Quantum dot light emitting device and preparation method thereof, display device

Abstract

A quantum dot light emitting device, a preparation method thereof, and a display device, the quantum dot light emitting device comprising: a quantum dot light emitting layer and a hole injection layer disposed on one side of the quantum dot light emitting layer, the quantum dot light emitting layer comprising a first surface close to the hole injection layer, and a passivation functional layer disposed on the first surface, the passivation functional layer being configured to modify the first surface.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to, but are not limited to, the technical field of display, and in particular, to a quantum dot light-emitting device, a preparation method thereof, and a display device. BACKGROUND

[0002] Quantum dots, also known as semiconductor nanocrystals, are zero-dimensional nanostructures composed of a small number of atoms, and the size of three dimensions is usually 1-100 nm. Quantum dots have a tunable band gap and a narrow emission spectrum. In recent years, they have been widely used in LED (light-emitting diode) devices. Quantum dot light-emitting diodes have the advantages of self-luminescence, high color purity, low energy consumption, stable images, wide viewing angle range, rich colors, and the like. In recent years, they have been considered as a new generation of display technology after LCD and OLED (organic light-emitting diode), and have broad application prospects.

[0003] A quantum dot light-emitting diode (QLED) is a device in which quantum dots are used as a light-emitting layer. By introducing a light-emitting layer formed of quantum dots between different conductive materials, light of a desired wavelength can be obtained. QLED has a high color gamut, self-luminescence, low starting voltage, fast response speed, and the like, making it have broad application prospects in the fields of display and lighting, and is a current popular research direction. SUMMARY

[0004] The following is an overview of the subject matter of the detailed description of the present disclosure. This overview is not intended to limit the scope of protection of the claims.

[0005] In a first aspect, embodiments of the present disclosure provide a quantum dot light-emitting device, comprising: a quantum dot light-emitting layer and a hole injection layer disposed on one side of the quantum dot light-emitting layer, the quantum dot light-emitting layer comprising a first surface close to the hole injection layer, and a passivation functional layer disposed on the first surface, the passivation functional layer being configured to modify the first surface.

[0006] In an example embodiment, the passivation functional layer comprises at least passivation ions, the passivation ions being configured to bind to the first surface and passivate the first surface.

[0007] In an example embodiment, the passivation functional layer further comprises metal ions, the hole injection layer comprises a second surface close to the quantum dot light-emitting layer, and the metal ions are disposed on one side of the second surface.

[0008] In an example embodiment, the metal ions are closer to the hole injection layer than the passivation ions; and / or, the passivation ions are closer to the quantum dot light-emitting layer than the metal ions.

[0009] In an exemplary embodiment, the passivation ions are halogen ions.

[0010] In an exemplary embodiment, a hole transport layer is further included, the hole transport layer is located between the quantum dot light emitting layer and the hole injection layer, at least part of the hole transport layer is doped together with at least part of the passivation functional layer.

[0011] In an exemplary embodiment, the doping ratio of the hole transport layer to the passivation functional layer is 1:1 to 20:1.

[0012] In an exemplary embodiment, the thickness of the passivation functional layer is 1-20 nm.

[0013] In an exemplary embodiment, a first electrode and a second electrode are further included, the first electrode is located on the side of the hole injection layer away from the quantum dot light emitting layer, and the second electrode is located on the side of the quantum dot light emitting layer away from the hole injection layer.

[0014] In a second aspect, the embodiments of the present disclosure further provide a display device including the foregoing quantum dot light emitting device.

[0015] In a third aspect, the embodiments of the present disclosure further provide a preparation method of a quantum dot light emitting device, including:

[0016] forming a quantum dot light emitting layer;

[0017] forming a passivation functional layer on a first surface of the quantum dot light emitting layer, the passivation functional layer is configured to modify the first surface;

[0018] forming a hole injection layer on the side of the passivation functional layer away from the quantum dot light emitting layer.

[0019] In an exemplary embodiment, forming a passivation functional layer on a first surface of the quantum dot light emitting layer includes:

[0020] forming the passivation functional layer by a metal halide on the first surface of the quantum dot light emitting layer through an evaporation process.

