene group having 6 to 20 carbon atoms, and a heteroaryl group having 5 to 20 carbon atoms; Ar is selected from a group containing only one heteroatom, and the heteroatom is nitrogen, oxygen or sulfur.

[0009] In a second aspect, an embodiment of the present disclosure provides a display substrate, comprising: a substrate and a plurality of light-emitting devices arranged on one side of the substrate, at least one of the plurality of light-emitting devices is the organic electroluminescent device described in the above exemplary embodiment.

[0010] In a third aspect, an embodiment of the present disclosure provides a display device, comprising: the display substrate described in the above exemplary embodiment.

[0011] The organic electroluminescent device, display substrate and display apparatus provided by the embodiments of the present disclosure effectively improve the refractive index of the cover layer and the hole mobility in the film region between the anode and the light-emitting layer, thereby effectively improving the luminous efficiency and life of the entire organic electroluminescent device.

[0012] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or be understood by implementing the present disclosure. Other advantages of the present disclosure can be realized and obtained by the schemes described in the description and the drawings.

[0013] Other aspects will be apparent upon reading and understanding the drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to provide an understanding of the technical solution of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solution of the present disclosure and do not constitute a limitation on the technical solution of the present disclosure. The shapes and sizes of the components in the accompanying drawings do not reflect the actual proportions and are only intended to illustrate the contents of the present disclosure.

[0015] Figure 1 is a structural schematic diagram of an OLED display device;

[0016] Figure 2 A schematic diagram of a planar structure of a display area of ​​a display substrate;

[0017] Figure 3 A schematic diagram of a cross-sectional structure of a display substrate;

[0018] Figure 4is a schematic structural diagram of an organic electroluminescent device in an exemplary embodiment of the present disclosure;

[0019] Figure 5 It is a schematic structural diagram of another organic electroluminescent device in an exemplary embodiment of the present disclosure.

[0020] Description of reference numerals:

[0021] 101—substrate; 102—driving circuit layer; 103—light emitting structure layer;

[0022] 104—packaging structure layer; 210—transistor; 211—storage capacitor;

[0023] 302—pixel definition layer; 303—organic light-emitting layer; 401—first encapsulation layer.

[0024] 402—second packaging layer; 403—third packaging layer; 501—anode;

[0025] 502—first functional layer; 503—luminescent layer; 504—second functional layer;

[0026] 505 - cathode; 506 - cover layer; 601 - hole injection layer;

[0027] 602—hole transport layer; 603—auxiliary light emitting layer; 604—hole blocking layer;

[0028] 605—electron transport layer; 606—electron injection layer. DETAILED DESCRIPTION

[0029] The present disclosure describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present disclosure. Although many possible feature combinations are shown in the drawings and discussed in the exemplary embodiments, many other combinations of the disclosed features are possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0030] The proportions of the drawings in this disclosure can be used as a reference in the actual process, but are not limited to this. For example: the width-to-length ratio of the channel, the thickness and spacing of each film layer, the width and spacing of each signal line can be adjusted according to actual needs. The number of pixels in the display substrate and the number of sub-pixels in each pixel are not limited to the numbers shown in the figures. The drawings described in this disclosure are only structural schematic diagrams, and one method of this disclosure is not limited to the shapes or values ​​shown in the drawings.

[0031] In the exemplary embodiments of the present disclosure, ordinal numbers such as "first", "second" or "third" and similar words are provided to avoid confusion of constituent elements, rather than to limit in terms of quantity, order or importance, etc. They cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, a feature defined as "first", "second", etc. may explicitly or implicitly include at least one such feature.

[0032] In the exemplary embodiments of the present disclosure, for the sake of convenience, words and phrases indicating orientation or positional relationship such as "middle", "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial" or "circumferential" are used to illustrate the positional relationship of constituent elements with reference to the drawings. This is only for the convenience of describing the present disclosure and simplifying the description, and does not indicate or imply that the device or element referred to has a specific orientation, is constructed and operates in a specific orientation, and therefore cannot be understood as a limitation to the present disclosure. The positional relationship of the constituent elements is appropriately changed according to the direction of describing each constituent element. Therefore, it is not limited to the words and phrases described in the specification and can be appropriately replaced according to the circumstances.

[0033] In the exemplary embodiments of the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" or "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the meanings of the above terms in the present disclosure can be understood according to actual conditions.

[0034] In the embodiments of the present disclosure, a transistor refers to an element including at least three terminals: a gate electrode (also referred to as a gate or a control electrode), a drain electrode (also referred to as a drain electrode terminal, a drain region or a drain electrode), and a source electrode (also referred to as a source electrode terminal, a source region or a source electrode). The transistor has a channel region between the drain electrode and the source electrode, and current can flow through the drain electrode, the channel region, and the source electrode. Note that in this specification, the channel region refers to the region where the current mainly flows.

[0035] In the embodiments of the present disclosure, in order to distinguish the two poles of the transistor other than the control pole, one pole is directly described as the first pole and the other pole is the second pole, wherein the first pole can be the drain electrode and the second pole can be the source electrode, or the first pole can be the source electrode and the second pole can be the drain electrode. In the case of using transistors with opposite polarities or the case where the current direction changes during circuit operation, the functions of the "source electrode" and the "drain electrode" are sometimes interchanged. Therefore, in this specification, the "source electrode" and the "drain electrode" can be interchanged.

[0036] The transistors in the embodiments of the present disclosure may be thin film transistors (TFT) or field effect transistors (FET) or other devices with the same characteristics. For example, the thin film transistors used in the embodiments of the present disclosure may include but are not limited to oxide transistors (Oxide TFT) or low temperature polysilicon thin film transistors (LTPS TFT). For example, the thin film transistor can be a bottom gate thin film transistor or a top gate thin film transistor, as long as the switching function can be realized. Here, the embodiments of the present disclosure do not limit this.

[0037] In the embodiments of the present disclosure, the term “about” is used to refer to values ​​that are not strictly limited and allow for process and measurement errors.

[0038] In the embodiments of the present disclosure, the term “stacked in sequence” may mean that a plurality of film layers are stacked in one direction, but does not mean that the film layers must be bonded to each other in pairs.

[0039] In the embodiments of the present disclosure, the expressions "on", "formed on", "disposed on" or similar expressions may indicate that a layer is directly formed or disposed on another layer, or may indicate that a layer is indirectly formed or disposed on another layer, that is, there are other layers between the two layers. Moreover, the first feature "on", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature. In this article, unless otherwise specified, the term "located in the same layer" used means that two layers, parts, components, elements or parts can be formed by the same composition process, and the two layers, parts, components, elements or parts are generally formed of the same material. In this article, unless otherwise specified, the expression "composition process" generally includes steps such as coating, exposure, development, etching, and stripping of photoresist. The expression "one-time composition process" means a process of forming a patterned layer, part, component, etc. using a mask.

[0040] In the embodiments of the present disclosure, “thickness” refers to the height of a surface far from the substrate from a surface close to the substrate in a direction perpendicular to the plane of the substrate.

[0041] The following describes the embodiments with reference to the accompanying drawings. The embodiments can be implemented in a plurality of different forms. A person skilled in the art can easily understand that the method and content can be transformed into different forms without departing from the purpose and scope of the present disclosure. Therefore, the present disclosure should not be interpreted as being limited to the contents described in the following embodiments.

[0042] In order to keep the following description of the embodiments of the present disclosure clear and concise, the present disclosure omits detailed descriptions of some known functions and known components. The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure, and other structures can refer to the general design.

