Composite material and preparation method thereof, photoelectric device and display device

Abstract

The invention discloses a composite material and a preparation method thereof, a photoelectric device and a display device, and relates to the technical field of display. The composite material comprises a main body material and a modification material, the main body material comprises a semiconductor material, and the modification material comprises doped carbon quantum dots. The composite material provided by the invention is good in performance.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a composite material and its preparation method, optoelectronic devices, and display apparatus. Background Technology

[0002] Semiconductor materials are a class of electronic materials with conductivity between that of conductors and insulators, possessing semiconductor properties and used to fabricate semiconductor devices and integrated circuits. Currently, the properties of semiconductor materials, such as their high-temperature resistance, are relatively poor and require further improvement. Summary of the Invention

[0003] In view of this, this application provides a composite material and its preparation method, an optoelectronic device, and a display device.

[0004] The embodiments of this application are implemented as follows: a composite material includes a host material and a modifying material, wherein the host material includes a semiconductor material and the modifying material includes doped carbon quantum dots.

[0005] Accordingly, this application also provides a method for preparing a composite material, comprising the following steps:

[0006] A host material and a modifying material are provided, wherein the host material includes a semiconductor material and the modifying material includes doped carbon quantum dots;

[0007] The main material and the modifying material are mixed to obtain a composite material.

[0008] Accordingly, embodiments of this application also provide an optoelectronic device, comprising an anode, a functional layer, and a cathode stacked sequentially;

[0009] The material of the functional layer includes a composite material, which comprises a host material and a modifying material, wherein the host material includes a semiconductor material; and / or

[0010] The optoelectronic device further includes a first interface layer located between the anode and the functional layer; and / or, the optoelectronic device further includes a second interface layer located between the functional layer and the cathode; and / or, the optoelectronic device further includes a third interface layer, the functional layer including a plurality of sub-functional layers, the third interface layer located between two adjacent sub-functional layers.

[0011] The modifying material includes a first doped carbon quantum dot, the material of the first interface layer includes a second doped carbon quantum dot, the material of the second interface layer includes a third doped carbon quantum dot, and the material of the third interface layer includes a fourth doped carbon quantum dot.

[0012] Accordingly, this application also provides a display device, which includes the above-mentioned optoelectronic device.

[0013] The composite material provided in this application has good performance. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a flowchart of the method for preparing composite materials provided in the embodiments of this application;

[0016] Figure 2 This is a schematic diagram of the structure of the optoelectronic device provided in the embodiments of this application;

[0017] Figure 3 This is a schematic diagram of the structure of another optoelectronic device provided in the embodiments of this application.

[0018] Figure label:

[0019] Optoelectronic device 100; anode 10; hole functional layer 20; hole injection layer 21; hole transport layer 22; light-emitting layer 30; electron functional layer 40; electron injection layer 41; electron transport layer 42; cathode 50; interface layer 60; first interface layer 63; second interface layer 64; first interface sublayer 65; second interface sublayer 61; third interface sublayer 62; fourth interface sublayer 66. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0021] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the orientation shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0022] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0023] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0024] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0025] The technical solution of this application is as follows:

[0026] In a first aspect, embodiments of this application provide a composite material, including a main material and a modifying material, wherein the main material includes a semiconductor material and the modifying material includes doped carbon quantum dots.

[0027] The composite material provided in this application includes carbon-doped quantum dots as a modifying material. Carbon-doped quantum dots have many advantages, such as good water solubility, low toxicity, environmental friendliness, wide availability of raw materials, and low cost. At the same time, carbon-doped quantum dots also have good electrical and thermal conductivity and abundant active groups. The introduction of carbon-doped quantum dots into the composite material can significantly improve the carrier mobility, heat dissipation, and high-temperature stability of the composite material. Carbon-doped quantum dots can also passivate defects in semiconductor materials and improve the fluorescence quantum yield of semiconductor materials.

[0028] In some embodiments, the mass ratio of the base material to the modifying material is (5-50):1, for example, it can be 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, etc. Within the range of the mass ratio, it is beneficial for the modifying material to passivate defects in the base material and improve the conductivity, heat dissipation, stability, and other properties of the base material.

[0029] In some embodiments, the doped carbon quantum dot includes carbon quantum dots and doping elements.

[0030] In some embodiments, the average particle size of the carbon quantum dots is 2nm to 10nm, for example, it can be 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, etc.

[0031] Furthermore, the doping element includes one or more of alkali metals, alkaline earth metals, group IIB elements, and group VIA elements.

[0032] The alkali metals include K.

[0033] The alkaline earth metals include Mg.

[0034] Both the alkali metal and the alkaline earth metal can further improve the high-temperature resistance of the composite material.

[0035] The group IIB elements include one or more of Cd and Zn.

[0036] The VIA group elements include one or more of Se and S.

[0037] The group IIB elements and group VIA elements have good compatibility, which can significantly promote the compatibility of the carbon quantum dots with the host material.

[0038] In some embodiments, the doping mass fraction of the doping element in the doped carbon quantum dots is 1 wt% to 20 wt%, for example, it can be 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, etc. It is understood that within the aforementioned doping mass fraction range, the doping element can improve the high-temperature resistance of the composite material and / or promote the compatibility of the modifying material with the host material.

[0039] Furthermore, when the doping element in the doped carbon quantum dots includes at least one of the alkali metal, the alkaline earth metal, and at least one of the Group IIB and Group VIA elements, the mass ratio of the sum of the alkali metal and the alkaline earth metal to the sum of the mass of the Group IIB and Group VIA elements is (1-3):(1-3), for example, 1:1, 1:2, 1:3, 2:1, 3:1, etc. Within the range of the above mass ratio, it is beneficial for the doped carbon quantum dots to be compatible with the host material and to improve the high-temperature resistance of the composite material. In other words, the doping element can coordinate the beneficial effects of improving the high-temperature resistance of the composite material and promoting compatibility.

[0040] In some embodiments, the doped carbon quantum dots are connected to active groups.

[0041] Furthermore, the active group includes one or more of amino, carboxyl, hydroxyl, mercapto, carbonyl, quinone, pyrrole, and pyridyl groups. It is understood that the active group can passivate defects in the composite material and improve the carrier mobility and fluorescence quantum yield of the composite material.

[0042] In some embodiments, the semiconductor material includes one or more of N-type semiconductor materials, P-type semiconductor materials, and luminescent materials.

[0043] It should be noted that the N-type semiconductor material and the P-type semiconductor material are materials known in the art for use in electronic functional layers and hole functional layers, and the light-emitting material is a material known in the art for use in light-emitting layers.

[0044] Combining doped carbon quantum dots with N-type and P-type semiconductor materials can improve the carrier mobility, heat dissipation, and high-temperature stability of the composite material. Combining doped carbon quantum dots with luminescent materials can passivate defects in the luminescent materials and improve their fluorescence quantum yield. Applying these composite materials to the functional layer of optoelectronic devices can effectively improve the luminous efficiency of the devices, stabilize the voltage, and reduce voltage amplification.

