Engineering Solar Cell Absorbers by Exploring the Band Alignment and Defect Disparity: The Case of Cu- and Ag-Based Kesterite Compounds

Zhen Kun Yuan, Shiyou Chen, Hongjun Xiang, Xin Gao Gong, Aron Walsh, Ji Sang Park, Ingrid Repins, Su Huai Wei

Research output: Contribution to journalArticle

101 Citations (Scopus)

Abstract

The development of kesterite Cu2ZnSn(S,Se)4 thin-film solar cells is currently hindered by the large deficit of open-circuit voltage (Voc), which results from the easy formation of CuZn antisite acceptor defects. Suppressing the formation of CuZn defects, especially near the absorber/buffer interface, is thus critical for the further improvement of kesterite solar cells. In this paper, it is shown that there is a large disparity between the defects in Cu- and Ag-based kesterite semiconductors, i.e., the CuZn or CuCd acceptor defects have high concentration and are the dominant defects in Cu2ZnSn(S,Se)4 or Cu2CdSnS4, but the AgZn acceptor has only a low concentration and the dominant defects are donors in Ag2ZnSnS4. Therefore, the Cu-based kesterites always show p-type conductivity, while the Ag-based kesterites show either intrinsic or weak n-type conductivity. Based on this defect disparity and calculated band alignment, it is proposed that the Voc limit of the kesterite solar cells can be overcome by alloying Cu2ZnSn(S,Se)4 with Ag2ZnSn(S,Se)4, and the composition-graded (Cu,Ag)2ZnSn(S,Se)4 alloys should be ideal light-absorber materials for achieving higher efficiency kesterite solar cells. A new strategy is proposed to overcome the Voc bottleneck and increase the efficiency of the kesterite solar cells. This is achieved by forming composition-graded (Cu1-xAgx)2ZnSn(S,Se)4 alloys as the absorber layer.

Original languageEnglish
Pages (from-to)6733-6743
Number of pages11
JournalAdvanced Functional Materials
Volume25
Issue number43
DOIs
Publication statusPublished - 2015 Nov 18

Fingerprint

absorbers
Solar cells
solar cells
alignment
engineering
Defects
defects
absorbers (materials)
conductivity
Open circuit voltage
open circuit voltage
Chemical analysis
Alloying
alloying
low concentrations
Buffers
buffers
Semiconductor materials
thin films

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Electrochemistry

Cite this

Yuan, Zhen Kun ; Chen, Shiyou ; Xiang, Hongjun ; Gong, Xin Gao ; Walsh, Aron ; Park, Ji Sang ; Repins, Ingrid ; Wei, Su Huai. / Engineering Solar Cell Absorbers by Exploring the Band Alignment and Defect Disparity : The Case of Cu- and Ag-Based Kesterite Compounds. In: Advanced Functional Materials. 2015 ; Vol. 25, No. 43. pp. 6733-6743.
@article{2e715276140c4013bae117313a5cb168,
title = "Engineering Solar Cell Absorbers by Exploring the Band Alignment and Defect Disparity: The Case of Cu- and Ag-Based Kesterite Compounds",
abstract = "The development of kesterite Cu2ZnSn(S,Se)4 thin-film solar cells is currently hindered by the large deficit of open-circuit voltage (Voc), which results from the easy formation of CuZn antisite acceptor defects. Suppressing the formation of CuZn defects, especially near the absorber/buffer interface, is thus critical for the further improvement of kesterite solar cells. In this paper, it is shown that there is a large disparity between the defects in Cu- and Ag-based kesterite semiconductors, i.e., the CuZn or CuCd acceptor defects have high concentration and are the dominant defects in Cu2ZnSn(S,Se)4 or Cu2CdSnS4, but the AgZn acceptor has only a low concentration and the dominant defects are donors in Ag2ZnSnS4. Therefore, the Cu-based kesterites always show p-type conductivity, while the Ag-based kesterites show either intrinsic or weak n-type conductivity. Based on this defect disparity and calculated band alignment, it is proposed that the Voc limit of the kesterite solar cells can be overcome by alloying Cu2ZnSn(S,Se)4 with Ag2ZnSn(S,Se)4, and the composition-graded (Cu,Ag)2ZnSn(S,Se)4 alloys should be ideal light-absorber materials for achieving higher efficiency kesterite solar cells. A new strategy is proposed to overcome the Voc bottleneck and increase the efficiency of the kesterite solar cells. This is achieved by forming composition-graded (Cu1-xAgx)2ZnSn(S,Se)4 alloys as the absorber layer.",
author = "Yuan, {Zhen Kun} and Shiyou Chen and Hongjun Xiang and Gong, {Xin Gao} and Aron Walsh and Park, {Ji Sang} and Ingrid Repins and Wei, {Su Huai}",
year = "2015",
month = "11",
day = "18",
doi = "10.1002/adfm.201502272",
language = "English",
volume = "25",
pages = "6733--6743",
journal = "Advanced Functional Materials",
issn = "1616-301X",
publisher = "Wiley-VCH Verlag",
number = "43",