[0021] In an exemplary embodiment, forming a passivation functional layer on a first surface of the quantum dot light emitting layer includes:

[0022] forming the passivation functional layer by a metal halide, forming the hole transport layer by a hole transport material, and doping at least part of the passivation functional layer together with at least part of the hole transport layer on the first surface of the quantum dot light emitting layer through the same evaporation process.

[0023] Other aspects can become apparent upon reading and understanding the following detailed description with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Structure of quantum dot light emitting device of the embodiment of the present application Figure 1 ;

[0025] Figure 2 Structure of quantum dot light emitting device of the embodiment of the present application after power on Figure 1 ;

[0026] Figure 3 Structure of quantum dot light emitting device of the embodiment of the present application after the passivation ions are combined with the first surface

[0027] Figure 4 Structure of quantum dot light emitting device of the embodiment of the present application Figure 2 ;

[0028] Figure 5 Structure of quantum dot light emitting device of the embodiment of the present application after power on Figure 2 ;

[0029] Figure 6 Current density and voltage linear graph of quantum dot light emitting device of the embodiment of the present application

[0030] Figure 7 Structure of quantum dot light emitting device of the embodiment of the present application Figure 3 ;

[0031] Figure 8 Structure of quantum dot light emitting device of the embodiment of the present application Figure 4 . DETAILED DESCRIPTION

[0032] Embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the embodiments can be implemented in various different forms. It is readily apparent to those skilled in the art that the modes and contents can be variously changed without departing from the gist of the present disclosure and the scope thereof. Thus, the present disclosure should not be construed as being limited to the contents described in the following embodiments. The embodiments in the present disclosure and the features in the embodiments can be arbitrarily combined with each other as long as they are not inconsistent with each other.

[0033] In this specification, the words "center", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like used to indicate the positional relationship of the components in the description with reference to the drawings are used only for the convenience of describing this specification and simplifying the description, and do not indicate or imply that the referred device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present disclosure. The positional relationship of the components is appropriately changed according to the direction of describing each component. Therefore, it is not limited to the words described in the specification, and can be appropriately replaced according to the situation.

[0034] In this specification, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection" should be broadly understood. For example, it can be fixedly connected, or detachably connected, or integrally connected; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate, or the communication inside two elements. For those skilled in the art, the meaning of the above terms in this disclosure can be understood according to the situation.

[0035] In this disclosure, "about" means not strictly limited boundaries, allowing values within the range of process and measurement errors.

[0036] Through the research of the present inventor, it is found that the contact interface between the quantum dot light-emitting layer and other functional layers is one of the factors affecting the performance of the quantum dot device. The main performance is that the functional layer material quenches the quantum dot, or does not match the quantum dot material, such as energy level mismatch, mobility mismatch, etc.

[0037] In the related art, the method for improving the stability of quantum dot material includes changing the core-shell structure of quantum dot, introducing new quantum dot ligand, etc. The improvement of hole injection ability includes selecting hole transport material with energy level matching. However, these methods all have certain problems, such as the modification engineering of quantum dots is relatively complex, and the process controllability is poor; there are few hole transport materials matching the energy level of quantum dots, etc.

[0038] Figure 1 The structure diagram of the quantum dot light-emitting device of the embodiment of the present application is shown in the figure. Figure 1As shown, the quantum dot light-emitting device of this invention includes a substrate 10, a second electrode 11, an electron transport layer 12 (ETL), a quantum dot emitting layer 13 (QD EML), a passivation functional layer 14, a hole transport layer 15 (HTL), a hole injection layer 16 (HIL), and a first electrode 17, which are stacked sequentially. The first electrode 17 is the anode, and the second electrode 11 is the cathode. The thickness of the hole transport layer 15 can be 5 nm to 50 nm; the thickness of the hole injection layer 16 can be 5 nm to 50 nm; the thickness of the quantum dot emitting layer 13 can be 10 nm to 60 nm; and the thickness of the passivation functional layer 14 can be 1 nm to 20 nm.

[0039] In an exemplary embodiment, the quantum dot light-emitting layer 13 includes a first surface 131 near the hole injection layer 16, and a passivation functional layer 14 is disposed on the first surface 131, with the surface of the passivation functional layer 14 near the quantum dot light-emitting layer 13 in at least partial contact with the first surface 131. When the quantum dot light-emitting device of this embodiment emits light, the passivation functional layer 14 is configured to modify the first surface 131, passivate defects in the first surface 131, and stabilize the quantum dot light-emitting layer 13.

