skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Beyond 11% efficient sulfide kesterite Cu 2Zn xCd 1–xSnS 4 solar cell: Effects of cadmium alloying

Abstract

Here, kesterite Cu 2ZnSnS 4 (CZTS) thin-film solar cells have drawn worldwide attention because of outstanding performance and earth-abundant constituents. However, problems such as coexistence of complex secondary phases, the band tailing issue, short minority lifetime, bulk defects, and undesirable band alignment at p-n interfaces need to be addressed for further efficiency improvement. In this regard, Cd alloying shows promise for dealing with some of these problems. In this work, a beyond 11% efficient Cd-alloyed CZTS solar cell is achieved, and the effects of Cd-alloying and mechanism underpinning the performance improvement have been investigated. The introduction of Cd can significantly reduce the band tailing issue, which is confirmed by the reduction in the difference between the photoluminescence peak and optical band gap (E g) as well as decreased Urbach energy. The microstructure, minority lifetime, and electrical properties of CZTS absorber are greatly improved by Cd alloying. Further XPS analyses show that the partial Cd alloying slightly reduces the band gap of CZTS via elevating the valence band maximum of CZTS. This suggests that there are opportunities for further efficiency improvement by engineering the absorber and the associated interface with the buffer.

Authors:
ORCiD logo [1];  [1];  [1];  [2];  [1];  [1];  [3];  [1];  [1];  [1]; ORCiD logo [1];  [1]
  1. Univ. of New South Wales, Sydney, NSW (Australia)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. Central South Univ., ChangSha (China)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1360662
Report Number(s):
NREL/JA-5K00-68607
Journal ID: ISSN 2380-8195
Grant/Contract Number:
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
ACS Energy Letters
Additional Journal Information:
Journal Volume: 2; Journal Issue: 4; Journal ID: ISSN 2380-8195
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; thin film solar cells; efficiency; alloying; performance

Citation Formats

Yan, Chang, Sun, Kaiwen, Huang, Jialiang, Johnston, Steve, Liu, Fangyang, Veettil, Binesh Puthen, Sun, Kaile, Pu, Aobo, Zhou, Fangzhou, Stride, John A., Green, Martin A., and Hao, Xiaojing. Beyond 11% efficient sulfide kesterite Cu2ZnxCd1–xSnS4 solar cell: Effects of cadmium alloying. United States: N. p., 2017. Web. doi:10.1021/acsenergylett.7b00129.
Yan, Chang, Sun, Kaiwen, Huang, Jialiang, Johnston, Steve, Liu, Fangyang, Veettil, Binesh Puthen, Sun, Kaile, Pu, Aobo, Zhou, Fangzhou, Stride, John A., Green, Martin A., & Hao, Xiaojing. Beyond 11% efficient sulfide kesterite Cu2ZnxCd1–xSnS4 solar cell: Effects of cadmium alloying. United States. doi:10.1021/acsenergylett.7b00129.
Yan, Chang, Sun, Kaiwen, Huang, Jialiang, Johnston, Steve, Liu, Fangyang, Veettil, Binesh Puthen, Sun, Kaile, Pu, Aobo, Zhou, Fangzhou, Stride, John A., Green, Martin A., and Hao, Xiaojing. Mon . "Beyond 11% efficient sulfide kesterite Cu2ZnxCd1–xSnS4 solar cell: Effects of cadmium alloying". United States. doi:10.1021/acsenergylett.7b00129. https://www.osti.gov/servlets/purl/1360662.
@article{osti_1360662,
title = {Beyond 11% efficient sulfide kesterite Cu2ZnxCd1–xSnS4 solar cell: Effects of cadmium alloying},
author = {Yan, Chang and Sun, Kaiwen and Huang, Jialiang and Johnston, Steve and Liu, Fangyang and Veettil, Binesh Puthen and Sun, Kaile and Pu, Aobo and Zhou, Fangzhou and Stride, John A. and Green, Martin A. and Hao, Xiaojing},
abstractNote = {Here, kesterite Cu2ZnSnS4 (CZTS) thin-film solar cells have drawn worldwide attention because of outstanding performance and earth-abundant constituents. However, problems such as coexistence of complex secondary phases, the band tailing issue, short minority lifetime, bulk defects, and undesirable band alignment at p-n interfaces need to be addressed for further efficiency improvement. In this regard, Cd alloying shows promise for dealing with some of these problems. In this work, a beyond 11% efficient Cd-alloyed CZTS solar cell is achieved, and the effects of Cd-alloying and mechanism underpinning the performance improvement have been investigated. The introduction of Cd can significantly reduce the band tailing issue, which is confirmed by the reduction in the difference between the photoluminescence peak and optical band gap (Eg) as well as decreased Urbach energy. The microstructure, minority lifetime, and electrical properties of CZTS absorber are greatly improved by Cd alloying. Further XPS analyses show that the partial Cd alloying slightly reduces the band gap of CZTS via elevating the valence band maximum of CZTS. This suggests that there are opportunities for further efficiency improvement by engineering the absorber and the associated interface with the buffer.},
doi = {10.1021/acsenergylett.7b00129},
journal = {ACS Energy Letters},
number = 4,
volume = 2,
place = {United States},
year = {Mon Apr 03 00:00:00 EDT 2017},
month = {Mon Apr 03 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 8works
Citation information provided by
Web of Science