[0043] Figure 1 FIG. 1 is a schematic diagram of the structure of a display device. Figure 1As shown, the display device may include a timing controller, a data driver, a scan driver, a light emitting driver and a pixel array, the timing controller is respectively connected to the data driver, the scan driver and the light emitting driver, the data driver is respectively connected to a plurality of data signal lines (D1 to Dn), the scan driver is respectively connected to a plurality of scan signal lines (S1 to Sm), and the light emitting driver is respectively connected to a plurality of light emitting signal lines (E1 to Eo). The pixel array may include a plurality of sub-pixels Pxij, i and j may be natural numbers, at least one sub-pixel Pxij may include a circuit unit and a light emitting device connected to the circuit unit, the circuit unit may include a pixel driving circuit, and the pixel driving circuit may be respectively connected to the scan signal line, the light emitting signal line and the data signal line. In some exemplary embodiments, the timing controller may provide a grayscale value and a control signal suitable for the specifications of the data driver to the data driver, may provide a clock signal suitable for the specifications of the scan driver, a scan start signal, etc. to the scan driver, and may provide a clock signal suitable for the specifications of the light emitting driver, an emission stop signal, etc. to the light emitting driver. The data driver can generate data voltages to be provided to data signal lines D1, D2, D3, ... and Dn using grayscale values ​​and control signals received from the timing controller. For example, the data driver can sample grayscale values ​​using a clock signal, and apply data voltages corresponding to grayscale values ​​to data signal lines D1 to Dn in units of pixel rows, where n can be a natural number. The scan driver can generate scan signals to be provided to scan signal lines S1, S2, S3, ... and Sm by receiving clock signals, scan start signals, etc. from the timing controller. For example, the scan driver can sequentially provide scan signals with conduction level pulses to scan signal lines S1 to Sm. For example, the scan driver can be constructed in the form of a shift register, and can sequentially transmit scan start signals provided in the form of conduction level pulses to the next level circuit under the control of the clock signal to generate scan signals, where m can be a natural number. The light-emitting driver can generate emission signals to be provided to light-emitting signal lines E1, E2, E3, ... and Eo by receiving clock signals, emission stop signals, etc. from the timing controller. For example, the light emitting driver may sequentially provide an emission signal having a cut-off level pulse to the light emitting signal lines E1 to Eo. For example, the light emitting driver may be constructed in the form of a shift register, and may generate an emission signal in a manner of sequentially transmitting an emission stop signal provided in the form of a cut-off level pulse to a next stage circuit under the control of a clock signal, and o may be a natural number.

[0044] Figure 2 FIG. 1 is a schematic diagram of a planar structure of a display substrate. Figure 2As shown, the display substrate may include a plurality of pixel units P arranged regularly (such as arranged in a matrix), at least one of the plurality of pixel units P may include a first sub-pixel P1 emitting a first color light, a second sub-pixel P2 emitting a second color light, and a third sub-pixel P3 emitting a third color light, each sub-pixel may include a circuit unit and a light-emitting device connected to the circuit unit, the circuit unit may include a pixel driving circuit and a scanning signal line, a data signal line, and a light-emitting signal line connected to the pixel driving circuit, etc., the pixel driving circuit is configured to receive a data voltage transmitted by the data signal line under the control of the scanning signal line and the light-emitting signal line, and output a corresponding current to the light-emitting device. The light-emitting device in each sub-pixel is respectively connected to the pixel driving circuit of the sub-pixel, and the light-emitting device is configured to emit light of corresponding brightness in response to the current output by the pixel driving circuit of the sub-pixel.

[0045] In some exemplary embodiments, the pixel unit P may include a red sub-pixel, a green sub-pixel, and a blue sub-pixel, or may include a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel, which is not limited in the present disclosure. In some exemplary embodiments, the shape of the sub-pixel in the pixel unit may be a rectangle, a rhombus, a pentagon, a hexagon, etc. In some exemplary embodiments, when the pixel unit includes three sub-pixels, the three sub-pixels may be arranged in parallel horizontally, vertically, or in a square. In other exemplary embodiments, when the pixel unit includes four sub-pixels, the four sub-pixels may be arranged in parallel horizontally, vertically, or in a square, which is not limited in the present disclosure.

[0046] Figure 3 FIG. 1 is a schematic diagram of a cross-sectional structure of a display substrate, illustrating the structure of three sub-pixels of an OLED display substrate. Figure 3 As shown, on a plane perpendicular to the display substrate, the display substrate may include a driving circuit layer 102 disposed on a substrate 101, a light emitting structure layer 103 disposed on a side of the driving circuit layer 102 away from the substrate 101, and a packaging structure layer 104 disposed on a side of the light emitting structure layer 103 away from the substrate 101. In some possible implementations, the display substrate may include other film layers, such as a touch structure layer, etc., which is not limited in the present disclosure.

[0047] In some exemplary embodiments, the substrate 101 may be a flexible substrate, or may be a rigid substrate.

[0048] In some exemplary embodiments, the driving circuit layer 102 of each sub-pixel may include a plurality of transistors and storage capacitors constituting a pixel driving circuit. Figure 3Only one transistor 210 and one storage capacitor 211 are used as examples. In some exemplary embodiments, the light emitting structure layer 103 may include an anode 501, a pixel definition layer 302, an organic light emitting layer 303 and a cathode 505, wherein the anode 501 is connected to the drain electrode of the driving transistor 210 through a via hole, the pixel definition layer 302 is provided with a pixel opening, the pixel opening exposes the anode 501, the organic light emitting layer 303 is connected to the anode 501, the cathode 505 is connected to the organic light emitting layer 303, and the organic light emitting layer 303 emits light of corresponding colors under the drive of the anode 501 and the cathode 505.

[0049] In some exemplary embodiments, the organic light-emitting layer 303 may include an emitting layer (Emitting Layer, EML) and any one or more of the following layers: a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), a hole blocking layer (HBL), an electron transport layer (ETL) and an electron injection layer (EIL). The emitting layer is configured to cause electrons and holes to recombine and emit light. The hole injection layer is configured to reduce the barrier for injecting holes from the anode so that holes can be effectively injected from the anode into the emitting layer. The hole transport layer is configured to achieve directional, orderly and controllable migration of injected holes. The electron blocking layer is configured to form a migration barrier for electrons to prevent electrons from migrating out of the emitting layer. The hole blocking layer is configured to form a migration barrier for holes to prevent holes from migrating out of the emitting layer. The electron transport layer is configured to achieve directional, orderly, and controllable migration of injected electrons. The electron injection layer is configured to reduce the barrier for injecting electrons from the cathode so that electrons can be effectively injected from the cathode into the light-emitting layer. In some exemplary embodiments, one or more of the hole injection layer, hole transport layer, electron blocking layer, hole blocking layer, electron transport layer, and electron injection layer of all sub-pixels may be a common layer connected together, and the light-emitting layers of adjacent sub-pixels may have a small amount of overlap, or may be isolated.

[0050] In some exemplary embodiments, the encapsulation structure layer 104 may include a stacked first encapsulation layer 401, a second encapsulation layer 402, and a third encapsulation layer 403. For example, the first encapsulation layer 401 and the third encapsulation layer 403 may be made of inorganic materials, the second encapsulation layer 402 may be made of organic materials, and the second encapsulation layer 402 is disposed between the first encapsulation layer 401 and the third encapsulation layer 403, which can ensure that external water vapor cannot enter the light-emitting structure layer 103.

