Quantum dot light emitting device and manufacture method thereof and liquid crystal display device

• US 9,978,972 B2
• Filed: 04/20/2016
• Issued: 05/22/2018
• Est. Priority Date: 03/25/2016
• Status: Active Grant

• Current Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Original Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Inventors: Xu, Chao
• Primary Examiner(s): AHMED, SELIM U
• Application Number:
  US15/039,426
• Publication Number:
  US 20180083214A1
• Time in Patent Office: 762 Days
• CPC Class Codes: G02F 1/1336 Illuminating devices
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: G02F 2201/44 Arrangements combining different electro-active layers, e.g. electrochromic, liquid crystal or electroluminescent layers
• CPC Class Codes: H10K 2102/00 Constructional details relating to the organic devices covered by this subclass
• CPC Class Codes: H10K 2102/103 comprising indium oxides, e.g. ITO
• CPC Class Codes: H10K 2102/3023 Direction of light emission
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/115 comprising active inorganic nanostructures, e.g. luminescent quantum dots
• CPC Class Codes: H10K 50/13 comprising stacked EL layers within one EL unit
• CPC Class Codes: H10K 50/15 Hole transporting layers
• CPC Class Codes: H10K 50/16 Electron transporting layers
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/82 Cathodes
• CPC Class Codes: H10K 50/822 characterised by their shape
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass
• CPC Class Codes: H10K 85/1135 Polyethylene dioxythiophene [PEDOT]; Derivatives thereof

Abstract

A quantum dot light emitting device includes a base plate and an anode, a hole transportation layer, a light emissive layer, an electron transportation layer, and a cathode arranged on the same side of the base plate. The anode and the cathode are opposite to and spaced from each other and receive the hole transportation layer, the light emissive layer, and the electron transportation layer to be interposed therebetween. The hole transportation layer is connected to the anode. The light emissive layer and the electron transportation layer are sequentially stacked on the hole transportation layer that is distant from the anode. The electron transportation layer is connected to the cathode. The light emissive layer includes a quantum dot light emitting material and a small-molecule organic light emitting material, which is filled in gaps present in the quantum dot light emitting material.

Claims

1. A quantum dot light emitting device, comprising a base plate, an anode, a hole transportation layer, a light emissive layer, an electron transportation layer, and a cathode, the anode, the hole transportation layer, the light emissive layer, the electron transportation layer and the cathode being arranged on the same side of the base plate, the anode and the cathode being opposite to and spaced from each other, the hole transportation layer, the light emissive layer, and the electron transportation layer being interposed between the anode and the cathode, a surface of the hole transportation layer being connected to the anode, the light emissive layer and the electron transportation layer being sequentially stacked on a surface of the hole transportation layer that is distant from the anode, a surface of the electron transportation layer that is distant from the light emissive layer being connected to the cathode, the anode supplying holes, the hole transportation layer transporting the holes to the light emissive layer, the cathode supplying electrons, the electron transportation layer transporting the electrons to the light emissive layer, the holes and the electrons being re-combined in the light emissive layer to emit light, wherein the light emissive layer comprises a quantum dot light emitting material and a small-molecule organic light emitting material, the small-molecule organic light emitting material being filled in gaps present in the quantum dot light emitting material;

wherein the light emissive layer comprises a first sub light emissive layer that is formed of a mixture of multiple materials comprising the quantum dot light emitting material and the small-molecule organic light emitting material and a second sub light emissive layer that is formed of a signal substance comprising only the small-molecule organic light emitting material, the second sub light emissive layer being deposited on the first sub light emissive layer to allow the small-molecule organic light emitting material to penetrate into gaps present in the quantum dot light emitting material of the first sub light emissive layer to form the mixture of multiple materials.

2. The quantum dot light emitting device as claimed in claim 1, wherein a surface of the anode that is distant from the hole transportation layer is disposed on the base plate, the anode being a transparent electrode, the cathode being a metal electrode, light generated by the re-combination of the holes and the electrons in the light emissive layer being projected out through a surface of the base plate that is distant from the anode.

3. The quantum dot light emitting device as claimed in claim 2, wherein the anode comprises indium tin oxide (ITO) and the cathode comprises aluminum (Al).

4. The quantum dot light emitting device as claimed in claim 3, wherein the cathode has a thickness of 100-150 nm.

5. The quantum dot light emitting device as claimed in claim 1, wherein a surface of the cathode that is distant from the electron transportation layer is disposed on the base plate, the cathode being a transparent electrode, the anode being a metal electrode, the light generated by the re-combination of the holes and the electrons in the light emissive layer being projected out through a surface of the base plate that is distant from the cathode.

6. The quantum dot light emitting device as claimed in claim 1, wherein a surface of the first sub light emissive layer that is opposite to the second sub light emissive layer is in contact engagement with a surface of the hole transportation layer that is distant from the anode, and a surface of the second sub light emissive layer that is opposite to the first sub light emissive layer is in contact engagement with a surface of the electron transportation layer that is distant from the cathode.