[0040] Figure 2 This is a schematic diagram of the structure of the quantum dot light-emitting device after it is powered on, according to an embodiment of the present invention. Figure 1 In an exemplary implementation, such as Figure 2 As shown, the passivation functional layer 14 includes at least passivation ions 141, which are configured to bind to the first surface 131 of the quantum dot light-emitting layer 13, passivating defects on the first surface 131. When the quantum dot light-emitting device of this embodiment emits light, the passivation ions 141 bind to the first surface 131 of the quantum dot light-emitting layer 13 under the action of an electric field, passivating defects on the first surface 131, and significantly improving the thermal stability of the passivated quantum dot light-emitting layer 13. Compared to a quantum dot light-emitting device without passivation, the temperature tolerance of the quantum dot light-emitting device of this embodiment is improved by 20 degrees Celsius.

[0041] In an exemplary embodiment, passivation ions 141 can bind to the first surface 131 via dangling bonds on the quantum dots of the first surface 131 of the quantum dot light-emitting layer 13; and / or, passivation ions 141 can adsorb onto the quantum dots of the first surface 131 of the quantum dot light-emitting layer 13; and / or, passivation ions 141 can enter the shallow layer inside the quantum dot light-emitting layer 13 near the hole injection layer 16 and bind to the first surface 131 of the quantum dot light-emitting layer 13.

[0042] Figure 3 This is a schematic diagram of the structure of a quantum dot light-emitting device after passivation ions have bonded to the first surface, according to an embodiment of the present invention. In an exemplary embodiment, such as... Figure 3 As shown, taking chloride ions as an example, when the quantum dot light-emitting device of this embodiment emits light, the passivation ions 141 combine with the quantum dots on the first surface 131 of the quantum dot light-emitting layer 13 under the action of the electric field. Compared with long-chain ligands such as oleic acid on the surface of the quantum dots, the passivation ions 141 can better passivate the defects of the first surface 131.

[0043] In an exemplary implementation, such as Figure 2 As shown, the passivation functional layer 14 also includes metal ions 142, and the hole injection layer 16 includes a second surface 151 near the side of the quantum dot light-emitting layer 14. When the quantum dot light-emitting device of this embodiment emits light, the metal ions 142 move towards the second surface 151 of the hole injection layer 16 under the action of the electric field, and the metal ions 142 are disposed on one side of the second surface 151 of the hole transport layer 15. Since the carrier mobility of the metal ions 142 is higher than that of the hole injection layer 16, the interface performance between the quantum dot light-emitting layer 13 and the hole injection layer 16 is improved, thereby increasing the hole injection and transport rate of the quantum dot light-emitting device.

[0044] In an exemplary embodiment, when the quantum dot light-emitting device of the present invention is powered on and emits light, the metal ions 142 in the passivation functional layer 14 are closer to the hole injection layer 16 than the passivation ions 141, so that more metal ions 142 can be disposed on one side of the second surface 151 of the hole transport layer 15; and / or, the passivation ions 141 in the passivation functional layer 14 are closer to the quantum dot light-emitting layer 13 than the metal ions 142, so that more passivation ions 141 can combine with the quantum dots on the first surface 131 of the quantum dot light-emitting layer 13.

[0045] In an exemplary embodiment, the passivation functional layer 14 material can be a metal halide, such as ferric chloride or zinc chloride. The passivation ions 141 in the passivation functional layer 14 can be halide ions, such as fluoride ions, chloride ions, bromide ions, iodide ions, or astatine ions. The metal ions 142 in the passivation functional layer 14 can be iron ions, zinc ions, or aluminum ions. After the halide ions combine with the first surface 131 of the quantum dot light-emitting layer 13, they passivate the defects on the first surface 131 of the quantum dot light-emitting layer 13, making the quantum dot light-emitting layer 13 more stable. The metal ions 142 are disposed on one side of the second surface 151 of the hole transport layer 15, modifying the second surface 151 of the hole transport layer 15, improving the interface performance between the quantum dot light-emitting layer 13 and the hole transport layer 15, and enhancing the ability to inject holes into the quantum dot light-emitting layer 13.