[0051] In some exemplary embodiments, the pixel driving circuit may adopt a pixel circuit of nTmC (n, m are positive integers) structure such as 2T1C (i.e., two transistors and one capacitor), 3T1C, 4T1C, 5T1C, 5T2C, 6T1C, 7T1C or 8T1C. In different exemplary embodiments, the pixel circuit may further include a compensation subcircuit, which may include an internal compensation subcircuit or an external compensation subcircuit, and the compensation subcircuit may include a transistor, a capacitor, etc. For example, as required, the pixel circuit may further include: a reset subcircuit, a light emitting control subcircuit, etc. The embodiments of the present disclosure are not limited to this.

[0052] In some OLED structures, top-emitting device structures are often used to reflect the anode and transparent cathode, and the light extraction efficiency is enhanced through the microcavity effect. In such devices, a very important film layer is the capping layer (CPL), also known as the light extraction layer. The capping layer can generally use organic or inorganic transparent materials with a higher refractive index, and basically has no absorption range in the visible light range. Light-emitting devices with a capping layer can improve the light extraction mode. The capping layer has a higher refractive index and forms a high-low refractive index combination on the upper layer of the cathode, so that the light originally confined inside the device can be emitted from the device, showing a higher light extraction efficiency, thereby achieving a better light extraction effect. The higher the refractive index of the capping layer material, the more obvious the light extraction effect and the better the performance of the device. However, the capping layer material in some technologies has a lower refractive index (such as a refractive index of 2.0 at a wavelength of 460nm), which has little effect on improving the light extraction effect and device efficiency.

[0053] The exemplary embodiments of the present disclosure provide an organic electroluminescent device, which effectively improves the refractive index of the cover layer (CPL) by introducing a cycloalkylnaphthalene group, and can improve the hole mobility in the film region between the anode and the light-emitting layer, thereby effectively improving the luminous efficiency and life of the entire organic electroluminescent device.

[0054] In some exemplary embodiments, the organic electroluminescent device may be a blue organic electroluminescent device, a red organic electroluminescent device, or a green organic electroluminescent device.

[0055] The exemplary embodiments of the present disclosure provide an organic electroluminescent device, Figure 4 FIG. 1 is a schematic diagram of the structure of an organic electroluminescent device in an exemplary embodiment of the present disclosure. Figure 4 As shown, the organic electroluminescent device may include: an anode 501, a first functional layer 502, a light-emitting layer 503, a second functional layer 504, a cathode 505 and a cover layer (CPL) 506 which are stacked in sequence, wherein the material of the cover layer (CPL) 506 may include: a compound having a structure as shown in formula (I) or a compound having a structure as shown in formula (II);

[0056]

[0057] In formula (I) and formula (II), L3, L4 and L5 are each independently selected from any one of the following groups: a single bond, a substituted or unsubstituted alkyl group having 2 to 30 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a substituted or unsubstituted fused aryl group having 6 to 20 carbon atoms, and a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms; at least one of Ar3 and Ar4 is selected from any one of the groups having structures shown in formula (2-1) to formula (2-7);

[0058]

[0059] in, represents a chemical bond; X is selected from CR, NR, oxygen (O) or sulfur (S); CR is a carbon atom connected to hydrogen or an alkyl group; NR is a nitrogen atom connected to hydrogen or an alkyl group, Y, Y1, Y2, Y3 and Y4 are each independently CR or nitrogen (N), and only one of Y1 to Y4 is N; Z is CR or NR; R is selected from any one of the following: hydrogen, deuterium (D), an alkyl group with 2 to 30 carbon atoms, an arylene group with 6 to 20 carbon atoms, and a heteroaryl group with 5 to 20 carbon atoms. Ar is selected from a group containing only one heteroatom, and the heteroatom is nitrogen (N), oxygen (O) or sulfur (S).

[0060] Thus, in the organic electroluminescent device provided by the exemplary embodiment of the present disclosure, by introducing cycloalkylnaphthalene groups into the covering layer material, the refractive index of the covering layer (CPL) can be improved, and since the covering layer material has a strong electron donating ability, the hole mobility in the film region between the anode and the light-emitting layer can be improved, and the molecular weight is increased relative to naphthalene, thereby improving the device life, thereby improving the luminous efficiency and life of the entire organic electroluminescent device, and realizing a high-efficiency, long-life OLED device.

[0061] In some exemplary embodiments, L3 and L4 may be the same or different.

[0062] In some exemplary embodiments, X is oxygen (O) or sulfur (S).

[0063] In some exemplary embodiments, Ar3 and Ar4 that are not selected from the structures shown in Formulas (2-1) to (2-7) are selected from any one of the following groups: a substituted or unsubstituted alkyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms containing one or more heteroatoms; wherein the heteroatom is nitrogen, oxygen or sulfur.

[0064] In some other exemplary embodiments, Ar3 and Ar4 that are not selected from the groups having structures shown in formulae (2-1) to (2-7) are selected from any one of the groups having structures shown in formulae (2-8) to (2-10):

[0065]

[0066] In some exemplary embodiments, the material of the covering layer is selected from any one of the compounds having structures shown in Formula (3-1) to Formula (3-53):

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073] In the following disclosure, the compound with the structure shown in formula (3-1) is recorded as compound 1. Similarly, the compound with the structure shown in formula (3-2) is recorded as compound 2. The compound with the structure shown in formula (3-3) is recorded as compound 3, ..., and the compound with the structure shown in formula (3-53) is recorded as compound 53. They are not listed one by one here.

[0074] In some exemplary embodiments, the first functional layer between the light-emitting layer 503 and the anode 501 may include multiple organic layers, and the materials of at least two layers of the multiple organic layers may include aromatic amine groups, and the materials of at least one layer of the multiple organic layers may include cycloalkylnaphthalene groups. For example, the first functional layer may include: one or more layers of a hole injection layer 601, a hole transport layer 602, an auxiliary light-emitting layer (AEML) 603, etc. Among them, the hole injection layer 601 is configured to reduce the barrier of injecting holes from the anode, so that the holes can be effectively injected from the anode into the light-emitting layer 503. The hole transport layer 602 is configured to achieve a directional and orderly controllable migration of the injected holes. The auxiliary light-emitting layer (AEML) 603 is configured to have the same function as the electron blocking layer (EBL) (such as being configured to form a migration barrier for electrons to prevent electrons from migrating out of the light-emitting layer (EML) 503), and can share the same chamber and fine metal mask (FMM mask) with the light-emitting layer (EML) 503, reducing the preparation cost and preparation difficulty. The auxiliary light-emitting layer (AEML) 603 can also be configured to reduce the potential barrier between the hole transport layer and the main material in the light-emitting layer (EML) 503, and efficiently transfer holes to the light-emitting layer (EML) 503 to recombine with electrons to form excitons, thereby improving the light-emitting efficiency.

[0075] In some exemplary embodiments, Figure 5 As shown, the first functional layer may include: a hole injection layer 601 disposed on one side of the anode, a hole transport layer 602 disposed on the side of the hole injection layer 601 away from the anode, and an auxiliary light-emitting layer (AEML) 603 disposed on the side away from the hole transport layer 602, and the materials of at least two layers of the hole injection layer 601, the hole transport layer 602, the auxiliary light-emitting layer 603, etc. may include aromatic amine groups, and the materials of at least one layer of the hole injection layer 601, the hole transport layer 602, the auxiliary light-emitting layer 603, etc. may include cycloalkylnaphthalene groups. For example, multiple layers of the hole injection layer 601, the hole transport layer 602, the auxiliary light-emitting layer 603, etc. may include aromatic amine groups and cycloalkylnaphthalene groups, so that the hole transport rate of the first functional layer located between the light-emitting layer 503 and the anode 501 can be increased, and since the photoluminescence (PL) spectrum range of the aromatic amine material is 400nm to 450nm, it is beneficial to improve the device efficiency.

