CN-119730567-B - Quantum dot light emitting device and display device

CN119730567BCN 119730567 BCN119730567 BCN 119730567BCN-119730567-B

Abstract

The invention discloses a quantum dot light-emitting device and a display device, wherein the quantum dot light-emitting device comprises a cathode, an anode and a light-emitting layer arranged between the cathode and the anode, the light-emitting layer comprises a plurality of layers of quantum dot layers which are arranged in a laminated mode, each layer of quantum dot layer comprises a first quantum dot layer and a second quantum dot layer which are arranged adjacently, and the diameters of quantum dots in the first quantum dot layer are different from those of quantum dots in the second quantum dot layer. Through the scheme, the probability of electric leakage of the quantum dot light-emitting device can be reduced, and the light-emitting efficiency is improved.

Inventors

JIN FENGJIE
YAN ZHIMIN
Jiao Fuxing
SU LIANG

Assignees

云谷（固安）科技有限公司
合肥维信诺科技有限公司

Dates

Publication Date: 20260508
Application Date: 20230927

Claims (12)

1. A quantum dot light emitting device comprising a cathode, an anode, and a light emitting layer disposed between the cathode and the anode; the light-emitting layer comprises a plurality of quantum dot layers which are arranged in a stacked manner, wherein each of the plurality of quantum dot layers comprises a first quantum dot layer and a second quantum dot layer which are arranged adjacently, and the diameters of quantum dots in the first quantum dot layer are different from those of quantum dots in the second quantum dot layer; The first quantum dot layer and the second quantum dot layer are sequentially stacked in the direction that the cathode points to the anode, the diameter of the quantum dots in the first quantum dot layer is smaller than that of the quantum dots in the second quantum dot layer, and the quantum dots in the first quantum dot layer are filled in gaps among the quantum dots in the second quantum dot layer; The quantum dot in the first quantum dot layer is defined as a first quantum dot, the quantum dot in the second quantum dot layer is defined as a second quantum dot, the first quantum dot comprises a first inner core and a first shell layer coating the first inner core, the second quantum dot comprises a second inner core and a second shell layer coating the second inner core, the diameter of the first inner core is equal to that of the second inner core, and the thickness of the first shell layer is smaller than that of the second shell layer.
2. The quantum dot light emitting device according to claim 1, wherein, The number of layers of the quantum dot layers is greater than or equal to three, and the diameters of quantum dots in the plurality of quantum dot layers are increased in the direction that the cathode points to the anode.
3. The quantum dot light emitting device according to claim 2, wherein, The number of layers of the quantum dot layer is less than or equal to five.
4. The quantum dot light emitting device according to claim 1, wherein, And the luminescence peak position of the quantum dots in the first quantum dot layer is the same as the luminescence peak position of the quantum dots in the second quantum dot layer.
5. The quantum dot light emitting device of claim 4, wherein the luminescent peak positions of the quantum dots in the plurality of quantum dot layers are all the same.
6. The quantum dot light emitting device according to claim 1, wherein, The material of the first core/the second core comprises at least one of cadmium selenide CdSe, cadmium zinc selenium CdZnSe, cadmium zinc sulfur CdZnS, zinc selenide ZnSe and indium phosphide InP.
7. The quantum dot light emitting device of claim 6, wherein the material of the first core and the material of the second core are the same.
8. The quantum dot light emitting device according to claim 6, wherein the material of the first shell layer and the material of the second shell layer are the same.
9. The quantum dot light emitting device according to claim 1, wherein, The thickness of the first quantum dot layer is smaller than that of the second quantum dot layer.
10. The quantum dot light emitting device according to claim 1, wherein, An electron transport layer is arranged between the cathode and the light-emitting layer, a hole transport layer and a hole injection layer are arranged between the light-emitting layer and the anode, and the hole transport layer is arranged on one side of the hole injection layer, which is away from the anode.
11. The quantum dot light emitting device according to claim 1, wherein, The first quantum dots form a virtual polygon, the orthographic projection of the first quantum dots at the vertex positions of the virtual polygon at the anode is at least partially overlapped with the orthographic projection of gaps between two adjacent second quantum dots at the anode, and the orthographic projection of the first quantum dots at the central positions of the virtual polygon at the anode is positioned inside the orthographic projection of the second quantum dots at the anode.
12. A display device comprising a quantum dot light emitting device according to any one of claims 1 to 11.

