WO2024104139A1

WO2024104139A1 - Composite material, light-emitting device comprising same, and preparation method therefor

Info

Publication number: WO2024104139A1
Application number: PCT/CN2023/128304
Authority: WO
Inventors: 田鹍飞
Original assignee: Tcl科技集团股份有限公司
Priority date: 2022-11-18
Filing date: 2023-10-31
Publication date: 2024-05-23
Also published as: CN118057941A

Abstract

The present invention relates to the field of photoelectricity, and provides a composite material, a light-emitting device comprising same, and a preparation method therefor. The composite material comprises a hole transport material and a voltage stabilizer, wherein the voltage stabilizer comprises a substituted aromatic ketone, and at least one substituent of the aromatic ketone is an electron donating group. The composite material provided by the present invention has high electron affinity, and the charge transfer efficiency of the composite material is high.

Description

Composite material, light-emitting device containing the same and preparation method thereof

This application claims priority to the Chinese patent application filed with the China Patent Office on November 18, 2022, with application number 202211447264.2 and application name “Composite materials, light-emitting devices containing the same, preparation methods thereof, and display devices”, the entire contents of which are incorporated by reference in this application.

Technical Field

The present invention relates to the field of optoelectronic technology, and in particular to a composite material, a light-emitting device containing the composite material, and a method for preparing the light-emitting device.

Background technique

Light-emitting devices mainly rely on the interaction of the opposite motion of electron-hole pairs to work. Therefore, the transmission balance of electron-hole pairs is very important for light-emitting devices. If the material of the hole transport layer cannot ensure sufficient hole injection, electrons in the device will accumulate in large quantities and leak into the hole transport layer. Excessive electron accumulation will lead to uneven electric field distribution in the device, causing irreversible damage to the hole transport layer, resulting in device instability or failure, and the efficiency and life will also be reduced accordingly.

The prior art often achieves the transmission balance of electron-hole pairs in light-emitting devices by limiting electron injection to prevent excess electrons from damaging the hole transport layer. However, limiting electron injection will lead to a decrease in device efficiency.

Technical Solutions

At least one embodiment of the present application provides a composite material, the composite material comprising a hole transport material and a voltage stabilizer;

Wherein, the voltage stabilizer comprises a substituted aromatic ketone, and at least one substituent of the aromatic ketone is an electron-donating group.

Optionally, the electron donating group includes one or more of a hydroxyl group, an alkoxy group, a phenoxy group, a benzyloxy group, and an acyloxy group.

Optionally, the voltage stabilizer includes a substituted aromatic ketone having 2 to 5 benzene ring structures, and the aromatic ketone having 2 to 5 benzene ring structures includes one or more of 4-propyleneoxy-2-hydroxybenzophenone, 2-hydroxy-4-(methacryloyloxy)benzophenone, 4'-phenoxyacetophenone, 4'-benzyloxy-2'-hydroxyacetophenone, 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone), and 4-hydroxy-4'-phenoxybenzophenone.

Optionally, the mass ratio of the voltage stabilizer to the hole transport material is 1:2-20.

Optionally, the hole transport material includes at least one of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tri(N-3-methylphenyl-Nphenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tinides, doped graphene, undoped graphene and C60.

Correspondingly, the present invention further provides a light-emitting device, which includes a cathode, an anode, a light-emitting layer, and a hole transport layer, wherein the material of the hole transport layer is the above-mentioned composite material.

Optionally, the materials of the anode and the cathode independently include one or more of metals, carbon materials and metal oxides, the metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb and Mg; the carbon materials include graphite, One or more of carbon nanotubes, graphene and carbon fibers; the metal oxide comprises a doped or undoped metal oxide, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO, or comprises a composite electrode of a metal sandwiched between doped or undoped transparent metal oxides, the composite electrode comprising 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 ; and/or

The material of the light-emitting layer includes one or more of an organic light-emitting material and a quantum dot light-emitting material, wherein the organic light-emitting material includes at least one of 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridine-C2,N)iridium(III), 4,4',4"-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridine-C2,N)iridium, diaromatic anthracene derivatives, distilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials and DBP fluorescent materials; the quantum dot light-emitting material includes at least one of a single structure quantum dot, a core-shell structure quantum dot and a perovskite semiconductor material; the single structure quantum dot The material, the core material of the core-shell structure quantum dots and the shell material of the core-shell structure quantum dots respectively include at least one of II-VI group compounds, IV-VI group compounds, III-V group compounds and I-III-VI group compounds; the II-VI group compounds include 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 include at least one of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe and SnPbSTe; the III-V group compounds include 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 I-III-VI group compound includes CuInS ₂ , CuInSe ₂ and AgInS ₂ ; the perovskite semiconductor material includes a doped or undoped inorganic perovskite semiconductor, or an organic-inorganic hybrid perovskite semiconductor; the inorganic perovskite semiconductor has a general structural formula of AMX ₃ , wherein A is a Cs ⁺ ion, M is a divalent metal cation, including at least one of Pb ²⁺ , Sn ²⁺ , Cu ²⁺ , Ni ²⁺ , Cd ²⁺ , Cr ²⁺ , Mn ²⁺ , Co ²⁺ , Fe ²⁺ , Ge ²⁺ , Yb ²⁺ , and Eu ²⁺ , and X is a halogen anion, including at least one of Cl ^- , Br ^- , and I ^- ; the organic-inorganic hybrid perovskite semiconductor has a general structural formula of BMX ₃ , wherein B is an organic amine cation, including CH ₃ (CH ₂ )n-2NH ³⁺ or [NH ₃ (CH ₂ )nNH ₃ ] ²⁺ , wherein n≥2, M is a divalent metal cation, including at least one of Pb ²⁺ , Sn ²⁺ , Cu ²⁺ , Ni ²⁺ , Cd ²⁺ , Cr ²⁺ , Mn ²⁺ , Co ²⁺ , Fe ²⁺ , Ge ²⁺ , Yb ²⁺ , and Eu ²⁺ , and X is a halogen anion, including at least one of Cl ^- , Br ^- , and I ^- .

Optionally, the light emitting device further comprises a hole injection layer located between the anode and the hole transport layer, wherein the hole injection layer The material includes at least one of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-Nphenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tinides, doped graphene, undoped graphene and C60; and/or

The light-emitting device further comprises an electron transport layer and/or an electron injection layer located between the cathode and the light-emitting layer, and the materials of the electron transport layer and/or the electron injection layer comprise inorganic materials and/or organic materials; the inorganic materials comprise one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, and the doped elements comprise one or more of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the organic materials comprise one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, and hydroxyquinoline compounds.

Accordingly, the present invention also provides a method for preparing a light-emitting device, comprising:

Providing a light emitting device prefabricated part and the composite material; and

The composite material is deposited on the light emitting device preform to form a hole transport layer.

Optionally, after depositing the composite material on the light-emitting device preform and before forming the hole transport layer, the method further comprises: irradiating with ultraviolet light for 2 to 10 minutes.

Optionally, depositing the composite material on the light emitting device preform comprises:

Providing a solvent and a composite material, mixing them, and obtaining a film-forming solution; and

The film-forming solution is deposited on the light-emitting device preform by a solution method to form a hole transport layer.

