Light-emitting device, preparation method thereof and display device

Abstract

The invention provides a light-emitting device, a preparation method thereof and a display device. The light emitting device includes a composite hole transport layer including a matrix and a discotic liquid crystal component, the discotic liquid crystal component having a hole mobility greater than a hole mobility of the matrix.

Description

Light-emitting device, manufacturing method thereof, and display device Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a light-emitting device and a manufacturing method thereof, and a display apparatus. Background Art

[0002] Light-emitting diodes (LEDs) emit light through the release of energy from the recombination of electrons and holes. These diodes include, but are not limited to, organic light-emitting diodes (OLEDs) and quantum dot light-emitting diodes (QLEDs). Quantum dots, due to their numerous advantages, including high quantum efficiency, narrow excitation spectrum, high photostability, long fluorescence lifetime, and compatibility with solution processing, have enormous potential for high-quality color displays. Quantum dot luminescence technology has become the most promising next-generation self-luminous display technology.

[0003] Summary of the Invention

[0004] According to one aspect of the present disclosure, a light-emitting device is provided, comprising a composite hole transport layer including a host and a discotic liquid crystal component, wherein the hole mobility of the discotic liquid crystal component is greater than that of the host.

[0005] In some embodiments, the hole mobility of the composite hole transport layer is 10 -4 ~10 -3 cm 2 V -1 s -1 .

[0006] In some embodiments, the energy level of the highest occupied molecular orbital of the composite hole transport layer is -6.0 to -5.3 eV.

[0007] In some embodiments, the mass percentage of the discotic liquid crystal component in the composite hole transport layer is 1% to 40%.

[0008] In some embodiments, the discotic liquid crystal component accounts for 20% by weight of the composite hole transport layer.

[0009] In some embodiments, the composite hole transport layer has the general structural formula:

[0010] Among them, R8 includes any one of an alkyl chain, an alkoxy chain, and an alkyl ester chain, and R8 at different positions of the structural formula of the composite hole transport layer are the same or different from each other, and each of R1 to R7 includes any one of a benzene ring, a double bond, cyclohexane, and a hydrogen atom.

[0011] In some embodiments, the discotic liquid crystal component is formed by a discotic liquid crystal monomer, and the discotic liquid crystal monomer has the general structural formula:

[0012] Wherein, R9 is a polymerizable functional group and includes any one of tert-butyl ethyl ester, olefin bond, acrylate, vinyl ether, thiol, and epoxy.

[0013] In some embodiments, R8 is a flexible alkyl chain having 4 to 6 carbon atoms.

[0014] In some embodiments, R8 is any one of butoxy, pentyloxy, hexyloxy, butyl ester, pentyl ester, and hexyl ester.

[0015] In some embodiments, the matrix is ​​configured to cause holes to migrate in an orderly manner in the composite hole transport layer under the action of an electric field.

[0016] In some embodiments, the matrix is ​​formed from a matrix monomer having the general structural formula:

[0017] Wherein, R10 is a polymerizable functional group and includes any one of olefin bond, acrylate, vinyl ether, thiol, and epoxy.

[0018] In some embodiments, each of R1 to R7 is a hydrogen atom, R10 is an olefinic bond, R8 is an alkoxy chain, and R9 is tert-butyl ethyl ester.

[0019] In some embodiments, at least one of R9 and R10 is a UV-polymerizable functional group, and the UV-polymerizable functional group includes at least one difunctional monomer.

[0020] In some embodiments, at least one of R9 and R10 is a thermally polymerizable functional group, and the thermally polymerizable functional group includes at least one difunctional monomer.

[0021] In some embodiments, the discotic liquid crystal component is arranged in an ordered columnar structure in the composite hole transport layer, the height direction of the columnar structure is parallel to the thickness direction of the composite hole transport layer, and the matrix is ​​arranged at least between the columnar structures.

[0022] In some embodiments, the hole mobility of the discotic liquid crystal component is 10 -3 ~10 -2 cm2 V -1 s -1 .

[0023] In some embodiments, the energy level of the highest occupied molecular orbital of the discotic liquid crystal component is -6.5 to -5.5 eV, and the energy level of the lowest unoccupied molecular orbital of the discotic liquid crystal component is -3.0 to -1.8 eV.

[0024] In some embodiments, the light-emitting device further includes: a first electrode layer; a hole injection layer located between the first electrode layer and the composite hole transport layer; a light-emitting layer located on a side of the composite hole transport layer away from the first electrode layer; an electron transport layer located on a side of the light-emitting layer away from the first electrode layer; an electron injection layer located on a side of the electron transport layer away from the first electrode layer; and a second electrode layer located on a side of the electron injection layer away from the first electrode layer.

[0025] In some embodiments, the light emitting layer includes quantum dots configured to emit blue light.

[0026] In some embodiments, the material of the first electrode layer is indium tin oxide, the material of the hole injection layer is poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, the material of the electron transport layer is zinc oxide, the material of the electron injection layer is polyvinyl pyrrolidone, the material of the second electrode layer is aluminum, the wavelength of the blue light emitted by the light-emitting layer is 455-465 nm, the mass proportion of the discotic liquid crystal component in the composite hole transport layer is 20%, the mass proportion of the matrix in the composite hole transport layer is 80%, and the structural formula of the composite hole transport layer is:

[0027] In some embodiments, the light-emitting layer includes quantum dots configured to emit red light, the mass proportion of the discotic liquid crystal component in the composite hole transport layer is 25% to 30%, and the wavelength of the red light is 620 to 640 nm.

[0028] In some embodiments, the light-emitting layer includes quantum dots configured to emit green light, the mass proportion of the discotic liquid crystal component in the composite hole transport layer is 20% to 25%, and the wavelength of the green light is 525 to 535 nm.

[0029] According to another aspect of the present disclosure, a display device is provided, comprising a plurality of light-emitting devices described in any one of the foregoing embodiments.

[0030] According to another aspect of the present disclosure, a method for preparing a light-emitting device is provided, comprising: providing a mixed solution of a matrix monomer and a discotic liquid crystal monomer; removing the solvent from the mixed solution and performing an annealing treatment to allow the discotic liquid crystal monomer to self-assemble; and polymerizing the matrix monomer and the self-assembled discotic liquid crystal monomer to form a composite hole transport layer comprising a matrix and a discotic liquid crystal component, wherein the hole mobility of the discotic liquid crystal component is greater than the hole mobility of the matrix.

[0031] In some embodiments, the removing of the solvent from the mixed solution and performing annealing to allow the discotic liquid crystal monomers to self-assemble comprises: the discotic liquid crystal monomers self-assembling and forming an ordered columnar structure, the columnar structure being embedded in the matrix monomer, and the height direction of the columnar structure being parallel to the thickness direction of the composite hole transport layer.

[0032] In some embodiments, polymerizing the matrix monomer and the self-assembled discotic liquid crystal monomer to form a composite hole transport layer comprising a matrix and a discotic liquid crystal component comprises: irradiating the matrix monomer and the self-assembled discotic liquid crystal monomer with ultraviolet light to cause ultraviolet polymerization of the matrix monomer and the self-assembled discotic liquid crystal monomer to form the composite hole transport layer.

[0033] In some embodiments, polymerizing the matrix monomer and the self-assembled discotic liquid crystal monomer to form a composite hole transport layer comprising a matrix and a discotic liquid crystal component comprises heating the matrix monomer and the self-assembled discotic liquid crystal monomer to thermally polymerize the matrix monomer and the self-assembled discotic liquid crystal monomer to form the composite hole transport layer.

[0034] In some embodiments, providing a mixed solution of matrix monomers and discotic liquid crystal monomers includes: dissolving the matrix monomers and the discotic liquid crystal monomers in a toluene solvent at a mass ratio of 8:2 to form the mixed solution; removing the solvent from the mixed solution and performing annealing treatment to allow the discotic liquid crystal monomers to self-assemble, including: gradually evaporating the solvent at a first temperature until it is removed, and performing annealing treatment within a first time period to allow the discotic liquid crystal monomers to self-assemble; polymerizing the matrix monomers and the self-assembled discotic liquid crystal monomers to form a composite hole transport layer including matrix and discotic liquid crystal components, including: heating the matrix monomers and the self-assembled discotic liquid crystal monomers at a second temperature for a second time period, and thermally polymerizing the matrix monomers and the self-assembled discotic liquid crystal monomers to form the composite hole transport layer, wherein the structural formula of the matrix monomer is The structural formula of the discotic liquid crystal monomer is The structural formula of the composite hole transport layer is

[0035] In some embodiments, the method further includes: forming a first electrode layer; forming a hole injection layer on the first electrode layer; coating the mixed solution on the side of the hole injection layer away from the first electrode layer to form the composite hole transport layer; forming a light-emitting layer on the side of the composite hole transport layer away from the first electrode layer; forming an electron transport layer on the side of the light-emitting layer away from the first electrode layer; forming an electron injection layer on the side of the electron transport layer away from the first electrode layer; and forming a second electrode layer on the side of the electron injection layer away from the first electrode layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly describe the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] FIG1 is a schematic cross-sectional view showing a partial structure of a light emitting device according to an embodiment of the present disclosure;

[0038] FIG2 shows the general structural formula of the composite hole transport layer according to an embodiment of the present disclosure;

[0039] FIG3 shows the general structural formula of a discotic liquid crystal monomer according to an embodiment of the present disclosure;

[0040] FIG4 shows the general structural formula of a matrix monomer according to an embodiment of the present disclosure;