Save / Share:
  • The study report novel sensing plat of extended quinternart materials, Cu{sub 2}Zn{sub 1-x}d{sub x}SnS{sub 4} quinternary alloy nanostructures were fabricated onto oxidized silicon substrate by sol-gel method and characterized were synthesized by X-ray diffraction (XRD). The XRD peaks were shifted towered the lower angle side with increasing cadmium content. The practical size average of the Cu{sub 2}Zn{sub 1-x}d{sub x}SnS{sub 4} quinternary alloy nanostructures between 34.55 to 63.30 nm.
  • Cu/sub 2/S/Zn/sub x/Cd/sub 1-x/S solar cells with stable open-circuit voltages up to 0.784 v were formed on zinc-cadmium sulfide films deposited by spray pyrolysis. X was varied betwen zero and 0.7 by varying the spray solution composition. Zn/sub x/Cd/sub 1-x/S films formed Schottky diodes with evaporated chromium contacts; depletion layer width (in light) in the films increased with x, from 0.16 to 3.1 microns. Resistivity of the films increased exponentially with x. Optical band gap increased with x from 2.41 ev at x.0 to 2.82 ev at x.0.6. 13 refs.
  • A simple empirical theory has been given for the short-circuit current (i/sub sc/ ) and the open-circuit voltage (v/sub oc/ ) of the Zn/sub z/Cd/sub 1-//sub z/S/CU/sub 2/S solar cell. The heterojunction band lineup at the interface is assumed to be determined by the pinning of the Fermi level at the collector surface by the copper impurity/cation vacancy level. Since the impurity level remains fixed with respect to the collector valence-band edge and the collector band gap goes up with z, such a pinning produces a potential barrier (''spike'') at the junction. The height of the spike increases with z.more » An estimate is made of the Cd impurity level in the emitter. This level is believed to act as the recombination center for electrons diffusing back to the emitter from the collector conduction band. These electrons would normally face a strong opposing field but because of an expected incipient Zener breadkdown of the potential barrier in the narrow highest field region they would face a substantially smaller opposing field. Zener breakdown field for CdS is known and for the mixed sulfide we have considered this field as a parameter obtained by fitting the v/sub oc/ values. The parameter, thus« less
  • It is proposed that a new and potentially extensive class of scaffolding-like materials may be afforded by linking together centers with either a tetrahedral or an octahedral array of valences by rodlike connecting units. Some simple general principles concerning the design and construction of these frameworks are presented together with reasons for expecting them to show unusual and useful properties. Two of the simplest conceivable systems of this type are isomorphous Zn(CN){sub 2} and Cd(CN){sub 2} whose structures have been reexamined by single-crystal X-ray diffraction, confirming the earlier