[0046] In an exemplary embodiment, the quantum dot light-emitting layer 13 binds to passivation ions 141 only on the side away from the electron transport layer 12 and close to the passivation functional layer 14, thereby selectively improving the hole injection performance of the quantum dot light-emitting layer 13 on the side close to the hole injection layer 16.

[0047] In an exemplary embodiment, the quantum dot light-emitting device of this invention can be top-emitting, with the first electrode 17 being a transparent conductive electrode, which can be a metal nanowire, indium tin oxide (ITO), thin silver, thin aluminum, etc. Alternatively, the quantum dot light-emitting device of this invention can be bottom-emitting. The second electrode 11 is a transparent conductive electrode, which can be a metal nanowire, indium tin oxide (ITO), thin silver, thin aluminum, etc.

[0048] In the quantum dot light-emitting device of this invention, the electron transport layer 12 receives electrons from the cathode and can transfer the supplied electrons to the quantum dot light-emitting layer. The electron transport layer 12 also facilitates electron transport. The material of the electron transport layer 12 can be azo compound nanoparticles (AZO-NPs), zinc oxide magnesium alloy nanoparticles (ZMO-NPs), zinc oxide nanoparticles (ZnO-NPs), sputtered zinc oxide non-nanoparticles, and zinc oxide aluminum alloy nanoparticles. However, the exemplary embodiments of this application are not limited thereto.

[0049] In the quantum dot light-emitting device of this embodiment of the invention, the quantum dot light-emitting layer 13 is used for emitting light. The material of the quantum dot light-emitting layer 13 can be selected from binary quantum dots, ternary quantum dots, or quaternary quantum dots, etc., and is not limited thereto. For example, binary quantum dots are selected from CdS, CdSe, CdTe, InP, AgS, PbS, PbSe, or HgS, etc., and are not limited thereto; ternary quantum dots are selected from ZnCdS, CuInS, ZnCdSe, ZnSeS, ZnCdTe, or PbSeS, etc., and are not limited thereto; quaternary quantum dots are selected from ZnCdS / ZnSe, CuInS / ZnS, ZnCdSe / ZnS, CuInSeS, or ZnCdTe / ZnS, PbSeS / ZnS, etc., and are not limited thereto.

[0050] In the quantum dot light-emitting device of this invention, the hole transport layer 15 can promote hole transport. The material of the hole transport layer 15 can be selected from organic materials with hole transport capabilities, including but not limited to poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB), polyvinylcarbazole (PVK), poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine) (poly-TPD), poly(9,9-dioctylfluorene-co-bis-N,N-phenyl-1,4-phenylenediamine) (PFB), 4,4',4'-tris(carbazole-9-yl)triphenylamine (TCTA), 4,4'-bis(9-carbazole)biphenyl (CBP), N,N'-diphenyl- N,N'-Di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), doped graphene, undoped graphene, and C60 are selected as one or more. The hole transport layer 15 may also be selected from inorganic materials with hole transport capability, including but not limited to one or more of doped or undoped MoOx, VOx, WOx, CrOx, CuO, MoS2, MoSe2, WS2, WSe2, and CuS, but the exemplary embodiments of this application are not limited thereto.

[0051] In the quantum dot light-emitting device of this invention, the hole injection layer 16 can promote hole injection. The materials of the hole injection layer 16 include, but are not limited to, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), copper phthalocyanine (CuPc), 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinone-dimethane (F4-TCNQ), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene (HATCN), polythiophene (PTT) doped with perfluoroethylene-perfluoroether sulfonic acid (PFFSA), transition metal oxides, and metal chalcogenides. Preferably, the transition metal oxides include one or more of MoO3, VO2, WO3, CrO3, and CuO, and the metal chalcogenides include one or more of MoS2, MoSe2, WS2, WSe2, and CuS. However, the exemplary embodiments of this application are not limited thereto.

[0052] In the quantum dot light-emitting device of this embodiment of the invention, the first electrode 17 is the anode, and the first electrode 17 comprises an oxide material, a metal material, or a composite material of an oxide and a metal. For example, the oxide material includes, but is not limited to, at least one or more of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium gallium oxide (IGO), zinc gallium oxide (GZO), indium gallium zinc oxide (IGZO), indium oxide (In2O3), zinc aluminum oxide (AZO), magnesium-doped zinc oxide (MZO), aluminum-doped magnesium oxide (AMO), antimony-doped tin oxide (ATO), fluorine-doped tin dioxide (FTO), and fluorine-phosphorus co-doped tin dioxide (FPTO). However, the exemplary embodiments of this application are not limited thereto.