[0041] FIG5A is a schematic cross-sectional view showing a partial structure of a light emitting device according to an embodiment of the present disclosure;

[0042] FIG5B shows a schematic cross-sectional view of a partial structure of another light emitting device according to an embodiment of the present disclosure;

[0043] FIG6 shows the structural formula of a discotic liquid crystal monomer according to an embodiment of the present disclosure;

[0044] FIG7 shows the structural formula of a matrix monomer according to an embodiment of the present disclosure;

[0045] FIG8 shows the structural formula of a composite hole transport layer formed by polymerizing the discotic liquid crystal monomer of FIG6 and the matrix monomer of FIG7 ;

[0046] FIG9 shows another structural formula of a discotic liquid crystal monomer according to an embodiment of the present disclosure;

[0047] FIG10 shows another structural formula of a discotic liquid crystal monomer according to an embodiment of the present disclosure;

[0048] FIG11 shows another structural formula of a discotic liquid crystal monomer according to an embodiment of the present disclosure;

[0049] FIG12 shows another structural formula of a discotic liquid crystal monomer according to an embodiment of the present disclosure;

[0050] FIG13 shows another structural formula of a discotic liquid crystal monomer according to an embodiment of the present disclosure;

[0051] FIG14 shows a block diagram of an array substrate according to an embodiment of the present disclosure;

[0052] FIG15 shows a schematic structural diagram of a display device according to an embodiment of the present disclosure;

[0053] FIG16 shows a flow chart of a method for preparing a light-emitting device according to an embodiment of the present disclosure;

[0054] FIG17 shows a polarizing microscope image of a composite hole transport layer before annealing according to an embodiment of the present disclosure; and

[0055] FIG18 shows a polarizing microscope image of the composite hole transport layer after annealing according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0056] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present disclosure.

[0057] Quantum dot light-emitting diodes have become a competitive next-generation display technology due to their advantages such as wide color gamut, spectral tunability, and high color saturation. The industry's development focus is mostly on the material processing or structural design of the functional layers of red quantum dot light-emitting diode devices and green quantum dot light-emitting diode devices, whose external quantum efficiency (EQE) can be as high as 30%. In contrast, the development of the external quantum efficiency of blue quantum dot light-emitting diode devices lags far behind that of red quantum dot light-emitting diode devices and green quantum dot light-emitting diode devices, and has become a key obstacle to the practical application of full-color display of quantum dot light-emitting diode devices. Severe non-radiative recombination caused by unbalanced charge injection is one of the main factors causing the above obstacles, and unbalanced charge injection is mainly related to insufficient hole injection.

[0058] Quantum dot light emitting diode devices include structures such as electron transport layer and hole transport layer. Generally speaking, compared with the electron transport layer, the hole transport layer is more mismatched with the energy level of the quantum dot light emitting diode device. In addition, the hole mobility of the hole transport layer (for example, about 10 -6 ~10 - 3 cm 2 V -1 s -1 ) is significantly lower than the electron mobility of the electron transport layer (e.g., about 10 -3 ~10 -2 cm 2 V -1 s -1 How to improve the hole mobility of the hole transport layer and how to better match the energy level of the hole transport layer with the energy level of the quantum dot light-emitting diode device have a crucial impact on improving the performance of blue quantum dot light-emitting diode devices.

[0059] In order to overcome the problems existing in the prior art, the inventors of this application proposed a composite hole transport layer, which has at least one of high hole mobility and an energy level matching the quantum dot light-emitting diode device, thereby significantly improving the performance of the blue quantum dot light-emitting diode device.

[0060] Figure 1 shows a schematic cross-sectional view of a partial structure of a light-emitting device 100 according to an embodiment of the present disclosure. As shown in Figure 1, the light-emitting device 100 includes a composite hole transport layer 101, which includes a matrix 102 and a discotic liquid crystal component 103. The hole mobility of the discotic liquid crystal component 103 is greater than that of the matrix 102.

[0061] By introducing a discotic liquid crystal component 103 having high hole mobility into the composite hole transport layer 101, the discotic liquid crystal component 103 can construct a molecular channel with higher hole mobility in the composite hole transport layer 101, thereby enabling the composite hole transport layer 101 to have a higher hole mobility. As previously mentioned, since the hole mobility in quantum dot light-emitting diode devices is generally lower than the electron mobility, improving the hole mobility of the composite hole transport layer 101 can promote the balance between the hole mobility and the electron mobility of the light-emitting device 100, thereby improving the charge injection and transport capabilities, and thus significantly improving the overall efficiency and life of the light-emitting device 100.

[0062] In some embodiments, the hole mobility of the composite hole transport layer 101 is 10 -4 ~10 -3 cm 2 V -1 s -1 , for example it can be 10 -4cm 2 V -1 s -1 , 10 -3 cm 2 V -1 s -1 It can be seen that compared with the hole mobility of conventional hole transport layer 10 -6 ~10 -3 cm 2 V -1 s -1 The introduction of the discotic liquid crystal component 103 with high hole mobility significantly improves the hole mobility of the composite hole transport layer 101, thereby promoting the balance between the hole mobility and the electron mobility of the light-emitting device 100, thereby significantly improving the overall efficiency and life of the light-emitting device 100.

[0063] In some embodiments, the energy level of the highest occupied molecular orbital (HOMO) of the composite hole transport layer 101 is -6.0 to -5.3 eV, such as -6.0 eV, -5.8 eV, -5.6 eV, -5.4 eV, -5.3 eV, etc. Therefore, the composite hole transport layer 103 not only has high hole mobility, but also has a deeper HOMO energy level. This deeper HOMO energy level can better match the energy level of the light-emitting device 100, thereby helping to further promote the overall improvement of the efficiency and life of the light-emitting device 100. In some examples, the matrix 102 can have a deeper HOMO energy level, such as a HOMO energy level of -5.8 to -5.2 eV. The HOMO energy level of the matrix 102 in the composite hole transport layer 101 causes the composite hole transport layer 101 to exhibit a deeper HOMO energy level as a whole.

[0064] In some embodiments, the energy level of the lowest unoccupied molecular orbital (LUMO) of the composite hole transport layer 101 is -3.3 to -1.9 eV, such as -3.3 eV, -2.8 eV, -2.3 eV, -2.0 eV, and -1.9 eV.

[0065] In some embodiments, the composite hole transport layer 101 has a thickness of 100-150 nm, such as 100 nm, 125 nm, 150 nm, etc. In some embodiments, the composite hole transport layer 101 has a surface roughness of 1-5 nm, such as 1 nm, 3 nm, 5 nm, etc.

[0066] As shown in Figure 1, the discotic liquid crystal component 103 is arranged in an ordered columnar structure in the composite hole transport layer 101. The height direction of the columnar structure is parallel to the thickness direction of the composite hole transport layer 101, and the matrix 102 is arranged at least between multiple columnar structures. During the preparation of the composite hole transport layer 101, the discotic liquid crystal monomers self-assemble to form ordered columnar structures with high hole mobility. The height direction of each columnar structure is parallel to the thickness direction of the composite hole transport layer 101 to form an ordered molecular orientation. This can construct higher hole mobility molecular channels in the composite hole transport layer 101, promoting carrier transport.

[0067] The matrix 102 and the discotic liquid crystal component 103 in the composite hole transport layer 101 need to be in an appropriate ratio, as the mass fraction of the discotic liquid crystal component 103 in the composite hole transport layer 101 has a significant impact on the performance of the composite hole transport layer 101. Specifically, if the mass fraction of the discotic liquid crystal component 103 in the composite hole transport layer 101 is too low, the hole mobility of the composite hole transport layer 101 will be poor; if the mass fraction of the discotic liquid crystal component 103 in the composite hole transport layer 101 is too high, the film uniformity of the composite hole transport layer 101 will deteriorate, affecting the potential barrier at the functional layer interface, thereby reducing carrier transport. Therefore, it is necessary to comprehensively consider the carrier mobility and film uniformity of the composite hole transport layer 101 and rationally design the relative ratio of the discotic liquid crystal component 103 to the matrix 102 to ensure that the composite hole transport layer 101 has high hole mobility and excellent film uniformity. In some embodiments, the mass percentage of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 1% to 40%. For example, the mass percentage of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 1%, 5%, 10%, 15%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 30%, 35%, 40%, etc.

[0068] FIG2 shows the general structural formula of the composite hole transport layer 101, that is, the general structural formula of the composite hole transport layer 101 is: Discotic liquid crystal monomers and matrix monomers are polymerized under specific conditions to form the composite hole transport layer 101. In the general structural formula of the composite hole transport layer 101, R8 is a branched chain, and the molecular structure connected to the branched chain R8 corresponds to the discotic core of the discotic liquid crystal monomer. R8 includes, but is not limited to, an alkyl chain, an alkoxy chain, or an alkyl ester chain. In some examples, R8 can be any of butoxy, pentoxy, hexoxy, butyl ester, pentyl ester, and hexyl ester. R8 at different positions in the general structural formula of the composite hole transport layer 101 can be identical, partially identical, or different. In one embodiment, R8 at different positions in the general structural formula of the composite hole transport layer 101 is identical, which improves the symmetry of the general structural formula of the composite hole transport layer 101 and thus improves the liquid crystal properties of the discotic liquid crystal component 103. R1-R7 are branched chains, and the molecular structure connected to the branched chains R1-R7 corresponds to the main chain of the matrix 102. Each of R1-R7 can be a benzene ring, a double bond, cyclohexane, or a hydrogen atom. The general structural formula of the composite hole transport layer 101 shows that the matrix monomer has a rigid core molecular structure, while the discotic liquid crystal monomer has a rigid disc-shaped core and flexible side chains. After specific treatment, the discotic liquid crystal monomer can self-assemble into an ordered molecular stack with high hole mobility and embed into the matrix 102 with good film-forming properties, thereby forming the composite hole transport layer 101. The composite hole transport layer 101 having the above general structural formula combines the good film-forming properties of the matrix 102 with the high mobility characteristics of the discotic liquid crystal component 103.

