Electrodeposition of thin-film cells containing non-toxic elements

Patent metadata

Field	Value
Publication number	US-9447514-B2
Application number	US-201514699550-A
Country	US
Kind code	B2
Filing date	Apr 29, 2015
Priority date	Aug 31, 2010
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A structure and method of making a thin-film solar cell is provided. A thin-film solar cell includes a substrate, absorber layer and a buffer layer. The absorber layer is deposited by a single-step bulk electrochemical process, or a multi-layer electrochemical process. The buffer layer is deposited by an electrochemical deposition process such as a multi-layer deposition or an atomic layer deposition. The absorber and buffer layers are non-toxic materials which can include sulfur incorporated during the deposition process or incorporated after deposition by an anneal step.

First claim

What is claimed is:

1. A method of manufacturing a thin-film cell, the method comprising:
providing a substrate;
depositing an absorber layer onto the substrate; and
depositing a buffer layer onto the absorber layer, wherein the absorber layer and the buffer layer are made from non-toxic materials;
wherein the depositing the absorber layer and the buffer layer is performed using an electrochemical atomic layer deposition process carried out under illumination so as to excite electrons from a valence band to a conduction band, wherein the electrons at an edge of the conduction band at a solid/liquid interface are energetically higher than that of a redox potential of S 2 O 3 2− /ZnS; and
wherein the electrochemical deposition process for depositing the buffer layer is carried out by:
filling a cell with a solution comprising: SnCl 2 ; Na 2 S 2 O 3 ; and about 0.2 mM of tartaric acid;
adjusting a pH of the solution to about 2.5;
adjusting a temperature of the solution to about 70 degrees Celsius;
exposing the absorber layer to a light source; and
applying a voltage to the substrate of about −0.8 V with reference to a Ag/AgCl reference electrode to produce a thin-film of SnS.

2. The method of claim 1 , wherein the step of depositing the absorber layer onto the substrate is carried out using a single-step bulk electrochemical deposition process.

3. The method of claim 1 , wherein the absorber layer is made of a material selected from the group consisting of Cu 2 ZnSeS 4 , Cu 2 SnSeS 4 , Cu 2 ZnSn(SeS) 4 , Cu 2 ZnSnTe 4 and Cu 2 ZnSnS 4 .

4. The method of claim 1 , wherein the step of depositing the absorber layer onto the substrate is carried out using multiple-layer electrochemical deposition.

5. The method of claim 1 , wherein the step of depositing the absorber layer onto the substrate is carried out using a single-step bulk electrochemical deposition process and wherein the electrochemical deposition process used to deposit the buffer layer is a multiple layer electrochemical deposition process.

6. The method of claim 1 , wherein the step of depositing the absorber layer onto the substrate is carried out by:
depositing a thin-film of Cu 2 ZnSn using an electrochemical deposition process, wherein sulfur is not contained in a solution used in the process; and
annealing the thin-film in the presence of sulfur (solid) and/or hydrogen sulfide (H 2 S) in an Argon (Ar) containing atmosphere in order to implant sulfur into the thin-film of Cu 2 ZnSn.

7. The method of claim 1 , wherein the step of depositing the absorber layer onto the substrate is carried out by:
contacting: (i) a solution comprising: 1 mM to 100 mM of CuSO 4 .5H 2 O; 1 mM to 100 mM of SnSO 4 ; 1 mM to 100 mM of ZnSO 4 ; 20 mM to 5M NaOH solution; and 0.1 M to 2 M of sorbitol solution; and (ii) the substrate;
adjusting a pH of the solution to a range from about 9 to about 12; and
applying a voltage to the substrate of about −0.4 V to −1.5 V with reference to a Ag/AgCl reference electrode to produce a thin-film of Cu 2 ZnSn.

8. The method of claim 7 , wherein the solution further comprises about 1 mM-1000 mM of Na 2 S, thereby producing a thin-film of Cu 2 ZnSnS 4 .

9. The method of claim 7 , further comprising:
annealing the thin film of Cu 2 ZnSn in the presence of sulfur (solid) and/or hydrogen sulfide (H 2 S) in an Argon (Ar) containing atmosphere for about 1 hour at a temperature of 550 degrees Celsius, thereby producing a thin-film of Cu 2 ZnSnS 4 .

Assignees

• IBM

Inventors

• Deligianni Hariklia
• Guo Lian
• Vaidyanathan Raman

Classifications

• C25D3/58 Primary

  containing more than 50% by weight of copper · CPC title

• H10F77/128

  comprising only Group I-II-IV-VI kesterite materials, e.g. Cu2ZnSnSe4 or Cu2ZnSnS4 · CPC title

• H10F77/12

  Active materials · CPC title

• H10F71/128

  Annealing · CPC title

• H10F71/00 Primary

  Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00) · CPC title