Optionally, in the film-forming solution, the concentration of the composite material is 4 to 10 mg/mL; and/or

The solvent includes a non-polar organic solvent, and the non-polar organic solvent includes one or more of an alkane solvent, an olefin solvent and an aromatic solvent, wherein the alkane solvent includes one or more of n-hexane, n-heptane, n-octane, cyclohexane, cycloheptane, chloroform, tetradecane and cyclooctane, the olefin solvent includes one or more of 1-decene, 1-dodecene, 1-tetradecene and 1-hexadecene, and the aromatic solvent includes one or more of benzene, toluene, chlorobenzene and xylene.

The voltage stabilizer in the composite material provided by the present invention is a substituted aromatic ketone, which has good conjugation characteristics and electron delocalization, so the composite material of the present invention has good electron affinity. In addition, the molecules of the composite material of the present invention have good π-π stacking effect, so the composite material of the present invention also has good charge transfer performance. When the composite material provided by the present invention is applied to the hole transport layer of the light-emitting device, based on the strong conjugation effect and electron delocalization of the voltage stabilizer molecules in the composite material, the voltage stabilizer can absorb the energy of electrons by excitation or ionization, especially the energy of high-energy electrons induced by electron aggregation, and The kinetic energy of high-energy electrons is greatly weakened and the number of high-energy electrons is reduced, thereby reducing the damage of electrons to the materials of the hole transport layer and improving the ability of the hole transport layer materials to resist electron damage.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

FIG1 is a flow chart of a method for preparing a light emitting device;

FIG2 is an operating voltage curve of a single electron device;

FIG3 is a J-V curve of a single electron device;

FIG4 is an operating voltage curve of a single hole device;

FIG5 is a J-V curve of a single hole device;

FIG6 is an EL spectrum diagram of a quantum dot light emitting diode;

7 is an AFM test image of the hole transport layer of the quantum dot light-emitting diode provided in Example 2 of the present invention;

FIG8 is an AFM test image of the hole transport layer of the quantum dot light-emitting diode provided in the comparative example of the present invention;

9 is an AFM test image of the quantum dot light-emitting layer of the quantum dot light-emitting diode provided in Example 2 of the present invention;

FIG. 10 is an AFM test image of the quantum dot light-emitting layer of the quantum dot light-emitting diode provided in the comparative example of the present invention.

Embodiments of the present application

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

In the present invention, "and/or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and/or B may represent: A exists alone, A and B exist at the same time, and B exists alone. A and B may be singular or plural.

In the present invention, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, where a, b, c can be single or multiple, respectively.

The technical solution provided by the present invention will be described in detail in the following content. It should be noted that the description order of the following embodiments is not Definition of the preferred order of embodiments. In addition, in the description of the present invention, the term "including" means "including but not limited to". Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values within the range.

The present invention solves the technical problem by adopting the following technical solutions:

The present invention provides a composite material, which includes a hole transport material and a voltage stabilizer;

The voltage stabilizer comprises a substituted aromatic ketone, and at least one substituent of the aromatic ketone is an electron-donating group.

The molecular structure of the voltage stabilizer simultaneously gives the voltage stabilizer a strong conjugation effect and a strong electron delocalization performance, so the composite material of the present invention has good electron affinity. In addition, there is a good π-π stacking effect between the molecules of the composite material of the present invention, so the composite material of the present invention also has good charge transport performance (hole transport performance).

In some embodiments, the electron donating group may include one or more of a hydroxyl group, an alkoxy group, a phenoxy group, a benzyloxy group, and an acyloxy group.

In some embodiments, the voltage stabilizer may include a substituted aromatic ketone having 2 to 5 benzene ring structures. The substituted aromatic ketone having 2 to 5 benzene ring structures includes one or more of 4-propyleneoxy-2-hydroxybenzophenone, 2-hydroxy-4-(methacryloyloxy)benzophenone, 4'-phenoxyacetophenone, 4'-benzyloxy-2'-hydroxyacetophenone, 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone), and 4-hydroxy-4'-phenoxybenzophenone. When the voltage stabilizer includes the above substances, the conjugated structure in the molecular structure of the voltage stabilizer can greatly improve the electron affinity of the voltage stabilizer molecule, thereby improving the electron affinity efficiency of the voltage stabilizer. Based on the strong conjugation effect and electron delocalization of the voltage stabilizer molecules in the composite material, the voltage stabilizer can absorb the energy of electrons by excitation or ionization, especially the energy of high-energy electrons induced by electron aggregation, and greatly weaken the kinetic energy of high-energy electrons and reduce the number of high-energy electrons, thereby reducing the damage of electrons to the materials of the hole transport layer and improving the ability of the hole transport layer materials to resist electron damage.

In at least one preferred embodiment, the voltage stabilizer may be 4-propyleneoxy-2-hydroxybenzophenone.

In some embodiments, the mass ratio of the voltage stabilizer to the hole transport material may be 1:2 to 20. Specifically, the mass ratio of the voltage stabilizer to the hole transport material may be 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, etc. Within the ratio range, the composite material may have a higher electron affinity, and may have a better π-π stacking effect between the molecules of the composite material, so that the composite material has good hole transport performance.

In some embodiments, the hole transport material may include at least one of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-Nphenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tinides, doped graphene, undoped graphene, and C60.

In addition, the present invention also provides a method for preparing a composite material, comprising the following steps:

A hole transport material and a voltage stabilizer are provided and mixed to obtain a composite material.

The hole transport material, the voltage stabilizer, and the ratio of the two are as described above and will not be elaborated here.

In some embodiments, the method for obtaining the composite material is: providing a hole transport material and a voltage stabilizer, adding the hole transport material and the voltage stabilizer to an organic solvent, stirring at 40-60° C. for 2-4 hours, and drying to obtain the composite material. Thus, stirring at 40-60° C. for 2-4 hours can allow the hole transport material and the voltage stabilizer to be quickly and evenly dispersed and mixed.

In some embodiments, the organic solvent is a non-polar organic solvent. The non-polar organic solvent includes one or more of an alkane solvent, an olefin solvent and an aromatic solvent. The alkane solvent includes one or more of n-hexane, n-heptane, n-octane, cyclohexane, cycloheptane, chloroform, tetradecane and cyclooctane. The olefin solvent includes one or more of 1-decene, 1-dodecene, 1-tetradecene and 1-hexadecene. The aromatic solvent includes one or more of benzene, toluene, chlorobenzene and xylene. The non-polar organic solvent can make the composite material fully and evenly dispersed.

In addition, the present invention provides a light-emitting device, which includes a hole transport layer, and the material of the hole transport layer includes the above composite material.

The material of the hole transport layer of the light-emitting device in the present invention includes the composite material provided by the present invention, based on the composite material of the present invention having a higher electron affinity, and can make the composite material molecules have a better π-π stacking effect, so that the hole transport layer has good hole transport performance. In addition, based on the strong ability of the composite material in the present invention to resist electronic damage, the hole transport layer of the light-emitting device in the present invention has a strong ability to resist electronic damage.

In some embodiments, the light emitting device may be one of a light emitting diode, a solar cell, and a photodetector.