[0053] In the quantum dot light-emitting device of this invention, the second electrode 11 is a cathode, and the second electrode 11 comprises an oxide material, a metal material, or a composite material of an oxide and a metal. For example, the oxide material includes, but is not limited to, at least one or more of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium gallium oxide (IGO), zinc gallium oxide (GZO), indium gallium zinc oxide (IGZO), indium oxide (In₂O₃), zinc aluminum oxide (AZO), magnesium-doped zinc oxide (MZO), aluminum-doped magnesium oxide (AMO), antimony-doped tin oxide (ATO), fluorine-doped tin dioxide (FTO), and fluorine-phosphorus co-doped tin dioxide (FPTO). However, the exemplary embodiments of this application are not limited thereto.

[0054] like Figure 1 As shown, the fabrication process of the quantum dot light-emitting device in this embodiment includes:

[0055] (1) A substrate material is coated onto a glass substrate and cured to form a film, thereby forming a substrate 10. A second electrode 11 is then formed on the substrate 10. In this embodiment of the invention, the substrate 10 can be a rigid substrate or a flexible substrate. The rigid substrate includes, but is not limited to, one or more of glass, metal foil, or ceramic materials. The flexible substrate can be made of materials such as polyimide (PI), polyethylene terephthalate (PET), or a surface-treated polymer film.

[0056] (2) A 30 nm thick electron transport layer material film is spin-coated on the second electrode 11 by spin coating process, and then annealed at a temperature between 10 and 50 degrees to form an electron transport layer 12; wherein the spin coating speed is 1000-4000 r / min and the spin coating time is 10-50 seconds.

[0057] (3) A 20 nm thick quantum dot light-emitting layer material film is spin-coated on the electron transport layer 12 by spin coating process, and then annealed at a temperature between 100 and 200 degrees to form a quantum dot light-emitting layer 13; wherein the spin coating speed is 1000-5000 r / min.

[0058] (4) A passivation functional layer 14 with a thickness of 1 to 20 nm is formed on the first surface 131 of the quantum dot light-emitting layer 13 by vapor deposition process; wherein, the passivation functional layer 14 may be a metal halide.

[0059] (5) A hole transport material film is spin-coated on the passivation functional layer 14 by spin coating process, and then annealed at a temperature between 80 degrees and 200 degrees to form a hole transport layer 15; wherein the spin coating speed is 1000-5000 r / min.

[0060] (6) A hole injection material film is spin-coated on the hole transport layer 15 by spin coating process, and then annealed at a temperature between 100 degrees and 250 degrees to form a hole injection layer 16; wherein the spin coating speed is 1000-5000 r / min.

[0061] As can be seen from the structure of the quantum dot light-emitting device in this embodiment of the invention and the above-described fabrication process, the quantum dot light-emitting device provided in this embodiment of the invention passivates the defects on the first surface 131 of the quantum dot light-emitting layer 13 by using the passivation functional layer 14. The thermal stability of the quantum dot light-emitting layer 13 is significantly improved after passivation. Furthermore, by modifying the second surface 151 of the hole transport layer 15 by the passivation functional layer 14, the interface performance between the quantum dot light-emitting layer 13 and the hole transport layer 15 is improved, thereby enhancing the ability to inject holes into the quantum dot light-emitting layer 13.

[0062] The quantum dot light-emitting device fabrication process of this invention can be achieved using existing mature fabrication equipment with minimal modifications to existing processes. It is well compatible with existing fabrication processes and has advantages such as simple process implementation, high production efficiency, low production cost, and high yield, thus showing good application prospects.

[0063] Figure 4 This is a schematic diagram of the structure of a quantum dot light-emitting device according to an embodiment of the present invention. Figure 2 In an exemplary implementation, such as Figure 4 As shown, the hole transport layer 15 is located between the quantum dot light-emitting layer 13 and the hole injection layer 16, and at least a portion of the hole transport layer 15 is doped together with at least a portion of the passivation functional layer 14. For example, the passivation functional layer 14 and the hole transport layer 15 are partially or completely doped together using the same vapor deposition process. By doping the passivation functional layer 14 and the hole transport layer 15 together in this embodiment of the invention, the thickness of the quantum dot light-emitting device can be reduced, the manufacturing process simplified, and production efficiency improved.

