Quantum dot light-emitting diode and method for fabricating the same
11485908 · 2022-11-01
Assignee
Inventors
Cpc classification
H10K2102/00
ELECTRICITY
H10K71/00
ELECTRICITY
B82Y20/00
PERFORMING OPERATIONS; TRANSPORTING
B82Y40/00
PERFORMING OPERATIONS; TRANSPORTING
C01B19/04
CHEMISTRY; METALLURGY
H10K50/115
ELECTRICITY
International classification
C09K11/88
CHEMISTRY; METALLURGY
B82Y20/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A quantum dot light-emitting diode and a method for fabricating the same. The quantum dot light-emitting diode, includes: an anode, a cathode, and a quantum dot light-emitting layer arranged between the anode and the cathode. A composite electron transport layer is arranged between the cathode and the quantum dot light-emitting layer, and the composite electron transport layer contains an electron transport material and an ultraviolet absorbing material.
Claims
1. A quantum dot light-emitting diode, comprising: an anode, a cathode, and a quantum dot light-emitting layer arranged between the anode and the cathode; wherein a composite electron transport layer is arranged between the cathode and the quantum dot light-emitting layer, and the composite electron transport layer contains an electron transport material and an ultraviolet absorbing material; and the ultraviolet absorbing material is at least one selected from the group consisting of cinnamic acid, a cinnamic acid derivative, salicylic acid, a salicylic acid derivative, methoxyphenone, a methoxyphenone derivative, benzotriazole, a benzotriazole derivative, cyanoacrylic acid, a cyanoacrylic acid derivative, benzoic acid, the benzoic acid derivative, a hindered amine compound, an organic nickel compound, phenylbenzimidazole sulfonic acid, terephthalylidene dicamphor sulfonie acid, drometrizde trisiloxane, butyl methoxydibenzoylmethane, and 3-(4-methylbenzylidene)-camphor.
2. The quantum dot light-emitting diode of claim 1, wherein the composite electron transport layer comprises: an electron transport layer made of the electron transport material, and an interfacial modification layer made of the ultraviolet absorbing material, wherein the interfacial modification layer is arranged between the electron transport layer and the cathode; or alternatively, the interfacial modification layer is arranged between the electron transport layer and the quantum dot light-emitting layer.
3. The quantum dot light-emitting diode of claim 1, wherein the composite electron transport layer comprises: a first interfacial modification layer, an electron transport layer, and a second interfacial modification layer that are stacked; the electron transport layer is made of the electron transport material, and the first interfacial modification layer and the second interfacial modification layer are made of the ultraviolet absorbing material, wherein the first interfacial modification layer is arranged between the electron transport layer and the cathode; and the second interfacial modification layer is arranged between the electron transport layer and the quantum dot light-emitting layer.
4. The quantum dot light-emitting diode of claim 2, wherein the interfacial modification layer has a thickness of 2-90 nm.
5. The quantum dot light-emitting diode of claim 3, wherein the first interfacial modification layer has a thickness of 2-90 nm; and the second interfacial modification layer has a thickness of 2-90 nm.
6. The quantum dot light-emitting diode of claim 1, wherein the composite electron transport layer is formed by a mixture of the electron transport material and the ultraviolet absorbing material.
7. The quantum dot light-emitting diode of claim 6, wherein the composite electron transport layer has a thickness of 2-170 nm; and the electron transport material and the ultraviolet absorbing material are mixed at a molar ratio of (0.05-200):(0.03-90).
8. The quantum dot light-emitting diode of claim 1, wherein the electron transport material is selected from a metal oxide electron transport material.
9. The quantum dot light-emitting diode of claim 8, wherein the cinnamic acid derivative is at least one selected from the group consisting of octyl methoxycinnamate, isooctyl methoxycinnamate, 2-ethylhexyl 4-methoxycinnamate, pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate, sinapic acid, and a sinapic acid derivative; and the salicylic acid derivative is at least one selected from the group consisting of octyl salicylate, homosalate, phenyl 3,5-dichlorosalicylate, 4,4′-isopropylidene-bis(phenolsalicylate), p-tert-butylphenyl salicylate, and p-octylphenyl salicylate; and the methoxyphenone derivative is at least one selected from the group consisting of 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, benzophenone-3, 2-hydroxy-4-(2′-ethylhexoxy)-benzophenone, 2-hydroxy-4-dodecyl-benzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2-hydroxy-4(2′-hydroxy-3′-acryloxypropoxy) benzophenone, 2-hydroxy-4-[2′-hydroxy-3′-(methacryloxypropoxy)] benzophenone, 2,2′-dihydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxy-4-chlorobenzophenone, 2-hydroxy-4-methoxy-2′,4′-dichlorobenzophenone, 1,3-bis(3′-hydroxy-4′-benzoylphenoxy)-2-propanol, 2-hydroxy-4-octadecyloxybenzophenone, 2,2′-dihydroxy-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2′,4,4′-tetrahydroxybenzophenone, and 2-hydroxy-4-acryloyloxyethoxybenzophenone; and the benzotriazole derivative is at least one selected from the group consisting of 2-(2′-hydroxy-3′,5′-di-tert-phenyl)-5-chlorobenzotriazole, 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, (2′-hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotriazole, 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)-5-chlorobenzotriazole, methyl 3-(3-(2H-benzotriazol-2-yl)5-tert-butyl-4-hydroxyphenyl) acrylate, 2-(2′-hydroxy-3′,5′-dipentylphenyl)benzotriazole, 2-(2′-hydroxy-4′-n-octyloxyphenyl)benzotriazole, 2-(2′-hydroxy-5′-tert-octylphenyl)benzotriazole, 2-(2H-benzotriazol-2-yl)-4-(tert-butyl-6-sec-butyl)phenol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2,2′-methylenebis(6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol), 2-(2H-benzotriazol-2-yl)-6-(dodecyl)-4-methylphenol, and methylenebis-benzotriazolyltetramethylbutylphenol; and the cyanoacrylic acid derivative is at least one selected from the group consisting of 2-cyano-3,3-diphenylacrylic acid 2-ethylhexyl ester, 2-cyano-3,3′-diphenyl ethyl acrylate, and 2-cyano-3,3-diphenyl isooctyl acrylate; and the benzoic acid derivative is at least one selected from the group consisting of diethylaminohydroxybenzoyl hexyl benzoate, 2-ethylhexyl-4-dimethylaminobenzoate, octyl-dimethyl-p-aminobenzoic acid, phenyl 2-hydroxybenzoate, m-phenylene dibenzoate, 3,5-di-tert-butyl-4-hydroxybenzoic acid-2,4-di-tert-butylphenyl ester, and 3,5-di-tert-butyl-4-hydroxybenzoic acid n-hexadecyl ester; and the hindered amine compound is at least one selected from the group consisting of ethyl bis (2,2,6,6-tetramethylpiperazinone), 4-benzoyloxy-2,2,6,6tetramethylpiperidine, 2-(3,5-di-tert-butyl-4-hydroxy-benzyl)-2-butyl 1,3-malonic acid bis (1,2,2,6,6-pentamethyl-4-piper pyridyl) ester, tetra(2,2,6,6-tetramethyl-4-piperidinyl)-1,2,3,4-butane tetracarboxylate, bis (2,2,6,6-tetramethylpiperidinyl) sebacate, poly-{[6-[(1,1,3,3-tetramethylbutyl)-imino]-1,3,5, -triazine-2,4-diyl] [2-(2, 2,6,6, -tetramethylpiperidinyl)-imino-hexamethylene-[4-(2,2,6,6-tetramethylpyridinyl)-imino]], polymers of succinic acid and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol, [[6-[(1, 1, 3,3-tetramethylbutyl) amino] s-triazine-2,4-di] [[(2,2,6,6-tetramethyl-4-piperidinyl) imino] hexylidene [(2,2,6,6-tetramethyl-4-piperidinyl) imino]] polymer, bis (or tri) (2,2,6,6-tetramethyl-4-piperidinyl)-bis (or mono) tridecyl-1,2,3,4-butane tetracarboxylate, bis (or tri) (1,2,2,6,6-pentamethyl-4-piperidinyl)-bis (or mono) tridecyl-1,2,3,4-butane tetracarboxylic acid ester, 4-(p-toluenesulfonamido)-2,2,6,6-tetramethylpiperidine, bis (1,2,2,6,6-pentamethyl 4-piperidinyl)-sebacate, N-triacetic acid (2,2,6,6-tetramethyl-4-piperidinyl) ester, N-triacetic acid (1,2,2,6,6-pentamethyl-4-piperidinyl) ester, tris (1,2,2,6,6-pentamethyl-4-piperidinyl)-phosphite, poly-(4(2,2,6,6-tetramethylpiperidinyl) imino-hexamethylene [4-(2,2,6,6-tetramethylpiperidinyl) imino]-ethylene, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, and hexamethylphosphoric triamide; and the organic nickel compound is at least one selected from the group consisting of nickel tetra-n-butyl dithiocarbamate, 2,2′-thiobis (p-tert-octylphenol) nickel-n-butylamine complex, 2,2′-thiobis (p-tert-octylphenol) nickel, and 2,2′-thiobis (4-tert-octylphenoloxy) nickel.