In some embodiments, the light emitting device may be a light emitting diode, and the light emitting diode may be one of an organic light emitting diode (OLED), a quantum dot light emitting diode (QLED), and a micron light emitting diode (Micro-LED). Furthermore, the light emitting diode in the present invention may be a light emitting diode of a positive structure or a light emitting diode of an inverted structure, and the light emitting diode in the present invention may be any one of a light emitting diode of a top emission structure, a light emitting diode of a bottom emission structure, and a light emitting diode of a double-sided emission structure.

Preferably, the light emitting diode in the present invention may be a quantum dot light emitting diode.

The material of the hole transport layer of the quantum dot light-emitting diode in the present invention is the composite material provided by the present invention. Based on the strong conjugation effect and electron delocalization of the voltage stabilizer molecules, the voltage stabilizer can absorb the energy of electrons, especially high-energy electrons, by excitation or ionization, greatly weakening the kinetic energy of high-energy electrons and reducing the number of high-energy electrons, thereby reducing the damage of electrons to the material of the hole transport layer and improving the stability of the quantum dot light-emitting diode device. In addition, the composite material has a high electron affinity and can make the molecules of the composite material have a good π-π stacking effect, so that the hole transport layer has good hole transport performance.

In addition, the nonlinear voltage stabilizer (e.g., 4-propyleneoxy-2-hydroxybenzophenone) in the material (composite material) of the hole transport layer is The linear conductivity characteristics can reduce the degree of electric field distortion of quantum dot light-emitting diode devices, reduce or even avoid the accumulation of excess electrons between the hole transport layer and the light-emitting layer, thereby reducing the damage of electric field distortion to materials in quantum dot light-emitting diode devices and further improving the stability of quantum dot light-emitting diode devices; at the same time, the reduction in the accumulation of electrons between the hole transport layer and the light-emitting layer also reduces non-radiative recombination (such as Auger recombination) in quantum dot light-emitting diode devices, thereby improving the efficiency of quantum dot light-emitting diode devices.

In some embodiments, in addition to the hole transport layer, the quantum dot light emitting diode may also include a stacked anode, a hole injection layer, a quantum dot light emitting layer, an electron transport layer and a cathode. In some embodiments, the quantum dot light emitting diode may also include other common functional layers such as an electron injection layer.

In some embodiments, the material of the hole injection layer can be selected from one or more of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4-TCNQ), copper phthalocyanine (CuPc), 1,4,5,8,9,11-hexaazabenzonitrile (HATCN), NiO _x , MoO _x , WO _x , CrO _x , CuO, MoS _x , MoSe _x , WS _x , WSe _x , CuS, and the value of x ranges from 1 to 3. In some embodiments, the hole transport layer can also be other metal sulfide compounds.

In some embodiments, the material of the light-emitting layer includes one or more of an organic light-emitting material and a quantum dot light-emitting material, the organic light-emitting material includes 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridine-C2,N)iridium(III), 4,4',4"-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridine-C2,N)iridium, diaromatic anthracene derivatives, distilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials and DBP fluorescent materials; the quantum dot light-emitting material includes at least one of a single structure quantum dot, a core-shell structure quantum dot and a perovskite semiconductor material; the single The material of the structured quantum dots, the core material of the core-shell structured quantum dots and the shell material of the core-shell structured quantum dots respectively include at least one of a II-VI group compound, a IV-VI group compound, a III-V group compound and a I-III-VI group compound; the II-VI group compound includes 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, Hg The IV-VI group compounds include at least one of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe; the III-V group compounds include at least one of GaN, GaP, GaAs, GaSb, AlN, AlP, Al As, 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 I-III-VI group compound comprises at least one of _CuInS2 , _CuInSe2 and _AgInS2 ; the perovskite semiconductor material comprises a doped or undoped inorganic perovskite semiconductor, or an organic-inorganic hybrid perovskite semiconductor; the inorganic perovskite semiconductor has a general structural formula of _AMX3 , wherein A is a Cs ⁺ ion, M is a divalent The metal cation includes at least one of Pb ²⁺ , Sn ²⁺ , Cu ²⁺ , Ni ²⁺ , Cd ²⁺ , Cr ²⁺ , Mn ²⁺ , Co ²⁺ , Fe ²⁺ , Ge ²⁺ , Yb ²⁺ , and Eu ²⁺ ; X is a halogen anion including at least one of Cl ^- , Br ^- , and I ^- ; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX ₃ , wherein B is an organic amine cation including CH ₃ (CH ₂ )n-2NH ³⁺ or [NH ₃ (CH ₂ )nNH ₃ ] ²⁺ , wherein n≥2, and M is a divalent metal cation including Pb ²⁺ , Sn ²⁺ , Cu ²⁺ , Ni ²⁺ , Cd ²⁺ , Cr ²⁺ , Mn ²⁺ , Co ²⁺ , Fe ²⁺ , Ge ²⁺ , Yb ²⁺ , Eu ²⁺ , X is a halogen anion including at least one of Cl ^- , Br ^- , I ^- .

In some embodiments, the material of the electron transport layer includes inorganic materials and/or organic materials; the inorganic material includes one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, and the doped elements include one or more of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the organic material includes one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene compounds, and hydroxyquinoline compounds.

In some embodiments, the materials of the anode and the cathode independently include one or more of metals, carbon materials and metal oxides, the metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb and Mg; the carbon materials include one or more of graphite, carbon nanotubes, graphene and carbon fibers; the metal oxides include doped or undoped metal oxides, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO, or include a composite electrode in which a metal is sandwiched between doped or undoped transparent metal oxides, and the composite electrode includes 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 some embodiments, the light-emitting device further comprises an electron injection layer between the cathode and the light-emitting layer, and the material of the electron injection layer comprises an inorganic material and/or an organic material; the inorganic material comprises one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, and the doped elements comprise one or more of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the organic material comprises one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene compounds, and hydroxyquinoline compounds.

In addition, referring to FIG. 1 , the present invention further provides a method for preparing a light emitting device, comprising:

Step S1, providing a light emitting device prefabricated part and a composite material; and

Step S2: depositing the composite material on a light-emitting device preform to form a hole transport layer.

A light-emitting device preform refers to a semi-finished light-emitting device on which a hole transport layer is to be deposited. The parts may include different layer structures. In some embodiments, the light emitting device may be a light emitting diode of a positive structure, in which case the light emitting device preform may include an anode and a hole injection layer stacked in sequence; in some embodiments, the light emitting device may be a light emitting diode of an inverted structure, in which case the light emitting device may be a light emitting diode of a positive structure, in which case the light emitting device may include a cathode, an electron transport layer, and a light emitting layer stacked in sequence.

The method for depositing the composite material on the preform of the light-emitting device can be a method that can adopt a chemical method or a physical method. Among them, the chemical method includes chemical vapor deposition, continuous ion layer adsorption and reaction, anodization, electrolytic deposition, and coprecipitation. The physical method includes physical coating and solution method, among which the physical coating method includes: thermal evaporation coating, electron beam evaporation coating, magnetron sputtering, multi-arc ion coating, physical vapor deposition, atomic layer deposition, pulsed laser deposition, etc.; the solution method can be spin coating, printing, inkjet printing, scraping, printing, dip pulling, immersion, spraying, rolling, casting, slit coating, strip coating, etc.