Description

Quantum dot light emitting device and display device Technical Field The invention relates to the technical field of display, in particular to a quantum dot light emitting device and a display device. Background QLED (Quantum dot light emitting diode) is an active light emitting display technology based on the quantum dot electroluminescent principle, has the characteristics of ultra-thin, high color gamut, flexibility, high contrast ratio and the like, can bring about an unparalleled image quality experience, is certainly the most attractive technical direction in quantum dot camping under the eyes, and is also called as the next generation display technology. The QLED works in the principle that under the drive of an applied voltage, holes are injected from an anode, electrons are injected from a cathode, and exciton recombination luminescence is formed in a quantum dot layer. The luminous efficiency and stability of the existing QLED still need to be improved. Disclosure of Invention The invention mainly solves the technical problem of providing a quantum dot light-emitting device and a display device, which reduce the probability of electric leakage and improve the light-emitting efficiency. In order to solve the technical problems, the technical scheme adopted by the invention is that the quantum dot light-emitting device comprises a cathode, an anode and a light-emitting layer arranged between the cathode and the anode, wherein the light-emitting layer comprises a plurality of quantum dot layers which are arranged in a stacked manner, each quantum dot layer comprises a first quantum dot layer and a second quantum dot layer which are arranged adjacently, and the diameters of quantum dots in the first quantum dot layer are different from those of quantum dots in the second quantum dot layer. In order to solve the technical problems, the other technical scheme adopted by the invention is to provide a display device which comprises the quantum dot light emitting device in any embodiment. The quantum dot luminescent device has the advantages that the luminescent layer in the quantum dot luminescent device comprises the adjacent first quantum dot layer and the adjacent second quantum dot layer, the diameters of the quantum dots in the first quantum dot layer and the second quantum dot layer are different, and the two quantum dots with larger diameters are arranged adjacently, so that the quantum dots with smaller diameters can be filled in the gap, the quantum dots in the adjacent quantum dot layers realize self-filling, a denser luminescent layer is formed, on one hand, the probability that holes on one side of the luminescent layer facing an anode pass through the gap of the luminescent layer and are directly transferred to the other side of the luminescent layer is reduced, on the other hand, the problem of leakage current of the quantum dot luminescent device is further reduced, the stability of the luminescent device is improved, on the other hand, the probability that materials on one side of the luminescent layer close to a cathode are filled in the luminescent layer is reduced, the quantum dots are prevented from being blocked from being emitted, and the luminescent efficiency is improved. Drawings Fig. 1 is a schematic structural diagram of an embodiment of a quantum dot light emitting device of the present invention; FIG. 2 is a top view of an embodiment of a light emitting layer of the present invention; Fig. 3 is a schematic structural view of another embodiment of a quantum dot light emitting device of the present invention; fig. 4 is a schematic structural view of another embodiment of the quantum dot light emitting device of the present invention. Detailed Description In order to make the objects, technical solutions and effects of the present invention clearer and more specific, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. The conventional Quantum dot light emitting device generally includes a cathode, an anode, and a Quantum dot light emitting layer disposed between the cathode and the anode, wherein the Quantum dot light emitting layer includes a Quantum Dot (QD) material, and the Quantum dot can emit light with a relatively pure color after being excited. The inventors found that because of the particle nature of the quantum dots, it is difficult to form a dense quantum dot light-emitting layer, so that the material on the side of the light-emitting layer close to the cathode is easily filled in the gaps between the quantum dots, on the one hand, emission of the quantum dots is inhibited, light-emitting effi