[0069] To ensure the mobility and polymerization performance of the discotic liquid crystal component 103, the substituent R8 of the discotic liquid crystal monomer can be a flexible alkyl chain of moderate chain length to ensure the formation of liquid crystal molecules. Specifically, the discotic liquid crystal monomer has both a rigid core and flexible segments. In some embodiments, R8 is a flexible alkyl chain having 4 to 6 carbon atoms, for example, a flexible alkyl chain having 4 carbon atoms, a flexible alkyl chain having 5 carbon atoms, or a flexible alkyl chain having 6 carbon atoms.

[0070] FIG3 shows the general structural formula of the discotic liquid crystal monomer, that is, the general structural formula is In the general structural formula of the discotic liquid crystal monomer, the substituents of the discotic liquid crystal monomer include two parts: a substituent functional group R8 and a polymerizable functional group substituent R9. As described above, R8 includes but is not limited to an alkyl chain, an alkoxy chain, or an alkyl ester chain. In some examples, R8 can be any of butoxy, pentoxy, hexoxy, butyl ester, pentyl ester, and hexyl ester. R8 at different positions in the discotic liquid crystal monomer's general structural formula can be identical, partially identical, or different. In one embodiment, R8 at different positions in the discotic liquid crystal monomer's general structural formula are identical, which makes the discotic liquid crystal monomer's general structural formula have better symmetry, thereby making the discotic liquid crystal monomer have better liquid crystal properties. The polymerizable functional group substituent R9 can be tert-butyl ethyl ester, olefinic bond, acrylate, vinyl ether, thiol, or epoxy, etc. As shown in Figure 3, two substituents R9 can be located at two substitution positions that are relatively far apart in the discotic liquid crystal monomer to facilitate cross-linking polymerization. However, this does not necessarily mean that the two substituents R9 must be positioned far apart. As needed, the two substituents R9 can be designed at any two positions within the discotic liquid crystal monomer. Discotic liquid crystal monomers have a rigid disc-shaped core and flexible side chains. After certain treatments, the discotic liquid crystal monomers can self-assemble into an ordered molecular stack with high hole mobility, such as an ordered columnar structure. This can result in the discotic liquid crystal component 103 having high hole mobility.

[0071] The discotic liquid crystal monomer can be a liquid crystal monomer or liquid crystal polymer material containing a UV- or thermally polymerizable functional group, such as derivatives of a discotic mother core such as triphenylene, hexabenzocoronene, and porphyrin.

[0072] In some embodiments, the hole mobility of the discotic liquid crystal component 103 is 10 -3 ~10 -2 cm 2 V -1 s -1 , for example 10 -3 cm 2 V -1 s -1 , 10 -2 cm 2 V -1 s -1 The hole mobility of the discotic liquid crystal component 103 is greater than that of the matrix 102. By introducing the discotic liquid crystal component 103 with high hole mobility into the composite hole transport layer 101, the hole mobility of the composite hole transport layer 101 can be improved as a whole, promoting the balance between the hole mobility and the electron mobility of the light-emitting device 100, thereby significantly improving the overall efficiency and life of the light-emitting device 100.

[0073] In some embodiments, the HOMO energy level of the discotic liquid crystal component 103 is between -6.5 and -5.5 eV, for example, -6.5 eV, -6.3 eV, -6.0 eV, -5.8 eV, and -5.5 eV. The HOMO energy level of the discotic liquid crystal component 103 is compatible with the HOMO energy level of the matrix 102, resulting in the composite hole transport layer 101 having a deeper HOMO energy level (for example, between -6.0 and -5.3 eV). This allows the HOMO energy level of the composite hole transport layer 101 to better match the energy level of the light-emitting device 100, further contributing to an overall improvement in the efficiency and lifespan of the light-emitting device 100. In some embodiments, the LUMO energy level of the discotic liquid crystal component 103 is between -3.0 and -1.8 eV, for example, -3.0 eV, -2.5 eV, -2.0 eV, and -1.8 eV. In some embodiments, the temperature range of the discotic liquid crystal component 103 can be between -20 and 120°C.

[0074] In some embodiments, the matrix 102 in the composite hole transport layer 101 has no hole transport properties, and the high hole mobility of the composite hole transport layer 101 is only achieved by the discotic liquid crystal component 103. In some alternative embodiments, the matrix 102 in the composite hole transport layer 101 also has hole transport properties. The matrix 102 and the discotic liquid crystal component 103 can enable holes to migrate in an orderly manner in the composite hole transport layer 101 under the action of an electric field, thereby achieving hole transport. Therefore, the high hole mobility of the composite hole transport layer 101 depends on the cooperation of the matrix 102 and the discotic liquid crystal component 103, but the hole mobility of the matrix 102 is less than that of the discotic liquid crystal component 103. Figure 4 shows the general structural formula of the matrix monomer, that is, the general structural formula is Matrix monomers include, but are not limited to, TFB, poly-TFD, and CBP-V. In the general structural formula of the matrix monomer, the substituents comprise two components: functional substituent groups R1-R7 and polymerizable functional substituent R10. As previously described, each of R1-R7 can be an olefinic bond, acrylate, vinyl ether, thiol, epoxy, or the like. The polymerizable functional substituent R10 can be a rigid substituent, such as an olefinic bond, acrylate, vinyl ether, thiol, or epoxy. The matrix monomer possesses a rigid core molecular structure, resulting in excellent film-forming properties.

[0075] In some embodiments, the hole mobility of the matrix 102 is 10 -6 ~10 -3 cm 2 V -1 s -1 , for example 10 -6 cm 2 V -1 s -1 , 10-5 cm 2 V -1 s -1 , 10 -4 cm 2 V -1 s -1 , 10 -3 cm 2 V -1 s -1 The HOMO energy level of the matrix 102 is -5.8 to -5.2 eV, for example, -5.8 eV, -5.6 eV, -5.4 eV, -5.2 eV, etc. The LUMO energy level of the matrix 102 is -3.6 to -2.0 eV, for example, -3.6 eV, -3.0 eV, -2.5 eV, -2.0 eV, etc. The matrix 102 has a deeper HOMO energy level, which enables the composite hole transport layer 101 including the matrix 102 to not only have high hole mobility but also have a HOMO energy level that is more closely matched to the energy level of the light-emitting device 100, thereby further promoting the overall improvement of the efficiency and lifespan of the light-emitting device 100.

[0076] In some embodiments, each of R1 to R7 of the matrix monomer is a hydrogen atom, the polymerizable functional group substituent R10 of the matrix monomer is an olefinic bond, the substituent R8 of the discotic liquid crystal monomer is an alkoxy chain, and the polymerizable functional group substituent R9 of the discotic liquid crystal monomer is tert-butyl ethyl ester.

[0077] The preparation of the composite hole transport layer 101 can be achieved by processes such as ultraviolet polymerization or thermal polymerization. The specific preparation method will be clearly described below. When the composite hole transport layer 101 is achieved by ultraviolet polymerization, at least one of the polymerizable functional group substituents R9 of the discotic liquid crystal monomer and the polymerizable functional group substituents R10 of the matrix monomer is an ultraviolet polymerizable functional group, and the ultraviolet polymerizable functional group includes at least one bifunctional monomer. During ultraviolet polymerization, the monomer with the ultraviolet polymerizable functional group undergoes polymerization and cross-linking in the entire material system, thereby forming the composite hole transport layer 101. When the composite hole transport layer 101 is achieved by thermal polymerization, at least one of the polymerizable functional group substituents R9 of the discotic liquid crystal monomer and the polymerizable functional group substituents R10 of the matrix monomer is a thermal polymerizable functional group, and the thermal polymerizable functional group includes at least one bifunctional monomer. During thermal polymerization, the monomer with the thermal polymerizable functional group undergoes polymerization and cross-linking in the entire material system, thereby forming the composite hole transport layer 101.

[0078] Figure 5A shows a schematic cross-sectional view of a partial structure of a light-emitting device 100. As shown in Figure 5A , the light-emitting device 100 may further include: a first electrode layer 104; a hole injection layer 105 located on the first electrode layer 104; a composite hole transport layer 101 located on a side of the hole injection layer 105 away from the first electrode layer 104; the composite hole transport layer 101 may be a composite hole transport layer described in any of the previous embodiments; a light-emitting layer 106 located on a side of the composite hole transport layer 101 away from the first electrode layer 104; an electron transport layer 107 located on a side of the light-emitting layer 106 away from the first electrode layer 104; an electron injection layer 108 located on a side of the electron transport layer 107 away from the first electrode layer 104; and a second electrode layer 109 located on a side of the electron injection layer 108 away from the first electrode layer 104. The light-emitting device 100 shown in Figure 5A may be referred to as an upright structure.