In at least one embodiment, the method of disposing the composite material on the light emitting device preform is a solution method. In this case, depositing the composite material on the light emitting device preform includes:

The film-forming solution is disposed on the light-emitting device preform by a solution method to form a hole transport layer.

In some embodiments, the method of mixing the solvent and the composite material is: stirring at 40-60° C. for 2-4 hours, so that the composite material can be quickly and evenly dispersed in the solvent.

In some embodiments, the solvent may be a non-polar organic solvent. The non-polar organic solvent includes one or more of an alkane solvent, an olefin solvent and an aromatic solvent. The alkane solvent includes one or more of n-hexane, n-heptane, n-octane, cyclohexane, cycloheptane, chloroform, tetradecane and cyclooctane. The olefin solvent includes one or more of 1-decene, 1-dodecene, 1-tetradecene and 1-hexadecene. The aromatic solvent includes one or more of benzene, toluene, chlorobenzene and xylene. The non-polar organic solvent can make the composite material fully and evenly dispersed, improve the film-forming uniformity of the composite material, and the non-polar solvent will not dissolve and damage other film layers of the light-emitting device preform.

In at least one preferred implementation, the solvent may be chlorobenzene, the hole transport material in the composite material may be TFB, and the voltage stabilizer in the composite material may be 4-propyleneoxy-2-hydroxybenzophenone (AOHBP). In this way, a hole transport layer and a light-emitting device with excellent hole transport performance can be prepared.

In some embodiments, in the film-forming solution, the concentration of the composite material is 4 to 10 mg/mL. Within the concentration range, the film-forming property of the film-forming solution is good, and the prepared hole transport layer has good conductivity, hole injection performance and stability, so that the prepared light-emitting device has higher luminous efficiency and life.

The film-forming solution can also be prepared by the following method: providing a solvent; adding a hole transport material and a voltage stabilizer to the solvent; It is understood that there is no restriction on the order of adding the hole transport material and the voltage stabilizer. The hole transport material can be added first and then the voltage stabilizer, or the voltage stabilizer can be added first and then the hole transport material, or the hole transport material and the voltage stabilizer can be added to the solvent at the same time.

In at least one specific embodiment, the preparation of the film-forming solution may include: dispersing 160 mg of TFB material in 20 ml of chlorobenzene, heating at 60°C for 6 hours to prepare an 8 mg/ml TFB chlorobenzene solution; taking different amounts of AOHBP and adding them to 1 ml of the above 8 mg/ml TFB chlorobenzene solution to prepare three film-forming solutions with mass ratios of AOHBP to TFB of 1:15, 1:10 and 1:5 respectively.

In some embodiments, in order to form a hole transport layer, the method for preparing a light-emitting device may further include process steps such as high-temperature annealing.

In some embodiments, after depositing the composite material on the light-emitting device preform and before forming the hole transport layer, the method further includes: irradiating the film formed by the film-forming solution with ultraviolet light.

Under ultraviolet (UV) irradiation, voltage stabilizer molecules such as 4-propyleneoxy-2-hydroxybenzophenone can undergo hydrogen absorption reaction (free radical reaction mechanism) with hydrogen atom donors such as C-H bonds on organic matter. Therefore, voltage stabilizer molecules such as 4-propyleneoxy-2-hydroxybenzophenone can cross-link hole transport material molecules under photoinitiation, so that the formed hole transport layer has good film uniformity, and the surface of the hole transport layer has a smoother morphology and lower roughness.

In some embodiments, the ultraviolet light irradiation time is 2 to 10 minutes. Within the above range, the hydrogen absorption reaction between the hole transport material and the voltage stabilizer molecules can be effectively promoted, which is conducive to preparing a hole transport layer with good film uniformity, smoother surface morphology and lower roughness.

The hole transport material may preferably be a polymer having benzyl hydrogen and tertiary hydrogen (present on the side chain of TFB) such as TFB. The voltage stabilizer molecule can react with the benzyl hydrogen and tertiary hydrogen in the aforementioned polymer to form relatively stable free radicals, which is beneficial to improving the efficiency of the free radical reaction.

In some embodiments, the light-emitting device is a quantum dot light-emitting diode with an upright structure. At this time, based on the good film uniformity of the hole transport layer, the quantum dot light-emitting layer can be spread more evenly on the hole transport layer, and the thickness of the quantum dot light-emitting layer can also be reduced under the same process conditions. Therefore, the improvement of the film uniformity of the hole transport layer can effectively improve the film uniformity of the quantum dot light-emitting layer and reduce the thickness of the quantum dot light-emitting layer. On the one hand, the improvement of the film uniformity of the quantum dot light-emitting layer ensures that the quantum dot light-emitting diode has a higher electroluminescence (EL) efficiency; on the other hand, the reduction of the thickness of the quantum dot light-emitting layer can give the quantum dot light-emitting diode a higher device performance.

Example 1

This embodiment provides a composite material, including a hole transport material and a voltage stabilizer, wherein the hole transport material is TFB, the voltage stabilizer is AOHBP, and the mass ratio of AOHBP to TFB is 1:15.

In this embodiment, the preparation method of the composite material is: providing a voltage stabilizer AOHBP and a hole transport material in a mass ratio of 1:15. The materials TFB are mixed evenly to obtain a composite material.

In addition, this embodiment also provides a quantum dot light-emitting diode, including an anode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a cathode which are stacked in sequence.

Among them, the thickness of the anode is 100nm, and the material of the anode is ITO; the thickness of the hole injection layer is 25nm, and the material of the hole injection layer is PEDOT:PSS; the thickness of the hole transport layer is 25nm, and the material of the hole transport layer is the composite material provided in this embodiment; the thickness of the quantum dot light-emitting layer is 25nm, and the material of the quantum dot light-emitting layer is CdZnSe/ZnSe/Cd _0.6 ZnS ₂ /ZnSe; the thickness of the electron transport layer is 30nm, and the material of the electron transport layer is ZnMgO; the thickness of the cathode is 100nm, and the material of the cathode is Ag.

In addition, this embodiment also provides a method for preparing a quantum dot light-emitting diode, comprising:

Step S101: providing a glass substrate prepared with an ITO anode, placing the glass substrate in a glass dish filled with an ethanol solvent, replacing the solvent in the glass dish with acetone, deionized water, and ethanol in turn, ultrasonically treating the glass substrate for 20 minutes respectively, then drying the glass substrate with a nitrogen gun, then placing the glass substrate in an oxygen ion environment for further cleaning for 10 minutes, and treating the surface of the glass substrate with ultraviolet-ozone for 15 minutes;

Step S102: Spin coating the surface of the ITO anode with a PEDOT:PSS solution at a spin coating speed of 3500 r/min for 30 seconds; after the spin coating is completed, the glass substrate spin-coated with the PEDOT:PSS solution is placed in air for annealing at an annealing temperature of 150° C. for 30 minutes to obtain a hole injection layer with a thickness of 25 nm. After the annealing is completed, the glass substrate with the hole injection layer formed thereon is quickly transferred to a glove box in a nitrogen atmosphere;

