Wide band gap kesterite absorbers for thin film solar cells: Potential and challenges for their deployment in tandem devices

Bart Vermang, Guy Brammertz, Marc Meuris, Thomas Schnabel, Erik Ahlswede, Leo Choubrac, Sylvie Harel, Christophe Cardinaud, Ludovic Arzel, Nicolas Barreau, Joop Van Deelen, Pieter Jan Bolt, Patrice Bras, Yi Ren, Eric Jaremalm, Samira Khelifi, Sheng Yang, Johan Lauwaert, Maria Batuk, Joke HadermannXeniya Kozina, Evelyn Handick, Claudia Hartmann, Dominic Gerlach, Asahiko Matsuda, Shigenori Ueda, Toyohiro Chikyow, Roberto Félix, Yufeng Zhang, Regan G. Wilks, Marcus Bär

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


This work reports on developments in the field of wide band gap Cu2ZnXY4 (with X = Sn, Si or Ge, and Y = S, Se) kesterite thin film solar cells. An overview on recent developments and the current understanding of wide band gap kesterite absorber layers, alternative buffer layers, and suitable transparent back contacts is presented. Cu2ZnGe(S,Se)4 absorbers with absorber band gaps up to 1.7 eV have been successfully developed and integrated into solar cells. Combining a CdS buffer layer prepared by an optimized chemical bath deposition process with a 1.36 eV band gap absorber resulted in a record Cu2ZnGeSe4 cell efficiency of 7.6%, while the highest open-circuit voltage of 730 mV could be obtained for a 1.54 eV band gap absorber and a Zn(O,S) buffer layer. Employing InZnOx or TiO2 protective top layers on SnO2:In transparent back contacts yields 85-90% of the solar cell performance of reference cells (with Mo back contact). These advances show the potential as well as the challenges of wide band gap kesterites for future applications in high-efficiency and low-cost tandem photovoltaic devices.

Original languageEnglish
Pages (from-to)2246-2259
Number of pages14
JournalSustainable Energy and Fuels
Issue number9
Publication statusPublished - 2019

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology


Dive into the research topics of 'Wide band gap kesterite absorbers for thin film solar cells: Potential and challenges for their deployment in tandem devices'. Together they form a unique fingerprint.

Cite this