10. The quantum dot light-emitting diode of claim 8, wherein the metal oxide electron transport material is at least one selected from ZnO, TiO.sub.2, SnO.sub.2, Ta.sub.2O.sub.3, ZrO.sub.2, NiO, TiLiO, ZnAlO, ZnMgO, ZnSnO, ZnLiO, and InSnO.
11. The quantum dot light-emitting diode of claim 1, wherein an electron injection layer is arranged between the cathode and the composite electron transport layer; and a hole function layer is arranged between the anode and the quantum dot light-emitting layer.
12. A method for fabricating a quantum dot light-emitting diode, comprising the following steps: preparing a composite electron transport layer on a cathode or a quantum dot light-emitting layer, wherein the composite electron transport layer contains an electron transport material and an ultraviolet absorbing material; wherein the ultraviolet absorbing material is at least one selected from the group consisting of cinnamic acid, a cinnamic acid derivative, salicylic acid, a salicylic acid derivative, methoxyphenone, a methoxyphenone derivative, benzotriazole, a benzotriazole derivative, cyanoacrylic acid, a cyanoacrylic acid derivative, benzoic acid, the benzoic acid derivative, a hindered amine compound, an organic nickel compound, phenylbenzimidazole sulfonic acid, terephthalylidene dicamphor sulfonie acid, drometrizde trisiloxane, butyl methoxydibenzoylmethane, and 3-(4-methylbenzylidene)-camphor.
13. The method of claim 12, wherein the step of preparing the composite electron transport layer on the cathode or the quantum dot light-emitting layer comprises: mixing the electron transport material and the ultraviolet absorbing material to obtain a composite material; and depositing the composite material on the cathode or the quantum dot light-emitting layer to obtain the composite electron transport layer formed by a mixture of the electron transport material and the ultraviolet absorbing material.
14. The method of claim 13, wherein the step of depositing the composite material on the cathode or the quantum dot light-emitting layer to obtain the composite electron transport layer formed by the mixture of the electron transport material and the ultraviolet absorbing material, comprises: dissolving the composite material in a solvent to prepare a mixed solution, then depositing the mixed solution on the cathode or the quantum dot light-emitting layer, and performing annealing treatment.
15. The method of claim 14, wherein in the mixed solution, the electron transport material has a concentration of 0.05-200 mol/L; and the ultraviolet absorbing material has a concentration of 0.03-90 mmol/L.
16. The method of claim 14, wherein the annealing treatment is performed at a temperature of 25-120° C.
17. The method of claim 12, wherein the step of preparing the composite electron transport layer on the cathode or the quantum dot light-emitting layer comprises: depositing the electron transport material on the cathode or the quantum dot light-emitting layer to obtain an electron transport layer; and depositing the ultraviolet absorbing material on the electron transport layer to obtain an interfacial modification layer; wherein the interfacial modification layer and the electron transport layer form the composite electron transport layer.
18. The method of claim 17, wherein the step of depositing the ultraviolet absorbing material on the electron transport layer to obtain the interfacial modification layer comprises: dissolving the ultraviolet absorbing material in a solvent to obtain an ultraviolet absorbing material-containing solution, then depositing the ultraviolet absorbing material-containing solution on the electron transport layer, and performing annealing treatment.
19. The method of claim 12, wherein the step of preparing the composite electron transport layer on the cathode or the quantum dot light- emitting layer comprises: depositing the ultraviolet absorbing material on the cathode or the quantum dot light-emitting layer to obtain an interfacial modification layer; and depositing the electron transport material on the interfacial modification layer to obtain an electron transport layer; wherein the interfacial modification layer and the electron transport layer form the composite electron transport layer.
20. The method of claim 19, wherein the step of depositing the ultraviolet absorbing material on the cathode or the quantum dot light-emitting layer to obtain the interfacial modification layer comprises: dissolving the ultraviolet absorbing material in a solvent to obtain an ultraviolet absorbing material-containing solution, then depositing the ultraviolet absorbing material-containing solution on the cathode or the quantum dot light-emitting layer, and performing annealing treatment.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE EMBODIMENTS
(5) In order to make the technical problems, technical solutions, and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below in accompany with the drawings and embodiments.
(6) It should be understood that the specific embodiments described herein are only used to explain the present application, and are not intended to limit the present application.
(7) It should be understood that the terms “first” and “second” in embodiments of the present application are used for description purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as “first” and “second” may explicitly or implicitly include one or more of such features.
(8) In one aspect, the present application provides a quantum dot light-emitting diode, which comprises: an anode, a cathode, and a quantum dot light-emitting layer arranged between the anode and the cathode. A composite electron transport layer is arranged between the cathode and the quantum dot light-emitting layer, and the composite electron transport layer contains an electron transport material and an ultraviolet absorbing material.
(9) In the quantum dot light-emitting diode provided by the present application, the composite electron transport layer is arranged between the cathode and the quantum dot light-emitting layer, and the composite electron transport layer contains the electron transport material and the ultraviolet absorbing material. Functional groups in the ultraviolet absorbing material are combined with vacancies or dangling bonds on the surface of the electron transport material to passivate the surface defects of the electron transport material, thereby avoiding the luminescence quenching of the quantum dot light-emitting diode and in turn improving the luminous performance of the device.
