Transparent quantum dot light-emitting diodes with dielectric/metal/dielectric electrode

• US 9,419,174 B2
• Filed: 09/26/2013
• Issued: 08/16/2016
• Est. Priority Date: 09/26/2012
• Status: Active Grant

• Current Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Original Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Inventors: Zheng, Ying, Cao, Weiran, Xue, Jiangeng, Holloway, Paul H.
• Primary Examiner(s): Sandvik, Benjamin
• Assistant Examiner(s): ASSOUMAN, HERVE-LOUIS Y
• Application Number:
  US14/424,540
• Publication Number:
  US 20150228850A1
• Time in Patent Office: 1,055 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C09K 11/565 with zinc cadmium
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: H01L 33/002 having heterojunctions or graded gap
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/26 Materials of the light emitting region
• CPC Class Codes: H01L 33/285 characterised by the doping materials
• CPC Class Codes: H01L 33/305 characterised by the doping materials
• CPC Class Codes: H01L 33/40 Materials therefor
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: H05B 33/22 characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers
• CPC Class Codes: H05B 33/26 characterised by the composition or arrangement of the conductive material used as an electrode
• CPC Class Codes: H10K 50/115 comprising active inorganic nanostructures, e.g. luminescent quantum dots
• CPC Class Codes: H10K 85/1135 Polyethylene dioxythiophene [PEDOT]; Derivatives thereof
• CPC Class Codes: H10K 85/115 Polyfluorene; Derivatives thereof

Abstract

Quantum dot light emitting diodes (QD-LEDs) are formed that are transparent and emit light from the top and bottom faces. At least one electrode of the QD-LEDs is a dielectric/metal/dielectric layered structure, where the first dielectric comprises metal oxide nanoparticles or polymer-nanoparticle blends and is 10 to 40 nm in thickness, the metal layer is 5 to 25 nm in thickness, and the second dielectric layer is a nanoparticulate, polymer-nanoparticle blend or continuous layer of 30 to 200 nm in thickness and is situated distal to the light emitting layer of the QD-LED.

Claims

1. A quantum dot light emitting diode (QD-LED) comprising:

a light emitting layer comprising a plurality of quantum dots (QDs); and

at least one dielectric/metal/dielectric (DMD) electrode comprising a first dielectric layer proximal to the light emitting layer, a metal layer and a second dielectric layer distal to the light emitting layer, wherein the first dielectric layer and the second dielectric layer comprise nanoparticles or polymer-nanoparticle blends, wherein the DMD electrode is a transparent cathode.

2. The QD-LED of claim 1, wherein said QDs comprise Group II-VI compound semiconductor nanocrystals, Group III-V or IV-VI compound semiconductor nanocrystals, CuInS₂, CuInSe₂ nanocrystals, metal oxide nanoparticles, core-shell structured nanocrystals, semiconductor nanocrystals doped with rare earth elements or transition metal elements or any combination thereof.

3. The QD-LED of claim 2, wherein said Group II-VI compound semiconductor nanocrystals comprise CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, CdSTe, alloys thereof, or any mixtures thereof.

4. The QD-LED of claim 2, wherein said Group III-V or IV-VI compound semiconductor nanocrystals comprise GaP, GaAs, GaSb, InP, InAs, InSb, PbS, PbSe, PbTe, alloys thereof, or any mixtures thereof.

5. The QD-LED of claim 2, wherein said metal oxide nanoparticles comprise ZnO, TiO₂, or a combination thereof.

6. The QD-LED of claim 2, wherein said core-shell structured nanocrystals comprise CdSe/ZnSe, CdSe/CdS, CdSe/ZnS, CdS/ZnSe, CdS/ZnS, ZnSe/ZnS, InP/ZnS, ZnO/MgO, CuInS₂/ZnS, CuInSe₂/ZnS, alloys thereof, or any mixtures thereof.

7. The QD-LED of claim 2, wherein said semiconductor nanoparticles doped with rare earth element comprise Eu, Er, Tb, Tm, Dy or any combination thereof.

8. The QD-LED of claim 1, wherein said first dielectric layer comprises nanoparticles.

9. The QD-LED of claim 1, wherein said first dielectric layer comprises polymer-nanoparticle blends.

10. The QD-LED of claim 1, wherein said first dielectric layer comprises ZnO, TiO₂, Cs₂O, MoO₃, WO₃, NiO, Cr₂O₃, V₂O₅, or any combination thereof.

11. The QD-LED of claim 1, wherein said first dielectric layer comprises a polymer containing ZnO, TiO₂, Cs₂O, MoO₃, WO₃, NiO, Cr₂O₃, or V₂O₅.

12. The QD-LED of claim 1, wherein said first dielectric layer is 10 to 60 nm in thickness.

13. The QD-LED of claim 1, wherein said metal layer of said DMD electrode comprises Ag, Au, Al, Ca, Mg, Cu, Mo or Mg:

Ag alloy.

14. The QD-LED of claim 1, wherein said metal layer of said DMD electrode is 5 to 25 nm in thickness.

15. The QD-LED of claim 1, wherein said second dielectric layer comprises ZnO, ZnS, ZnSe, MoO₃, WO₃, TiO₂, Al₂O₃, V₂O₅, Cr₂O₃, SiO₂, SiN_x, or any combination thereof.

16. The QD-LED of claim 1, wherein said second dielectric layer comprises polymer blends with ZnO, ZnS, ZnSe, MoO₃, WO₃, TiO₂, Al₂O₃, V₂O₅, Cr₂O₃, SiO₂, SiN_x, or any combination thereof.

17. The QD-LED of claim 1, wherein said second dielectric layer is 30 to 200 nm in thickness.

18. The QD-LED of claim 1, wherein light is emitted from the top and bottom faces of said QD-LED.