Beyond 11% Efficient Sulfide Kesterite Cu2ZnxCd1-xSnS4 Solar Cell: Effects of Cadmium Alloying

Steven Johnston, Chang Yan, Kaiwen Sun, Jialiang Huang, Fangyang Liu, Binesh Veettil, Kaile Sun, Aobo Pu, Fangzhou Zhou, John Stride, Martin Green, Xiaojing Hao

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254 Scopus Citations


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.

Original languageAmerican English
Pages (from-to)930-936
Number of pages7
JournalACS Energy Letters
Issue number4
StatePublished - 14 Apr 2017

Bibliographical note

Publisher Copyright:
© 2017 American Chemical Society.

NREL Publication Number

  • NREL/JA-5K00-68607


  • alloying
  • efficiency
  • performance
  • thin film solar cells


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