(10) Further, in the quantum dot light-emitting diode provided by an embodiment of the present application, the composite electron transport layer comprises: an electron transport layer made of the electron transport material, and an interfacial modification layer made of the ultraviolet absorbing material, in which, the interfacial modification layer is arranged between the electron transport layer and the cathode, or alternatively, the interfacial modification layer is arranged between the electron transport layer and the quantum dot light-emitting layer. Or alternatively, the composite electron transport layer comprises: a first interfacial modification layer, an electron transport layer, and a second interfacial modification layer that are stacked; the electron transport layer is made of the electron transport material, and the first interfacial modification layer and the second interfacial modification layer are made of the ultraviolet absorbing material, in which, the first interfacial modification layer is arranged between the electron transport layer and the cathode, and the second interfacial modification layer is arranged between the electron transport layer and the quantum dot light-emitting layer. That is, the interfacial modification layer in the embodiment of the present application may be one layer stacked between the electron transport layer and the cathode; or alternatively, the interfacial modification layer may be one layer stacked between the electron transport layer and the quantum dot light-emitting layer; or alternatively, the interfacial modification layer can be two layers, with one layer arranged between the electron transport layer and the cathode and the other layer arranged between the electron transport layer and the quantum dot light-emitting layer. The interfacial modification layer made of the ultraviolet absorbing material is arranged on the surface of the electron transport layer, which can passivate the surface defects of the electron transport layer; in addition, coordination groups contained in the ultraviolet absorbing material (as hydroxyl groups or carboxyl groups of sinapic acid ester shown in
(11) Further, in the quantum dot light-emitting diode provided by an embodiment of the present application, the composite electron transport layer is formed by a mixture of the electron transport material and the ultraviolet absorbing material. The ultraviolet absorbing material can passivate the surface defects of the electron transport material. When the ultraviolet absorbing material is mixed with the electron transport material, the ultraviolet absorbing material can passivate the internal defects of the composite electron transport layer. Further, when the composite electron transport layer is formed by a mixture of the electron transport material and the ultraviolet absorbing material, the composite electron transport layer has a thickness of 2-170 nm. In an embodiment, the electron transport material and the ultraviolet absorbing material are mixed at a molar ratio of (0.05-200):(0.03-90).
(12) Further, in the quantum dot light-emitting diode provided by an embodiment of the present application, the above electron transport material is selected from a metal oxide electron transport material. The metal oxide electron transport material (such as titanium dioxide, zinc oxide, etc.) has excellent electron transport property, but also has strong photocatalytic capability, that is, having photocatalytic effect under the excitation of photons. Under the photocatalytic effect of the metal oxide electron transport material, the ultraviolet light or the light containing an ultraviolet component damages inorganic materials (including quantum dot materials, oxide nanoparticle materials, etc.) inside the device and/or organic materials (including nanoparticle surface ligands, organic transport layer, organic modification layer, etc.), resulting in adverse effects on material property and device performance, such as quantum dot surface ligand shedding, quantum dot reunion, increased nanoparticle surface defects, increased interface defects of the functional layer, changes in particle energy band, increased carrier transport barrier, etc. In the embodiment of the present application, one or more of the ultraviolet absorbing material is introduced into the interface between the quantum dot light-emitting layer and the electron transport layer made of the metal oxide electron transport material, and/or inside the electron transport layer made of the metal oxide electron transport material, and/or into the interface between the electron transport layer made of the metal oxide electron transport material and the cathode, that is, the metal oxide electron transport materials and ultraviolet absorbing material are mixed to form the composite electron transport layer, or alternatively, at least one surface of the electron transport layer made of the metal oxide electron transport material is provided with the interfacial modification layer made of the ultraviolet absorbing material. In this way, not only can the surface defects of the metal oxide electron transport material be passivated, but also the impact of ultraviolet light on device materials and device performance is inhibited, thereby ultimately improving the device performance and extending the device life.
(13) Further, the above ultraviolet absorbing material is at least one selected from the group consisting of cinnamic acid, a cinnamic acid derivative, salicylic acid, a salicylic acid derivative, methoxyphenone, a methoxyphenone derivative, benzotriazole, a benzotriazole derivative, cyanoacrylic acid, a cyanoacrylic acid derivative, triazine, a triazine derivative, benzoic acid, the benzoic acid derivative, a hindered amine compound, an organic nickel compound, phenylbenzimidazole sulfonic acid, terephthalylidene dicamphor sulfonie acid, drometrizde trisiloxane, butyl methoxydibenzoylmethane, and 3-(4-methylbenzylidene)-camphor. In other words, the ultraviolet absorbing material may be any one selected from said group, for example, cinnamic acid , or a cinnamic acid derivative, or salicylic acid; the ultraviolet absorbing material may be any two selected from said group, for example, cinnamic acid and a cinnamic acid derivative; or salicylic acid and a salicylic acid derivative; or methoxyphenone and a methoxyphenone derivative; and the ultraviolet absorbing material may be any three selected from said group, for example, cinnamic acid, a cinnamic acid derivative, and salicylic acid; or a salicylic acid derivative, methoxyphenone, and a methoxyphenone derivative; etc.
(14) In the above ultraviolet absorbing material: the cinnamic acid derivative is at least one selected from the group consisting of octyl methoxycinnamate, isooctyl methoxycinnamate, 2-ethylhexyl 4-methoxycinnamate, pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate, sinapic acid, and a sinapic acid derivative (such as one or more of sinapic acid ester, sinapoyl glucose, sinapoyl malate, sinapoyl choline). In other words, the cinnamic acid derivative may be any one selected from said group, for example, octyl methoxycinnamate, or isooctyl methoxycinnamate, or 2-ethylhexyl 4-methoxycinnamate, or pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate; the cinnamic acid derivative may be any two selected from said group, for example, octyl methoxycinnamate and isooctyl methoxycinnamate, or 2-ethylhexyl 4-methoxycinnamate and pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate; and the cinnamic acid derivative may be any three selected from said group, for example, octyl methoxycinnamate, isooctyl methoxycinnamate, and 2-ethylhexyl 4-methoxycinnamate; or pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate, sinapic acid, and a sinapic acid derivative; etc. The salicylic acid derivative is at least one selected from the group consisting of octyl salicylate, homosalate, phenyl 3,5-dichlorosalicylate, 4,4′-isopropylidene-bis(phenolsalicylate), p-tert-butylphenyl salicylate, and p-octylphenyl salicylate. In other words, the salicylic acid derivative may be any one selected from said group, for example, octyl salicylate, or homosalate, or phenyl 3,5-dichlorosalicylate, or 4,4′-isopropylidene-bis(phenolsalicylate), or p-tert-butylphenyl salicylate, or p-octylphenyl salicylate, the salicylic acid derivative may be any two selected from said group, for example, octyl salicylate and homosalate, or phenyl 3,5-dichlorosalicylate and 4,4′-isopropylidene-bis(phenolsalicylate), or p-tert-butylphenyl salicylate and p-octylphenyl salicylate, and the salicylic acid derivative may be any three selected from said group, for example, octyl salicylate, homosalate, and phenyl; or 3,5-dichlorosalicylate, 4,4′-isopropylidene-bis(phenolsalicylate), and p-tert-butylphenyl salicylate; etc. The methoxyphenone derivative is at least one selected from the group consisting of 