Methods of producing a photovoltaic junction including ligand exchange of quantum dots of a film

Patent metadata

Field	Value
Publication number	US-11935975-B2
Application number	US-202218074665-A
Country	US
Kind code	B2
Filing date	Dec 5, 2022
Priority date	Jun 26, 2019
Publication date	Mar 19, 2024
Grant date	Mar 19, 2024

Abstract

The present disclosure is directed to methods for producing a photovoltaic junction that can include coating a bare junction with a composition. In one embodiment, the composition includes a plurality of quantum dots to create a film; exposing the film to a ligand to create a first layer; coating the first layer with the composition to form a film on the first layer; and exposing the film on the first layer to the ligand to create a second layer.

First claim

What is claimed is:

1. A method for producing a photovoltaic junction, the method comprising:
applying a metallic contact to a first surface area of a semiconductor layer to form a first physical junction between a first surface area of the metallic contact and the first surface area of the semiconductor layer, the first physical junction forming a Schottky diode;
coating a second surface area of the semiconductor layer and a second surface area of the metallic contact with a composition including a plurality of ligand-protected quantum dots;
carrying out a ligand-exchange with the ligand-protected quantum dots to form a light absorbing layer, wherein a second physical junction exists between a first surface area of the light absorbing layer and the second surface area of the semiconductor layer and a third physical junction exists between a second surface area of the light absorbing layer and the second surface area of the metallic contact, the second physical junction forming a diode that exhibits Shockley-Read Hall trap-assisted recombination, and the third physical junction forming an ohmic contact; wherein
the photovoltaic junction exhibits absorption across one or more wavelengths in the range from about 200 nm to about 2000 nm.

2. The method of claim 1 , wherein the composition is spin coated on the second surface area of the semiconductor layer and the second surface area of the metallic contact.

3. The method of claim 1 , wherein the composition is painted on the second surface area of the semiconductor layer and the second surface area of the metallic contact.

4. The method of claim 1 , wherein the semiconductor layer comprises a nitride or a carbide.

5. The method of claim 1 , wherein the semiconductor layer comprises a semiconductor that has a bandgap greater than a bandgap of the light absorbing layer.

6. The method of claim 1 , wherein the ligand exchange comprises exchanging a 1,2-ethane dithiol with a ligand of the ligand-protected quantum dots.

7. The method of claim 1 , wherein the ligand-protected quantum dots comprise lead sulfide quantum dots.

8. The method of claim 1 , wherein the light absorbing layer has thickness from about 8 nm to about 400 nm.

9. The method of claim 1 , wherein the light absorbing layer has a thickness of from about 10 nm to about 300 nm.

10. The method of claim 1 , wherein the semiconductor layer has a thickness that is greater than the thickness of the light absorbing layer.

11. The method of claim 1 , wherein the semiconductor layer has a thickness that is from about 5 micrometers to about 200 micrometers.

12. The method of claim 1 , wherein the metallic contact comprises graphene, graphite, or a metal.

13. The method of claim 1 , further comprising:
coating the light absorbing layer with a further amount of the composition including the plurality of ligand-protected quantum dots; and
carrying out a ligand-exchange with the ligand-protected quantum dots and thereby increasing the thickness of the light absorbing layer.

14. The method of claim 13 , further comprising repeating the coating and ligand-exchange steps one or more additional times.

15. The method of claim 1 , wherein the metallic contact includes multiple monolayers of graphene.

16. The method of claim 1 , wherein the ligand-protected quantum dots comprise alkyl carboxylate coated quantum dots.

Assignees

• Univ South Carolina

Inventors

• Kelley Mathew
• Greytak Andrew B
• Chandrashekhar Mvs
• Letton Joshua

Classifications

• H10K30/50

  Photovoltaic [PV] devices · CPC title

• H10F77/12485

  comprising nitride compounds, e.g. InGaN · CPC title

• H10F77/1226

  comprising multiple Group IV elements, e.g. SiC · CPC title

• H10F77/206

  for devices having potential barriers · CPC title

• H10F77/127

  comprising only Group IV-VI or only Group II-IV-VI chalcogenide materials, e.g. PbSnTe · CPC title