[0064] In an exemplary implementation, such as Figure 4 As shown, the hole transport layer 15 includes a first sub-hole transport layer 18 and a second sub-hole transport layer 19 stacked together. The first sub-hole transport layer 18 is located on the side of the hole transport layer 15 closer to the quantum dot light-emitting layer 13, and the second sub-hole transport layer 19 is located on the side of the hole transport layer 15 away from the quantum dot light-emitting layer 13. The first sub-hole transport layer 18 and the passivation functional layer 14 are doped together using the same vapor deposition process to form a doped film. The surface of the doped film near the second sub-hole transport layer 19 is in at least partial contact with the second sub-hole transport layer 19; the surface of the doped film near the quantum dot light-emitting layer 13 is also in at least partial contact with the quantum dot light-emitting layer 13.

[0065] In an exemplary embodiment, the first sub-hole transport layer 18 and the second sub-hole transport layer 19 may use the same hole transport material or different hole transport materials. This embodiment of the present invention does not impose any limitations on this.

[0066] Figure 5 This is a schematic diagram of the structure of the quantum dot light-emitting device after it is powered on, according to an embodiment of the present invention. Figure 2 In an exemplary implementation, such as Figure 5As shown, the passivation functional layer 14 includes passivation ions 141 and metal ions 142. When the quantum dot light-emitting device of this embodiment emits light, in the doped film layer where the hole transport layer 15 and the passivation functional layer 14 are doped together, the passivation ions 141 move to the first surface 131 of the quantum dot light-emitting layer 13 under the action of an electric field. The passivation ions 141 are configured to combine with the first surface 131 of the quantum dot light-emitting layer 13, passivating defects on the first surface 131 of the quantum dot light-emitting layer 13. The thermal stability of the passivated quantum dot light-emitting layer 13 is significantly improved. The metal ions 142 move to the second surface 151 of the hole transport layer 15 under the action of an electric field. The metal ions 142 are disposed on one side of the second surface 151 of the hole transport layer 15, modifying the second surface 151 of the hole transport layer 15, improving the interface performance between the quantum dot light-emitting layer 13 and the hole transport layer 15, and improving the hole injection and transport capabilities of the quantum dot light-emitting layer 13.

[0067] In an exemplary embodiment, in the doped film layer where the hole transport layer 15 and the passivation functional layer 14 are doped together, the doping ratio of the hole transport layer 15 to the passivation functional layer 14 is from 1:1 to 20:1. By adjusting the doping ratio of the hole transport layer 15 to the passivation functional layer 14, the hole injection and transport capabilities can be significantly improved.

[0068] Figure 6This is a line graph showing the current density versus voltage of a quantum dot light-emitting device according to an embodiment of the present invention. The quantum dot light-emitting device includes a substrate 10, a second electrode 11, an electron transport layer 12, a quantum dot light-emitting layer 13, a passivation functional layer 14, a hole transport layer 15, a hole injection layer 16, and a first electrode 17, which are stacked sequentially. The electron transport layer 12 is made of zinc oxide nanoparticles (ZnO-NPs) and has a thickness of 30 nm; the quantum dot light-emitting layer 13 is made of CdS and has a thickness of 20 nm; the passivation functional layer 14 is made of ferric chloride; and the hole transport layer 15 is made of an organic material with hole transport capability. The hole transport layer 15 includes a first sub-hole transport layer 18 and a second sub-hole transport layer 19, which are stacked together. The first sub-hole transport layer 18 is located on the side of the hole transport layer 15 closer to the quantum dot light-emitting layer 13, and the second sub-hole transport layer 19 is located on the side of the hole transport layer 15 away from the quantum dot light-emitting layer 13. The first sub-hole transport layer 18 and the passivation functional layer 14 are doped together using the same vapor deposition process to form a doped film with a thickness of 20 nm; the hole injection layer 16 is made of organic material and has a thickness of 5 nm. In Experiment 1, the doping ratio of hole transport layer 15 (HTL) to passivation functional layer 14 (FeCl3) in the controlled doped film was 20:1; in Experiment 2, the doping ratio of hole transport layer 15 (HTL) to passivation functional layer 14 (FeCl3) in the controlled doped film was 20:2; in Experiment 3, the doping ratio of hole transport layer 15 (HTL) to passivation functional layer 14 (FeCl3) in the controlled doped film was 20:3; in Experiment 4, the doping ratio of hole transport layer 15 (HTL) to passivation functional layer 14 (FeCl3) in the controlled doped film was 20:4; in Experiment 5, the doping ratio of hole transport layer 15 (HTL) to passivation functional layer 14 (FeCl3) in the controlled doped film was 20:6; and in Experiment 6, the passivation functional layer 14 (FeCl3) was not doped in the doped film. An electrification experiment was conducted on Experiments 1 to 6 above, and the current density of the quantum dot light-emitting devices was measured at voltages ranging from 2V to 8V. The experimental results are as follows: Figure 6 As shown.