[0045] In some embodiments, the N-type semiconductor material includes 8-hydroxyquinoline aluminum, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 4,7-diphenyl-1,10-o-diazaphenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, and bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum. 1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, 2,2'-(1,3-phenyl)bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole], tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane, tetra[(m-pyridyl)-phenyl-3-yl]biphenyl, 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1”-terphenyl]-3,3”-diyl]dipyridine, 1,3-bis(3,5-dipyridyl-3-ylphenyl)benzene, n,n′-bis(naphthyl-1-yl) The semiconductor material comprises one or more of the following: )-n,n′-bis(phenyl)benzidine, first-doped metal oxide particles, first-undoped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials; wherein the first-undoped metal oxide particles are composed of one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5; and the metal oxide in the first-doped metal oxide particles comprises ZnO, TiO2, SnO2, ZrO2, and T2O5. One or more of a2O5 and Al2O3, wherein the doping element in the first doped metal oxide particle includes one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga, wherein the IIB-VIA group semiconductor material includes one or more of ZnS, ZnSe, and CdS, wherein the IIIA-VA group semiconductor material includes one or more of InP and GaP, and wherein the IB-IIIA-VIA group semiconductor material includes one or more of CuInS and CuGaS.

[0046] In some embodiments, the P-type semiconductor material includes 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(carbazolyl-9-yl)triphenylamine, trichloroisocyanuric acid, and terbium-doped phosphate-based green luminescent material. Materials, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzphenanthrene, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly[bis(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p-)phenylenevinylene, poly(phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)- 1,4-Phenylacetide], copper phthalocyanine, aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT, PEDOT:PSS and its derivatives, PEDOT:PSS derivatives doped with s-MoO3, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-di(naphthyl-1-yl)-N,N'-diphenylbenzidine, spiroNPB, nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinone dimethane, doped graphene, undoped graphene, second-doped metal oxide The metal oxide particles are selected from one or more of the following: metal oxide particles, second undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides. The metal oxides in the second doped metal oxide particles and the metal oxides in the second undoped metal oxide particles each independently include one or more of the following: MoO3, WO3, NiO, CrO3, CuO, and V2O5. The doping element in the second doped metal oxide particles includes one or more of the following: Mo, W, Ni, Cr, Cu, and V. The metal sulfides include one or more of the following: CuS, MoS3, and WS3. The metal selenides include one or more of the following: MoSe3 and WSe3. The metal nitrides include p-type gallium nitride.

[0047] It should be noted that when the N-type semiconductor material and the P-type semiconductor material are inorganic materials, the doped carbon quantum dots can passivate the defects of the inorganic materials; when the N-type semiconductor material and the P-type semiconductor material are organic materials, the active groups on the doped carbon quantum dots can crosslink with the organic materials, increasing the compatibility between the doped carbon quantum dots and the organic materials, improving the carrier migration efficiency, and improving the heat dissipation of the composite material.

[0048] In some embodiments, the luminescent material includes one or more of organic luminescent materials and quantum dot luminescent materials.

[0049] The organic light-emitting material may be selected from, but is not limited to, one or more of the following: CBP:Ir(mppy)3(4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridinium(III)]), TCTX:Ir(mmpy)(4,4',4”-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridinium(III)]), diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, delayed fluorescent materials, TTA materials, TADF (thermally activated delayed) materials, polymers containing BN covalent bonds, HLCT (hybrid local charge transfer excited state) materials, and Exciplex (excitoplex) light-emitting materials.

[0050] The quantum dot luminescent material may be selected from, but is not limited to, one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials.

[0051] The materials for the single-structure quantum dots, the core material of the core-shell quantum dots, and the shell material of the core-shell quantum dots can be selected from, but are not limited to, one or more of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds. The shell of the core-shell quantum dots may include one or more layers. The group II-VI compounds may be selected from, but are not limited to, one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe. The IV-VI group compounds may be selected from, but are not limited to, one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe. The group III-V compounds may be selected from, but are not limited to, one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb. The group I-III-VI compounds may be selected from, but are not limited to, one or more of CuInS2, CuInSe2, and AgInS2.

[0052] As an example, the core-shell structured quantum dots can be selected from, but are not limited to, one or more of CdSe / CdSeS / CdS, InP / ZnSeS / ZnS, CdZnSe / ZnSe / ZnS, CdSeS / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, ZnSe / ZnS, ZnSeTe / ZnS, CdSe / CdZnSeS / ZnS, and InP / ZnSe / ZnS. In the above descriptions of CdSe / ZnS, etc., the " / " indicates that the material after the " / " (as the shell) covers the material before the " / " (as the core).

[0053] The perovskite semiconductor material can be selected from, but is not limited to, doped or undoped inorganic perovskite semiconductors, or organic-inorganic hybrid perovskite semiconductors. The general structural formula of the inorganic perovskite semiconductor is AMX3, where A is Cs. + Ion, M is a divalent metal cation selected from Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ One or more of them, where X is a halide anion selected from Cl. - ,Br - I - One or more of the following. The general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation selected from CH3(CH2). n-2 NH3 + Or [NH3(CH2)] n NH3] 2+ Where n≥2, M is a divalent metal cation selected from Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ One or more of them, where X is a halide anion selected from Cl. - ,Br - I -One or more of them.

[0054] In some embodiments, the doped carbon quantum dots and the quantum dot luminescent material are connected via the active group. In other words, the composite material comprises a structure of doped carbon quantum dots-active group-quantum dot luminescent material. Specifically, the active group can be connected to the doped carbon quantum dots and the quantum dot luminescent material respectively via coordination bonds, chelate bonds, etc. The doped carbon quantum dots surround the surface of the quantum dot luminescent material. The active group facilitates a tight connection between the doped carbon quantum dots and the quantum dot luminescent material, enabling the doped carbon quantum dots to more effectively passivate defects in the quantum dot luminescent material.

[0055] Preferably, when the composite material includes doped carbon quantum dots and a luminescent material, the doping elements of the doped carbon quantum dots are the same as those in the luminescent material, which is beneficial to the compatibility of the doped carbon quantum dots and the luminescent material.

[0056] Secondly, please refer to Figure 1 This application also provides a method for preparing a composite material, comprising the following steps:

[0057] S11. Provide a main material and a modifying material, wherein the main material includes a semiconductor material and the modifying material includes doped carbon quantum dots;

[0058] S12. Mix the main material and the modification material to obtain a composite material.

[0059] In some embodiments, the mixture of the body material and the modification material includes:

[0060] S121. Provide the main material, the modifying material and the solvent, mix them to obtain a mixture;

[0061] S122. The mixture is subjected to ultrasonic treatment to obtain a composite material.

[0062] In some embodiments, the mass ratio of the main material to the modifying material in the mixture is (5-50):1, for example, it can be 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, etc. Within the range of the mass ratio, it is beneficial for the modifying material to passivate defects in the main material and improve the heat dissipation, stability, and other properties of the main material.

[0063] In some embodiments, the semiconductor material includes one or more of N-type semiconductor materials, P-type semiconductor materials, and luminescent materials.

[0064] In some embodiments, when the main material in the mixture is the P-type semiconductor material, the mass concentration of the P-type semiconductor material is 4 mg / mL to 15 mg / mL, for example, 5 mg / mL, 6 mg / mL, 8 mg / mL, 10 mg / mL, 12 mg / mL, etc. When the main material is the N-type semiconductor material, the mass concentration of the N-type semiconductor material is 10 mg / mL to 40 mg / mL, for example, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, 35 mg / mL, etc. When the main material is the luminescent material, the mass concentration of the luminescent material is 10 mg / mL to 40 mg / mL, for example, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, 35 mg / mL, etc. Within these mass concentration ranges, uniform dispersion of the main material is beneficial.