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, benzophenone-3, 2-hydroxy-4-(2′-ethylhexoxy) -benzophenone, 2-hydroxy-4-dodecyl-benzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2-hydroxy-4(2′-hydroxy-3′-acryloxypropoxy) benzophenone, 2-hydroxy-4-[2′-hydroxy-3′-(methacryloxypropoxy)] benzophenone, 2,2′- dihydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxy-4-chlorobenzophenone, 2-hydroxy-4-methoxy-2′,4′-dichlorobenzophenone, 1,3-bis(3′-hydroxy-4′- benzoylphenoxy)-2-propanol, 2-hydroxy-4-octadecyloxybenzophenone, 2,2′-dihydroxy-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2′,4,4′-tetrahydroxybenzophenone, and 2-hydroxy-4-acryloyloxyethoxybenzophenone. In other words, the methoxyphenone derivative may be any one selected from said group, for example, 2-hydroxy-4-n-octyloxybenzophenone, or 2-hydroxy-4-methoxybenzophenone; the methoxyphenone derivative may be any two selected from said group, for example, 2-hydroxy-4-n-octyloxybenzophenone and 2-hydroxy-4-methoxybenzophenone, or 2,4-dihydroxybenzophenone and benzophenone-3, the methoxyphenone derivative may be any two selected from said group, for example, 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, and 2,4-dihydroxybenzophenone; or benzophenone-3, 2-hydroxy-4-(2′- ethylhexoxy)-benzophenone, and 2-hydroxy-4-dodecyl-benzophenone; etc. The benzotriazole derivative is at least one selected from the group consisting of 2-(2′-hydroxy-3′,5′-di-tert-phenyl)-5-chlorobenzotriazole, 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, (2′-hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotrizole, 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)-5-chlorobenzotriazole, methyl 3-(3-(2H-benzotriazol-2-yl)5-tert-butyl-4-hydroxyphenyl) acrylate, 2-(2′-hydroxy-3′,5′-dipentylphenyl)benzotriazole, 2-(2′-hydroxy-4′-n-octyloxyphenyl)benzotriazole, 2-(2′-hydroxy-5′-tert-octylphenyl)benzotriazole, 2-(2H- benzotriazol-2-yl)-4-(tert-butyl-6-sec-butyl)phenol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2,2′-methylenebis(6-(2H-benzotriazol- 2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol), 2-(2H-benzotriazol-2-yl)-6-(dodecyl)-4-methylphenol, and methylenebis-benzotriazolyltetramethylbutylphenol. In other words, the benzotriazole derivative may be any one selected from said group, for example, 2-(2′-hydroxy-3′, 5′-di-tert-phenyl)-5-chlorobenzotriazole, or 2-(2′-hydroxy-5′-methylphenyl)benzotriazole; the benzotriazole derivative may be any two selected from said group, for example, 2-(2′-hydroxy-3′,5′-di-tert-phenyl)-5-chlorobenzotriazole and 2-(2′-hydroxy -5′-methylphenyl)benzotriazole, or 2-(2′-hydroxy-5′-methylphenyl)benzotriazole and (2′-hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotriazole; the benzotriazole derivative may be any three selected from said group, for example, 2-(2′-hydroxy-3′,5′-di-tert-phenyl)-5-chlorobenzotriazole, 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, and 2-(2′-hydroxy-5′-methylphenyl)benzotriazole; or (2′-hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotriazole, 2-(2′-hydroxy-3′-di-tert -butylphenyl)-5-chlorobenzotriazole, and methyl 3-(3-(2H-benzotriazol-2-yl)5-tert-butyl-4-hydroxyphenyl) acrylate; etc. The cyanoacrylic acid derivative is at least one selected from the group consisting of 2-cyano-3,3-diphenylacrylic acid 2-ethylhexyl ester, 2-cyano-3,3′-diphenyl ethyl acrylate, and 2-cyano-3,3-diphenyl isooctyl acrylate. In other words, the cyanoacrylic acid derivative may be any one selected from said group, for example, 2-cyano-3,3-diphenylacrylic acid 2-ethylhexyl ester, or 2-cyano-3,3′-diphenyl ethyl acrylate, or 2-cyano-3,3-diphenyl isooctyl acrylate; the cyanoacrylic acid derivative may be any two selected from said group, for example, 2-cyano-3,3-diphenylacrylic acid 2-ethylhexyl ester and 2-cyano-3,3′-diphenyl ethyl acrylate, or 2-cyano-3,3-diphenylacrylic acid 2-ethylhexyl ester and 2-cyano-3,3-diphenyl isooctyl acrylate, or 2-cyano-3,3′-diphenyl ethyl acrylate and 2-cyano-3,3-diphenyl isooctyl acrylate; and the cyanoacrylic acid derivative may be the three selected from said group, for example, 2-cyano-3,3-diphenylacrylic acid 2-ethylhexyl ester, 2-cyano-3,3′-diphenyl ethyl acrylate, and 2-cyano-3,3-diphenyl isooctyl acrylate. The triazine derivative is at least one selected from the group consisting of 2,4,6-tris(2′n-butoxyphenyl) -1,3,5-triazine, ethylhexyl triazinone, diethylhexylbutyramidotriazinone, tris(2,2,6,6-tetramethyl-4-oxy-piperidinyl)-1,3,5-triazine, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl) oxy]-phenol, 2-[4,6-bis(2,4-xylyl)-2-(1,3,5-triazinyl)]-5-octyloxyphenol, and bis- ethylhexyloxyphenol methoxyphenyl triazine. In other words, the triazine derivative may be any one selected from said group, for example, 2,4,6-tris(2′n-butoxyphenyl) -1,3,5-triazine or ethylhexyl triazinone, diethylhexylbutyramidotriazinone, the triazine derivative may be any two selected from said group, for example, 2,4,6-tris(2′n-butoxyphenyl) -1,3,5-triazine and ethylhexyl triazinone, or diethylhexylbutyramidotriazinone and tris(2,2,6,6-tetramethyl-4-oxy-piperidinyl)-1,3,5-triazine; and the triazine derivative may be any three selected from said group, for example, 2,4,6-tris(2′n-butoxyphenyl) -1,3,5-triazine, ethylhexyl triazinone, and diethylhexylbutyramidotriazinone; etc. The benzoic acid derivative is at least one selected from the group consisting of diethylaminohydroxybenzoyl hexyl benzoate, 2-ethylhexyl-4-dimethylaminobenzoate, octyl-dimethyl-p-aminobenzoic acid, phenyl 2-hydroxybenzoate, m-phenylene dibenzoate, 3,5-di-tert-butyl-4-hydroxybenzoic acid-2,4-di-tert-butylphenyl ester, and 3,5-di-tert-butyl-4-hydroxybenzoic acid n-hexadecyl ester. In other words, the benzoic acid derivative may be any one selected from said group, for example, diethylaminohydroxybenzoyl hexyl benzoate, or 2-ethylhexyl-4-dimethylaminobenzoate, or octyl-dimethyl-p-aminobenzoic acid; the benzoic acid derivative may be any two selected from said group, for example, diethylaminohydroxybenzoyl hexyl benzoate and 2-ethylhexyl-4-dimethylaminobenzoate; the benzoic acid derivative may be any three selected from said group, for example, diethylaminohydroxybenzoyl hexyl benzoate, 2-ethylhexyl-4-dimethylaminobenzoate, and octyl-dimethyl-p-aminobenzoic acid; etc. The hindered amine compound is at least one selected from the group consisting of ethyl bis (2,2,6,6-tetramethylpiperazinone), 4-benzoyloxy-2,2,6,6 tetramethylpiperidine, 2-(3,5-di-tert-butyl-4-hydroxy-benzyl)-2-butyl 1,3-malonic acid bis (1,2,2,6,6-pentamethyl-4-piper pyridyl) ester, tetra(2,2,6,6-tetramethyl-4-piperidinyl)-1,2,3,4-butane tetracarboxylate, bis (2,2,6,6-tetramethylpiperidinyl) sebacate, poly-{[6-[(1,1,3,3-tetramethylbutyl) -imino]-1,3,5, -triazine-2,4-diyl] [2-(2,2,6,6-tetramethylpiperidinyl) -imino-hexamethylene- [4-(2,2,6,6-tetramethylpyridinyl) -imino]], polymers of succinic acid and 4-hydroxy-2,2,6,6-tetramethyl-l-piperidinol, [[6-[(1, 1, 3,3-tetramethylbutyl) amino] s-triazine-2,4-di] [[(2,2,6,6-tetramethyl-4-piperidinyl) imino] hexylidene [(2,2,6,6-tetramethyl-4-piperidinyl) imino]] polymer, bis (or tri) (2,2,6,6-tetramethyl-4-piperidinyl) -bis (or mono) tridecyl-1,2,3,4-butane tetracarboxylate, bis (or tri) (1,2,2,6,6-pentamethyl-4-piperidinyl) -bis (or mono) tridecyl-1,2,3,4-butane tetracarboxylic acid ester, 4-(p-toluenesulfonamido) -2,2,6,6-tetramethylpiperidine, bis (1,2,2,6,6-pentamethyl 4-piperidinyl) -sebacate, N-triacetic acid (2,2,6,6-tetramethyl-4-piperidinyl) ester, N-triacetic acid (1,2,2,6,6-pentamethyl-4-piperidinyl) ester, tris (1,2,2,6,6-pentamethyl-4-piperidinyl) -phosphite, poly-(4(2,2,6,6-tetramethylpiperidinyl) imino-hexamethylene [4-(2,2,6,6-tetramethylpiperidinyl) imino]-ethylene, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, and hexamethylphosphoric triamide. In other words, the hindered amine compound may be any one selected from said group, for example, ethyl bis (2,2,6,6-tetramethylpiperazinone), or 4-benzoyloxy-2,2,6,6tetramethylpiperidine; the hindered amine compound may be any two selected from said group, for example, ethyl bis (2,2,6,6-tetramethylpiperazinone) and 4-benzoyloxy -2,2,6,6tetramethylpiperidine, or 2-(3,5-di-tert-butyl-4-hydroxy-benzyl)-2-butyl 1,3-malonic acid bis (1,2,2,6,6-pentamethyl-4-piper pyridyl) ester and tetra(2,2,6,6-tetramethyl -4-piperidinyl)-1,2,3,4-butane tetracarboxylate; the hindered amine compound may be any three selected from said group, for example, ethyl bis (2,2,6,6-tetramethylpiperazinone), 4-benzoyloxy-2,2,6,6tetramethylpiperidine, and 2-(3,5-di-tert-butyl-4-hydroxy-benzyl)-2-butyl 1,3-malonic acid bis (1,2,2,6,6-pentamethyl-4-piper pyridyl) ester; etc. The organic nickel compound is at least one selected from the group consisting of nickel tetra-n-butyl dithiocarbamate, 2,2′-thiobis (p-tert-octylphenol) nickel-n-butylamine complex, 2,2′-thiobis (p-tert-octylphenol) nickel, and 2,2′-thiobis (4-tert-octylphenoloxy) nickel.