Step 3: Spin coating a film-forming solution of the hole transport layer on the surface of the hole transport layer, wherein the solvent of the film-forming solution is chlorobenzene, the solute of the film-forming solution is the composite material provided in this embodiment, the spin coating speed is 3000 r/min, and the spin coating time is 30 seconds; after the spin coating is completed, the film layer formed by the film-forming solution is irradiated under an ultraviolet lamp (360 nm) for 5 minutes, and then annealed at an annealing temperature of 180° C. for 30 minutes to obtain a hole transport layer with a thickness of 25 nm;

Step 4: Spin coating the hole transport layer with a CdZnSe/ZnSe/Cd _0.6 ZnS ₂ /ZnSe quantum dot solution at a spin coating speed of 2000 r/min for 30 seconds; after the spin coating, anneal the glass substrate with the CdZnSe/ZnSe/Cd _0.6 ZnS ₂ /ZnSe quantum dot solution in a glove box at a temperature of 60° C. for 5 minutes to obtain a quantum dot light-emitting layer with a thickness of 25 nm;

Step 5: Spin-coat a 30 mg/mL ZnMgO ethanol solution on the quantum dot light-emitting layer at a spin-coating speed of 3000 r/min for 30 seconds to obtain an electron transport layer with a thickness of 30 nm;

Step 6: Place the glass substrate prepared with the electron transport layer into a vacuum chamber, evaporate silver on the electron transport layer to obtain a cathode with a thickness of 100 nm, and encapsulate to obtain a quantum dot light-emitting diode.

For testing purposes, this embodiment also provides a single electron device (EOD) and a single hole device (HOD) corresponding to the quantum dot light emitting diode.

The single electron device includes an anode, a quantum dot light emitting layer, an electron transport layer and a cathode which are stacked in sequence.

The thickness of the anode is 100nm, and the material of the anode is ITO; the thickness of the quantum dot light-emitting layer is 25nm, and the material of the quantum dot light-emitting layer is CdZnSe/ZnSe/Cd _0.6 ZnS ₂ /ZnSe; the thickness of the electron transport layer is 30nm, and the material of the electron transport layer is ZnMgO; the thickness of the cathode is 100nm, and the material of the cathode is Ag.

The single hole device includes an anode, a hole injection layer, a hole transport layer, a quantum dot light emitting layer and a cathode which are stacked in sequence.

Among them, the thickness of the anode is 100nm, and the material of the anode is ITO; the thickness of the hole injection layer is 25nm, and the material of the hole injection layer is PEDOT:PSS; the thickness of the hole transport layer is 25nm, and the material of the hole transport layer is the composite material provided in this embodiment; the material of the quantum dot light-emitting layer is CdZnSe/ZnSe/Cd _0.6 ZnS ₂ /ZnSe; the thickness of the cathode is 100nm, and the material of the cathode is Ag.

Correspondingly, this embodiment also provides a method for preparing the above-mentioned single-electron device and single-hole device.

The method for preparing the single electron device comprises:

Step S201: providing a glass substrate prepared with an ITO anode, placing the glass substrate in a glass dish filled with an ethanol solvent, replacing the solvent in the glass dish with acetone, deionized water, and ethanol in turn, ultrasonicating the glass substrate for 20 minutes respectively, then drying the glass substrate with a nitrogen gun, then placing the glass substrate in an oxygen plasma environment for further cleaning for 10 minutes, and treating the surface of the glass substrate with ultraviolet-ozone for 15 minutes;

Step S202: spin coating a CdZnSe/ZnSe/Cd _0.6 ZnS ₂ /ZnSe quantum dot solution on the ITO anode at a spin coating speed of 2000 r/min for 30 seconds; after the spin coating is completed, annealing the glass substrate spin coated with the CdZnSe/ZnSe/Cd _0.6 ZnS ₂ /ZnSe quantum dot solution in a glove box at an annealing temperature of 60° C. for 5 minutes to obtain a quantum dot light-emitting layer with a thickness of 25 nm;

Step 3: Spin-coat a 30 mg/mL ZnMgO ethanol solution on the quantum dot light-emitting layer at a spin-coating speed of 3000 r/min for 30 seconds to obtain an electron transport layer with a thickness of 30 nm;

Step 4: Place the glass substrate prepared with the electron transport layer into a vacuum chamber, evaporate silver on the electron transport layer to obtain a cathode with a thickness of 100 nm, and obtain a single electron device.

The method for preparing a single hole device comprises:

Step S301: providing a glass substrate prepared with an ITO anode, placing the glass substrate in a glass dish filled with an ethanol solvent, replacing the solvent in the glass dish with acetone, deionized water, and ethanol in turn, ultrasonicating the glass substrate for 20 minutes respectively, then drying the glass substrate with a nitrogen gun, then placing the glass substrate in an oxygen ion environment for further cleaning for 10 minutes, and treating the surface of the glass substrate with ultraviolet-ozone for 15 minutes;

Step 2: Spin-coat the surface of the ITO anode with a PEDOT:PSS solution at a speed of 3500 r/min for 30 seconds. After the spin coating is completed, place the glass substrate with the PEDOT:PSS solution spin-coated in air for annealing at a temperature of 150°C for 30 minutes to obtain a hole injection layer with a thickness of 25 nm. After the annealing is completed, quickly transfer the glass substrate with the hole injection layer to a glove box with a nitrogen atmosphere. middle;

Step 4: Spin-coat the hole transport layer with a CdZnSe/ZnSe/Cd _0.6 ZnS ₂ /ZnSe quantum dot solution at a speed of 2000 r/min for 30 seconds; after the spin coating, anneal the glass substrate with the CdZnSe/ZnSe/Cd _0.6 ZnS ₂ /ZnSe quantum dot solution in a glove box at a temperature of 60° C. for 5 minutes to obtain a quantum dot light-emitting layer with a thickness of 25 nm.

Step 5: Place the glass substrate prepared with the quantum dot light-emitting layer into a vacuum cavity, evaporate silver on the quantum dot light-emitting layer to obtain a cathode with a thickness of 100 nm, and obtain a single-electron device.

Example 2

This embodiment provides a composite material, including a hole transport material and a voltage stabilizer, wherein the hole transport material is TFB, the voltage stabilizer is AOHBP, and the mass ratio of AOHBP to TFB is 1:10.

In this embodiment, the preparation method of the composite material is: provide a voltage stabilizer AOHBP and a hole transport material TFB in a mass ratio of 1:10, mix them evenly, and obtain a composite material.

In addition, this embodiment also provides a quantum dot light-emitting diode, which only replaces the material in the hole transport layer of the quantum dot light-emitting diode provided in Example 1 with the composite material provided in this embodiment, and the rest of the parts are the same as the quantum dot light-emitting diode provided in Example 1.

In addition, this embodiment also provides a method for preparing a quantum dot light-emitting diode. This preparation method only replaces the solute of the film-forming solution in step 3 of the method for preparing a quantum dot light-emitting diode provided in Example 1 with the composite material provided in this embodiment, and the remaining steps are the same as the steps of the method for preparing a quantum dot light-emitting diode provided in Example 1.

For testing purposes, this embodiment also provides a single hole device (HOD) corresponding to the above quantum dot light emitting diode.

The single hole device is the same as the single hole device provided in Example 1 except that the material in the hole transport layer of the single hole device provided in Example 1 is replaced by the composite material provided in this example. The rest of the material is the same as the single hole device provided in Example 1.