[0065] In some embodiments, the solvent is selected from one or more of chlorobenzene, diethylene glycol monobutyl ether, trimethoxybutanol, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, methanol, ethanol, propanol, butanol, ethylene glycol, isopropanol, glycerol, dimethyl sulfoxide, acetone, acetophenone, tetrahydrofuran, N,N-dimethylformamide, ethyl acetate, pyrrole, butyric acid, and cresol.

[0066] In some embodiments, the frequency of the ultrasound is 20kHz to 40kHz, for example, 22kHz, 25kHz, 28kHz, 30kHz, 32kHz, 35kHz, 38kHz, etc.; the duration is 10min to 30min, for example, 12min, 15min, 18min, 20min, 22min, 25min, 28min, etc. Thus, under the ultrasound conditions, it is beneficial for the main material and the modifying material to mix uniformly.

[0067] It should be noted that when the main material is a quantum dot luminescent material, the surface of the quantum dot luminescent material contains ligands. These ligands are conventional ligands known in the art, such as one or more of acid ligands, phosphine ligands, amine ligands, and thiol ligands. The acid ligands include one or more of oleic acid, mercaptoacetic acid, and mercaptopropionic acid. The phosphine ligands include one or more of trioctylphosphine, trioctylphosphine oxide, and tributylphosphine. The amine ligands include oleylamine. The thiol ligands include one or more of 1,2-ethanedithiol, propanethiol, butanethiol, octylthiol, dodecanethiol, octadecylthiol, benzylthiol, 1,2-benzenethiol, 1,3-benzenethiol, and 1,4-benzenethiol. When the doped carbon quantum dots are mixed with the quantum dot luminescent material, the ligands on the surface of the quantum dot luminescent material detach, and one end of the active group of the doped carbon quantum dots connects to the doped carbon quantum dots, while the other end connects to the quantum dot luminescent material, forming a composite material.

[0068] The method for preparing composite materials provided in this application is simple to operate, low in cost, and can effectively prepare composite materials.

[0069] Thirdly, please refer to Figure 2 This application also provides an optoelectronic device 100, which includes an anode 10, a functional layer and a cathode 50 stacked sequentially.

[0070] The material of the functional layer includes a composite material, which comprises a host material and a modifying material, wherein the host material includes a semiconductor material; and / or

[0071] The optoelectronic device 100 further includes an interface layer 60, which includes one or more of a first interface layer 63, a second interface layer 64, and a third interface layer; the first interface layer 63 is located between the anode 10 and the functional layer; the second interface layer 64 is located between the functional layer and the cathode 50; the functional layer includes several sub-functional layers, and the third interface layer is located between two adjacent sub-functional layers.

[0072] The modifying material includes a first doped carbon quantum dot, the material of the first interface layer 63 includes a second doped carbon quantum dot, the material of the second interface layer 64 includes a third doped carbon quantum dot, and the material of the third interface layer includes a fourth doped carbon quantum dot.

[0073] In the optoelectronic device 100 provided in this application, the composite material incorporates doped carbon quantum dots applied to the functional layer, and / or an interface layer 60 formed by doped carbon quantum dots is provided in the optoelectronic device 100, which can effectively improve the luminous efficiency of the optoelectronic device 100, stabilize the voltage of the optoelectronic device 100, and reduce the voltage increase.

[0074] In some embodiments, the anode 10 and the cathode 50 each independently comprise one or more of a metal, a carbon material, and a metal oxide; the metal comprises one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material comprises one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxide comprises a metal oxide electrode or a composite electrode in which a metal is disposed between doped or undoped transparent metal oxides; the material of the metal oxide electrode comprises one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO; and the composite electrode comprises one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2. In this context, " / " indicates a stacked structure. For example, AZO / Ag / AZO represents a composite electrode consisting of sequentially stacked AZO, Ag, and AZO layers.

[0075] In some embodiments, the functional layer includes one or more of a hole functional layer 20, a light-emitting layer 30, and an electronic functional layer 40, wherein the hole functional layer 20 is disposed between the anode 10 and the light-emitting layer 30, and the electronic functional layer 40 is disposed between the light-emitting layer 30 and the cathode 50.

[0076] It is understood that when the material of the functional layer includes the composite material, that is, at least one of the hole functional layer 20, the light-emitting layer 30, and the electronic functional layer 40 includes the composite material, and the main material in the composite material is an N-type semiconductor material, a P-type semiconductor material, or a light-emitting material.

[0077] Specifically, when the material of the hole functional layer 20 includes the composite material, the main material in the composite material is a P-type semiconductor material. When the material of the hole functional layer 20 does not include the composite material, the material of the hole functional layer 20 can be a P-type semiconductor material, that is, a material without carbon quantum dot modification.

[0078] When the material of the light-emitting layer 30 includes the composite material, the main material in the composite material is a light-emitting material. When the material of the light-emitting layer 30 does not include the composite material, the material of the light-emitting layer 30 can be a light-emitting material, that is, a material without carbon quantum dot modification.

[0079] When the material of the electronic functional layer 40 includes the composite material, the main material in the composite material is an N-type semiconductor material. When the material of the electronic functional layer 40 does not include the composite material, the material of the electronic functional layer 40 can be an N-type semiconductor material, that is, without carbon quantum dot modification materials.

[0080] It is understood that when the hole functional layer 20 and the electron functional layer 40 are made of P-type semiconductor material and N-type semiconductor material, respectively, and the material of the light-emitting layer 30 is quantum dot light-emitting material, adding a modifying material to dope carbon quantum dots in the P-type semiconductor material and N-type semiconductor material can promote the compatibility of the hole functional layer 20 and / or the electron functional layer 40 with the light-emitting layer 30, promote the migration and recombination of charge carriers, and improve device efficiency.

[0081] Furthermore, the third interface layer includes at least one interface sublayer. In any sub-functional layer, interface layer, and interface sublayer, the particle size and surface ligands of the carbon quantum dots in the doped carbon quantum dots are the same or different, and the materials and doping mass fractions of the doping elements in the doped carbon quantum dots are the same or different.

[0082] In some embodiments, the hole functional layer 20 includes one or more of a hole injection layer 21 and a hole transport layer 22, wherein the hole injection layer 21 is located between the anode 10 and the hole transport layer 22. The electron functional layer 40 includes one or more of an electron injection layer 42 and an electron transport layer 41, wherein the electron injection layer 42 is located between the electron transport layer 41 and the cathode 50.

[0083] Please see Figure 3 The third interface layer includes one or more of the following: a first interface sublayer 65 located between the hole injection layer 21 and the hole transport layer 22; a second interface sublayer 61 located between the hole transport layer 22 and the light-emitting layer 30; a third interface sublayer 62 located between the light-emitting layer 30 and the electron transport layer 41; and a fourth interface sublayer 66 located between the electron transport layer 41 and the electron injection layer 42.

[0084] In some embodiments, the doping mass fraction of the dopant element in the first doped carbon quantum dot is 1 wt% to 20 wt%, for example, it can be 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, etc. It is understood that, for the subfunctional layer, within the aforementioned doping mass fraction range, the doping element can improve the performance of the composite material, thereby improving the carrier mobility, fluorescence quantum yield, and stability of the functional layer.