(15) The ultraviolet absorbing material is optionally selected from hydroxycinnamic acid derivatives, and specifically selected from the group consisting of sinapic acid, sinapic acid ester, and derivatives thereof, which includes but are not limited to one or more of sinapoyl glucose, sinapoyl malate, and sinapoyl choline. Specifically, sinapic acid ester is a lipid derivative of sinapic acid, which is a type of hydroxycinnamic acid derivatives abundant in Arabidopsis and other cruciferous plants. In plants, it is evenly distributed on leave surfaces, and protects the life processes such as plant photosynthesis from excessive ultraviolet rays, thus being a natural green environmental protective ultraviolet absorbing material. Sinapic acid ester is able to effectively absorb ultraviolet light, when absorbing the ultraviolet light and reaching an electronically excited state, it will be switched back to a ground state through fast light isomerization, thereby effectively avoiding the adverse effects of ultraviolet light components on the materials and device performance inside the QLED device.
(16) As shown in
(17) In the quantum dot light-emitting diode provided by an embodiment of the present application, the electron transport layer is one or more selected from the group consisting of doped or undoped metal oxides, and doped or undoped metal sulfides.
(18) Among them, the doped or undoped metal oxides comprises one or more of ZnO, TiO.sub.2, SnO.sub.2, Ta.sub.2O.sub.3, ZrO.sub.2, NiO, TiLiO, ZnAlO, ZnMgO, ZnSnO, ZnLiO, and InSnO.
(19) The doped or undoped metal sulfides comprise one or more of CdS, ZnS, MoS, WS, and CuS.
(20) The quantum dot light-emitting layer is made of one or more of II-VI compounds, III-V compounds, II-V compounds, III-VI compounds, IV-VI compounds, I-III-VI compounds, II-IV-VI compounds, and IV simple substances.
(21) Specifically, the semiconductor materials used in the quantum dot light-emitting layer include, but are not limited to, nano-crystalline of II-VI semiconductors, such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, PbS, PbSe, PbTe, and other binary, ternary, and quaternary II-VI compounds, and nano-crystalline of III-V group semiconductors, such as GaP, GaAs, InP, InAs, and other binary, ternary and quaternary III-V compounds. The semiconductor materials configured for electroluminescence are not limited to II-V compounds, III-VI compounds, IV-VI compounds, I-III-VI compounds, II-IV-VI compounds, and IV simple substances. The material for the quantum dot light-emitting layer may also be a doped or undoped inorganic perovskite semiconductor, and/or an organic-inorganic hybrid perovskite semiconductor. Specifically, the inorganic perovskite semiconductor has a structural formula of AMX.sub.3, where A is Cs.sup.+ ion, M is a divalent metal cation, including but not limited to Pb.sup.2+, Sn.sup.2+, Cu.sup.2+, Ni.sup.2+, Cd.sup.2+, Cr.sup.2+, Mn.sup.2+, Co2+, Fe.sup.2+, Ge.sup.2+, Yb.sup.2+, Eu.sup.2+, and X is halogen anion, including but not limited to Cl.sup.−, Br.sup.−, I.sup.−. The organic-inorganic hybrid perovskite semiconductor has a structural formula of BMX.sub.3, where B is an organic amine cation, including but not limited to CH.sub.3(CH.sub.2).sub.n-2NH.sub.3.sup.+ (n≥2) or NH.sub.3(CH.sub.2).sub.nNH.sub.3.sup.2+ (n≥2). When n=2, the inorganic metal halide octahedrons MX.sub.6.sup.4− are connected in a manner of co-apex, the metal cation M is located in the body center of each halogen octahedron, and the organic amine cations B are filled in the gap between the octahedrons, forming an infinitely extending three-dimensional structure. When n>2, the inorganic metal halide octahedrons MX.sub.6.sup.4− connected in the manner of co-apex extend in a two-dimensional direction to form a layered structure, and an organic amine cationic bilayer (protonated monoamine) or organic amine cation monolayer (protonated diamine) is intercalated in the layered structure, the organic layer and the inorganic layer overlap to form a stable two-dimensional layered structure; M is a divalent metal cation, including but not limited to Pb.sup.2+, Sn.sup.2+, Cu.sup.2+, Ni.sup.2+, Cd.sup.2+, Cr.sup.2+, Mn.sup.2+, Co2+, Fe.sup.2+, Ge.sup.2+, Yb.sup.2+, and Eu.sup.2+; X is a halogen anion, including but not limited to Cl.sup.−, Br.sup.−, and I.sup.−.
(22) The quantum dot light-emitting diode may be disposed on a substrate, the substrate is a rigid substrate or a flexible substrate, and the rigid substrate includes but is not limited to glass and metal foil. The flexible substrate includes but is not limited to one or more of polyethylene terephthalates (PET), polyethylene naphthalates (PEN), polyetheretherketones (PEEK), polystyrenes (PS), polyethersulfones (PES), polycarbonates (PC), polyarylates (PAT), polyarylates (PAR), polyimides (PI), polyvinyl chlorides (PVC), polyethylenes (PE), polyvinylpyrrolidones (PVP), and textile fibers. The anode and the cathode include but are not limited to one or more of metal materials, carbon materials, and metal oxides. The metal material includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, and Mg. The carbon material includes one or more of graphite, carbon nanotubes, graphene, and carbon fibers. The metal oxide may be doped or undoped metal oxide, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, AMO, and may also include a composite electrode formed by sandwiching metals between the doped or undoped metal oxide, where the composite electrode includes AZO/Ag/AZO, AZO/Al/AZO, ITO/Ag/ITO, ITO/Al/ITO, ZnO/Ag/ZnO, ZnO/Al/ZnO, TiO.sub.2/Ag/TiO.sub.2, TiO.sub.2/Al/TiO.sub.2, ZnS/Ag/ZnS, ZnS/Al/ZnS, TiO.sub.2/Ag/TiO.sub.2, and TiO.sub.2/Al/TiO.sub.2. In particular, the anode and the cathode of different materials can be used to construct the quantum dot light-emitting diode with different light emitting characteristics, including top-emitting devices, bottom-emitting devices, and fully transparent devices.