Since the single electron device corresponding to the quantum dot light emitting diode in this embodiment is the same as the single electron device provided in Embodiment 1, this embodiment does not provide an additional single electron device.

Correspondingly, this embodiment also provides a method for preparing the above-mentioned single-hole device.

The preparation method of the single hole device is as follows: the solute of the film-forming solution in step 3 of the preparation method of the single hole device provided in Example 1 is replaced by The remaining steps of the composite material provided in this embodiment are the same as those of the method for preparing the single hole device provided in Example 1.

Example 3

This embodiment provides a composite material, including a hole transport material and a voltage stabilizer, wherein the hole transport material is TFB, the voltage stabilizer is AOHBP, and the mass ratio of AOHBP to TFB is 1:5.

In this embodiment, the preparation method of the composite material is: provide a voltage stabilizer AOHBP and a hole transport material TFB in a mass ratio of 1:5, mix them evenly, and obtain a composite material.

The preparation method of the single-hole device only replaces the solute of the film-forming solution in step 3 of the preparation method of the single-hole device provided in Example 1 with the composite material provided in this example, and the remaining steps are the same as the steps of the preparation method of the single-hole device provided in Example 1.

Example 4

This embodiment provides a composite material, including a hole transport material and a voltage stabilizer, wherein the hole transport material is TFB, the voltage stabilizer is 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone), and the mass ratio of 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone) to TFB is 1:10.

In this embodiment, the preparation method of the composite material is: provide a voltage stabilizer 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone) and a hole transport material TFB in a mass ratio of 1:10, mix them evenly, and obtain a composite material.

In addition, this embodiment also provides a quantum dot light-emitting diode, in which only the material in the hole transport layer of the quantum dot light-emitting diode provided in Example 1 is replaced with the composite material provided in this embodiment, and the rest of the material is the same as the quantum dot light-emitting diode provided in Example 1. Same for diodes.

Example 5

Example 6

This embodiment provides a composite material, including a hole transport material and a voltage stabilizer, wherein the hole transport material is TFB, the voltage stabilizer is 2-hydroxy-4-methoxybenzophenone, and the mass ratio of 2-hydroxy-4-methoxybenzophenone to TFB is 1:10.

In this embodiment, the preparation method of the composite material is: provide a voltage stabilizer 2-hydroxy-4-methoxybenzophenone and a hole transport material TFB in a mass ratio of 1:10, mix them evenly, and obtain a composite material.

Example 7

This embodiment provides a composite material, including a hole transport material and a voltage stabilizer, wherein the hole transport material is TFB, the voltage stabilizer is 4'-phenoxyacetophenone, and the mass ratio of 4'-phenoxyacetophenone to TFB is 1:10.

In this embodiment, the preparation method of the composite material is: provide a voltage stabilizer 4'-phenoxyacetophenone and a hole transport material TFB in a mass ratio of 1:10, mix them evenly, and obtain the composite material.

Example 8

This embodiment provides a composite material, including a hole transport material and a voltage stabilizer, wherein the hole transport material is TFB, the voltage stabilizer is 4'-benzyloxy-2'-hydroxyacetophenone, and the mass ratio of 4'-benzyloxy-2'-hydroxyacetophenone to TFB is 1:10.

In this embodiment, the composite material is prepared by providing a voltage stabilizer 4'-benzyloxy-2'-hydroxyacetophenone and a hole transport material TFB in a mass ratio of 1:10, and mixing them evenly to obtain a composite material.

Example 9

This embodiment provides a composite material, including a hole transport material and a voltage stabilizer, wherein the hole transport material is TFB, the voltage stabilizer includes AOHBP and 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone), and the mass ratio of AOHBP, 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone) and TFB is 0.5:0.5:10.

In this embodiment, the composite material is prepared by providing a voltage stabilizer AOHBP, a voltage stabilizer 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone) and a hole transport material TFB in a mass ratio of 0.5:0.5:10, and mixing them uniformly to obtain a composite material.

Example 10

This embodiment provides a composite material, including a hole transport material and a voltage stabilizer, wherein the hole transport material is TFB, the voltage stabilizer includes AOHBP and 2-hydroxy-4-(methacryloyloxy)benzophenone, and the mass ratio of AOHBP, 2-hydroxy-4-(methacryloyloxy)benzophenone and TFB is 0.5:0.5:10.

In this embodiment, the preparation method of the composite material is: provide a voltage stabilizer AOHBP, a voltage stabilizer 2-hydroxy-4-(methacryloyloxy)benzophenone and a hole transport material TFB in a mass ratio of 0.5:0.5:10, mix them evenly, and obtain a composite material.

In addition, this embodiment also provides a quantum dot light emitting diode, which only uses the quantum dot light emitting diode provided in embodiment 1. The material in the hole transport layer of the photodiode is replaced with the composite material provided in this embodiment, and the rest is the same as the quantum dot light-emitting diode provided in Example 1.

Embodiment 11

This embodiment provides a composite material, including a hole transport material and a voltage stabilizer, wherein the hole transport material is PVK, the voltage stabilizer is AOHBP, and the mass ratio of AOHBP to PVK is 1:20.

In this embodiment, the preparation method of the composite material is: provide a voltage stabilizer AOHBP and a hole transport material PVK in a mass ratio of 1:20, mix them evenly, and obtain a composite material.

In addition, the present embodiment further provides an organic light emitting diode, comprising an anode, a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer and a cathode which are stacked in sequence.

Among them, the thickness of the anode is 100nm, and the material of the anode is FTO; the thickness of the hole injection layer is 25nm, and the material of the hole injection layer is CuPc; the thickness of the hole transport layer is 25nm, and the material of the hole transport layer is the composite material provided in this embodiment; the thickness of the quantum dot light-emitting layer is 25nm, and the material of the organic light-emitting layer is Alq3; the thickness of the electron transport layer is 30nm, and the material of the electron transport layer is ZnO; the thickness of the cathode is 100nm, and the material of the cathode is Ag.

In addition, this embodiment also provides a method for preparing an organic light emitting diode, comprising:

Step 1: providing a glass substrate prepared with a FTO anode;

Step 2: Inkjet print the CuPc solution on the surface of the FTO anode to prepare a hole injection layer with a thickness of 25 nm;

Step 3: inkjet printing a film-forming solution of the hole transport layer on the surface of the hole transport layer, wherein the solvent of the film-forming solution is chlorobenzene, and the solute of the film-forming solution is the composite material provided in this embodiment, to obtain a hole transport layer with a thickness of 25 nm;

Step 4: Alq3 is evaporated on the hole transport layer to obtain an organic light-emitting layer with a thickness of 25 nm;

Step 5: inkjet printing a ZnO solution on the organic light-emitting layer to obtain an electron transport layer with a thickness of 30 nm;

Step 6: Place the glass substrate prepared with the electron transport layer into a vacuum chamber, evaporate silver on the electron transport layer to obtain a cathode with a thickness of 100 nm, and encapsulate to obtain an organic light emitting diode.

Example 12

This embodiment provides a composite material, including a hole transport material and a voltage stabilizer, wherein the hole transport material is TPD, the voltage stabilizer is AOHBP, and the mass ratio of AOHBP to TPD is 1:2.