[0085] The doping mass fraction of the doping element in the second doped carbon quantum dot is 1wt% to 20wt%, for example, it can be 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, etc. The doping mass fraction of the doping element in the third doped carbon quantum dot is 1wt% to 20wt%, for example, it can be 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, etc. The doping mass fraction of the dopant element in the fourth doped carbon quantum dot is 1wt% to 20wt%, for example, it can be 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, etc. For the interface layer 60 and the interface sublayer, the interface layer 60 can promote the interfacial compatibility between the various film layers in the optoelectronic device 100, further promote the transport of charge carriers to the light-emitting layer 30 for recombination and light emission, and improve the luminous efficiency of the optoelectronic device 100.

[0086] In some embodiments, the doping elements in the first, second, third, and fourth doped carbon quantum dots each independently include one or more of alkali metals, alkaline earth metals, Group IIB elements, and Group VIA elements. The alkali metal includes K. The alkaline earth metal includes Mg. The Group IIB elements include one or more of Cd and Zn. The Group VIA elements include one or more of Se and S.

[0087] In some embodiments, the thickness of the first interface layer 63 is 5nm to 20nm, for example, it can be 6nm, 8nm, 10nm, 12nm, 14nm, 16nm, 18nm, etc.

[0088] In some embodiments, the thickness of the second interface layer 64 is 5nm to 20nm, for example, it can be 6nm, 8nm, 10nm, 12nm, 14nm, 16nm, 18nm, etc.

[0089] In some embodiments, the thickness of the third interface layer is 5nm to 20nm, for example, it can be 6nm, 8nm, 10nm, 12nm, 14nm, 16nm, 18nm, etc.

[0090] Furthermore, in some embodiments, the thickness of the first interface sublayer 65 is 5nm to 20nm, for example, it can be 6nm, 8nm, 10nm, 12nm, 14nm, 16nm, 18nm, etc.

[0091] In some embodiments, the thickness of the second interface sublayer 61 is 5nm to 20nm, for example, it can be 6nm, 8nm, 10nm, 12nm, 14nm, 16nm, 18nm, etc.

[0092] In some embodiments, the thickness of the third interface sublayer 62 is 5nm to 20nm, for example, it can be 6nm, 8nm, 10nm, 12nm, 14nm, 16nm, 18nm, etc.

[0093] In some embodiments, the thickness of the fourth interface sublayer 66 is 5nm to 20nm, for example, it can be 6nm, 8nm, 10nm, 12nm, 14nm, 16nm, 18nm, etc.

[0094] Within the thickness range of each interface layer 60 and interface sublayer, the carrier transport path is suitable, and the interfacial compatibility between each film layer in the optoelectronic device 100 can be effectively adjusted, promoting carrier transport recombination and luminescence, and improving the performance of the optoelectronic device 100.

[0095] In some embodiments, the optoelectronic device 100 includes a light-emitting diode.

[0096] Fourthly, embodiments of this application also provide a display device, which includes the aforementioned optoelectronic device 100.

[0097] The display device can be any electronic product with display function, including but not limited to smartphones, tablets, laptops, digital cameras, digital camcorders, smart wearable devices, smart weighing scales, in-vehicle displays, televisions, or e-book readers. Among them, smart wearable devices can be, for example, smart bracelets, smartwatches, virtual reality (VR) headsets, etc.

[0098] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0099] Example 1

[0100] This embodiment provides a composite material comprising an N-type semiconductor material, magnesium-doped zinc oxide, and zinc-doped carbon quantum dots, wherein the zinc doping mass fraction is 5%, and its preparation method is as follows:

[0101] Magnesium-doped zinc oxide, carbon quantum dots, and ethanol were mixed to obtain a mixture; the mass ratio of magnesium-doped zinc oxide to carbon quantum dots was 30:1, and the mass concentration of magnesium-doped zinc oxide in the mixture was 20 mg / mL.

[0102] The mixture was sonicated at 30 kHz for 20 min to obtain the composite material.

[0103] Example 2

[0104] This embodiment is basically the same as embodiment 1, except that zinc-doped carbon quantum dots are replaced with magnesium-doped carbon quantum dots, wherein the magnesium doping mass fraction is 10wt%.

[0105] Example 3

[0106] This embodiment is basically the same as Embodiment 1, except that the mass ratio of magnesium-doped zinc oxide to zinc-doped carbon quantum dots is 50:1.

[0107] Example 4

[0108] This embodiment is basically the same as Embodiment 1, except that the mass ratio of magnesium-doped zinc oxide to zinc-doped carbon quantum dots is 5:1.

[0109] Example 5

[0110] This embodiment is basically the same as Embodiment 1, except that the ultrasonic frequency in this embodiment is 40kHz.

[0111] Example 6

[0112] This embodiment is basically the same as Embodiment 1, except that the ultrasonic frequency in this embodiment is 20kHz.

[0113] Example 7

[0114] This embodiment is basically the same as Embodiment 1, except that the ultrasound time in this embodiment is 30 minutes.

[0115] Example 8

[0116] This embodiment is basically the same as Embodiment 1, except that the ultrasonic frequency in this embodiment is 10 min.

[0117] Example 9

[0118] This embodiment is basically the same as Embodiment 1, except that the N-type semiconductor material magnesium-doped zinc oxide is replaced with the P-type semiconductor material TFB in this embodiment.

[0119] Example 10

[0120] This embodiment is basically the same as embodiment 9, except that zinc-doped carbon quantum dots are replaced with potassium-doped carbon quantum dots, wherein the mass fraction of potassium doping is 10 wt%.

[0121] Example 11

[0122] This embodiment is basically the same as embodiment 9, except that the P-type semiconductor material TFB is replaced with the P-type semiconductor material NiO in this embodiment.

[0123] Example 12

[0124] This embodiment is basically the same as embodiment 9, except that the mass ratio of TFB to zinc-doped carbon quantum dots is 50:1 in this embodiment.

[0125] Example 13

[0126] This embodiment is basically the same as embodiment 9, except that the mass ratio of TFB to zinc-doped carbon quantum dots is 5:1 in this embodiment.

[0127] Example 14

[0128] This embodiment is basically the same as Embodiment 1, except that the N-type semiconductor material magnesium-doped zinc oxide is replaced with the luminescent material CdZnSe.

[0129] Example 15

[0130] This embodiment is basically the same as embodiment 14, except that zinc-doped carbon quantum dots are replaced with cadmium-doped carbon quantum dots, wherein the cadmium doping mass fraction is 10 wt%.

[0131] Example 16

[0132] This embodiment is basically the same as embodiment 14, except that the mass ratio of CdZnSe to zinc-doped carbon quantum dots is 50:1 in this embodiment.

[0133] Example 17

[0134] This embodiment is basically the same as embodiment 14, except that the mass ratio of CdZnSe to zinc-doped carbon quantum dots is 5:1 in this embodiment.

[0135] Comparative Example 1

[0136] This comparative example provides a material, including an N-type semiconductor material, magnesium-doped zinc oxide.

[0137] Comparative Example 2

[0138] This comparative example is basically the same as Example 1, except that zinc-doped carbon quantum dots are replaced with carbon quantum dots.