(23) In addition, an electron injection layer may be arranged between the composite electron transport layer and the cathode, and a hole blocking layer may be arranged between the composite electron transport layer and the quantum dot light-emitting layer. A hole function layer (for example, a hole transport layer, or a hole injection layer and a hole transport layer that are stacked) is arranged between the anode and the quantum dot light-emitting layer. An electron blocking layer may be arranged between the hole function layer and the quantum dot light-emitting layer. The hole injection layer is one or more selected from the group consisting of PEDOT:PSS, CuPc, F4-TCNQ, HATCN, transition metal oxides, and transition metal chalcogenides. The transition metal oxides comprise one or more of NiOx, MoOx, WOx, CrOx, and CuO. The transition metal chalcogenides comprise one or more of MoSx, MoSex, WSx, WSex, and CuS. The hole transport layer is at least one selected from the group consisting of poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine), polyvinylcarbazole, poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine], poly(9,9-dioctylfluorene-co-bis-N,N-phenyl-1,4-phenylenediamine), 4,4′,4″-tris(carbazol-9-yl)-triphenylamine, 4,4′-bis(9-carbazolyl)-1,1′-biphenyl, N,N′-bis-(3-methylphenyl)-N,N′-Bis-phenyl-(1,1′-biphenyl)-4,4′-diamine, N,N′-Bis(1-naphthalenyl)-N,N′-bisphenyl-(1,1′-biphenyl)-4,4′-diamine, graphene, and C60. As another embodiment, the hole transport layer is selected from inorganic materials having hole transport capabilities, including but not limited to at least one of NiOx, MoOx, WOx, CrOx, CuO, MoSx, MoSex, WSx, WSex, and CuS.
(24) Another aspect of the present application provides a method for fabricating a quantum dot light-emitting diode, and the method comprises the following steps:
(25) preparing a composite electron transport layer on a cathode or a quantum dot light-emitting layer, in which, the composite electron transport layer contains an electron transport material and an ultraviolet absorbing material.
(26) In the quantum dot light-emitting diode provided by embodiments of the present application, the composite electron transport layer is arranged between the cathode and the quantum dot light-emitting layer. The composite electron transport layer contains the electron transport material and the ultraviolet absorbing material, the ultraviolet absorbing material can passivate the surface defects of the electron transport material, thereby avoiding the luminescence quenching of the quantum dot light-emitting diode and in turn improving the luminous performance of the device.
(27) In the above fabrication method, when the substrate is an anode substrate, the quantum dot light-emitting layer is arranged on a surface of the anode substrate, the composite electron transport layer containing the electron transport material and the ultraviolet absorbing material is prepared on the quantum dot light-emitting layer, and the cathode is subsequently prepared on the composite electron transport layer (thereby obtaining a quantum dot light-emitting diode in a positive structure). When the substrate is a cathode substrate, the composite electron transport layer containing the electron transport material and the ultraviolet absorbing material is prepared on the cathode substrate, and the quantum dot light-emitting layer is subsequently prepared on the composite electron transport layer, and then the anode is prepared on the quantum dot light-emitting layer (thereby obtaining a quantum dot light-emitting diode in an inverted structure).
(28) Further, as shown in
(29) S01: mixing the electron transport material and the ultraviolet absorbing material to obtain a composite material; and
(30) S02: depositing the composite material on the cathode or the quantum dot light-emitting layer to obtain the composite electron transport layer formed by a mixture of the electron transport material and the ultraviolet absorbing material.
(31) Therefore, in the finally obtained quantum dot light-emitting diode, the composite electron transport layer is a composite electron transport layer formed by a mixture of the electron transport material and the ultraviolet absorbing material.
(32) In particular, the step of depositing the composite material on the cathode or the quantum dot light-emitting layer to obtain the composite electron transport layer formed by a mixture of the electron transport material and the ultraviolet absorbing material, comprises: dissolving the composite material in a solvent to prepare a mixed solution, then depositing the mixed solution on the cathode or the quantum dot light-emitting layer, and performing annealing treatment.
(33) Further, as shown in
(34) T011: depositing the electron transport material on the cathode or the quantum dot light-emitting layer to obtain an electron transport layer; and
(35) T012: depositing the ultraviolet absorbing material on the electron transport layer to obtain an interfacial modification layer;
(36) in which, the interfacial modification layer and the electron transport layer form the composite electron transport layer.
(37) Or alternatively, as shown in
(38) T021: depositing the ultraviolet absorbing material on the cathode or the quantum dot light-emitting layer to obtain an interfacial modification layer; and
(39) T022: depositing the electron transport material on the interfacial modification layer to obtain an electron transport layer;
(40) in which, the interfacial modification layer and the electron transport layer form the composite electron transport layer.
(41) Or alternatively, the first interfacial modification layer, the electron transport layer, and the second interfacial modification layer are sequentially prepared and stacked on the cathode or the quantum dot light-emitting layer. In this way, in the quantum dot light-emitting diode finally obtained, the composite electron transport layer comprises the electron transport layer made of the electron transport material and the interfacial modification layer made of the ultraviolet absorbing material, and the interfacial modification is arranged on at least one side of the electron transport layer.
(42) In step T102, the step of depositing the ultraviolet absorbing material on the electron transport layer to obtain an interfacial modification layer comprises: dissolving the ultraviolet absorbing material in a solvent to obtain an ultraviolet absorbing material-containing solution, then depositing the ultraviolet absorbing material-containing solution on the electron transport layer, and performing annealing treatment.
(43) In step T021, the step of depositing the ultraviolet absorbing material on the cathode or the quantum dot light-emitting layer to obtain an interfacial modification layer comprises: dissolving the ultraviolet absorbing material in a solvent to obtain an ultraviolet absorbing material-containing solution, then depositing the ultraviolet absorbing material-containing solution on the cathode or the quantum dot light-emitting layer, and performing annealing treatment.
(44) The quantum dot light-emitting diode obtained by the above fabrication method may be partially encapsulated, fully encapsulated, or not encapsulated, which is not strictly limited in the embodiments of the present application.
(45) For the composite electron transport layer formed by the interfacial modification layer and the electron transport layer, the following four cases are included:
(46) In particular, in a preferred embodiment, a method for fabricating a quantum dot light-emitting diode in a positive structure comprises the following steps:
(47) Step S1: preparing an anode on the substrate;
(48) Step S2: preparing a hole injection layer on the anode;
(49) Step S3: preparing a hole transport layer on the hole injection layer;
(50) Step S4: preparing a quantum dot light-emitting layer on the hole transport layer;
(51) Step S5: introducing the interfacial modification layer made of the ultraviolet absorbing material as described in the above onto the quantum dot light-emitting layer;
(52) Step S6: preparing an electron transport layer on the interfacial modification layer; and
(53) Step S7: preparing the cathode on the electron transport layer to obtain the quantum dot light-emitting diode.