[0076] In some exemplary embodiments, the first functional layer between the light-emitting layer 503 and the anode 501 may include multiple organic layers, and the material of at least one of the multiple organic layers may be selected from any one of the compounds having structures shown in formulas (4-1) to (4-3):

[0077]

[0078] In some exemplary embodiments, the material of one or more layers of the hole injection layer 601, the hole transport layer 602, the auxiliary light emitting layer (AEML) 603, etc. can be selected from any one of the compounds with structures shown in formulas (4-1) to (4-3).

[0079] In some exemplary embodiments, Figure 5 As shown, the first functional layer may include: a hole injection layer 601 disposed on one side of the anode and a hole transport layer 602 disposed on the side of the hole injection layer 601 away from the anode, wherein the hole injection layer comprises the same material as the hole transport layer. For example, the materials of the hole injection layer 601 and the hole transport layer 602 both include aromatic amine groups, and the material of at least one layer of the hole injection layer 601 and the hole transport layer 602 includes cycloalkylnaphthalene groups. Thus, in the organic electroluminescent device provided in the exemplary embodiment of the present disclosure, since the materials used in the hole injection layer and the hole transport layer have relatively fast mobility and more matched energy levels, the voltage can be reduced and the efficiency can be improved. In addition, the material used in the covering layer has a high refractive index and high thermal stability, thereby achieving high-performance devices.

[0080] In some exemplary embodiments, Figure 5 As shown, the second functional layer may include any one or more of a hole blocking layer 604, an electron transport layer 605 and an electron injection layer 606. The hole blocking layer 604 is configured to form a migration barrier for holes, preventing holes from migrating out of the light-emitting layer. The electron transport layer 605 is configured to achieve a directional and orderly controllable migration of injected electrons. The electron injection layer 606 is configured to reduce the barrier for injecting electrons from the cathode, so that electrons can be effectively injected from the cathode into the light-emitting layer.

[0081] In some exemplary embodiments, the first functional layer 502 may include multiple organic layers, and the material of at least one layer of the multiple organic layers may include: a compound having a structure as shown in formula (III);

[0082]

[0083] In formula (III), G1 and R are each independently selected from any one of the following groups: hydrogen (H), deuterium (D), a substituted or unsubstituted aryl group having 6 to 12 carbon atoms; L1 and L2 are each independently selected from any one of the following groups: a direct bond, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms; Ar1 ​​and Ar2 are each independently selected from any one of the following groups: a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 carbon atoms; (D)m represents a group having m deuterium (D) atoms, (D)n represents a group having n deuterium (D) atoms, and m and n are integers from 0 to 4; (D)o represents a group having o deuterium (D) atoms, and o is an integer from 0 to 8; p is an integer from 0 to 2. Thus, by introducing a cycloalkylnaphthalene group and an aromatic amine group into at least one layer of the first functional layer between the light-emitting layer and the anode, the electron cloud density can be increased due to the strong electron-donating ability of the cycloalkylnaphthalene group, thereby improving the hole mobility, and the molecular weight is increased relative to naphthalene, which can improve the thermal stability of the material, and the photoluminescence (PL) spectrum of the aromatic amine material ranges from 400nm to 450nm, which is conducive to improving the device efficiency. Thus, the luminous efficiency and life of the entire organic electroluminescent device can be improved.

[0084] In some exemplary embodiments, the material of one or more layers of the hole injection layer 601, the hole transport layer 602, the auxiliary light emitting layer (AEML) 603, etc. may include: a compound having a structure as shown in formula (III). In this way, by introducing a cycloalkylnaphthalene group and an aromatic amine group into at least one of the hole injection layer, the hole transport layer, and the auxiliary light emitting layer, the electron cloud density can be increased due to the strong electron donating ability of the cycloalkylnaphthalene group, thereby improving the hole mobility of at least one of the hole injection layer, the hole transport layer, and the auxiliary light emitting layer, and relative to naphthalene, the increase in molecular weight can improve the thermal stability of the material, thereby improving the luminous efficiency and life of the entire organic electroluminescent device; and since the photoluminescence (PL) spectrum of the aromatic amine material ranges from 400nm to 450nm, it is beneficial to improve the device efficiency. For example, the material of the hole injection layer may include: a compound with a structure as shown in formula (III), or the material of the hole transport layer may include: a compound with a structure as shown in formula (III). In this way, the hole mobility of the hole transport layer can be improved, and the efficiency and life of the device can be improved. Or, the materials of the hole injection layer and the hole transport layer may include: a compound with a structure as shown in formula (III), or, the materials of the hole injection layer, the hole transport layer and the auxiliary light-emitting layer may include: a compound with a structure as shown in formula (III), etc.

[0085] In some exemplary embodiments, G1 and R may be the same or different. L1 and L2 may be the same or different. Ar1 and Ar2 may be the same or different.

[0086] In some exemplary embodiments, in formula (III) Any one selected from the structures shown in formula (a1) to formula (a32):

[0087]

[0088] In some exemplary embodiments, the structures represented by Formula (a1) to Formula (a32) may be partially deuterated or fully deuterated.

[0089] In some exemplary embodiments, the material of at least one layer of the first functional layer between the light-emitting layer 503 and the anode 501 (such as at least one layer of the hole injection layer, the hole transport layer, and the auxiliary light-emitting layer) can be selected from any one of the compounds having structures shown in Formulae 1 to 249. Thus, by introducing an aromatic amine group and a cycloalkylnaphthalene group into at least one layer of the first functional layer between the light-emitting layer and the anode, since the photoluminescence (PL) spectrum of the aromatic amine material ranges from 400nm to 450nm, it is beneficial to improve the device efficiency, and since the cycloalkylnaphthalene group has a strong electron-donating ability, the electron cloud density can be increased, thereby improving the hole mobility and hole transport rate of the first functional layer between the light-emitting layer and the anode, and relative to naphthalene, the molecular weight is increased, which can improve the thermal stability of the material.

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104] In some exemplary embodiments, the compounds of the structures represented by Formulae 1 to 249 may be partially deuterated or fully deuterated.

[0105] In the present disclosure below, the compound with the structure shown in Formula 1 is recorded as Compound 1A. Similarly, the compound with the structure shown in Formula 2 is recorded as Compound 2A. The compound with the structure shown in Formula 3 is recorded as Compound 3A, ..., and the compound with the structure shown in Formula 249 is recorded as Compound 249A. They are not listed one by one here.

[0106] In some exemplary embodiments, the anode may be made of a material with a high work function. For bottom-emitting OLEDs, the anode may be made of a transparent oxide material, such as indium tin oxide (ITO) or indium zinc oxide (IZO), and the thickness of the anode may be about 80 nm to 200 nm. For top-emitting OLEDs, the anode may be made of a composite structure of metal and transparent oxide, such as Ag / ITO, Ag / IZO, or ITO / Ag / ITO, and the thickness of the metal layer in the anode may be about 80 nm to 100 nm, and the thickness of the transparent oxide in the anode may be about 5 nm to 20 nm, so that the average reflectivity of the anode in the visible light region is about 85% to 95%.

[0107] In some exemplary embodiments, for a bottom emission type OLED, the cathode may be made of magnesium (Mg), silver (Ag), aluminum (Al) or an alloy of Mg:Ag, and the thickness of the cathode may be greater than about 80 nm, so that the cathode 90 has good reflectivity. For a top emission type OLED, the cathode may be made of a metal material, formed by an evaporation process, and the metal material may be made of magnesium (Mg), silver (Ag) or aluminum (Al), or an alloy material, such as an alloy of Mg:Ag, with a Mg:Ag ratio of about 3:7 to 1:9, and the thickness of the cathode may be about 10 nm to 20 nm, so that the average transmittance of the cathode at a wavelength of 530 nm is about 50% to 60%.