[0139] Comparative Example 3

[0140] This comparative example provides a material, including the P-type semiconductor material TFB.

[0141] Comparative Example 4

[0142] This comparative example is basically the same as Example 9, except that zinc-doped carbon quantum dots are replaced with carbon quantum dots.

[0143] Comparative Example 5

[0144] This comparative example provides a material, including the P-type semiconductor material NiO.

[0145] Comparative Example 6

[0146] This comparative example is basically the same as Example 11, except that zinc-doped carbon quantum dots are replaced with carbon quantum dots.

[0147] Comparative Example 7

[0148] This comparative example provides a material, including the luminescent material CdZnSe.

[0149] Comparative Example 8

[0150] This comparative example is basically the same as Example 14, except that zinc-doped carbon quantum dots are replaced with carbon quantum dots.

[0151] The current density of the composite materials in Examples 1-13 and Comparative Examples 1-6, and the fluorescence quantum yield (PLQY) of the composite materials in Examples 14-17 and Comparative Examples 7-8 were tested respectively, and the results are shown in Table 1.

[0152] The current density was tested as follows: the current density-voltage curve of the optoelectronic device (single carrier transport thin film device HOD / EOD) was tested. The structure of EOD was anode / quantum dot light-emitting layer / electron transport layer / cathode, and the material of electron transport layer was the composite material of Examples 1-8 and Comparative Examples 1-2, respectively. The structure of HOD was anode / hole transport layer / quantum dot light-emitting layer / cathode, and the material of hole transport layer was the composite material of Examples 9-13 and Comparative Examples 3-6, respectively. The space charge confinement current (SCLC) region in the current density-voltage curve was obtained, and the current density at a voltage of 1V was obtained.

[0153] Fluorescence quantum yield (PLQY) was measured using a steady-state fluorescence spectrometer from Edinburgh Instruments, model FS5, with the corresponding accessory SC-30 for measuring PLQY.

[0154] Table 1

[0155]

[0156]

[0157] As shown in Table 1:

[0158] As can be seen from Examples 1-8 and Comparative Examples 1-2, when N-type semiconductor materials are modified with doped carbon quantum dots, the current density of the composite materials in Examples 1-8 is significantly improved compared to the N-type semiconductor materials in Comparative Examples 1-2. This indicates that more charge passes through a unit area, in other words, more electrons and a faster electron migration rate. Within the scope provided in this application, the modification effect of doped carbon quantum dots on N-type semiconductor materials can be guaranteed. The mixing stirring frequency and time have little impact on the performance of the composite material compared to Example 1, and both can effectively improve the current density and increase the electron mobility of the composite material. In Comparative Example 2, N-type semiconductor materials are modified with undoped carbon quantum dots, and the performance of the composite material is better than that of the N-type semiconductor material in Comparative Example 1, but it is still far inferior to that in Examples 1-8.

[0159] As shown in Examples 9-13 and Comparative Examples 3-6, adding carbon-doped quantum dots to P-type semiconductor materials significantly improves the current density, indicating strong current output capability and reflecting high hole migration efficiency. The carbon-doped quantum dots effectively enhance the hole mobility of the composite material. The carbon-doped quantum dots have a significant improvement effect on both organic and inorganic P-type semiconductor materials. The direct modification of P-type semiconductor materials with carbon quantum dots in Comparative Examples 4 and 6 also has a certain improvement effect, but its improvement effect is far less than that of the carbon-doped quantum dots provided in this application.

[0160] As can be seen from Examples 14-17 and Comparative Examples 7-8, adding doped carbon quantum dots to luminescent materials can effectively improve the fluorescence quantum yield of luminescent materials. This is because they are connected to luminescent materials through active groups, which passivates the defects of luminescent materials. In particular, in Example 15, the doped carbon quantum dots were doped with cadmium, which promoted the compatibility between the doped carbon quantum dots and the luminescent materials, and the fluorescence quantum yield was significantly improved, which was significantly better than that of the luminescent materials and the carbon quantum dot-modified luminescent materials.

[0161] Device Example 1

[0162] This embodiment provides an optoelectronic device, the fabrication method of which is as follows:

[0163] The ITO conductive glass was cleaned with a cleaning agent to initially remove the stains on the surface. Then, it was ultrasonically cleaned for 20 minutes each in deionized water, acetone, anhydrous ethanol, and deionized water to remove the impurities on the surface. Finally, it was dried with high-purity nitrogen to form an ITO anode with a thickness of 75 nm.

[0164] TFB was spin-coated onto the ITO anode at a speed of 3000 rpm for 30 seconds, and then baked at 150°C for 20 minutes to form a hole transport layer with a thickness of 40 nm.

[0165] A quantum dot solution of CdZnSe with a mass concentration of 10 mg / mL was prepared and spin-coated onto the hole transport layer at a speed of 3000 rpm for 30 s. The solution was then baked at 100 °C for 5 min to form a light-emitting layer with a thickness of 25 nm.

[0166] The composite material prepared in Example 1 was dissolved in ethanol and spin-coated onto the light-emitting layer at a spin speed of 4000 rpm for 30 s. Then it was baked at 80°C for 10 min to form a 50 nm electron transport layer.

[0167] TiO2 was dissolved in ethanol and spin-coated onto the electron transport layer at a speed of 4000 rpm for 30 s. Then it was baked at 80 °C for 10 min to form a 30 nm electron injection layer.

[0168] Ag is deposited on the electron-injected layer by thermal evaporation, with a vacuum level not exceeding 3 x 10⁻⁶. -4 Pa, velocity of 1 angstrom / second, time of 1000s, forming a cathode with a thickness of 100nm;

[0169] Packaging yields optoelectronic devices.

[0170] Device Examples 2-8

[0171] Device Examples 2-8 are basically the same as Device Example 1, except that the composite material of Example 1 is replaced with the composite material of Example 2-8 in Device Examples 2-8 respectively.

[0172] Device Examples 9-13

[0173] Device Examples 9-13 are basically the same as Device Example 1, except that the electron transport layer in Device Examples 9-13 is made of magnesium-doped zinc oxide and does not contain doped carbon quantum dots; the hole transport layer is made of the composite material of Examples 9-13.

[0174] Device Examples 14-17

[0175] Device Examples 14-17 are basically the same as Device Example 1, except that the electron transport layer in Device Examples 14-17 is made of magnesium-doped zinc oxide and does not contain doped carbon quantum dots; the light-emitting layer is made of the composite material of Examples 14-17.

[0176] Device Example 18

[0177] Device Example 18 is basically the same as Device Example 2, except that the hole transport layer in Device Example 18 is made of the composite material of Example 10.

[0178] Device Example 19

[0179] Device Example 19 is basically the same as Device Example 2, except that the material of the light-emitting layer in Device Example 19 is the composite material of Example 15.

[0180] Device Example 20

[0181] Device Example 20 is basically the same as Device Example 10, except that the material of the light-emitting layer in Device Example 20 is the composite material of Example 15.

[0182] Device Example 21

[0183] Device Example 21 is basically the same as Device Example 18, except that the material of the light-emitting layer in Device Example 21 is the composite material of Example 15.