In this embodiment, the preparation method of the composite material is: provide a voltage stabilizer AOHBP and a hole transport material TPD in a mass ratio of 1:2, mix them evenly, and obtain a composite material.

In addition, the present embodiment further provides an organic light emitting diode, comprising a cathode, an electron transport layer, an organic light emitting layer, a hole transport layer, a hole injection layer and an anode which are stacked in sequence.

Among them, the thickness of the anode is 100nm, and the material of the anode is IZO; the thickness of the hole injection layer is 25nm, and the material of the hole injection layer is TCNQ; the thickness of the hole transport layer is 25nm, and the material of the hole transport layer is the composite material provided in this embodiment; the thickness of the quantum dot light-emitting layer is 25nm, and the material of the organic light-emitting layer is Alq3; the thickness of the electron transport layer is 30nm, and the material of the electron transport layer is _TiO2 ; the thickness of the cathode is 100nm, and the material of the cathode is Al.

Step 1: providing a glass substrate prepared with an Al cathode;

Step 2: inkjet print _TiO2 solution on the surface of Al silver electrode to prepare an electron transport layer with a thickness of 30nm;

Step 3: Alq3 is evaporated on the surface of the electron transport layer to obtain an organic light-emitting layer with a thickness of 25 nm;

Step 4: inkjet printing a film-forming solution of a hole transport layer on the surface of the organic light-emitting layer, wherein the solvent of the film-forming solution is chlorobenzene and the solute of the film-forming solution is the composite material provided in this embodiment, to obtain a hole transport layer with a thickness of 25 nm;

Step 5: Inkjet print TCNQ solution on the hole transport layer to prepare a hole injection layer with a thickness of 25 nm;

Step 6: Deposit an IZO anode with a thickness of 100 nm on the hole injection layer, and encapsulate to obtain an organic light-emitting diode.

Comparative Example

This comparative example provides a quantum dot light-emitting diode, in which only the material in the hole transport layer of the quantum dot light-emitting diode provided in Example 1 is replaced with TFB, and the rest of the parts are the same as the quantum dot light-emitting diode provided in Example 1.

The single electron device is the same as the single electron device provided in Example 1, so this comparative example does not provide an additional single electron device.

The single hole device only replaces the material in the hole transport layer of the single hole device provided in Example 1 with TFB, and the rest of the material is the same as that provided in Example 1. The same as the single hole device provided.

The quantum dot light-emitting diodes and single-hole devices provided in Examples 1 to 12 and the comparative examples were tested. The test results are shown in Table 1.

Table 1

The lifetime refers to the time taken for the brightness of a quantum dot light emitting diode to drop to 95% of its maximum brightness at a constant current density (2 mA/cm ² ).

It can be seen from the data in the table that, compared with the prior art (comparative example), the external quantum efficiency and life of the quantum dot light-emitting diode provided by the present invention are significantly improved. Therefore, compared with the prior art, the hole transport layer of the quantum dot light-emitting diode provided by the present invention has strong resistance to electron damage, good device stability, and the carrier transport of the quantum dot light-emitting diode provided by the present invention is balanced.

The working voltage of the single-electron device provided in Example 1 was tested, and the test results are shown in Figure 2. The JV curve of the single-electron device was tested, and the test results are shown in Figure 3. The working voltage of the single-hole device provided in Examples 1 to 10 and the comparative example was tested, and the test results are shown in Figure 4. The JV curve of the single-hole device provided in Examples 1 to 10 and the comparative example was tested, and the test results are shown in Figure 5. It can be seen from the test results of the working voltage that compared with the comparative example, the working voltage of the single-hole device provided in Examples 1 to 10 is closer to the working voltage (5.5V) of the single-electron device. Therefore, compared with the prior art, the carrier transport of the quantum dot light-emitting diode provided by the present invention is more balanced. It can be seen from the test of the JV curve that, in order to achieve the same current density, the quantum dot light-emitting diode provided by the present invention The voltage required by the diode is smaller, so the efficiency of the quantum dot light-emitting diode provided by the present invention is higher.

The EL spectra of the quantum dot light-emitting diodes provided in Example 2 and the comparative example are shown in FIG6 . It can be seen that the quantum dot light-emitting diode provided in the comparative example has a small peak at about 530 nm, which is caused by excessive electron injection and the escape of high-energy electrons into the hole transport layer, resulting in a peak of non-radiative recombination. The EL spectrum of the quantum dot light-emitting diode provided in Example 2 is very symmetrical, indicating that the hole transport layer of the quantum dot light-emitting diode provided by the present invention has a strong ability to resist electron damage, and can avoid non-radiative recombination in the device, thereby improving the stability and luminous efficiency of the device.

AFM tests were performed on the hole transport layer of the quantum dot light-emitting diode provided in Example 2 and the hole transport layer of the quantum dot light-emitting diode provided in the comparative example, and the test results are shown in Figures 7 and 8. The test results show that the surface roughness R _q value of the hole transport layer of the quantum dot light-emitting diode provided in Example 2 is 0.69nm, while the surface roughness R _q value of the hole transport layer of the quantum dot light-emitting diode provided in the comparative example is 1.69nm. It can be seen that compared with the prior art, the film uniformity of the hole transport layer of the quantum dot light-emitting diode provided by the present invention is significantly improved.

AFM tests were performed on the hole transport layer of the quantum dot light-emitting diode provided in Example 2 and the quantum dot light-emitting layer of the quantum dot light-emitting diode provided in the comparative example, and the test results are shown in Figures 9 to 10. The test results show that the surface roughness R _q value of the quantum dot light-emitting layer of the quantum dot light-emitting diode provided in Example 2 is 0.98nm, while the surface roughness R _q value of the quantum dot light-emitting layer of the quantum dot light-emitting diode provided in the comparative example is 2.14nm. It can be seen that compared with the prior art, the film uniformity of the quantum dot light-emitting layer of the quantum dot light-emitting diode provided by the present invention is also significantly improved. In addition, the thickness of the quantum dot light-emitting layer of the quantum dot light-emitting diode provided in Example 2 is 23.56nm, while the thickness of the quantum dot light-emitting layer of the quantum dot light-emitting diode provided in the comparative example is 30.45nm. It can be seen that under the same process conditions, compared with the quantum dot light-emitting diode in the comparative example, the film thickness of the quantum dot light-emitting layer of the quantum dot light-emitting diode provided in Example 2 is thinner (the thinner film thickness of the quantum dot light-emitting layer is conducive to improving the device life), that is, the improvement of the film uniformity of the hole transport layer is conducive to the improvement of the film uniformity of the quantum dot light-emitting layer, thereby reducing the thickness of the quantum dot light-emitting layer under the same process conditions.

The hole transport layer of the light-emitting device of the present invention includes the composite material described above, in which the voltage stabilizer is a substituted aromatic ketone, which has good conjugation characteristics and electron delocalization, so the composite material of the present invention has good electron affinity, and the molecules of the composite material in the present invention have good π-π stacking effect, so the composite material in the present invention also has good charge transfer performance. In this way, based on the strong conjugation effect and electron delocalization of the voltage stabilizer molecules in the composite material, the voltage stabilizer can absorb the energy of electrons by excitation or ionization, especially the energy of high-energy electrons induced by electron aggregation, and greatly weaken the kinetic energy of high-energy electrons and reduce the number of high-energy electrons, thereby reducing the damage of electrons to the materials of the hole transport layer, improving the ability of the hole transport layer materials to resist electron damage, and thus improving the current density, hole mobility, external quantum efficiency and life of the light-emitting device.