[0079] Figure 5B shows a cross-sectional schematic diagram of a partial structure of another light-emitting device 100'. As shown in Figure 5B, light-emitting device 100' includes: a second electrode layer 109; an electron injection layer 108 located on the second electrode layer 109; an electron transport layer 107 located on the side of the electron injection layer 108 away from the second electrode layer 109; a light-emitting layer 106 located on the side of the electron transport layer 107 away from the second electrode layer 109; a composite hole transport layer 101 located on the side of the light-emitting layer 106 away from the second electrode layer 109. The composite hole transport layer 101 can be any of the composite hole transport layers described in any of the previous embodiments; a hole injection layer 105 located on the side of the composite hole transport layer 101 away from the second electrode layer 109; and a first electrode layer 104 located on the side of the hole injection layer 105 away from the second electrode layer 109. The light-emitting device 100' shown in Figure 5B can be referred to as an inverted structure.

[0080] The light-emitting layer 106 can be made of various suitable materials, such as InP, CdSe / ZnS core-shell structure, perovskite, etc. The embodiments of the present disclosure do not specifically limit the material of the light-emitting layer 106. In some embodiments, the light-emitting layer 106 includes quantum dots configured to emit blue light. The emission peak of the blue quantum dot light-emitting layer can be 455 to 465 nm, which corresponds to deep blue light. The full width at half maximum can be 15 to 30 nm, and the y value of the color coordinate CIE can be 0.035 to 0.050. The material of the electron transport layer 107 can be an inorganic oxide material with high electron mobility, such as ZnO. The material of the electron injection layer 108 can be polyvinyl pyrrolidone (PVP). The material of the hole injection layer 105 can be a material with high injection ability, such as poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). The first electrode layer 104 may be an anode, and its material may be, for example, indium tin oxide (ITO). The second electrode layer 109 may be a cathode, and its material may be, for example, Al.

[0081] In one example, the material of the first electrode layer 104 in the light-emitting device 100 is ITO, the material of the hole injection layer 105 is PEDOT:PSS, the material of the electron transport layer 107 is ZnO, the material of the electron injection layer 108 is PVP, and the material of the second electrode 109 is Al. The discotic liquid crystal monomer used to form the discotic liquid crystal component 103 in the composite hole transport layer 101 is DLC-1. FIG6 shows the structural formula of the discotic liquid crystal monomer DLC-1, namely: The matrix monomer used to form the matrix 102 in the composite hole transport layer 101 is CBP-V. FIG7 shows the structural formula of the matrix monomer CBP-V, namely: FIG8 shows the structural formula of the composite hole transport layer 101 composed of the discotic liquid crystal monomer DLC-1 and the matrix monomer CBP-V, namely In this example, the mass ratio of the discotic liquid crystal component 103 to the matrix 102 in the composite hole transport layer 101 is 20%, and the mass ratio of the matrix 102 to the composite hole transport layer 101 is 80%, that is, the mass ratio of the discotic liquid crystal component 103 to the matrix 102 is 2:8.

[0082] In this example, the discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, resulting in excellent performance. When the discotic liquid crystal component 103 accounts for less than 20% by weight of the composite hole transport layer 101, the liquid crystal molecule content is relatively low, affecting the carrier mobility of the composite hole transport layer 101. When the discotic liquid crystal component 103 accounts for more than 20% by weight of the composite hole transport layer 101, the film uniformity of the composite hole transport layer 101 deteriorates, affecting the potential barrier at the functional layer interface and thus impairing carrier transport. Therefore, when the discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, the composite hole transport layer 101 can achieve both high carrier mobility and good film uniformity. By improving the hole mobility of the composite hole transport layer 101, the balance between hole mobility and electron mobility in the light-emitting device 100 can be improved, enhancing charge injection and transport capabilities. The light-emitting device 100 in this example has high current efficiency, high external quantum efficiency, and long operating life. The light-emitting device 100 in this example corresponds to the device of Example 3 in Table 1. The specific values ​​of its current efficiency, quantum efficiency, and operating life can refer to the values ​​listed in Example 3 in Table 1.

[0083] It should be noted that, in addition to blue quantum dots, the light-emitting layer 106 of the light-emitting device 100 in the embodiment of the present disclosure may also be red quantum dots or green quantum dots.

[0084] In some embodiments, the light-emitting layer 106 includes quantum dots configured to emit red light, the mass fraction of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 25% to 30%, for example, 25%, 27.5%, 30%, etc., and the red light emission peak wavelength is 620 to 640 nm, for example, 620 nm, 630 nm, 640 nm, etc. While ensuring hole mobility, by ensuring that the mass fraction of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 25% to 30%, the composite hole transport layer 101 can better match the energy level of the red quantum dot light-emitting layer 106, thereby further promoting carrier transport.

[0085] In some alternative embodiments, the light-emitting layer 106 includes quantum dots configured to emit green light, the mass fraction of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 20% to 25%, for example, 20%, 22.5%, 25%, etc., and the peak wavelength of the green light emission is 525 to 535 nm, for example, 525 nm, 530 nm, 535 nm, etc. While ensuring hole mobility, by ensuring that the mass fraction of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 20% to 25%, the composite hole transport layer 101 can better match the energy level of the green quantum dot light-emitting layer 106, thereby further promoting carrier transport.

[0086] The following provides several examples of the preparation methods and corresponding electro-optical parameters of different light-emitting devices.

[0087] Example 1

[0088] In Example 1, the materials of the various film layers of the light-emitting device are: the material of the first electrode layer 104 is ITO, the material of the hole injection layer 105 is PEDOT:PSS, the light-emitting layer 106 is blue quantum dots with an emission peak of 455-465 nm, the material of the electron transport layer 107 is ZnO, the material of the electron injection layer 108 is PVP, the material of the second electrode layer 109 is Al, and the composite hole transport layer 101 is formed by cross-linking and polymerization of the discotic liquid crystal monomer DLC-1 shown in Figure 6 and the matrix monomer CBP-V shown in Figure 7, wherein the mass proportion of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 0%, that is, the mass ratio of the matrix 102 to the discotic liquid crystal component 103 is equal to 1:0. The preparation process for the composite hole transport layer 101 is generally as follows: the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-1 are dissolved in toluene at a mass ratio of 1:0 to form a mixed solution. This mixed solution is then applied to the surface of the hole injection layer 105 away from the first electrode layer 104. The solvent is removed from the mixed solution, and the solution is annealed at 120°C for approximately 0.5 hours to allow the discotic liquid crystal monomer DLC-1 to self-assemble. The solution is then heated at 240°C for approximately 1.5 hours to polymerize and crosslink the discotic liquid crystal monomer DLC-1 and the matrix monomer CBP-V to form a uniform polymer film, thereby forming the composite hole transport layer 101. Subsequently, the light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 are sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The driving voltage, current efficiency, external quantum efficiency, and service life of the light emitting device of Example 1 were characterized using a photoelectric testing system. The test results are shown in Example 1 of Table 1. Example 1 can be used as a control example.

[0089] Example 2

[0090] In Example 2, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, second electrode layer 109, and composite hole transport layer 101 of the light-emitting device are the same as those in Example 1. The difference is that the discotic liquid crystal component 103 in this Example 2 accounts for 10% by weight of the composite hole transport layer 101, meaning the mass ratio of the matrix 102 to the discotic liquid crystal component 103 is 9:1. The composite hole transport layer 101 is generally prepared as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-1 are dissolved in toluene solvent at a mass ratio of 9:1 to form a mixed solution. Then, the solvent is removed, annealed, and polymerized under the same conditions as in Example 1 to form the composite hole transport layer 101. Then, the light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 are sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. A photoelectric testing system was used to characterize the driving voltage, current efficiency, external quantum efficiency, and operating life of the light-emitting device of Example 2. The test results are shown in Example 2 of Table 1.

[0091] Example 3

[0092] In Example 3, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, second electrode layer 109, and composite hole transport layer 101 of the light-emitting device are the same as those in Example 1. The difference is that the discotic liquid crystal component 103 in this Example 3 accounts for 20% by weight of the composite hole transport layer 101, meaning the mass ratio of the matrix 102 to the discotic liquid crystal component 103 is 8:2. The composite hole transport layer 101 is generally prepared as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-1 are dissolved in toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent is removed, annealed, and polymerized under the same conditions as in Example 1 to form the composite hole transport layer 101. Then, the light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 are sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. A photoelectric testing system was used to characterize the driving voltage, current efficiency, external quantum efficiency, and operating life of the light-emitting device of Example 3. The test results are shown in Example 3 of Table 1.

[0093] Example 4

[0094] In Example 4, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, second electrode layer 109, and composite hole transport layer 101 of the light-emitting device are the same as those in Example 1. The difference is that the discotic liquid crystal component 103 in Example 4 accounts for 30% by weight of the composite hole transport layer 101, meaning the mass ratio of matrix 102 to discotic liquid crystal component 103 is 7:3. The composite hole transport layer 101 is generally prepared as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-1 are dissolved in toluene solvent at a mass ratio of 7:3 to form a mixed solution. Then, the solvent is removed, annealed, and polymerized according to the same conditions as in Example 1 to form the composite hole transport layer 101. Then, a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The light-emitting device of Example 4 was characterized using a photoelectric testing system for performance, including driving voltage, current efficiency, external quantum efficiency, and operating life. The test results are shown in Table 1, Example 4.

[0095] Example 5

[0096] In Example 5, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, second electrode layer 109, and composite hole transport layer 101 of the light-emitting device are the same as those in Example 1. The difference is that the discotic liquid crystal component 103 in this Example 5 accounts for 40% by weight of the composite hole transport layer 101, meaning the mass ratio of the matrix 102 to the discotic liquid crystal component 103 is 6:4. The preparation process for the composite hole transport layer 101 is generally as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-1 are dissolved in toluene solvent at a mass ratio of 6:4 to form a mixed solution. Then, the solvent is removed, annealed, and polymerized under the same conditions as in Example 1 to form the composite hole transport layer 101. Then, the light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 are sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. A photoelectric testing system was used to characterize the driving voltage, current efficiency, external quantum efficiency, and operating life of the light-emitting device of Example 5. The test results are shown in Example 5 of Table 1.