[0184] Device Example 22

[0185] Device Example 22 is basically the same as Device Example 1, except that the electron transport layer in Device Example 22 is made of magnesium-doped zinc oxide and does not contain doped carbon quantum dots; after forming the hole transport layer, it also includes: providing a zinc-doped carbon quantum dot dispersion containing zinc-doped carbon quantum dots with a zinc doping mass fraction of 5%, spin-coating the dispersion onto the hole transport layer to form a second interface sublayer with a thickness of 5 nm, and forming a light-emitting layer on the second interface sublayer.

[0186] Device Example 23

[0187] Device Example 23 is basically the same as Device Example 1, except that the electron transport layer in Device Example 23 is made of magnesium-doped zinc oxide and does not contain doped carbon quantum dots. After the light-emitting layer is formed, the device further includes: providing a zinc-doped carbon quantum dot dispersion containing zinc-doped carbon quantum dots with a zinc doping mass fraction of 5%, and spin-coating the dispersion onto the light-emitting layer to form a third interface sublayer with a thickness of 5 nm, and forming an electron transport layer on the third interface sublayer.

[0188] Device Example 24

[0189] Device Example 24 is basically the same as Device Example 22, except that after forming the light-emitting layer, Device Example 24 further includes: providing a zinc-doped carbon quantum dot dispersion containing zinc-doped carbon quantum dots with a zinc doping mass fraction of 5%, spin-coating the dispersion onto the light-emitting layer to form a third interface sublayer with a thickness of 5 nm, and forming an electron transport layer on the third interface sublayer.

[0190] Device Example 25

[0191] Device Example 25 is basically the same as Device Example 20, except that after forming the hole transport layer, Device Example 25 further includes: providing a zinc-doped carbon quantum dot dispersion containing zinc-doped carbon quantum dots with a zinc doping mass fraction of 5%, spin-coating the dispersion onto the hole transport layer to form a second interface sublayer with a thickness of 5 nm, and forming a light-emitting layer on the second interface sublayer.

[0192] Device Example 26

[0193] Device Example 26 is basically the same as Device Example 19, except that after forming the light-emitting layer, Device Example 26 further includes: providing a zinc-doped carbon quantum dot dispersion containing zinc-doped carbon quantum dots with a zinc doping mass fraction of 5%, spin-coating the dispersion onto the light-emitting layer to form a third interface sublayer with a thickness of 5 nm, and forming an electron transport layer on the third interface sublayer.

[0194] Device Example 27

[0195] Device Example 27 is basically the same as Device Example 21, except that after forming the hole transport layer, Device Example 27 further includes: providing a zinc-doped carbon quantum dot dispersion containing zinc-doped carbon quantum dots with a zinc doping mass fraction of 5%, spin-coating the dispersion onto the hole transport layer to form a second interface sublayer with a thickness of 5 nm, and forming a light-emitting layer on the second interface sublayer; after forming the light-emitting layer, it further includes: providing a zinc-doped carbon quantum dot dispersion containing zinc-doped carbon quantum dots with a zinc doping mass fraction of 5%, spin-coating the dispersion onto the light-emitting layer to form a third interface sublayer with a thickness of 5 nm, and forming an electron transport layer on the third interface sublayer.

[0196] Device Example 28

[0197] Device Example 28 is basically the same as Device Example 1, except that the electron transport layer in Device Example 28 is made of magnesium-doped zinc oxide and does not contain doped carbon quantum dots. After forming the anode, it also includes: providing a zinc-doped carbon quantum dot dispersion containing zinc-doped carbon quantum dots with a zinc doping mass fraction of 5%, spin-coating the dispersion onto the anode to form a first interface layer with a thickness of 5 nm, and forming an electron emitting layer on the first interface layer.

[0198] Device Example 29

[0199] Device Example 29 is basically the same as Device Example 1, except that the electron transport layer in Device Example 29 is made of magnesium-doped zinc oxide and does not contain doped carbon quantum dots. After forming the electron injection layer, the device further includes: providing a zinc-doped carbon quantum dot dispersion containing zinc-doped carbon quantum dots with a zinc doping mass fraction of 5%, spin-coating the dispersion onto the electron injection layer to form a second interface layer with a thickness of 5 nm, and forming a cathode on the second interface layer.

[0200] Device Example 30

[0201] Device Example 30 is basically the same as Device Example 1, except that the electron transport layer in Device Example 30 is made of magnesium-doped zinc oxide and does not contain doped carbon quantum dots. After forming the hole injection layer, the device further includes: providing a zinc-doped carbon quantum dot dispersion containing zinc-doped carbon quantum dots with a zinc doping mass fraction of 5%, spin-coating the dispersion onto the hole injection layer to form a first interface sublayer with a thickness of 5 nm, and forming a hole transport layer on the first interface sublayer.

[0202] Device Example 31

[0203] Device Example 31 is basically the same as Device Example 1, except that the electron transport layer material in Device Example 28 is magnesium-doped zinc oxide, without carbon quantum dots; after forming the electron transport layer, it also includes: providing a zinc-doped carbon quantum dot dispersion containing zinc-doped carbon quantum dots with a zinc doping mass fraction of 5%, spin-coating the dispersion onto the electron transport layer to form a fourth interface layer with a thickness of 5 nm, and forming the electron transport layer on the fourth interface layer.

[0204] Device Example 32

[0205] Device embodiment 32 is basically the same as device embodiment 24, except that device embodiment 32 also forms a first interface layer, a second interface layer, a first interface sub-layer and a fourth interface sub-layer, as in device embodiments 28 to 31.

[0206] Device Example 33

[0207] Device embodiment 33 is basically the same as device embodiment 27, except that device embodiment 33 also forms a first interface layer, a second interface layer, a first interface sub-layer and a fourth interface sub-layer, as described in device embodiments 28 to 31.

[0208] Device Comparison Example 1

[0209] The device comparative example 1 is basically the same as the device example 1, except that the composite material of example 1 is replaced with the material of comparative example 1 in this device comparative example.

[0210] Device Comparison Example 2

[0211] Device Comparison Example 2 is basically the same as Device Comparison Example 1, except that the hole transport layer material TFB is replaced with NiO material in Comparison Example 5 in this device comparison example.

[0212] Device Comparison Example 3

[0213] Comparative Example 3 is basically the same as Comparative Example 1, except that the composite material of Comparative Example 1 is replaced with the material of Comparative Example 2, the hole transport layer material is replaced with the material of Comparative Example 4, and the light-emitting layer material is replaced with the material of Comparative Example 8.

[0214] The brightness, external quantum efficiency, voltage difference, and lifetime T95@1000nit of the optoelectronic devices of Device Examples 1-33 and Device Comparative Examples 1-3 were tested respectively, and the results are shown in Table 2.

[0215] Among them, the brightness was measured using a photometer after the device was stabilized.

[0216] External quantum efficiency (EQE) is measured as the ratio of electron-hole pairs injected into a quantum dot to the number of emitted photons, expressed as a percentage (%). It is an important parameter for evaluating the quality of electroluminescent devices and can be obtained using an EQE optical testing instrument. The specific calculation formula is as follows:

[0217]

[0218] Where, η e For optical output coupling efficiency, η r χ is the ratio of recombination carriers to injected carriers, and K is the ratio of excitons producing photons to the total number of excitons. R K is the radiation process rate. NR This represents the rate of a non-radiative process.