[0108] In some exemplary embodiments, the light-emitting layer may include a light-emitting host material and a light-emitting guest material. The light-emitting host material may be a bipolar single host, or may be a dual host formed by blending a hole-type host and an electron-type host. The light-emitting guest material may be a phosphorescent material, a fluorescent material, a delayed fluorescent material, etc., and the doping ratio of the light-emitting guest material is about 2% to 12%. For example, the doping ratio of the blue light guest material BD in the blue light-emitting layer is about 3%.

[0109] In some exemplary embodiments, the electron transport layer can be prepared by blending thiophene, imidazole or azine derivatives with lithium quinoline, the doping ratio of lithium quinoline in the electron transport layer is about 30% to 70%, and the thickness of the electron transport layer can be about 20nm to 70nm.

[0110] In some exemplary embodiments, the electron injection layer may be formed by an evaporation process using materials such as lithium fluoride (LiF), 8-hydroxyquinoline lithium (LiQ), ytterbium (Yb) or calcium (Ca), and the thickness of the electron injection layer may be about 0.5 nm to 2 nm.

[0111] In some exemplary embodiments, for top-emitting OLEDs, the thickness of the film layers (such as the first functional layer, the light-emitting layer, and the second functional layer) between the anode and the cathode can be designed to meet the optical path requirements of the optical microresonator to obtain optimal light output intensity and color.

[0112] In the exemplary embodiments of the present disclosure, the descriptions "each independently is" and "each independently selected from" used are interchangeable and should be understood in a broad sense, which may mean that in different groups, the example options expressed by the same symbols do not affect each other, or that in the same group, the example options expressed by the same symbols do not affect each other.

[0113] In the exemplary embodiments of the present disclosure, the carbon number of L1, L2, L3, L4, L5, Ar1, Ar2, Ar3 and Ar4 refers to the total number of carbon atoms. For example, when L3 is selected from a substituted arylene group having 6 carbon atoms, the total number of carbon atoms of the arylene group and the substituents thereon is 12.

[0114] In the exemplary embodiments of the present disclosure, when no specific definition is provided, "hetero" may refer to a functional group including at least one heteroatom such as boron (B), nitrogen (N), oxygen (O), sulfur (S), selenium (Se), silicon (Si) or phosphorus (P) and the remaining atoms are carbon (C) and hydrogen (H). The unsubstituted alkyl group may be a "saturated alkyl group" without any double or triple bonds.

[0115] In the exemplary embodiment of the present disclosure, "alkyl" may include straight chain alkyl or branched chain alkyl. Depending on the situation, the alkyl may have 2 to 30 carbon atoms, or, the alkyl may have 2 to 20 carbon atoms, etc. In the exemplary embodiment of the present disclosure, a numerical range such as "2 to 20" refers to each integer in a given range; for example, "alkyl having 2 to 20 carbon atoms" may refer to an alkyl containing 2 carbon atoms, 3 carbon atoms, 4 carbon atoms, 5 carbon atoms, 6 carbon atoms, 7 carbon atoms, 8 carbon atoms, 9 carbon atoms, 10 carbon atoms, 11 carbon atoms, 12 carbon atoms, 13 carbon atoms, 14 carbon atoms, 15 carbon atoms, 16 carbon atoms, 17 carbon atoms, 18 carbon atoms, 19 carbon atoms or 20 carbon atoms. In addition, the alkyl may be substituted or unsubstituted.

[0116] In the exemplary embodiments of the present disclosure, aryl refers to an optional functional group or substituent derived from an aromatic carbocyclic ring. The aryl can be a monocyclic aryl (e.g., phenyl) or a polycyclic aryl, for example, the aryl can be a monocyclic aryl, a condensed ring aryl, two or more monocyclic aryl groups connected by carbon-carbon bond conjugation, a monocyclic aryl and a condensed ring aryl connected by carbon-carbon bond conjugation, two or more condensed ring aryl groups connected by carbon-carbon bond conjugation, etc. That is, unless otherwise specified, two or more aromatic groups connected by carbon-carbon bond conjugation can also be regarded as aryl of the present disclosure. Among them, condensed ring aryl refers to a group containing at least two aromatic rings in a molecule, and the aromatic rings are not independent of each other but share two adjacent carbon atoms fused to each other, for example, condensed ring aryl can include: bicyclic condensed aryl (e.g., naphthyl), tricyclic condensed aryl (e.g., phenanthrenyl, fluorenyl, anthracenyl), etc. The aryl does not contain heteroatoms such as B, N, O, S, P, Se, and Si. For example, in the present disclosure, biphenyl, terphenyl, etc. are aryl groups. Aryl groups may include, but are not limited to, phenyl, naphthyl, fluorenyl, anthracenyl, phenanthrenyl, biphenyl, terphenyl, quaterphenyl, pentaphenyl, benzo[9,10]phenanthrenyl, pyrenyl, benzofluoranthenyl, etc.

[0117] In the exemplary embodiments of the present disclosure, the described "aryl group" may contain 6 to 20 carbon atoms. In some exemplary embodiments, the number of carbon atoms in the aryl group may be 6 to 19; in other exemplary embodiments, the number of carbon atoms in the aryl group may be 6 to 14; in yet other exemplary embodiments, the number of carbon atoms in the aryl group may be 6 to 8. For example, in the present disclosure, the number of carbon atoms in the aryl group may be 6, 10, 12, 13, 14, 15, 18, 20, etc. Of course, the number of carbon atoms may also be other numbers, which are not listed here one by one. In the present disclosure, biphenyl can be understood as an aryl group substituted with a phenyl group, and can also be understood as an unsubstituted aryl group.

[0118] In the exemplary embodiments of the present disclosure, the arylene group may refer to a divalent group formed by an aryl group losing one hydrogen atom.

[0119] In the exemplary embodiments of the present disclosure, the substituted aryl group may be an aryl group in which one or more hydrogen atoms are replaced by groups such as deuterium atoms, halogen groups, cyano groups, aryl groups, heteroaryl groups, alkyl groups, cycloalkyl groups, etc. For example, the aryl group substituted with a heteroaryl group may include, but is not limited to, a phenyl group substituted with a dibenzofuranyl group, a phenyl group substituted with a dibenzothiophene group, a phenyl group substituted with a pyridine group, etc. The number of carbon atoms of the substituted aryl group refers to the total number of carbon atoms of the aryl group and the substituents on the aryl group. For example, a substituted aryl group with 18 carbon atoms refers to a total number of carbon atoms of the aryl group and its substituents of 18. For example, the aryl group as a substituent may include, but is not limited to, a phenyl group, a naphthyl group, a biphenyl group, etc.