[0097] Example 6

[0098] In Example 6, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 6 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-2 shown in FIG9 and the matrix monomer CBP-V shown in FIG7. The discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, meaning the mass ratio of matrix 102 to discotic liquid crystal component 103 is 8:2. The preparation process for composite hole transport layer 101 is generally as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-2 are dissolved in toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent is removed, annealed, and polymerized under the same conditions as in Example 1 to form composite hole transport layer 101. Then, a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The light-emitting device of Example 6 was characterized using a photoelectric testing system for performance, including driving voltage, current efficiency, external quantum efficiency, and operating life. The test results are shown in Table 1 for Example 6.

[0099] Example 7

[0100] In Example 7, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 7 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-3 shown in FIG10 and the matrix monomer CBP-V shown in FIG7. The discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, meaning the mass ratio of matrix 102 to discotic liquid crystal component 103 is 8:2. The preparation process for composite hole transport layer 101 is generally as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-3 are dissolved in toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent is removed, annealed, and polymerized according to the same conditions as in Example 1 to form composite hole transport layer 101. Then, a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The light-emitting device of Example 7 was characterized using a photoelectric testing system for performance, including driving voltage, current efficiency, external quantum efficiency, and operating life. The test results are shown in Table 1 for Example 7.

[0101] Example 8

[0102] In Example 8, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 8 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-4 shown in FIG11 and the matrix monomer CBP-V shown in FIG7. The discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, meaning the mass ratio of matrix 102 to discotic liquid crystal component 103 is 8:2. The preparation process for the composite hole transport layer 101 is generally as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-4 are dissolved in toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent is removed, annealed, and polymerized according to the same conditions as in Example 1 to form the composite hole transport layer 101. Then, a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The light-emitting device of Example 8 was characterized using a photoelectric testing system for performance, including driving voltage, current efficiency, external quantum efficiency, and operating life. The test results are shown in Table 1 for Example 8.

[0103] Example 9

[0104] In Example 9, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 9 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-5 shown in Figure 12 and the matrix monomer CBP-V shown in Figure 7. In Figure 12, when the discotic liquid crystal monomer is DLC-5, n in the molecular structure is equal to 2. The discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, meaning the mass ratio of matrix 102 to discotic liquid crystal component 103 is 8:2. The general process for preparing the composite hole transport layer 101 is as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-5 are dissolved in toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent was removed, annealed, and polymerized under the same conditions as in Example 1 to form a composite hole transport layer 101. Then, layers such as a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The performance of the light-emitting device of Example 9, including driving voltage, current efficiency, external quantum efficiency, and operating life, was characterized using a photoelectric testing system. The test results are shown in Table 1 for Example 9.

[0105] Example 10

[0106] In Example 10, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 10 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-6 shown in Figure 12 and the matrix monomer CBP-V shown in Figure 7. In Figure 12, when the discotic liquid crystal monomer is DLC-6, n in the molecular structure is 5. The discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, meaning the mass ratio of matrix 102 to discotic liquid crystal component 103 is 8:2. The general process for preparing the composite hole transport layer 101 is as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-6 are dissolved in toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent was removed, annealed, and polymerized under the same conditions as in Example 1 to form a composite hole transport layer 101. Then, layers such as a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The performance of the light-emitting device of Example 10, including driving voltage, current efficiency, external quantum efficiency, and operating life, was characterized using a photoelectric testing system. The test results are shown in Table 1 for Example 10.

[0107] Example 11

[0108] In Example 11, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 11 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-7 shown in Figure 12 and the matrix monomer CBP-V shown in Figure 7. In Figure 12, when the discotic liquid crystal monomer is DLC-7, n in the molecular structure is 10. The discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, meaning the mass ratio of matrix 102 to discotic liquid crystal component 103 is 8:2. The general process for preparing the composite hole transport layer 101 is as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-7 are dissolved in toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent was removed, annealed, and polymerized under the same conditions as in Example 1 to form a composite hole transport layer 101. Then, layers such as a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The performance of the light-emitting device of Example 11, including its driving voltage, current efficiency, external quantum efficiency, and operating life, was characterized using a photoelectric testing system. The test results are shown in Table 1 for Example 11.

[0109] Example 12

[0110] In Example 12, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 12 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-8 shown in Figure 12 and the matrix monomer CBP-V shown in Figure 7. In Figure 12, when the discotic liquid crystal monomer is DLC-8, n in the molecular structure is 15. The discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, meaning the mass ratio of matrix 102 to discotic liquid crystal component 103 is 8:2. The general process for preparing the composite hole transport layer 101 is as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-8 are dissolved in toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent was removed, annealed, and polymerized under the same conditions as in Example 1 to form a composite hole transport layer 101. Then, layers such as a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The performance of the light-emitting device of Example 12, including driving voltage, current efficiency, external quantum efficiency, and operating life, was characterized using a photoelectric testing system. The test results are shown in Table 1 for Example 12.

[0111] Example 13

[0112] In Example 13, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 13 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-9 shown in FIG12 and the matrix monomer CBP-V shown in FIG7 . In FIG12 , when the discotic liquid crystal monomer is DLC-9, n in the molecular structure is 20. The mass fraction of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 20%, meaning the mass ratio of the matrix 102 to the discotic liquid crystal component 103 is 8:2. The general process for preparing the composite hole transport layer 101 is as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-9 are dissolved in a toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent was removed, annealed, and polymerized under the same conditions as in Example 1 to form a composite hole transport layer 101. Then, layers such as a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The performance of the light-emitting device of Example 13, including its driving voltage, current efficiency, external quantum efficiency, and operating life, was characterized using a photoelectric testing system. The test results are shown in Table 1 for Example 13.

[0113] Example 14

[0114] In Example 14, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 14 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-10 shown in FIG13 and the matrix monomer CBP-V shown in FIG7 . In FIG13 , when the discotic liquid crystal monomer is DLC-10, n in the molecular structure is equal to 2. The discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, meaning the mass ratio of the matrix 102 to the discotic liquid crystal component 103 is 8:2. The general process for preparing the composite hole transport layer 101 is as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-10 are dissolved in a toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent was removed, annealed, and polymerized under the same conditions as in Example 1 to form a composite hole transport layer 101. Then, layers such as a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The performance of the light-emitting device of Example 14, including its driving voltage, current efficiency, external quantum efficiency, and operating life, was characterized using a photoelectric testing system. The test results are shown in Table 1 for Example 14.

[0115] Example 15

[0116] In Example 15, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 15 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-11 shown in FIG13 and the matrix monomer CBP-V shown in FIG7 . In FIG13 , when the discotic liquid crystal monomer is DLC-11, n in the molecular structure is equal to 5. The discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, meaning the mass ratio of matrix 102 to discotic liquid crystal component 103 is 8:2. The general process for preparing the composite hole transport layer 101 is as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-11 are dissolved in toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent was removed, annealed, and polymerized under the same conditions as in Example 1 to form a composite hole transport layer 101. Then, layers such as a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The performance of the light-emitting device of Example 15, including its driving voltage, current efficiency, external quantum efficiency, and operating life, was characterized using a photoelectric testing system. The test results are shown in Table 1 for Example 15.

[0117] Example 16

[0118] In Example 16, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 16 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-12 shown in FIG13 and the matrix monomer CBP-V shown in FIG7 . In FIG13 , when the discotic liquid crystal monomer is DLC-12, n in the molecular structure is 10. The mass fraction of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 20%, meaning the mass ratio of the matrix 102 to the discotic liquid crystal component 103 is 8:2. The general process for preparing the composite hole transport layer 101 is as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-12 are dissolved in a toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent was removed, annealed, and polymerized under the same conditions as in Example 1 to form a composite hole transport layer 101. Then, layers such as a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The performance of the light-emitting device of Example 16, including its driving voltage, current efficiency, external quantum efficiency, and operating life, was characterized using a photoelectric testing system. The test results are shown in Table 1 for Example 16.

[0119] Example 17

[0120] In Example 17, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 17 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-13 shown in FIG13 and the matrix monomer CBP-V shown in FIG7 . In FIG13 , when the discotic liquid crystal monomer is DLC-13, n in the molecular structure is 15. The mass fraction of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 20%, meaning the mass ratio of the matrix 102 to the discotic liquid crystal component 103 is 8:2. The general process for preparing the composite hole transport layer 101 is as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-13 are dissolved in a toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent was removed, annealed, and polymerized under the same conditions as in Example 1 to form a composite hole transport layer 101. Then, layers such as a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The performance of the light-emitting device of Example 17, including its driving voltage, current efficiency, external quantum efficiency, and operating life, was characterized using a photoelectric testing system. The test results are shown in Table 1 for Example 17.