[0219] Test conditions: Conducted at room temperature with an air humidity of 30-60%.

[0220] Voltage difference can reflect the stability of a device. It is the time required for the brightness of a device to decrease to a certain percentage of its maximum brightness under constant current or voltage drive. The time for the brightness to decrease to 95% of the maximum brightness is defined as T95. The voltage at T95 and the minimum voltage of the device during operation are measured, and the difference is the voltage difference.

[0221] The measurement method for lifetime T95@1000nit is as follows: Under constant current or voltage drive, the time required for the brightness of the device to decrease to a certain percentage of its maximum brightness is defined as T95. This lifetime is the measured lifetime. To shorten the testing cycle, device lifetime testing is usually performed at high brightness by accelerating device aging, and the lifetime at high brightness is obtained by fitting an extended exponential decay brightness decay fitting formula. For example, the lifetime at 1000nit is measured as T95@1000nit. The specific calculation formula is as follows:

[0222]

[0223] Among them, T95 L For longer lifespan at low brightness, T95 H For the measured lifetime under high brightness, L H To accelerate the device to its maximum brightness, L L The value is 1000 nits, and A is the acceleration factor. In this experiment, the lifetime of several groups of QLED devices under rated brightness was measured, and the value of A was found to be 1.7.

[0224] Table 2

[0225]

[0226]

[0227] As shown in Table 2:

[0228] As can be seen from Device Examples 1-8 and Device Comparative Example 1, the application of composite materials modified with carbon quantum dots to the electron transport layer of optoelectronic devices can effectively improve the brightness, external quantum efficiency, and lifespan of optoelectronic devices, and reduce voltage rise, indicating that the stability of optoelectronic devices has been improved; corresponding to the current density results of Example 2, the performance of the optoelectronic device in Device Example 2 is more outstanding.

[0229] As can be seen from Device Examples 9-13 and Device Comparative Examples 1-2, the performance of the composite material applied to the hole transport layer is slightly worse than that of the modified N-type semiconductor material applied to the electron transport layer in Device Examples 1-8. However, compared with Device Comparative Examples 1-2, the performance of Device Examples 9-13 is also improved.

[0230] As can be seen from Device Examples 14-17 and Device Comparative Example 1, applying carbon quantum dot-modified luminescent material to the luminescent layer improves the brightness, external quantum efficiency, lifespan, and reduces voltage difference of optoelectronic devices. Device Example 15 has relatively high brightness because cadmium-doped carbon quantum dots have good compatibility with quantum dot luminescent materials, and carbon quantum dots themselves have luminescent properties.

[0231] Based on device embodiments 2, 10, 15, and 18-21, and device comparative examples 1 and 3, it can be seen that, overall, the performance of device embodiments 18-21 is superior to that of device comparative examples 1, 3, and other device embodiments. This is mainly because at least two of their functional layers utilize the composite material of this application. In device embodiment 21, the electron transport layer, light-emitting layer, and hole transport layer all utilize the composite material of this application, resulting in a significant improvement in the performance of the optoelectronic device. In device comparative example 3, a carbon quantum dot-modified composite material is used as the material for the functional layer. Compared to device comparative examples 1 and 2, the performance of the optoelectronic device is improved, but the performance improvement is still limited and far inferior to the device embodiments provided in this application.

[0232] As can be seen from Device Examples 22-33 and Device Comparative Example 1, setting an interface layer formed by doped carbon quantum dots between adjacent film layers in an optoelectronic device can effectively improve the brightness and external quantum efficiency of the optoelectronic device, reduce the voltage difference, and extend its service life. The effect of setting multiple interface layers is better than that of optoelectronic devices with only one interface layer. For example, the effect of Device Example 24 is better than that of Device Examples 22-23, and the effect of Device Example 32 is better than that of Device Examples 28-31. In Device Examples 25-27 and Device Example 33, the simultaneous setting of interface layers and the application of composite materials to the functional layers have significantly improved the performance of the optoelectronic devices. In particular, in Device Example 33, the brightness and external quantum efficiency of the optoelectronic device are significantly improved, and the voltage difference is significantly reduced, indicating that the stability of the optoelectronic device is improved and the service life is correspondingly extended.

[0233] The composite materials, their preparation methods, optoelectronic devices, and display devices provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A composite material, characterized in that, It includes a host material and a modifying material, wherein the host material includes a semiconductor material and the modifying material includes doped carbon quantum dots.

2. The composite material as described in claim 1, characterized in that, The mass ratio of the main material to the modifying material is (5-50):1; and / or The doped carbon quantum dots comprise carbon quantum dots and a doping element, wherein the doping element comprises one or more of alkali metals, alkaline earth metals, group IIB elements, and group VIA elements; and / or The doped carbon quantum dots are connected to active groups.

3. The composite material as described in claim 2, characterized in that, The average particle size of the carbon quantum dots is 2 nm to 10 nm; and / or In the doped carbon quantum dots, the doping element has a doping mass fraction of 1 wt% to 20 wt%; and / or The alkali metal includes K; and / or The alkaline earth metals include Mg; and / or The group IIB elements include one or more of Cd and Zn; and / or The VIA group elements include one or more of Se and S; and / or When the doping element includes at least one of the alkali metal, the alkaline earth metal, and at least one of the Group IIB element and the Group VIA element, the mass ratio of the sum of the alkali metal and the alkaline earth metal to the sum of the mass of the Group IIB element and the Group VIA element is (1-3):(1-3); and / or The active group includes one or more of amino, carboxyl, hydroxyl, mercapto, carbonyl, quinone, pyrrole, and pyridyl groups.