(54) In particular, in a preferred embodiment, a method for fabricating a quantum dot light-emitting diode in a positive structure comprises the following steps:
(55) Step S1: preparing an anode on a substrate;
(56) Step S2: preparing a hole injection layer on the anode;
(57) Step S3: preparing a hole transport layer on the hole injection layer;
(58) Step S4: preparing a quantum dot light-emitting layer on the hole transport layer;
(59) Step S5: preparing an electron transport layer on the quantum dot light-emitting layer;
(60) Step S6: introducing the interfacial modification layer made of the ultraviolet absorbing material as described in the above onto the electron transport layer;
(61) Step S7: preparing a cathode on the interfacial modification layer to obtain the quantum dot light-emitting diode.
(62) In particular, in a preferred embodiment, a method for fabricating a quantum dot light-emitting diode in an inverted structure comprises the following steps:
(63) Step S1: preparing a cathode on a substrate;
(64) Step S2: prepare an electron transport layer on the cathode;
(65) Step S3: introducing the interfacial modification layer made of the ultraviolet absorbing material as described in the above on the electron transport layer;
(66) Step S4: preparing a quantum dot light-emitting layer on the interfacial modification layer;
(67) Step S5: preparing a hole transport layer on the quantum dot light-emitting layer;
(68) Step S6: preparing a hole injection layer on the hole transport layer; and
(69) Step S7: preparing an anode on the hole injection layer to obtain the quantum dot light-emitting diode.
(70) In particular, in a preferred embodiment, a method for fabricating a quantum dot light-emitting diode in an inverted structure comprises the following steps:
(71) Step S1: preparing a cathode on a substrate;
(72) Step S2: introducing the interfacial modification layer made of the ultraviolet absorbing material as described in the above on the cathode;
(73) Step S3: preparing an electron transport layer on the interfacial modification layer;
(74) Step S4: preparing a quantum dot light-emitting layer on the electron transport layer;
(75) Step S5: preparing a hole transport layer on the quantum dot light-emitting layer;
(76) Step S6: preparing a hole injection layer on the hole transport layer; and
(77) Step S7: preparing an anode on the hole injection layer to obtain the quantum dot light-emitting diode.
(78) Among the above-mentioned four fabrication methods of the quantum dot light-emitting diode, the interfacial modification layer made of the ultraviolet absorbing material is prepared by a solution method, including but not limited to spin coating, printing, scrape coating, dip-coating, immersion, spraying, roller coating, casting, slot die coating, and stripe coating. Specifically, the ultraviolet absorbing material is firstly dissolved in a solvent to prepare the ultraviolet absorbing material-containing solution having a concentration of 0.03-120 mmol/L (optionally, 0.05-30 mmol/L), and then deposited by a solution method on a specific functional layer obtained from the fabrication method, a resulting product is annealed at 25-120° C. (optionally, 60-100° C.) for 0-60 min to obtain the interfacial modification layer. The interfacial modification layer has a thickness of 2-90 nm. The solvent is an organic solvent, including but not limited to a mixed organic solvent formed by one or more selected from the group consisting of a saturated hydrocarbon, an unsaturated hydrocarbon, an aromatic hydrocarbon, an alcohol solvent, an ether solvent, a ketone solvent, a nitrile solvent, an ester solvent, and derivatives thereof. In particular, the solvent is optionally an alcohol solvent, including but not limited to one or more of a monohydric alcohol, a polyhydric alcohol, and an aromatic alcohol, and specifically including, but not limited to, one or more of methanol, ethanol, ethylene glycol, propanol, propylene glycol, glycerin, isopropanol, butanol, pentanol, hexanol, cyclohexanol, n-butanol, benzyl alcohol, and phenethyl alcohol.
(79) Among the above four fabrication methods of the quantum dot light-emitting diode, in addition to the interfacial modification layer made of the ultraviolet absorbing material, preparation of the other layers may be achieved by chemical methods or physical layers. The chemical methods include but are not limited to one or more of chemical vapor deposition method, continuous ion layer adsorption and reaction method, the anode oxidation method, electrolytic deposition method, and co-precipitation method. The physical methods include but are not limited to physical coating methods or solution methods, of which, the solution methods include but are not limited to spin coating, printing, scrape coating, dip-coating, immersion, spraying, roller coating, casting, slot die coating, and stripe coating; while the physical coating methods include but are not limited to one or more of thermal evaporation coating, electron beam evaporation coating, magnetron sputtering, multi-arc ion coating, physical vapor deposition, atomic layer deposition, and pulsed laser deposition.
(80) For the composite electron transport layer formed by a mixture of the electron transport material and the ultraviolet absorbing material, the following two cases are included:
(81) In particular, in another preferred embodiment, a method for fabricating a quantum dot light-emitting diode in a positive structure comprises the following steps:
(82) Step S1: preparing an anode on a substrate;
(83) Step S2: preparing a hole injection layer on the anode;
(84) Step S3: preparing a hole transport layer on the hole injection layer;
(85) Step S4: preparing a quantum dot light-emitting layer on the hole transport layer;
(86) Step S5: uniformly mixing the electron transport material with the ultraviolet absorbing material as described in the above in advance to prepare a mixed solution, and then depositing the mixed solution on the quantum dot light-emitting layer to form a composite electron transport layer formed by a mixture of the electron transport material and the ultraviolet absorbing material; and
(87) Step S6: preparing the cathode on the composite electron transport layer obtained in step S5 to obtain the quantum dot light-emitting diode.
(88) In particular, in a preferred embodiment, a method for fabricating a quantum dot light-emitting diode in an inverted structure comprises the following steps:
(89) Step S1: preparing a cathode on a substrate;
(90) Step S2: mixing an electron transport material with the ultraviolet absorbing material as described in the above in advance to prepare a mixed solution, and then depositing the mixed solution on the cathode to form a composite electron transport layer formed by a mixture of the electron transport material and the ultraviolet absorbing material;
(91) Step S3: preparing the quantum dot light-emitting layer on the composite electron transport layer obtained in step S2;
(92) Step S4: preparing a hole transport layer on the quantum dot light-emitting layer;
(93) Step S5: preparing a hole injection layer on the hole transport layer; and
(94) Step S6: preparing an anode on the hole injection layer to obtain the quantum dot light-emitting diode.
(95) In the above two fabrication methods of the quantum dot light-emitting diode, the preparation of the composite electron transport layer are specifically performed as follows: first, the above electron transport material and the above ultraviolet absorbing material are mixed uniformly and dissolved in a solvent to prepare a mixed solution, and then the mixed solution is deposited on a specific functional layer using the solution method to form the composite electron transport layer formed by the electron transport material and the ultraviolet absorbing material. The composite electron transport layer is prepared by a solution method, including but not limited to spin coating, printing, scrape coating, dip-coating, immersion, spraying, roller coating, casting, slot die coating, and stripe coating. In the mixed solution, the electron transport material has concentration of 0.05-200 mol/L, and the ultraviolet absorbing material has a concentration of 0.03-90 mmol/L (optionally, 0.05-23 mmol/L). In particular, after the preparation of the composite electron transport layer, annealing is performed at 25-120° C. (optionally at 30-100° C.) for 0-60 min. Optionally, the composite electron transport layer has a thickness of 2-170 nm. The solvent is an organic solvent, including but not limited to a mixed organic solvent formed by one or more selected from the group consisting of a saturated hydrocarbon, an unsaturated hydrocarbon, an aromatic hydrocarbon, an alcohol solvent, an ether solvent, a ketone solvent, a nitrile solvent, an ester solvent, and derivatives thereof. In particular, the solvent is optionally an alcohol solvent, including but not limited to one or more of a monohydric alcohol, a polyhydric alcohol, and an aromatic alcohol, and specifically including, but not limited to, one or more of methanol, ethanol, ethylene glycol, propanol, propylene glycol, glycerin, isopropanol, butanol, pentanol, hexanol, cyclohexanol, n-butanol, benzyl alcohol, and phenethyl alcohol.