[0121] Example 18

[0122] In Example 18, the materials for the first electrode layer 104, hole injection layer 105, light-emitting layer 106, electron transport layer 107, electron injection layer 108, and second electrode layer 109 of the light-emitting device are the same as those in Example 1. However, the composite hole transport layer 101 in Example 18 is formed by cross-linking and polymerizing the discotic liquid crystal monomer DLC-14 shown in FIG13 and the matrix monomer CBP-V shown in FIG7 . In FIG13 , when the discotic liquid crystal monomer is DLC-14, n in the molecular structure is 20. The mass fraction of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 20%, meaning the mass ratio of the matrix 102 to the discotic liquid crystal component 103 is 8:2. The general process for preparing the composite hole transport layer 101 is as follows: First, the matrix monomer CBP-V and the discotic liquid crystal monomer DLC-14 are dissolved in a toluene solvent at a mass ratio of 8:2 to form a mixed solution. Then, the solvent was removed, annealed, and polymerized under the same conditions as in Example 1 to form a composite hole transport layer 101. Then, layers such as a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, and a second electrode layer 109 were sequentially formed on the composite hole transport layer 101 to produce a light-emitting device. The performance of the light-emitting device of Example 18, including its driving voltage, current efficiency, external quantum efficiency, and operating life, was characterized using a photoelectric testing system. The test results are shown in Table 1 for Example 18.

[0123] Table 1 Electro-optical parameters of light-emitting devices

[0124] Note: LT50 (Life Time to 50% output) in Table 1 refers to the time required for the output power of the light-emitting device to decrease to 50% of the rated output power within the set effective working range. This value reflects the aging degree of the light-emitting device.

[0125] As can be seen from the data in Table 1, the light-emitting device of Example 3 has the highest current efficiency, the highest external quantum efficiency, and the longest operating life. In the light-emitting device of Example 3, the matrix monomer constituting the matrix 102 in the composite hole transport layer 101 is CBP-V, and the discotic liquid crystal monomer constituting the discotic liquid crystal component 103 in the composite hole transport layer 101 is DLC-1. On the one hand, from the perspective of doping ratio, the discotic liquid crystal component 103 accounts for 20% by weight in the composite hole transport layer 101, which is a relatively optimal doping ratio. This is because when the discotic liquid crystal component 103 accounts for less than 20% by weight in the composite hole transport layer 101, the liquid crystal molecule content is relatively low, and the carrier mobility of the composite hole transport layer 101 is affected. On the other hand, when the discotic liquid crystal component 103 accounts for more than 20% by weight in the composite hole transport layer 101, the film uniformity of the composite hole transport layer 101 deteriorates, affecting the potential barrier at the interface of the functional layer, thereby reducing carrier transport. When the discotic liquid crystal component 103 accounts for 20% by mass in the composite hole transport layer 101, the composite hole transport layer 101 can achieve both high carrier mobility and good film uniformity. Improving the hole mobility of the composite hole transport layer 101 can improve the balance between hole mobility and electron mobility in the light-emitting device, enhancing charge injection and transport capabilities. Furthermore, from the perspective of the molecular structure of the discotic liquid crystal monomer DLC-1, as shown in Figure 6, the substituent R8 is a flexible alkoxy chain having 5 carbon atoms. This moderate chain length allows the discotic liquid crystal monomer DLC-1 to possess both a rigid core and flexible segments, ensuring high hole mobility and polymerization performance. The polymerizable functional group R9 is a thermally polymerizable functional group. The two polymerizable functional groups R9 are located at two widely separated substitution positions in the discotic liquid crystal monomer DLC-1, thereby facilitating cross-linking polymerization.

[0126] In addition, it should be noted that compared to the hole transport layer of the OLED device, the discotic liquid crystal molecules are more suitable for the hole transport layer of the QLED device, because the hole mobility of the hole transport layer used in the OLED device is usually significantly higher than the electron mobility of the electron transport layer. Therefore, there is no need to introduce additional discotic liquid crystal molecules to further improve the hole mobility of the hole transport layer. In contrast, the electron transport layer of the QLED device usually adopts metal oxides with high mobility such as ZnO. The hole mobility of the hole transport layer of the QLED device is significantly lower than the electron mobility of the electron transport layer. In order to achieve charge balance, it is necessary to adopt a hole transport material with higher mobility, such as introducing a discotic liquid crystal component with high hole mobility as in the present application to improve the hole mobility of the composite hole transport layer, thereby promoting the balance of the hole mobility and electron mobility of the QLED device, improving the charge injection and transport capabilities, and thus significantly improving the overall efficiency and life of the QLED device. In addition, the molecular weight of the discotic liquid crystal component is usually relatively large, and it has a flexible alkyl chain or alkoxy chain, which makes the thermal stability of the discotic liquid crystal component not particularly high. Therefore, it is not suitable for the evaporation process of OLED devices, but is suitable for the solution process of QLED devices.

[0127] While there have been reports of incorporating discotic liquid crystal molecules into organic solar cells, it's important to emphasize that the technical fields of QLED devices and organic solar cells differ significantly, and the role of discotic liquid crystal molecules in organic solar cells is completely different from that in QLED devices. For example, in terms of phase state, the discotic liquid crystal molecules in QLED devices need to be cross-linked within a stable polymer film to maintain the amorphous state of the composite film, thereby enhancing the stability of the QLED device during operation. In contrast, the discotic liquid crystal molecules in organic solar cells can exist independently as self-assembled molecules and serve as the interface layer between the charge transport and active layers, with no strict requirements for their phase state. For another example, from a functional layer perspective, the discotic liquid crystal molecules in QLED devices are doped into the matrix to serve as an active component of the composite hole transport layer, thereby increasing the hole mobility of the composite hole transport layer and balancing the charge carriers in the QLED device. In contrast, the discotic liquid crystal molecules in organic solar cells serve as the interface layer between the hole transport or transport layer and the organic active layer, improving defects at the bottom of the organic active layer and carrier mobility, thereby facilitating charge carrier extraction. For example, from the perspective of molecular orientation characteristics, the discotic liquid crystal monomers in QLED devices self-assemble to form microcolumns perpendicular to the device, thereby promoting the transport of carriers; while the discotic liquid crystal monomers in organic solar cells self-assemble to form microcolumns perpendicular to the device and microcolumns parallel to the device. The two orientations of microcolumns exist at the same time and form a three-dimensional transmission channel with the photovoltaic microcrystalline material, promoting the extraction of carriers.

[0128] Figure 14 shows a block diagram of an array substrate 200 according to another embodiment of the present disclosure. The array substrate 200 may include a plurality of light-emitting devices 100 or 100′ described in any of the previous embodiments. The material and molecular structure of the discotic liquid crystal component 103 of the composite hole transport layer 101 in the light-emitting device 100 or 100′ and the mass ratio of the discotic liquid crystal component 103 to the matrix 102 may be as described in the previous embodiments and will not be repeated here.

[0129] The array substrate 200 may have substantially the same technical effects as the light emitting device 100 or 100 ′ described in the previous embodiment, and therefore, for the purpose of brevity, a repeated description will not be given here.

[0130] Figure 15 shows a schematic structural diagram of a display device 300 according to another embodiment of the present disclosure. The display device 300 includes: an array substrate 200 according to the previous embodiment, which may include multiple light-emitting devices 100 or 100' described in any of the previous embodiments; and an opposing substrate 301 opposite to the array substrate 200. The display device 300 can be any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigator. In some embodiments, the display device 300 is a quantum dot light-emitting diode display device. Compared to traditional organic light-emitting diode displays, quantum dot light-emitting diode displays have better color purity, better contrast, and greater stability.

[0131] The display device 300 can have substantially the same technical effects as the light emitting device 100 or 100 ′ described in the previous embodiment, and therefore, for the purpose of brevity, a repeated description will not be given here.

[0132] FIG16 shows a flow chart of a method 400 for manufacturing a light emitting device according to another embodiment of the present disclosure.

[0133] S401: providing a mixed solution of a matrix monomer and a discotic liquid crystal monomer.

[0134] The discotic liquid crystal monomer may have the general structural formula shown in FIG. 3 , and the host monomer may have the general structural formula shown in FIG. 4 .

[0135] S402: removing the solvent from the mixed solution and performing annealing treatment to allow the discotic liquid crystal monomers to self-assemble.

[0136] For example, under specific temperature conditions, the solvent in the mixed solution slowly evaporates until it is removed, and the discotic liquid crystal monomers self-assemble to form an ordered columnar structure, which is embedded in the matrix monomer with good film-forming properties, thereby constructing a molecular channel with higher hole mobility.

[0137] S403: polymerizing the matrix monomer and the self-assembled discotic liquid crystal monomer to form a composite hole transport layer including a matrix and a discotic liquid crystal component, wherein the hole mobility of the discotic liquid crystal component is greater than the hole mobility of the matrix.

[0138] For example, the matrix monomers and the self-assembled discotic liquid crystal monomers can be cross-linked and polymerized by UV polymerization or thermal polymerization to form a composite hole transport layer that has both the good film-forming properties of the matrix and the high mobility properties of the discotic liquid crystal component. In some embodiments, the hole mobility of the discotic liquid crystal component 103 is 10 -3 ~10 -2 cm 2 V -1 s -1 , the hole mobility of the matrix 102 is 10 -6 ~10 -3 cm 2 V -1 s -1 .

[0139] The molecular structure of a matrix monomer is generally characterized by a rigid core, while the molecular structure of a discotic liquid crystal monomer consists of a rigid disc-shaped core and a certain number or proportion of flexible chains. Discotic liquid crystal monomers require specific processing conditions to self-assemble and form an ordered molecular stack, thereby enhancing their mobility. If the matrix monomer and discotic liquid crystal monomer are directly mixed without any treatment, the two molecular systems will intermix and polymerize directly, severely affecting the hole transport properties and film-forming properties of the matrix monomer, as well as the high hole mobility properties achieved by the self-assembly of the discotic liquid crystal monomer, resulting in a decrease in overall hole transport effectiveness. In contrast, in the method 400 provided in the embodiment of the present disclosure, after the matrix monomer and the discotic liquid crystal monomer are mixed, the mixed solution is heat-treated. Under specific temperature conditions, the solvent in the mixed solution slowly evaporates until it is removed, and the discotic liquid crystal monomer self-assembles to form a columnar structure with high mobility and is embedded in the matrix monomer with good film-forming properties. The matrix monomer and the discotic liquid crystal monomer are polymerized and solidified through a polymerization process, so that the composite hole transport layer formed has both the good film-forming properties of the matrix monomer and the high mobility properties of the discotic liquid crystal monomer.