[0120] In the exemplary embodiments of the present disclosure, heteroaryl refers to a monovalent aromatic ring or a derivative thereof containing at least one heteroatom in the ring, and the heteroatom may be at least one of B, O, N, P, Si, Se and S. The heteroaryl may be a monocyclic heteroaryl or a polycyclic heteroaryl, for example, the heteroaryl may be a single aromatic ring system, or may be a plurality of aromatic ring systems conjugated by carbon-carbon bonds, and any aromatic ring system is an aromatic monocyclic ring or an aromatic condensed ring. For example, the heteroaryl may include, but is not limited to, thienyl, furanyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidyl, triazine, acridinyl, pyridazinyl, pyrazinyl, quinolyl, quinazolinyl, quinoxalinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolyl, indolyl, carbazolyl, benzoxazolyl, benzimidazolyl , benzothiazolyl, benzotriazolyl, benzocarbazolyl, benzothienyl, dibenzothienyl, thienothiphenyl, benzofuranyl, phenanthrolinyl, isoxazolyl, thiadiazolyl, benzothiazolyl, phenothiazinyl, silafluorenyl, dibenzofuranyl, and N-arylcarbazolyl (such as N-phenylcarbazolyl), N-heteroarylcarbazolyl (such as N-pyridylcarbazolyl), N-alkylcarbazolyl (such as N-methylcarbazolyl), etc., but not limited thereto. Among them, thienyl, furanyl, phenanthrolinyl, etc. are heteroaryl groups of a single aromatic ring system type, and N-arylcarbazolyl, N-heteroarylcarbazolyl, etc. are heteroaryl groups of a polycyclic system type connected by conjugation of carbon-carbon bonds. The heteroaryl group of the present disclosure may contain 5 to 20 carbon atoms. In some exemplary embodiments, the number of carbon atoms in the heteroaryl group may be 5 to 10, and in other exemplary embodiments, the number of carbon atoms in the aryl group may be 5 to 19. For example, the number of carbon atoms in the heteroaryl group may be 5, 6, 7, 8, 9, 10, 11, 12, 13, 18, 19 or 20, etc., and the embodiments of the present disclosure are not limited thereto.

[0121] In the exemplary embodiments of the present disclosure, a heteroarylene group refers to a divalent group formed by a heteroaryl group losing a hydrogen atom.

[0122] In the exemplary embodiments of the present disclosure, the substituted heteroaryl group may be a heteroaryl group in which one or more hydrogen atoms are replaced by groups such as deuterium atoms, halogen groups, cyano groups, aryl groups, heteroaryl groups, alkyl groups, cycloalkyl groups, etc. The aryl-substituted heteroaryl group may include, but is not limited to, a phenyl-substituted dibenzofuranyl group, a phenyl-substituted dibenzothienyl group, an N-phenylcarbazolyl group, etc. In addition, the number of carbon atoms of the substituted heteroaryl group refers to the total number of carbon atoms of the heteroaryl group and the substituents on the heteroaryl group. Among them, the halogen group may include fluorine, iodine, bromine, chlorine, etc.

[0123] In the exemplary embodiments of the present disclosure, the heteroaryl group as a substituent may include, but is not limited to, a pyridyl group, a benzimidazolyl group, a benzothiazolyl group, a benzoxazolyl group, a benzopyridyl group, a benzotriazolyl group, and the like.

[0124] In the exemplary embodiments of the present disclosure, fused refers to any ring structure herein fused to an existing ring structure in the disclosed compound. When the fused ring is a heterocyclyl ring or a heteroaryl ring, any carbon atom on the existing ring structure that becomes part of the fused heterocyclyl ring or the fused heteroaryl ring is replaced by a nitrogen atom. Fused aryl refers to an aryl ring as defined herein that is fused to at least one other ring (e.g., an aryl ring, a heterocyclyl ring, or a heteroaryl ring). Fused bicyclic aryl refers to a fused aryl fused to one other ring.

[0125] In the exemplary embodiments of the present disclosure, an aromatic amine group refers to an amine having an aromatic substituent, that is, -NH2, -NH or a nitrogen-containing group connected to an aromatic hydrocarbon.

[0126] In the exemplary embodiments of the present disclosure, the molecular structure of the cycloalkylnaphthalene group may include two parts: a naphthalene-connected five-membered ring and an alkyl group, wherein the naphthalene-connected five-membered ring is formed by connecting two benzene rings with an external five-membered ring, and the alkyl group is a hydrocarbon group consisting of a carbon chain and hydrogen atoms. For example, the alkyl group may be an alkyl group of different lengths such as methyl, ethyl, and propyl.

[0127] The following takes the case where the covering layer material is selected from a compound having a structure represented by formula (3-1) (denoted as compound 1) as an example to illustrate the synthesis process of compound 1.

[0128] The synthesis process of compound 1 is as follows:

[0129]

[0130] The synthesis process of compound 1 may include:

[0131] 1. Synthesis of intermediate: Add 200 mL of toluene solvent to the reaction flask, then add raw material 1 (1 mol) and raw material 2 (1.1 mol) in turn to 200 mL of toluene solvent, heat to 110°C, stir to dissolve and continuously introduce nitrogen in small amounts, then add sodium tert-butoxide (1.5 mol), XantPhos (4,5-bis(diphenylphosphine-9,9-dimethylxanthene)) (0.02 mol) and Pd(AcO)2 (palladium acetate) (0.01 mol), react and reflux, the solution turns black, and floccules gradually appear after continuous reaction. React for 7 hours, filter and rinse with dichloromethane, and obtain the intermediate by purification means such as extraction and recrystallization.

[0132] 2. Synthesis of compound 1: Subsequently, 150 mL of toluene solvent was added to the reaction flask, and then the intermediate (1 mol) and raw material 3 (1.05 mol) were added to the 150 mL toluene solvent, stirred and heated to 110°C, refluxed for 30 minutes, the solution became clear, and sodium tert-butoxide (2 mol), Sphos (2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl) (0.04 mol) and Pd2(dba)3 (tri(dibenzylideneacetone)dipalladium) (0.02 mol) were added, and the reaction was continued for 7 hours. The mixture was filtered and rinsed with dichloromethane, and compound 1 was obtained by purification means such as extraction, column chromatography separation, and recrystallization, with a purity of 99.12% and a yield of 86%.

[0133] In addition, the synthesis process of Compounds 2 to 53 is similar to the synthesis process of Compound 1 in the above example. Compounds 2 to 53 can be synthesized by referring to the synthesis principle in the above example, and they are not listed one by one here.

[0134] Table 1 is a comparison of the refractive index of the compound materials and comparative materials at different wavelengths in the exemplary embodiments of the present disclosure. As shown in Table 1, the compound materials in the exemplary embodiments of the present disclosure include: Compound 1, Compound 9 Compound 14, Compound 15, Compound 22, Compound 23, Compound 28, Compound 30, and Compound 43; the comparative materials include: a compound with a structure as shown in Formula (5-1) (referred to as comparative material CP-1) and a compound with a structure as shown in Formula (5-2) (referred to as comparative material CP-2). Among them, the refractive index is measured by an ellipsometer test; the instrument scanning range is 245 to 1000nm; a silicon wafer evaporated film is used, and the material film thickness is 50nm, and the results shown in Table 1 can be obtained.

[0135]

[0136] Table 1. Refractive index of the disclosed materials and comparative examples at different wavelengths

[0137]

[0138]

[0139] It can be seen from the data in Table 1 that at different wavelengths (such as 460nm, 530nm and 620nm), compared with the refractive index of the comparative material CP-1 and the comparative material CP-2, the compound materials in the present disclosure have a significant improvement in refractive index. Since the refractive index is an important physical parameter of the covering layer material, the refractive index directly determines the light coupling efficiency of the device. Therefore, using the compound materials in the present disclosure as the covering layer in the organic electroluminescent device in the exemplary embodiment of the present disclosure can significantly improve the refractive index of the covering layer, which is beneficial to the light coupling output of the device and improves the light extraction efficiency of the device, thereby improving the luminous efficiency and life of the entire organic electroluminescent device.