}

Engineering Solar Cell Absorbers by Exploring the Band Alignment and Defect Disparity : The Case of Cu- and Ag-Based Kesterite Compounds. / Yuan, Zhen Kun; Chen, Shiyou; Xiang, Hongjun; Gong, Xin Gao; Walsh, Aron; Park, Ji Sang; Repins, Ingrid; Wei, Su Huai.

In: Advanced Functional Materials, Vol. 25, No. 43, 18.11.2015, p. 6733-6743.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Engineering Solar Cell Absorbers by Exploring the Band Alignment and Defect Disparity

T2 - The Case of Cu- and Ag-Based Kesterite Compounds

AU - Yuan, Zhen Kun

AU - Chen, Shiyou

AU - Xiang, Hongjun

AU - Gong, Xin Gao

AU - Walsh, Aron

AU - Park, Ji Sang

AU - Repins, Ingrid

AU - Wei, Su Huai

PY - 2015/11/18

Y1 - 2015/11/18

N2 - The development of kesterite Cu2ZnSn(S,Se)4 thin-film solar cells is currently hindered by the large deficit of open-circuit voltage (Voc), which results from the easy formation of CuZn antisite acceptor defects. Suppressing the formation of CuZn defects, especially near the absorber/buffer interface, is thus critical for the further improvement of kesterite solar cells. In this paper, it is shown that there is a large disparity between the defects in Cu- and Ag-based kesterite semiconductors, i.e., the CuZn or CuCd acceptor defects have high concentration and are the dominant defects in Cu2ZnSn(S,Se)4 or Cu2CdSnS4, but the AgZn acceptor has only a low concentration and the dominant defects are donors in Ag2ZnSnS4. Therefore, the Cu-based kesterites always show p-type conductivity, while the Ag-based kesterites show either intrinsic or weak n-type conductivity. Based on this defect disparity and calculated band alignment, it is proposed that the Voc limit of the kesterite solar cells can be overcome by alloying Cu2ZnSn(S,Se)4 with Ag2ZnSn(S,Se)4, and the composition-graded (Cu,Ag)2ZnSn(S,Se)4 alloys should be ideal light-absorber materials for achieving higher efficiency kesterite solar cells. A new strategy is proposed to overcome the Voc bottleneck and increase the efficiency of the kesterite solar cells. This is achieved by forming composition-graded (Cu1-xAgx)2ZnSn(S,Se)4 alloys as the absorber layer.

AB - The development of kesterite Cu2ZnSn(S,Se)4 thin-film solar cells is currently hindered by the large deficit of open-circuit voltage (Voc), which results from the easy formation of CuZn antisite acceptor defects. Suppressing the formation of CuZn defects, especially near the absorber/buffer interface, is thus critical for the further improvement of kesterite solar cells. In this paper, it is shown that there is a large disparity between the defects in Cu- and Ag-based kesterite semiconductors, i.e., the CuZn or CuCd acceptor defects have high concentration and are the dominant defects in Cu2ZnSn(S,Se)4 or Cu2CdSnS4, but the AgZn acceptor has only a low concentration and the dominant defects are donors in Ag2ZnSnS4. Therefore, the Cu-based kesterites always show p-type conductivity, while the Ag-based kesterites show either intrinsic or weak n-type conductivity. Based on this defect disparity and calculated band alignment, it is proposed that the Voc limit of the kesterite solar cells can be overcome by alloying Cu2ZnSn(S,Se)4 with Ag2ZnSn(S,Se)4, and the composition-graded (Cu,Ag)2ZnSn(S,Se)4 alloys should be ideal light-absorber materials for achieving higher efficiency kesterite solar cells. A new strategy is proposed to overcome the Voc bottleneck and increase the efficiency of the kesterite solar cells. This is achieved by forming composition-graded (Cu1-xAgx)2ZnSn(S,Se)4 alloys as the absorber layer.

UR - http://www.scopus.com/inward/record.url?scp=85000351116&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85000351116&partnerID=8YFLogxK

U2 - 10.1002/adfm.201502272

DO - 10.1002/adfm.201502272

M3 - Article

AN - SCOPUS:85000351116

VL - 25

SP - 6733

EP - 6743

JO - Advanced Functional Materials

JF - Advanced Functional Materials

SN - 1616-301X

IS - 43

ER -