The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the methods and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

A composite material, wherein the composite material comprises a hole transport material and a voltage stabilizer;

Wherein, the voltage stabilizer comprises a substituted aromatic ketone, and at least one substituent of the aromatic ketone is an electron-donating group.
The composite material according to claim 1, wherein the electron donating group comprises one or more of a hydroxyl group, an alkoxy group, a phenoxy group, a benzyloxy group, and an acyloxy group.
The composite material according to claim 1, wherein the voltage stabilizer comprises a substituted aromatic ketone having 2 to 5 benzene ring structures.
The composite material according to claim 3, wherein the aromatic ketone having 2 to 5 benzene ring structures includes one or more of 4-propyleneoxy-2-hydroxybenzophenone, 2-hydroxy-4-(methacryloyloxy)benzophenone, 4'-phenoxyacetophenone, 4'-benzyloxy-2'-hydroxyacetophenone, 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone), and 4-hydroxy-4'-phenoxybenzophenone.
The composite material according to claim 1, wherein the mass ratio of the voltage stabilizer to the hole transport material is 1:2 to 20.
The composite material according to claim 1, wherein the hole transport material includes at least one of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-Nphenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tinides, doped graphene, undoped graphene and C60.
A light-emitting device, wherein the light-emitting device comprises a cathode, an anode, a light-emitting layer, and a hole transport layer, and the material of the hole transport layer comprises the composite material according to any one of claims 1 to 6.
The light emitting device according to claim 7, wherein:

The materials of the anode and the cathode independently include one or more of metal, carbon material and metal oxide, the metal includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb and Mg; the carbon material includes one or more of graphite, carbon nanotubes, graphene and carbon fiber; the metal oxide includes doped or undoped metal oxide, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO, or includes a composite electrode with a metal sandwiched between doped or undoped transparent metal oxides, the composite electrode includes 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 ; and/or

The material of the light-emitting layer includes one or more of an organic light-emitting material and a quantum dot light-emitting material, wherein the organic light-emitting material includes at least one of 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridine-C2,N)iridium(III), 4,4',4"-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridine-C2,N)iridium, diaromatic anthracene derivatives, distilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials and DBP fluorescent materials; the quantum dot light-emitting material includes a single structure The material of the single structure quantum dot, the core material of the core-shell structure quantum dot and the shell material of the core-shell structure quantum dot respectively include at least one of the II-VI group compound, the IV-VI group compound, the III-V group compound and the I-III-VI group compound; the II-VI group compound includes CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSe At least one of S, 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 include SnS, SnSe, SnTe , PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe; the III-V group compounds include GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, A At least one of InNP, 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 I-III-VI group compound includes CuInS 2 , CuInSe 2 and AgInS 2 ; the perovskite semiconductor material includes a doped or undoped inorganic perovskite semiconductor, or an organic-inorganic hybrid perovskite semiconductor; the inorganic perovskite semiconductor has a general structural formula of AMX 3 , wherein A is a Cs + ion, M is a divalent metal cation, including at least one of Pb 2+ , Sn 2+ , Cu 2+ , Ni 2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2+ , and Eu 2+ , and X is a halogen anion, including at least one of Cl - , Br - , and I - ; the organic-inorganic hybrid perovskite semiconductor has a general structural formula of BMX 3 , wherein B is an organic amine cation, including CH 3 (CH 2 )n-2NH 3+ or [NH 3 (CH 2 )nNH 3 ] 2+ , wherein n≥2, M is a divalent metal cation, including at least one of Pb 2+ , Sn 2+ , Cu 2+ , Ni 2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2+ , and Eu 2+ , and X is a halogen anion, including at least one of Cl - , Br - , and I - .
The light emitting device according to claim 7, wherein:

The light-emitting device further comprises a hole injection layer located between the anode and the hole transport layer, wherein a material of the hole injection layer comprises one or more of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone, copper phthalocyanine, 1,4,5,8,9,11-hexaazabenzonitrile, NiOx , MoOx , WOx , CrOx , CuO, MoSx , MoSex , WSx , WSex , and CuS, wherein the value of x ranges from 1 to 3; and/or

The light emitting device further comprises an electron transport layer and/or an electron injection layer between the cathode and the light emitting layer, wherein the materials of the electron transport layer and/or the electron injection layer comprise inorganic materials and/or organic materials; the inorganic materials comprise one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, and the doped elements comprise aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, One or more of nickel, zirconium, cerium and gadolinium; the organic material includes one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene compounds and hydroxyquinoline compounds.
A method for preparing a light emitting device, comprising:

Providing a light-emitting device preform and a composite material, wherein the composite material comprises a hole transport material and a voltage stabilizer, wherein the voltage stabilizer comprises a substituted aromatic ketone, wherein at least one substituent of the aromatic ketone is an electron-donating group; and

The composite material is deposited on the light emitting device preform to form a hole transport layer.
The preparation method according to claim 10, wherein the electron donating group comprises one or more of a hydroxyl group, an alkoxy group, a phenoxy group, a benzyloxy group, and an acyloxy group.
The preparation method according to claim 10, wherein the voltage stabilizer comprises a substituted aromatic ketone having 2 to 5 benzene ring structures.
The preparation method according to claim 12, wherein the aromatic ketone having 2 to 5 benzene ring structures includes one or more of 4-propyleneoxy-2-hydroxybenzophenone, 2-hydroxy-4-(methacryloyloxy)benzophenone, 4'-phenoxyacetophenone, 4'-benzyloxy-2'-hydroxyacetophenone, 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone), and 4-hydroxy-4'-phenoxybenzophenone.
The preparation method according to claim 10, wherein the mass ratio of the voltage stabilizer to the hole transport material is 1:2 to 20.
The preparation method according to claim 10, wherein after depositing the composite material on the light-emitting device preform and before forming the hole transport layer, it further comprises: ultraviolet light irradiation for 2 to 10 minutes.
The preparation method according to claim 10, wherein depositing the composite material on the light emitting device preform comprises:

Providing a solvent and a composite material, mixing them, and obtaining a film-forming solution; and

The film-forming solution is deposited on the light-emitting device preform to form a hole transport layer.
The preparation method according to claim 16, wherein the method of mixing the solvent and the composite material is: stirring at 40-60°C for 2-4h.
The preparation method according to claim 16, wherein the concentration of the composite material in the film-forming solution is 4 to 10 mg/mL.
The preparation method according to claim 16, wherein the solvent comprises a non-polar organic solvent, and the non-polar organic solvent comprises one or more of an alkane solvent, an olefin solvent and an aromatic solvent.
The preparation method according to claim 19, wherein the alkane solvent includes one or more of n-hexane, n-heptane, n-octane, cyclohexane, cycloheptane, chloroform, tetradecane and cyclooctane, the olefin solvent includes one or more of 1-decene, 1-dodecene, 1-tetradecene and 1-hexadecene, and the aromatic solvent includes one or more of benzene, toluene, chlorobenzene and xylene.