(96) Among the above two fabrication methods of the quantum dot light-emitting diode, in addition to the composite electron transport layer, preparation of the other layers may be achieved by chemical methods or physical layers. The chemical methods include but are not limited to one or more of chemical vapor deposition method, continuous ion layer adsorption and reaction method, the anode oxidation method, electrolytic deposition method, and co-precipitation method. The physical methods include but are not limited to physical coating methods or solution methods, of which, the solution methods include but are not limited to spin coating, printing, scrape coating, dip-coating, immersion, spraying, roller coating, casting, slot die coating, and stripe coating; while the physical coating methods include but are not limited to one or more of thermal evaporation coating, electron beam evaporation coating, magnetron sputtering, multi-arc ion coating, physical vapor deposition, atomic layer deposition, and pulsed laser deposition.
(97) Finally, an embodiment of the present application further provides a printed quantum dot display screen, including the above-mentioned quantum dot light-emitting diode according to embodiments of the present application.
(98) The present application has been tested multiple times, and a part of the test results will now be used as a reference to describe the present application in further detail. The following detailed description will be made in accompany with specific examples.
Example 1
(99) A quantum dot light-emitting diode was fabricated as follows:
(100) sinapoyl malate was firstly dissolved at a concentration of 0.2 mmol/L in methanol to obtain a sinapoyl malate solution, then the following process was conducted:
(101) A. a PEDOT:PSS layer was spin coated on an ITO conductive glass;
(102) B. a TFB layer was spin coated on the PEDOT:PSS layer;
(103) C. a CdSe/ZnS quantum dot light-emitting layer was spin coated on the TFB layer;
(104) D. the sinapoyl malate solution prepared in the above was deposited on the CdSe/ZnS quantum dot light-emitting layer by spin coating, in which, the spin coating condition was 3000 rpm; and after the spin coating, a film was heated and annealed at 80° C. for 30 min to yield a sinapoyl malate layer;
(105) E. a ZnO electron transport layer was spin coated on the sinapoyl malate layer; and
(106) F. an Al cathode layer was vapor plated on the ZnO electron transport layer to obtain the quantum dot light-emitting diode.
Example 2
(107) A quantum dot light-emitting diode was fabricated as follows:
(108) sinapoyl malate was firstly dissolved at a concentration of 0.5 mmol/L in ethanol to obtain a sinapoyl malate solution, then the following process was conducted:
(109) A. a PEDOT:PSS layer was spin coated on an ITO conductive glass;
(110) B. a TFB layer was spin coated on the PEDOT:PSS layer;
(111) C. a CdSe/ZnS quantum dot light-emitting layer was spin coated on the TFB layer;
(112) D. a ZnO electron transport layer was spin coated on the CdSe/ZnS quantum dot light-emitting layer;
(113) E. the sinapoyl malate solution prepared in the above was deposited on the ZnO electron transport layer by spin coating, in which, the spin coating condition was 3000 rpm; and after the spin coating, a film was heated and annealed at 80° C. for 30 min to yield a sinapoyl malate layer;
(114) F. an Al cathode layer was vapor plated on the sinapoyl malate layer to obtain the quantum dot light-emitting diode.
Example 3
(115) A quantum dot light-emitting diode was fabricated as follows:
(116) sinapoyl malate was firstly dissolved at a concentration of 0.5 mmol/L in ethanol to obtain a sinapoyl malate solution, then the following process was conducted:
(117) A. a ZnO electron transport layer was spin coated on an ITO conductive glass;
(118) B. the sinapoyl malate solution prepared in the above was deposited on the ZnO electron transport layer by spin coating, in which, the spin coating condition was 3000 rpm; and after the spin coating, a film was heated and annealed at 80° C. for 30 min to yield a sinapoyl malate layer;
(119) C. a CdSe/ZnS quantum dot light-emitting layer was spin coated on the sinapoyl malate layer;
(120) D. a TCTA layer was vapor plated on the CdSe/ZnS quantum dot light-emitting layer;
(121) E. an NPB layer is vapor plated on the TCTA layer;
(122) F. a HATCN layer is vapor plated on the NPB layer; and
(123) G. an Al cathode layer is vapor plated on the HATCN layer to yield the quantum dot light-emitting diode.
Example 4
(124) A quantum dot light-emitting diode was fabricated as follows:
(125) sinapoyl malate was firstly dissolved at a concentration of 0.8 mmol/L in ethanol to obtain a sinapoyl malate solution, then the following process was conducted:
(126) A. the sinapoyl malate solution prepared in the above was deposited on an ITO conductive glass by spin coating, in which, the spin coating condition was 1500 rpm; and after the spin coating, a film was heated and annealed at 100° C. for 30 min to yield a sinapoyl malate layer;
(127) B. a ZnO electron transport layer was spin coated on the sinapoyl malate layer;
(128) C. a CdSe/ZnS quantum dot light-emitting layer was spin coated on the ZnO electron transport layer;
(129) D. a TCTA layer was vapor plated on the CdSe/ZnS quantum dot light-emitting layer;
(130) E. an NPB layer is vapor plated on the TCTA layer;
(131) F. a HATCN layer is vapor plated on the NPB layer; and
(132) G. an Al cathode layer is vapor plated on the HATCN layer to yield the quantum dot light-emitting diode.
Example 5
(133) A quantum dot light-emitting diode was fabricated as follows:
(134) zinc oxide and sinapoyl malate were firstly dissolved in ethanol to yield a mixed solution of zinc oxide and sinapoyl malate, in which, a concentration of zinc oxide was 1 mmol/L, and a concentration of sinapoyl malate was 0.2 mmol/L, then the following process was conducted:
(135) A. a PEDOT:PSS layer was spin coated on an ITO conductive glass;
(136) B. a TFB layer was spin coated on the PEDOT:PSS layer;
(137) C. a CdSe/ZnS quantum dot light-emitting layer was spin coated on the TFB layer;
(138) D. the mixed solution of zinc oxide and sinapoyl malate prepared in the above was deposited on the CdSe/ZnS quantum dot light-emitting layer by spin coating, in which, the spin coating condition was 3000 rpm; and after the spin coating, a film was heated and annealed at 80° C. for 30 min to yield a composite electron transport layer;
(139) E. an Al cathode layer was vapor plated on the composite electron transport layer to obtain the quantum dot light-emitting diode.
Example 6
(140) A quantum dot light-emitting diode was fabricated as follows:
(141) zinc oxide and sinapoyl malate were firstly dissolved in ethanol to yield a mixed solution of zinc oxide and sinapoyl malate, in which, a concentration of zinc oxide was 1 mmol/L, and a concentration of sinapoyl malate was 0.2 mmol/L, then the following process was conducted:
(142) A. the mixed solution of zinc oxide and sinapoyl malate prepared in the above was deposited on an ITO conductive glass by spin coating, in which, the spin coating condition was 1500 rpm; and after the spin coating, a film was heated and annealed at 100° C. for 30 min to yield a composite electron transport layer;
(143) B. a CdSe/ZnS quantum dot light-emitting layer was spin coated on the composite electron transport layer;
(144) C. a TCTA layer was vapor plated on the CdSe/ZnS quantum dot light-emitting layer;
(145) D. an NPB layer is vapor plated on the TCTA layer;
(146) E. a HATCN layer is vapor plated on the NPB layer; and
(147) F. an Al cathode layer is vapor plated on the HATCN layer to yield the quantum dot light-emitting diode.
(148) The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.