[0140] In some embodiments, step S403 of polymerizing the matrix monomer and the self-assembled discotic liquid crystal monomer to form a composite hole transport layer comprising a matrix and discotic liquid crystal components includes the following sub-steps: irradiating the matrix monomer and the self-assembled discotic liquid crystal monomer with ultraviolet light to cause UV polymerization of the matrix monomer and the self-assembled discotic liquid crystal monomer to form the composite hole transport layer. Specifically, at least one of the polymerizable functional group substituents R10 of the matrix monomer and the polymerizable functional group substituents R9 of the discotic liquid crystal monomer is a UV-polymerizable functional group, and the UV-polymerizable functional group includes at least one difunctional monomer. Under control of the solvent or its own concentration, a mixed solution of the matrix monomer and the discotic liquid crystal monomer is applied to the surface of the hole injection layer 105 away from the first electrode layer 104 using a process such as coating or inkjet printing, and the solvent in the mixed solution is removed to form a uniform thin film. An annealing treatment is performed in a specific temperature range, for example, 80-100°C, to allow the discotic liquid crystal monomer to self-assemble. Then, under specific UV irradiation conditions, for example, UV irradiation intensity is 2.0 to 10.0 mW / cm 2 The ultraviolet irradiation time is 2.0 to 15.0 minutes, and the monomers with polymerizable functional groups are polymerized and cross-linked in the entire material system to form a composite hole transport layer.

[0141] In some embodiments, step S403 of polymerizing the matrix monomer and the self-assembled discotic liquid crystal monomer to form a composite hole transport layer comprising a matrix and discotic liquid crystal components includes the following sub-step: heating the matrix monomer and the self-assembled discotic liquid crystal monomer to thermally polymerize the matrix monomer and the self-assembled discotic liquid crystal monomer to form the composite hole transport layer. Specifically, at least one of the polymerizable functional group substituents R10 of the matrix monomer and the polymerizable functional group substituents R9 of the discotic liquid crystal monomer is a thermally polymerizable functional group, and the thermally polymerizable functional group includes at least one difunctional monomer. Under control of the solvent or its own concentration, a mixed solution of the matrix monomer and the discotic liquid crystal monomer is applied to the surface of the hole injection layer 105 away from the first electrode layer 104 using a process such as coating or inkjet printing, and the solvent in the mixed solution is removed to form a uniform thin film. An annealing treatment is performed in a specific temperature range, such as 80-100°C, to allow the discotic liquid crystal monomer to self-assemble. Then, thermal polymerization is carried out at a specific temperature, for example, 180-260° C., for about 0.5-1.5 hours, and the monomers with polymerizable functional groups are polymerized and cross-linked in the entire material system to form a composite hole transport layer.

[0142] Figure 17 shows a polarizing microscope photograph of the composite hole transport layer film before annealing. Figure 17 shows that the discotic liquid crystal monomers have a typical focal conic texture, indicating that before annealing, the discotic liquid crystal monomers have poor orientation and are scattered.

[0143] Figure 18 shows a photograph of the composite hole transport layer film after annealing under a polarizing microscope. After annealing, the discotic liquid crystal monomers self-assemble into an orderly columnar arrangement with good molecular orientation, thus forming a dark field.

[0144] In some embodiments, referring to Figure 5A, method 400 may further include: forming a first electrode layer 104; forming a hole injection layer 105 on the first electrode layer 104; coating a mixed solution of a matrix monomer and a discotic liquid crystal monomer formed by step S401 on a side of the hole injection layer 105 away from the first electrode layer 104, and then forming a composite hole transport layer 101 by performing steps S402 and S403; forming a light-emitting layer 106 on a side of the composite hole transport layer 101 away from the first electrode layer 104; forming an electron transport layer 107 on a side of the light-emitting layer 106 away from the first electrode layer 104; forming an electron injection layer 108 on a side of the electron transport layer 107 away from the first electrode layer 104; and forming a second electrode layer 109 on a side of the electron injection layer 108 away from the first electrode layer 104.

[0145] In some alternative embodiments, referring to Figure 5B, method 400 may also include: forming a second electrode layer 109; forming an electron injection layer 108 on the second electrode layer 109; forming an electron transport layer 107 on the side of the electron injection layer 108 away from the second electrode layer 109; forming a light-emitting layer 106 on the side of the electron transport layer 107 away from the second electrode layer 109; coating a mixed solution of the matrix monomer and the discotic liquid crystal monomer formed by step S401 on the side of the light-emitting layer 106 away from the second electrode layer 109, and then performing steps S402 and S403 to form a composite hole transport layer 101; forming a hole injection layer 105 on the side of the composite hole transport layer 101 away from the second electrode layer 109; and forming a first electrode layer 104 on the side of the hole injection layer 105 away from the second electrode layer 109.

[0146] In one example, the material of the first electrode layer 104 may be ITO, the material of the hole injection layer 105 may be PEDOT:PSS, the light-emitting layer 106 may be blue quantum dots, the emission peak of the blue quantum dot light-emitting layer may be 455 to 465 nm, and this wavelength range corresponds to deep blue light. The material of the electron transport layer 107 may be ZnO, the material of the electron injection layer 108 may be polyvinyl pyrrolidone, and the material of the second electrode layer 109 may be Al. The composite hole transport layer 101 may be formed by cross-linking polymerization of the discotic liquid crystal monomer DLC-1 shown in Figure 6 and the matrix monomer CBP-V shown in Figure 7. The structural formula of the composite hole transport layer 101 is shown in Figure 8, wherein the mass proportion of the discotic liquid crystal component 103 in the composite hole transport layer 101 is 20%. The composite hole transport layer 101 is generally prepared as follows: A matrix monomer, CBP-V, and a discotic liquid crystal monomer, DLC-1, are dissolved in toluene at a mass ratio of 8:2 to form a mixed solution. This mixed solution is then applied to the surface of the hole injection layer 105 away from the first electrode layer 104. The solvent in the mixed solution is gradually evaporated and removed at a first temperature (e.g., 120°C). An annealing treatment is then performed over a first time period (e.g., 0.5 hours) to allow the discotic liquid crystal monomer, DLC-1, to self-assemble. The matrix monomer and the self-assembled discotic liquid crystal monomer are then heated at a second temperature (e.g., 240°C) for a second time period (e.g., 1.5 hours). The discotic liquid crystal monomer, DLC-1, and the matrix monomer, CBP-V, undergo thermal polymerization and cross-linking to form a uniform polymer film, thereby forming the composite hole transport layer 101.

[0147] The discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101. This doping ratio is relatively optimal. When the discotic liquid crystal component 103 accounts for less than 20% by weight of the composite hole transport layer 101, the liquid crystal molecule content is relatively low, affecting the carrier mobility of the composite hole transport layer 101. However, when the discotic liquid crystal component 103 accounts for more than 20% by weight of the composite hole transport layer 101, the film uniformity of the composite hole transport layer 101 deteriorates, affecting the potential barrier at the functional layer interface and thus impairing carrier transport. When the discotic liquid crystal component 103 accounts for 20% by weight of the composite hole transport layer 101, the composite hole transport layer 101 achieves both high carrier mobility and good film uniformity. By improving the hole mobility of the composite hole transport layer 101, the balance between hole mobility and electron mobility in the light-emitting device can be improved, enhancing charge injection and transport capabilities. The light-emitting device in this example corresponds to the light-emitting device in Example 3 of Table 1. The values ​​of the light-emitting device such as driving voltage, current efficiency, external quantum efficiency, and service life can refer to the values ​​listed in Example 3 of Table 1.

[0148] It will be understood that although the terms first, second, third, etc. may be used to describe various elements, components, areas, layers and / or parts in this article, these elements, components, areas, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer or part from another area, layer or part. Therefore, the first element, component, area, layer or part discussed above can be referred to as the second element, component, area, layer or part without departing from the teachings of the present disclosure.

[0149] Spatially relative terms such as "row," "column," "under," "above," "left," "right," and the like may be used herein to describe the relationship of one element or feature to another element or feature as illustrated in the figures for ease of description. It will be understood that these spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figure is flipped, the element described as "under other elements or features" will be oriented as "above other elements or features." Thus, the exemplary term "under" can encompass both orientations of "above" and "under." The device can be oriented otherwise (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein are interpreted accordingly. In addition, it will also be understood that when a layer is referred to as "between two layers," it can be the only layer between the two layers, or one or more intermediate layers may also be present.

[0150] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "one", "an" and "the" are intended to also include the plural forms, unless the context clearly indicates otherwise. It will be further understood that the terms "include" and / or "comprise" when used in this specification specify the presence of the features, wholes, steps, operations, elements and / or parts, but do not exclude the presence of one or more other features, wholes, steps, operations, elements, parts and / or their groups or add one or more other features, wholes, steps, operations, elements, parts and / or their groups. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In the description of this specification, the description of the reference terms "one embodiment", "another embodiment" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily need to be directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. Furthermore, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without mutual contradiction.