description based on powder diffraction data of two interpenetrating diamond-related frameworks: cubicmore » with space group P{bar 4}3m, Z = 2; a = 5.9002 (9) {angstrom} (Zn(CN){sub 2}) and 6.301 (1) {angstrom} (Cd(CN){sub 2}); two unique metal centers, one surrunded tetrahedrally by 4 C and the other by 4 N donors; MCNM rods linear; ZnC, 1.923 (6) {angstrom}; ZnN, 2.037 (5) {angstrom}; CdC, 2.099 (5) {angstrom}; CdN, 2.196 (4) {angstrom}; CN, 1.150 (5) {angstrom} in Zn(CN){sub 2} and 1.162 (5) {angstrom} in Cd(CN){sub 2}. The material (N(CH{sub 3}){sub 4})(CuZn(CN){sub 4}) was deliberately designed to demonstrate one conceivable way of preventing interpenetration; its structure was determined by single-crystal X-ray diffraction: cubic, F{bar 4}3m, a = 11.609 (3) {angstrom} Z = 4. Cu{sup I}(4,4{prime},4{double prime},4{prime}{double prime}-tetracyanotetraphenylmethane)-BF{sub 4}{center dot}xC{sub 6}H{sub 5}NO{sub 2} (x {ge} 7.7) represents the first attempt to generate an infinite 3D framework with rods of some complexity. The structure was determined by single-crystal X-ray diffraction.« less
  • The electrochemical oxidation of a metallic anode (zinc or cadmium) in an acetonitrile solution of a series of arenephosphinothiol ligands, 2-(Ph{sub 2}P)C{sub 6}H{sub 4}SH, 2-(Ph{sub 2}P)-6-(Me{sub 3}Si)C{sub 6}H{sub 3}SH, 2-(Ph{sub 2}PO)-6-(Me{sub 3}Si)C{sub 6}H{sub 3}SH, and PhP-(C{sub 6}H{sub 4}SH-2){sub 2} [abbreviated RP-(SH){sub x}, x = 1 or 2], affords [M(RP-S){sub 2}] and [M(RP-S{sub 2})], M = Zn, Cd. Adducts of several of these compounds with 1,10-phenanthroline and 2,2{prime}-bipyridine have also been obtained by addition of these coligands to the electrolysis phase. The compounds obtained have been characterized by microanalysis, IR, UV-visible, FAB spectrometry and {sup 1}H, {sup 31}P NMR spectroscopic studies.more » The compounds [Cd{sub 2}{l{underscore}brace}2-(Ph{sub 2}PO)-C{sub 6}H{sub 4}S{r{underscore}brace}{sub 4}]CH{sub 3}CN (1), [Zn{l{underscore}brace}2-(Ph{sub 2}P)-6-(Me{sub 3}Si)C{sub 6}H{sub 3}S{r{underscore}brace}{sub 2}] (2), [Cd{l{underscore}brace}2-(Ph{sub 2}PO)-6-(Me{sub 3}Si)C{sub 6}H{sub 3}S{r{underscore}brace}{sub 2}(CH{sub 3}OH)] (3), and [Zn{l{underscore}brace}PhPO(C{sub 6}H{sub 4}S-2){sub 2}{r{underscore}brace}(bipy)] (4), have been also characterized by single-crystal X-ray diffraction. Compound 1 is binuclear with a {l{underscore}brace}Cd{sub 2}S{sub 2}{r{underscore}brace} core and distorted trigonal bipyramidal {l{underscore}brace}CdO{sub 2}S{sub 3}{r{underscore}brace} geometry about the Cd sites. Compounds 2, 3, and 4 are mononuclear with distorted tetrahedral {l{underscore}brace}ZnP{sub 2}S{sub 2}{r{underscore}brace}, distorted square pyramidal {l{underscore}brace}CdO{sub 3}S{sub 2}{r{underscore}brace}, and distorted trigonal bipyramidal {l{underscore}brace}ZnON{sub 2}S{sub 2}{r{underscore}brace} geometries, respectively.« less