[0140] Table 2 is a performance comparison result of the device in the exemplary embodiment of the present disclosure and the comparative device. As shown in Table 2, the device in the exemplary embodiment of the present disclosure includes: D1, D1A, D14, D14A, D22, D22A, D23, D23A, D28, D28A, D43 and D43A; the comparative device includes: R1, R2, R3 and R4. The device structure is: ITO / Ag / ITO (80 / 1000 / 80nm) / HIL (10nm) / HTL (110nm) / EBL (5nm) / BH:BD (20nm, 3%) / HBL (5nm) / ETL:LIQ (30nm, 50%) / EIL (1nm) / Mg:Ag (13nm) / CPL (65nm). Among them, the anode is ITO / Ag / ITO, and the anode thickness is 80 / 1000 / 80nm; the cathode is Mg:Ag alloy, and the cathode thickness is 13nm; BH:BD (20nm, 3%) means that the blue light host material BH and the blue light guest material BD are co-evaporated at a volume ratio of 97:3 to form an emitting layer (EML), and the thickness of the emitting layer is 20nm; ETL:LIQ (30nm, 50%) means that the electron transport layer (ETL) adopts a doping structure, and the guest material in the electron transport layer adopts LIQ (an organic salt, 8-hydroxyquinoline lithium), the doping ratio is 50%, and the thickness of the electron transport layer is 30nm. The thickness of the hole injection layer (HIL) is 10nm; the thickness of the hole transport layer (HTL) is 110nm; the thickness of the electron blocking layer (EBL) is 5nm; the thickness of the hole blocking layer (HBL) is 5nm; the thickness of the electron injection layer (EIL) is 1nm; the thickness of the capping layer (CPL) is 65nm.

[0141] The comparative materials include: a compound having a structure as shown in formula (6-1) (referred to as comparative compound HTL1) and a compound having a structure as shown in formula (6-2) (referred to as comparative compound HTL2).

[0142]

[0143] Preparation process of device D1: The prepared ITO substrate is cleaned and dried, and HIL material, HTL material (using comparative material HTL1), and EBL material are sequentially evaporated on the anode (ITO); then, the light-emitting layer BH:BD material is evaporated; HBL material, ETL material, and EIL material are evaporated on the light-emitting layer; then, the cathode is evaporated; subsequently, CPL material (using compound 1 in the present disclosure) is evaporated on the cathode to obtain device D1.

[0144] The preparation process of other devices is similar to that of device D1, and the preparation process of device D1 can be used to prepare other devices. Among them, the preparation process of device D1A: replace the HTL material in device D1 with compound 1A, and the rest remains unchanged. The preparation process of device D14: replace the CPL material in device D1 with compound 14, and the rest remains unchanged. The preparation process of device D14A: replace the HTL material in device D1 with compound 14A, and replace the CPL material in device D1 with compound 14, and the rest remains unchanged. The preparation process of device D22: replace the CPL material in device D1 with compound 22, and the rest remains unchanged. The preparation process of device D22A: replace the HTL material in device D1 with compound 22A, and replace the CPL material in device D1 with compound 22, and the rest remains unchanged. The preparation process of device D23: replace the CPL material in device D1 with compound 23, and the rest remains unchanged. Preparation process of device D23A: replace the HTL material in device D1 with compound 23A, replace the CPL material in device D1 with compound 23, and keep the rest unchanged. Preparation process of device D28: replace the HTL material in device D1 with the comparative material HTL2, replace the CPL material in device D1 with compound 28, and keep the rest unchanged. Preparation process of device D28A: replace the HTL material in device D1 with compound 28A, replace the CPL material in device D1 with compound 28, and keep the rest unchanged. Preparation process of device D43: replace the HTL material in device D1 with the comparative material HTL2, replace the CPL material in device D1 with compound 43, and keep the rest unchanged. Preparation process of device D43A: replace the HTL material in device D1 with compound 43A, replace the CPL material in device D1 with compound 43, and keep the rest unchanged. Preparation process of comparative device R1: replace the HTL material in device D1 with the chemical comparison material HTL2, replace the CPL material in device D1 with the comparison material CP-1, and other things remain unchanged. Preparation process of comparative device R2: replace the HTL material in device D1 with the chemical comparison material HTL, replace the CPL material in device D1 with the comparison material CP-2, and other things remain unchanged. Preparation process of comparative device R3: replace the CPL material in device D1 with the comparison material CP-1, and other things remain unchanged. Preparation process of comparative device R4: replace the CPL material in device D1 with the comparison material CP-2, and other things remain unchanged.

[0145] Table 2. Performance comparison between the device disclosed in the present invention and the device of the comparative example

[0146] Devices HTL Materials CPL Materials Voltage (V) Efficiency (cd / A) Lifespan (h) D1 Comparative HTL1 Compound 1 99％ 103％ 103％ D1A Compound 1A Compound 1 98％ 105％ 103％ D14 Comparative HTL1 Compound 14 98％ 104％ 105％ D14A Compound 14A Compound 14 97％ 106％ 105％ D22 Comparative HTL1 Compound 22 99％ 106％ 101％ D22A Compound 22A Compound 22 98％ 107％ 102％ D23 Comparative HTL1 Compound 23 98％ 106％ 102％ D23A Compound 23A Compound 23 98％ 106％ 102％ D28 Comparative HTL2 Compound 28 98％ 107％ 101％ D28A Compound 28A Compound 28 97％ 109％ 103％ D43 Comparative HTL2 Compound 43 99％ 104％ 100％ D43A Compound 43A Compound 43 99％ 106％ 100％ R1 Comparative HTL2 Comparative CP-1 100％ 100％ 100％ R2 Comparative HTL2 Comparative CP-2 100％ 103％ 100％ R3 Comparative HTL1 Comparative CP-1 100％ 101％ 100％ R4 Comparative HTL1 Comparative CP-2 100％ 102％ 100％

[0147] It can be seen from the data in Table 2 that the devices D1, D1A, D14, D14A, D22, D22A, D23, D23A, D28, D28A, D43 and D43A adopt the scheme in the present disclosure, and their device efficiency and life are improved to varying degrees, and their voltage is reduced to varying degrees. The present disclosure introduces cycloalkylnaphthalene groups to increase the refractive index of the CPL material and increase the mobility and life of the hole transport layer, thereby improving the efficiency and life of the entire OLED device.

[0148] For example, it can be seen from the data in Table 2 that, compared with the comparative devices R3 and R4, the devices D1, D14, D22, and D23 in the present disclosure have a significant improvement in luminous efficiency and a significant reduction in voltage, indicating that the introduction of cycloalkylnaphthalene groups into the CPL material of the device in the present disclosure can improve the refractive index and thermal stability, which is beneficial to the light coupling output of the device, improves the mobility and life of the hole transport layer, improves the efficiency of the device, and reduces the voltage of the device; and the devices D1A, D14A, D22A, and D23A in the present disclosure have a more significant improvement in luminous efficiency and a more significant reduction in voltage, indicating that the CPL material of the device in the present disclosure has a high refractive index and high thermal stability, which can reduce the voltage and improve the efficiency of the device, and the HTL material of the device in the present disclosure has a relatively fast mobility and a more matched energy level, which can further reduce the voltage and improve the efficiency of the device, thereby more significantly improving the performance of the OLED device.

[0149] For another example, it can be seen from the data in Table 2 that, compared with the comparative devices R1 and R2, the devices D28 and D43 in the present disclosure have a significant improvement in luminous efficiency and a significant reduction in voltage, indicating that the CPL material of the device in the present disclosure has a high refractive index and high thermal stability, which is beneficial to the light coupling output of the device, improves the efficiency of the device, and reduces the voltage of the device; and the devices D28A and D43A in the present disclosure have a more significant improvement in luminous efficiency and a more significant reduction in voltage, indicating that the CPL material of the device in the present disclosure has a high refractive index and high thermal stability, which can reduce the voltage and improve the efficiency of the device, and the HTL material of the device in the present disclosure has a relatively fast hole mobility and a more matched energy level, which can further reduce the voltage and improve the efficiency of the device, thereby more significantly improving the performance of the OLED device.