[0151] It will be understood that when an element or layer is referred to as being “on,” “connected to,” “coupled to,” or “adjacent to” another element or layer, it can be directly on, directly connected to, directly coupled to, or directly adjacent to another element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to,” “directly coupled to,” or “directly adjacent to” another element or layer, no intervening elements or layers are present. However, in no case should “on” or “directly on” be interpreted as requiring that one layer completely cover the underlying layer.

[0152] Embodiments of the present disclosure are described herein with reference to schematic illustrations (and intermediate structures) of idealized embodiments of the present disclosure. Because of this, variations in the illustrated shapes, for example as a result of manufacturing techniques and / or tolerances, should be expected. Therefore, embodiments of the present disclosure should not be interpreted as being limited to the specific shapes of the regions illustrated herein, but should include shape deviations, for example, due to manufacturing. Therefore, the regions illustrated in the figures are schematic in nature, and their shapes are not intended to illustrate the actual shape of the regions of the device and are not intended to limit the scope of the present disclosure.

[0153] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present disclosure belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the relevant art and / or the context of this specification, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0154] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A light-emitting device comprising a composite hole transport layer, wherein: The composite hole transport layer includes a matrix and a discotic liquid crystal component, wherein the hole mobility of the discotic liquid crystal component is greater than the hole mobility of the matrix.

2. The light emitting device according to claim 1, wherein: The hole mobility of the composite hole transport layer is 10 -4 ~10 -3 cm 2 V -1 s -1 .

3. The light emitting device according to claim 1, wherein: The energy level of the highest occupied molecular orbital of the composite hole transport layer is -6.0 to -5.3 eV.

4. The light emitting device according to claim 1, wherein: The mass proportion of the discotic liquid crystal component in the composite hole transport layer is 1% to 40%.

5. The light emitting device according to claim 4, wherein: The mass proportion of the discotic liquid crystal component in the composite hole transport layer is 20%.

6. The light emitting device according to claim 1, wherein: The general structural formula of the composite hole transport layer is: Among them, R8 includes any one of an alkyl chain, an alkoxy chain, and an alkyl ester chain, and R8 at different positions of the structural formula of the composite hole transport layer are the same or different from each other, and each of R1 to R7 includes any one of a benzene ring, a double bond, cyclohexane, and a hydrogen atom.

7. The light emitting device according to claim 6, wherein: The discotic liquid crystal component is formed by a discotic liquid crystal monomer, and the structural formula of the discotic liquid crystal monomer is: Wherein, R9 is a polymerizable functional group and includes any one of tert-butyl ethyl ester, olefin bond, acrylate, vinyl ether, thiol, and epoxy.

8. The light emitting device according to claim 7, wherein: R8 is a flexible alkyl chain having 4 to 6 carbon atoms.

9. The light emitting device according to claim 7, wherein: R8 is any one of butoxy, pentyloxy, hexyloxy, butyl ester, pentyl ester, and hexyl ester.

10. The light emitting device according to any one of claims 1 to 9, wherein: The matrix is ​​configured to enable holes to migrate in the composite hole transport layer in an orderly manner under the action of an electric field.

11. The light emitting device according to claim 10, wherein: The matrix is ​​formed by a matrix monomer, and the general structural formula of the matrix monomer is: Wherein, R10 is a polymerizable functional group and includes any one of olefin bond, acrylate, vinyl ether, thiol, and epoxy.

12. The light emitting device according to claim 11, wherein: Each of R1 to R7 is a hydrogen atom, R10 is an olefinic bond, R8 is an alkoxy chain, and R9 is tert-butyl ethyl ester.

13. The light emitting device according to claim 11, wherein: At least one of R9 and R10 is a UV-polymerizable functional group, and the UV-polymerizable functional group includes at least one difunctional monomer.

14. The light emitting device according to claim 11, wherein: At least one of R9 and R10 is a thermally polymerizable functional group, and the thermally polymerizable functional group includes at least one difunctional monomer.

15. The light emitting device according to any one of claims 1 to 14, wherein: The discotic liquid crystal component is arranged in the composite hole transport layer as an ordered columnar structure, the height direction of the columnar structure is parallel to the thickness direction of the composite hole transport layer, and the matrix is ​​arranged at least between the columnar structures.

16. The light emitting device according to any one of claims 1 to 14, wherein: The hole mobility of the discotic liquid crystal component is 10 -3 ~10 -2 cm 2 V -1 s -1 .

17. The light emitting device according to claim 16, wherein: The energy level of the highest occupied molecular orbital of the discotic liquid crystal component is -6.5 to -5.5 eV, and the energy level of the lowest unoccupied molecular orbital of the discotic liquid crystal component is -3.0 to -1.8 eV.

18. The light emitting device according to any one of claims 1 to 17, further comprising: a first electrode layer; A hole injection layer, located between the first electrode layer and the composite hole transport layer; A light-emitting layer, located on a side of the composite hole transport layer away from the first electrode layer; An electron transport layer, located on a side of the light-emitting layer away from the first electrode layer; an electron injection layer, located on a side of the electron transport layer away from the first electrode layer; as well as The second electrode layer is located on a side of the electron injection layer away from the first electrode layer.

19. The light emitting device according to claim 18, wherein: The light emitting layer includes quantum dots configured to emit blue light.

20. The light emitting device according to claim 19, wherein: The material of the first electrode layer is indium tin oxide, the material of the hole injection layer is poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, the material of the electron transport layer is zinc oxide, the material of the electron injection layer is polyvinyl pyrrolidone, the material of the second electrode layer is aluminum, the wavelength of the blue light emitted by the light-emitting layer is 455-465nm, the mass proportion of the discotic liquid crystal component in the composite hole transport layer is 20%, the mass proportion of the matrix in the composite hole transport layer is 80%, and the structural formula of the composite hole transport layer is:

21. The light emitting device according to claim 18, wherein: The light-emitting layer includes quantum dots configured to emit red light, the mass proportion of the discotic liquid crystal component in the composite hole transport layer is 25% to 30%, and the wavelength of the red light is 620 to 640 nm.

22. The light emitting device according to claim 18, wherein: The light-emitting layer includes quantum dots configured to emit green light, the mass proportion of the discotic liquid crystal component in the composite hole transport layer is 20% to 25%, and the wavelength of the green light is 525 to 535 nm.

23. A display device comprising a plurality of light emitting devices according to any one of claims 1 to 22.

24. A method for preparing a light-emitting device, comprising: providing a mixed solution of a matrix monomer and a discotic liquid crystal monomer; removing the solvent in the mixed solution and performing annealing treatment to allow the discotic liquid crystal monomers to self-assemble; as well as The matrix monomers and the self-assembled discotic liquid crystal monomers are polymerized to form a composite hole transport layer including a matrix and a discotic liquid crystal component having a hole mobility greater than a hole mobility of the matrix.

25. The method according to claim 24, wherein: The removing of the solvent from the mixed solution and performing annealing treatment to allow the discotic liquid crystal monomers to self-assemble comprises: The discotic liquid crystal monomers are self-assembled and formed into an ordered columnar structure, the columnar structure is embedded in the matrix monomer, and the height direction of the columnar structure is parallel to the thickness direction of the composite hole transport layer.

26. The method according to claim 24, wherein: The step of polymerizing the matrix monomer and the self-assembled discotic liquid crystal monomer to form a composite hole transport layer including a matrix and a discotic liquid crystal component comprises: The matrix monomer and the self-assembled discotic liquid crystal monomer are irradiated with ultraviolet light to cause the matrix monomer and the self-assembled discotic liquid crystal monomer to undergo ultraviolet polymerization to form the composite Hole transport layer.

27. The method according to claim 24, wherein: The step of polymerizing the matrix monomer and the self-assembled discotic liquid crystal monomer to form a composite hole transport layer including a matrix and a discotic liquid crystal component comprises: The matrix monomer and the self-assembled discotic liquid crystal monomer are heated to enable the matrix monomer and the self-assembled discotic liquid crystal monomer to be thermally polymerized to form the composite hole transport layer.

28. The method of claim 24, wherein: The providing of a mixed solution of the matrix monomer and the discotic liquid crystal monomer comprises: dissolving the matrix monomer and the discotic liquid crystal monomer in a toluene solvent at a mass ratio of 8:2 to form the mixed solution; The removing the solvent from the mixed solution and performing annealing treatment to allow the discotic liquid crystal monomers to self-assemble comprises: gradually volatilizing the solvent at a first temperature until it is removed, and performing annealing treatment within a first time period to allow the discotic liquid crystal monomers to self-assemble; The step of polymerizing the matrix monomer and the self-assembled discotic liquid crystal monomer to form a composite hole transport layer including a matrix and a discotic liquid crystal component comprises: heating the matrix monomer and the self-assembled discotic liquid crystal monomer at a second temperature for a second time, so that the matrix monomer and the self-assembled discotic liquid crystal monomer undergo thermal polymerization to form the composite hole transport layer; Wherein, the structural formula of the matrix monomer is The structural formula of the discotic liquid crystal monomer is The structural formula of the composite hole transport layer is 29. The method according to any one of claims 24-28, further comprising: forming a first electrode layer; forming a hole injection layer on the first electrode layer; Applying the mixed solution on a side of the hole injection layer away from the first electrode layer to form the composite hole transport layer; forming a light-emitting layer on a side of the composite hole transport layer away from the first electrode layer; forming an electron transport layer on a side of the light-emitting layer away from the first electrode layer; forming an electron injection layer on a side of the electron transport layer away from the first electrode layer; as well as A second electrode layer is formed on a side of the electron injection layer away from the first electrode layer.

Images