[0069] The experimental results show that the current density of the quantum dot light-emitting device in Experiment 6 is approximately 10 mA / cm² at 5V. 2 As the FeCl3 doping ratio decreases, the current density of the quantum dot light-emitting device increases at the same voltage, indicating that FeCl3 doping can increase the current of the quantum dot light-emitting device and reduce the interfacial voltage drop of the film at the same voltage. The increased current at the same voltage indicates that more charge carriers are injected.

[0070] Figure 7This is a schematic diagram of the structure of a quantum dot light-emitting device according to an embodiment of the present invention. Figure 3 In an exemplary implementation, such as Figure 7 As shown, the hole transport layer 15 and the passivation functional layer 14 are doped together using the same vapor deposition process to form a doped film. The surface of the doped film near the hole injection layer 16 is in at least partial contact with the hole injection layer 16; the surface of the doped film near the quantum dot light-emitting layer 13 is in at least partial contact with the quantum dot light-emitting layer 13. This embodiment of the invention, by doping the passivation functional layer 14 and the hole transport layer 15 together, can reduce the thickness of the quantum dot light-emitting device, simplify the manufacturing process, and improve production efficiency.

[0071] Figure 8 This is a schematic diagram of the structure of a quantum dot light-emitting device according to an embodiment of the present invention. Figure 4 In an exemplary implementation, such as Figure 8 As shown, the quantum dot light-emitting device of this embodiment can adopt an upright structure. The quantum dot light-emitting device of this embodiment includes a substrate 10, a second electrode 11, a hole injection layer 16 (HIL), a hole transport layer 15 (HTL), a passivation functional layer 14, a quantum dot emitting layer 13 (QD EML), an electron transport layer 12 (ETL), and a first electrode 17, which are stacked sequentially.

[0072] This invention also provides a display device, including any of the quantum dot light-emitting devices described above. This display device includes mobile phones, tablet computers, smart wearable products (such as smartwatches, bracelets, etc.), personal digital assistants (PDAs), in-vehicle computers, etc. This application does not impose any special limitations on the specific form of the above-described foldable display device.

[0073] This invention also provides a method for fabricating a quantum dot light-emitting device, comprising:

[0074] Forming a quantum dot light-emitting layer;

[0075] A passivation functional layer is formed on the first surface of the quantum dot light-emitting layer, the passivation functional layer being configured to modify the first surface;

[0076] A hole transport layer is formed on the side of the passivation functional layer away from the quantum dot light-emitting layer.

[0077] In an exemplary embodiment, a passivation functional layer is formed on the first surface of the quantum dot light-emitting layer, including:

[0078] The passivation functional layer is formed on the first surface of the quantum dot light-emitting layer by means of a vapor deposition process, where metal halides are deposited.

[0079] In an exemplary embodiment, a passivation functional layer is formed on the first surface of the quantum dot light-emitting layer, including:

[0080] Using the same vapor deposition process, a metal halide is formed on the first surface of the quantum dot light-emitting layer to form the passivation functional layer, a hole transport material is formed on the hole transport layer, and at least a portion of the passivation functional layer is doped together with at least a portion of the hole transport layer.

[0081] The method for fabricating quantum dot light-emitting devices according to embodiments of the present invention can form a passivation functional layer on any surface of the quantum dot light-emitting layer through a vapor deposition process, thereby selectively improving the surface performance of the quantum dot light-emitting layer.