4. The composite material as described in claim 1, characterized in that, The semiconductor material includes one or more of N-type semiconductor materials and P-type semiconductor materials; Optionally, the N-type semiconductor material includes 8-hydroxyquinoline aluminum, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 4,7-diphenyl-1,10-o-diazaphenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, and bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum. 8)-(1,1'-biphenyl-4-hydroxy)aluminum, 2,2'-(1,3-phenyl)bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole], tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane, tetra[(m-pyridyl)-phenyl-3-yl]biphenyl, 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1”-terphenyl]-3,3”-diyl]dipyridine, 1,3-bis(3,5-dipyridyl-3-ylphenyl)benzene, n,n′-bis(naphthyl-1-yl)- The semiconductor material comprises one or more of n,n′-bis(phenyl)benzidine, a first doped metal oxide particle, a first undoped metal oxide particle, a group IIB-VIA semiconductor material, a group IIIA-VA semiconductor material, and a group IB-IIIA-VIA semiconductor material. The first undoped metal oxide particle comprises one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The first doped metal oxide particle comprises ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The first doped metal oxide particles contain one or more of Al₂O₅ and Al₂O₃, and the doping elements in the first doped metal oxide particles include one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga. The IIB-VIA group semiconductor material includes one or more of ZnS, ZnSe, and CdS. The IIIA-VA group semiconductor material includes one or more of InP and GaP. The IB-IIIA-VIA group semiconductor material includes one or more of CuInS and CuGaS. Optionally, the P-type semiconductor material includes 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(carbazolyl-9-yl)triphenylamine, trichloroisocyanuric acid, terbium-doped phosphate-based green luminescent materials, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzphenanthrene, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly[bis(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p-)phenylenevinylene, poly(phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1, [4-Phenylenevinylene], copper phthalocyanine, aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT, PEDOT:PSS and its derivatives, PEDOT:PSS derivatives doped with s-MoO3, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-di(naphthyl-1-yl)-N,N'-diphenylbenzidine, spiroNPB, nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinone dimethane, doped graphene, undoped graphene, second-doped metal oxides The metal oxide particles are selected from one or more of the following: a second undoped metal oxide particle, a metal sulfide, a metal selenide, and a metal nitride. The metal oxides in the second doped metal oxide particles and the second undoped metal oxide particles each independently include one or more of MoO3, WO3, NiO, CrO3, CuO, and V2O5. The doping element in the second doped metal oxide particles includes one or more of Mo, W, Ni, Cr, Cu, and V. The metal sulfide includes one or more of CuS, MoS3, and WS3. The metal selenide includes one or more of MoSe3 and WSe3. The metal nitride includes p-type gallium nitride. The semiconductor material includes a light-emitting material, which includes one or more of organic light-emitting materials and quantum dot light-emitting materials. Optionally, the organic light-emitting material is selected from one or more of the following: 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridinium(III)], 4,4',4”-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridinium(III)], diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, delayed fluorescence materials, TTA materials, TADF materials, polymers containing BN covalent bonds, HLCT materials, and Exciplex light-emitting materials; Optionally, the quantum dot luminescent material is selected from one or more of single-structure quantum dots, core-shell quantum dots, and perovskite semiconductor materials; the material of the single-structure quantum dot, the core material of the core-shell quantum dot, and the shell material of the core-shell quantum dot are respectively selected from one or more of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds; the shell of the core-shell quantum dot includes one or more layers; the group II-VI compounds are selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, and HgTe. One or more of the following compounds: CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; the IV-VI compounds are selected from SnS, S... The compounds are selected from one or more of the following: nSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; the III-V compounds are selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, and AlNA. One or more of the following: s, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; wherein the I-III-VI group compounds are selected from one or more of CuInS2, CuInSe2, and AgInS2;The core-shell quantum dots are selected from one or more of CdSe / CdSeS / CdS, InP / ZnSeS / ZnS, CdZnSe / ZnSe / ZnS, CdSeS / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, ZnSe / ZnS, ZnSeTe / ZnS, CdSe / CdZnSeS / ZnS, and InP / ZnSe / ZnS; the perovskite semiconductor material is selected from doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors; the general structural formula of the inorganic perovskite semiconductor is AMX3, where A is Cs; + Ion, M is a divalent metal cation selected from Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ One or more of them, where X is a halide anion selected from Cl. - ,Br - I - One or more of the following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation selected from CH3(CH2). n-2 NH3 + Or [NH3(CH2)] n NH3] 2+ Where n≥2, M is a divalent metal cation selected from Pb 2+ Sn 2+ Cu 2 + Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ One or more of them, where X is a halide anion selected from Cl. - ,Br - I - One or more of them; Optionally, the doped carbon quantum dots and the quantum dot luminescent material are connected through the active groups of the doped carbon quantum dots.

5. A method for preparing a composite material, characterized in that, The steps include: A host material and a modifying material are provided, wherein the host material includes a semiconductor material and the modifying material includes doped carbon quantum dots; The main material and the modifying material are mixed to obtain a composite material.

6. The preparation method according to claim 5, characterized in that, The mixture of the main material and the modifying material includes: Provide the main material, the modifying material and the solvent, mix them to obtain a mixture; The mixture is subjected to ultrasonic treatment to obtain a composite material.

7. The preparation method according to claim 6, characterized in that, In the mixture: The mass ratio of the main material to the modifying material is (5-50):1; and / or The doped carbon quantum dots include carbon quantum dots and doping elements, wherein the doping elements include one or more of alkali metals, alkaline earth metals, group IIB elements, and group VIA elements. Optionally, the alkali metal includes K; optionally, the alkaline earth metal includes Mg; optionally, the Group IIB element includes one or more of Cd and Zn; optionally, the Group VIA element includes one or more of Se and S; and / or The semiconductor material includes one or more of N-type semiconductor materials, P-type semiconductor materials, and luminescent materials; when the host material is the P-type semiconductor material, the mass concentration of the P-type semiconductor material is 4 mg / mL to 15 mg / mL; when the host material is the N-type semiconductor material, the mass concentration of the N-type semiconductor material is 10 mg / mL to 40 mg / mL; optionally, when the host material is the luminescent material, the mass concentration of the luminescent material is 10 mg / mL to 40 mg / mL; and / or The solvent is selected from one or more of chlorobenzene, diethylene glycol monobutyl ether, trimethoxybutanol, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, methanol, ethanol, propanol, butanol, ethylene glycol, isopropanol, glycerol, dimethyl sulfoxide, acetone, acetophenone, tetrahydrofuran, N,N-dimethylformamide, ethyl acetate, pyrrole, butyric acid, and cresol; and / or The frequency of the ultrasound is 20kHz to 40kHz; the duration is 10min to 30min.

8. An optoelectronic device, characterized in that, It includes an anode, a functional layer, and a cathode arranged in sequence; The material of the functional layer includes a composite material, which comprises a host material and a modifying material, wherein the host material includes a semiconductor material; and / or The optoelectronic device further includes a first interface layer located between the anode and the functional layer; and / or, the optoelectronic device further includes a second interface layer located between the functional layer and the cathode; and / or, the optoelectronic device further includes a third interface layer, the functional layer including a plurality of sub-functional layers, the third interface layer located between two adjacent sub-functional layers. The modifying material includes a first doped carbon quantum dot, the material of the first interface layer includes a second doped carbon quantum dot, the material of the second interface layer includes a third doped carbon quantum dot, and the material of the third interface layer includes a fourth doped carbon quantum dot.

9. The optoelectronic device as described in claim 8, characterized in that, The doping mass fraction of the doping element in the first doped carbon quantum dot is 1 wt% to 20 wt%; and / or The doping mass fraction of the dopant element in the second doped carbon quantum dot is 1 wt% to 20 wt%; and / or The doping mass fraction of the doping element in the third doped carbon quantum dot is 1 wt% to 20 wt%; and / or The doping mass fraction of the doping element in the fourth doped carbon quantum dot is 1 wt% to 20 wt%; and / or The doping elements in the first, second, third, and fourth doped carbon quantum dots each independently include one or more of alkali metals, alkaline earth metals, Group IIB elements, and Group VIA elements; optionally, the alkali metal includes K; optionally, the alkaline earth metal includes Mg; optionally, the Group IIB element includes one or more of Cd and Zn; optionally, the Group VIA element includes one or more of Se and S; and / or The thickness of the first interface layer is 5nm to 20nm; and / or The thickness of the second interface layer is 5 nm to 20 nm; and / or The thickness of the third interface layer is 5nm to 80nm.

10. The optoelectronic device as described in claim 8, characterized in that, The anode and the cathode each independently comprise one or more of a metal, a carbon material, and a metal oxide; the metal comprises one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material comprises one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxide comprises a metal oxide electrode or a composite electrode in which a metal is disposed between doped or undoped transparent metal oxides; the material of the metal oxide electrode comprises one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO; the composite electrode comprises one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2.

11. A display device, characterized in that, Including the optoelectronic device as described in any one of claims 8 to 10.

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