7. The quantum dot light emitting device as claimed in claim 1, wherein the hole transportation layer comprises poly(3,4-ethylenedioxythiophene):

poly styrenesulfonate (PEDOT;

PSS) or P-type metal oxide nanometer particle, wherein the P-type metal oxide nanometer particle comprises one or multiple ones of MoO₃, NiO, V₂O₅, and WO3.

8. The quantum dot light emitting device as claimed in claim 1, wherein the hole transportation layer has a thickness of 40 nm.

9. A manufacture method of a quantum dot light emitting device, comprising:

providing a base plate and forming an anode on a surface of the base plate;

coating a hole transportation material on a surface of the anode that is distant from the base plate to form a hole transportation layer;

depositing a quantum dot light emitting material on a surface of the hole transportation layer that is distant from the anode;

depositing a small-molecule organic light emitting material on a surface of the quantum dot light emitting material that is distant from the hole transportation layer such that the small-molecule organic light emitting material fills in gaps present in the quantum dot light emitting material to form a light emissive layer;

coating an electron transportation material on a surface of the light emissive layer that is distant from the hole transportation layer to form an electron transportation layer; and

forming a cathode on a surface of the electron transportation layer that is distant from the light emissive layer;

wherein the light emissive layer comprises a first sub light emissive layer that is formed of a mixture of multiple materials comprising the quantum dot light emitting material and the small-molecule organic light emitting material and a second sub light emissive layer that is formed of a signal substance comprising only the small-molecule organic light emitting material, the second sub light emissive layer being deposited on the first sub light emissive layer to allow the small-molecule organic light emitting material to penetrate into gaps present in the quantum dot light emitting material of the first sub light emissive layer to form the mixture of multiple materials.

10. A liquid crystal display device, comprising a quantum dot light emitting device, the quantum dot light emitting device comprising a base plate, an anode, a hole transportation layer, a light emissive layer, an electron transportation layer, and a cathode, the anode, the hole transportation layer, the light emissive layer, the electron transportation layer and the cathode being arranged on the same side of the base plate, the anode and the cathode being opposite to and spaced from each other, the hole transportation layer, the light emissive layer, and the electron transportation layer being interposed between the anode and the cathode, a surface of the hole transportation layer being connected to the anode, the light emissive layer and the electron transportation layer being sequentially stacked on a surface of the hole transportation layer that is distant from the anode, a surface of the electron transportation layer that is distant from the light emissive layer being connected to the cathode, the anode supplying holes, the hole transportation layer transporting the holes to the light emissive layer, the cathode supplying electrons, the electron transportation layer transporting the electrons to the light emissive layer, the holes and the electrons being re-combined in the light emissive layer to emit light, wherein the light emissive layer comprises a quantum dot light emitting material and a small-molecule organic light emitting material, the small-molecule organic light emitting material being filled in gaps present in the quantum dot light emitting material;

wherein the light emissive layer comprises a first sub light emissive layer that is formed of a mixture of multiple materials comprising the quantum dot light emitting material and the small-molecule organic light emitting material and a second sub light emissive layer that is formed of a signal substance comprising only the small-molecule organic light emitting material, the second sub light emissive layer being deposited on the first sub light emissive layer to allow the small-molecule organic light emitting material to penetrate into gaps present in the quantum dot light emitting material of the first sub light emissive layer to form the mixture of multiple materials.

11. The liquid crystal display device as claimed in claim 10, wherein a surface of the anode that is distant from the hole transportation layer is disposed on the base plate, the anode being a transparent electrode, the cathode being a metal electrode, light generated by the re-combination of the holes and the electrons in the light emissive layer being projected out through a surface of the base plate that is distant from the anode.

12. The liquid crystal display device as claimed in claim 11, wherein the anode comprises indium tin oxide (ITO) and the cathode comprises aluminum (Al).

13. The liquid crystal display device as claimed in claim 12, wherein the cathode has a thickness of 100-150 nm.

14. The liquid crystal display device as claimed in claim 10, wherein a surface of the cathode that is distant from the electron transportation layer is disposed on the base plate, the cathode being a transparent electrode, the anode being a metal electrode, the light generated by the re-combination of the holes and the electrons in the light emissive layer being projected out through a surface of the base plate that is distant from the cathode.

15. The liquid crystal display device as claimed in claim 10, wherein a surface of the first sub light emissive layer that is opposite to the second sub light emissive layer is in contact engagement with a surface of the hole transportation layer that is distant from the anode, and a surface of the second sub light emissive layer that is opposite to the first sub light emissive layer is in contact engagement with a surface of the electron transportation layer that is distant from the cathode.

16. The liquid crystal display device as claimed in claim 10, wherein the hole transportation layer comprises poly(3,4-ethylenedioxythiophene):

poly styrenesulfonate (PEDOT;

PSS) or P-type metal oxide nanometer particle, wherein the P-type metal oxide nanometer particle comprises one or multiple ones of MoO₃, NiO, V₂O₅, and WO3.

17. The liquid crystal display device as claimed in claim 10, wherein the hole transportation layer has a thickness of 40 nm.