[0082] The method for fabricating quantum dot light-emitting devices according to embodiments of the present invention forms a passivation functional layer through a vapor deposition process. This method eliminates the need to introduce solvents during the preparation of the passivation functional layer, thereby avoiding the influence of solvents on the morphology of the quantum dot light-emitting layer. Furthermore, the thickness of the introduced passivation functional layer can be precisely controlled through the vapor deposition process, resulting in good film formation properties.

[0083] The accompanying drawings in this disclosure only illustrate the structures relevant to this disclosure; other structures can be referenced to common designs. Unless otherwise specified, embodiments of this disclosure, i.e., features within the embodiments, can be combined with each other to obtain new embodiments.

[0084] Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions disclosed herein without departing from the spirit and scope of the technical solutions disclosed herein, and all such modifications and substitutions should be covered within the scope of the claims of this disclosure.

Claims

1. A quantum dot light-emitting device, characterized in that, include: The system comprises a quantum dot emitting layer and a hole injection layer disposed on one side of the quantum dot emitting layer. The quantum dot emitting layer includes a first surface near the hole injection layer. A passivation functional layer is disposed between the quantum dot emitting layer and the hole injection layer. The passivation functional layer is made of a metal halide and is configured to modify the first surface. The passivation functional layer includes at least passivation ions configured to bind to the first surface and passivate it. The passivation ions are halogen ions. The passivation functional layer also includes metal ions. The hole injection layer includes a second surface near the quantum dot emitting layer. The metal ions are disposed on one side of the second surface and are configured to improve the interfacial properties between the quantum dot emitting layer and the hole injection layer. The metal ions are closer to the hole injection layer than the passivation ions. And / or, the passivation ions are closer to the quantum dot emitting layer than the metal ions.

2. The quantum dot light-emitting device according to claim 1, characterized in that, It also includes a hole transport layer located between the quantum dot luminescent layer and the hole injection layer, wherein at least a portion of the hole transport layer is doped together with at least a portion of the passivation functional layer.

3. The quantum dot light-emitting device according to claim 2, characterized in that, The doping ratio of the hole transport layer to the passivation functional layer is from 1:1 to 20:

1.

4. The quantum dot light-emitting device according to any one of claims 1 to 3, characterized in that, The thickness of the passivation functional layer is 1-20 nm.

5. The quantum dot light-emitting device according to any one of claims 1 to 3, characterized in that, It also includes a first electrode and a second electrode, wherein the first electrode is located on the side of the hole injection layer away from the quantum dot light-emitting layer, and the second electrode is located on the side of the quantum dot light-emitting layer away from the hole injection layer.

6. A display device, characterized in that, Includes the quantum dot light-emitting device as described in any one of claims 1 to 5.

7. A method for fabricating a quantum dot light-emitting device, characterized in that, include: Forming a quantum dot light-emitting layer; A passivation functional layer is formed on the first surface of the quantum dot light-emitting layer, the passivation functional layer being configured to modify the first surface; A hole injection layer is formed on the side of the passivation functional layer away from the quantum dot light-emitting layer; The passivation functional layer is made of a metal halide and includes at least passivation ions configured to bind to the first surface and passivate it. The passivation ions are halogen ions. The passivation functional layer also includes metal ions. The hole injection layer includes a second surface near the quantum dot light-emitting layer. The metal ions are disposed on one side of the second surface and configured to improve the interface performance between the quantum dot light-emitting layer and the hole injection layer. The metal ions are closer to the hole injection layer than the passivation ions. And / or, the passivation ions are closer to the quantum dot light-emitting layer than the metal ions.

8. The method for fabricating a quantum dot light-emitting device according to claim 7, characterized in that, A passivation functional layer is formed on the first surface of the quantum dot light-emitting layer, comprising: The passivation functional layer is formed on the first surface of the quantum dot light-emitting layer by means of a vapor deposition process, where metal halides are deposited.

9. The method for fabricating a quantum dot light-emitting device according to claim 7, characterized in that, A passivation functional layer is formed on the first surface of the quantum dot light-emitting layer, comprising: Using the same vapor deposition process, a metal halide is formed on the first surface of the quantum dot light-emitting layer to form the passivation functional layer, a hole transport material is formed to form the hole transport layer, and at least a portion of the passivation functional layer is doped together with at least a portion of the hole transport layer.

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