[0150] Thus, the organic electroluminescent device in the exemplary embodiment of the present disclosure, by introducing a cycloalkylnaphthalene group into the CPL material, improves the refractive index and thermal stability of the CPL material, so that the CPL material has a strong electron-donating ability, thereby improving the hole mobility of the film layer region (such as the hole transport layer) between the anode and the light-emitting layer, and, relative to naphthalene, increases the molecular weight, improves the device life, thereby improving the luminous efficiency and life of the entire organic electroluminescent device. And, by setting the HTL material to include an aromatic amine group and a cycloalkylnaphthalene group, the mobility and hole transport rate of the HTL material can be increased, so that the HTL material has a more matched energy level, thereby further reducing the voltage and further improving the efficiency of the device, and because the photoluminescence (PL) spectrum of the aromatic amine material ranges from 400nm to 450nm, it is beneficial to improve the device efficiency. Then, better luminous efficiency is achieved, low voltage and long life are achieved, and high-performance OLED devices are obtained.

[0151] The disclosed embodiment further provides a display substrate, comprising: a substrate and a plurality of light-emitting devices arranged on one side of the substrate, at least one of the plurality of light-emitting devices being an organic electroluminescent device described in one or more of the above embodiments.

[0152] An embodiment of the present disclosure further provides a display device, which may include: a display substrate described in one or more of the above embodiments.

[0153] Here, the display device may be a product with an image (including a static image or a dynamic image, wherein the dynamic image may be a video) display function. In some exemplary embodiments, the display device may include, but is not limited to, any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a car display, or a navigator. Here, the embodiment of the present disclosure does not limit the type of display device. The other essential components of the display device should be understood by a person of ordinary skill in the art, and will not be elaborated here, nor should they be used as a limitation to the present disclosure.

[0154] In addition, the display device in the embodiment of the present disclosure may include other necessary components and structures in addition to the structures illustrated in the above embodiments, for example, a circuit for providing an electrical signal to the display substrate to drive the display substrate to emit light, which may be called a control circuit, which may include at least one of a circuit board and an integrated circuit (IC) electrically connected to the display substrate; another example, a power supply system for supplying power to the display substrate, etc. Those skilled in the art may design and supplement accordingly according to the type and use requirements of the display substrate, and will not be described in detail here.

[0155] The description of the above display device embodiment is similar to the description of the above organic electroluminescent device embodiment, and has similar beneficial effects as the organic electroluminescent device embodiment. For technical details not disclosed in the display device embodiment of the present disclosure, those skilled in the art should refer to the description in the organic electroluminescent device embodiment of the present disclosure for understanding, and no further description is given here.

[0156] Although the embodiments disclosed in the present disclosure are as above, the above contents are only embodiments adopted for facilitating the understanding of the present disclosure and are not intended to limit the present disclosure. Any technician in the field to which the present disclosure belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present disclosure, but the scope of patent protection of the present disclosure shall still be subject to the scope defined in the attached claims.

Claims

1. An organic electroluminescent device, comprising: An anode, a first functional layer, a light-emitting layer, a second functional layer, a cathode and a covering layer are sequentially stacked, wherein the material of the covering layer comprises: a compound having a structure as shown in formula (I) or a compound having a structure as shown in formula (II); In formula (I) and formula (II), L3, L4 and L5 are each independently selected from any one of the following groups: a single bond, a substituted or unsubstituted alkyl group having 2 to 30 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a substituted or unsubstituted fused aryl group having 6 to 20 carbon atoms, and a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms; at least one of Ar3 and Ar4 is selected from any one of the groups having structures shown in formula (2-1) to formula (2-7); in, represents a chemical bond; X is selected from CR, NR, oxygen or sulfur; CR is a carbon atom connected to hydrogen or an alkyl group; NR is a nitrogen atom connected to hydrogen or an alkyl group; Y, Y1, Y2, Y3 and Y4 are each independently CR or nitrogen, and only one of Y1 to Y4 is nitrogen; Z is CR or NR; R is selected from any one of the following: hydrogen, deuterium, an alkyl group having 2 to 30 carbon atoms, an arylene group having 6 to 20 carbon atoms, and a heteroaryl group having 5 to 20 carbon atoms; Ar is selected from a group containing only one heteroatom, and the heteroatom is nitrogen, oxygen or sulfur.

2. The organic electroluminescent device according to claim 1, characterized in that: Ar3 and Ar4 that are not selected from the structures shown in formulas (2-1) to (2-7) are selected from any one of the following groups: a substituted or unsubstituted alkyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms containing one or more heteroatoms; wherein the heteroatom is nitrogen, oxygen or sulfur.

3. The organic electroluminescent device according to claim 1, characterized in that: Ar3 and Ar4 that are not selected from the structures shown in formula (2-1) to formula (2-7) are selected from any one of the groups with the structures shown below:

4. The organic electroluminescent device according to claim 1, characterized in that: The material of the covering layer is selected from any one of the compounds with structures shown in formula (3-1) to formula (3-53):

5. The organic electroluminescent device according to any one of claims 1 to 4, characterized in that: The first functional layer comprises multiple organic layers, and the material of at least one layer of the multiple organic layers comprises: a compound having a structure as shown in formula (III); In formula (III), G1 and R are each independently selected from any one of the following groups: hydrogen, deuterium, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms; L1 and L2 are each independently selected from any one of the following groups: a direct bond, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms; Ar1 ​​and Ar2 are each independently selected from any one of the following groups: a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 carbon atoms; (D)m represents a group having m deuterium atoms, (D)n represents a group having n deuterium atoms, and m and n are integers from 0 to 4; (D)o represents a group having o deuterium atoms, and o is an integer from 0 to 8; p is an integer from 0 to 2.

6. The organic electroluminescent device according to claim 5, characterized in that: In formula (III) Any one selected from the structures shown in formula (a1) to formula (a32):

7. The organic electroluminescent device according to claim 5, characterized in that: At least one of the multiple organic layers is selected from any one of the compounds represented by the structures of formulae (4-1) to (4-3):

8. The organic electroluminescent device according to claim 5, characterized in that: At least one of the multiple organic layers includes at least one of a hole injection layer, a hole transport layer and an auxiliary light emitting layer.

9. The organic electroluminescent device according to any one of claims 1 to 4, characterized in that: The first functional layer includes a plurality of organic layers, materials of at least two layers of the plurality of organic layers include aromatic amine groups, and materials of at least one layer of the plurality of organic layers include cycloalkylnaphthalene groups.

10. The organic electroluminescent device according to claim 9, characterized in that: At least two of the multi-layer organic layers include at least two of a hole injection layer, a hole transport layer and an auxiliary light-emitting layer, and at least one of the multi-layer organic layers includes at least one of a hole injection layer, a hole transport layer and an auxiliary light-emitting layer.

11. The organic electroluminescent device according to claim 10, characterized in that: The hole injection layer includes the same material as the hole transport layer.

12. A display substrate, comprising: A substrate and a plurality of light-emitting devices arranged on one side of the substrate, at least one of the plurality of light-emitting devices is the organic electroluminescent device according to any one of claims 1 to 11.

13. A display device, comprising: The display substrate as claimed in claim 12.

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