Revealing the electronic structure, heterojunction band offset and alignment of Cu2ZnGeSe4: A combined experimental and computational study towards photovoltaic applications

Sachin R. Rondiya, Dilara Gokcen Buldu, Guy Brammertz, Yogesh A. Jadhav, Russell W. Cross, Hirendra N. Ghosh, Thomas E. Davies, Sandesh R. Jadkar, Nelson Y. Dzade, Bart Vermang

Research output: Contribution to journalArticlepeer-review

Abstract

Cu2ZnGeSe4 (CZGSe) is a promising earth-abundant and non-toxic semiconductor material for large-scale thin-film solar cell applications. Herein, we have employed a joint computational and experimental approach to characterize and assess the structural, optoelectronic, and heterojunction band offset and alignment properties of a CZGSe solar absorber. The CZGSe films were successfully prepared using DC-sputtering and e-beam evaporation systems and confirmed by XRD and Raman spectroscopy analyses. The CZGSe films exhibit a bandgap of 1.35 eV, as estimated from electrochemical cyclic voltammetry (CV) measurements and validated by first-principles density functional theory (DFT) calculations, which predicts a bandgap of 1.38 eV. A fabricated device based on the CZGSe as a light absorber and CdS as a buffer layer yields power conversion efficiency (PCE) of 4.4% with VOC of 0.69 V, FF of 37.15, and Jsc of 17.12 mA cm-2. Therefore, we suggest that interface and band offset engineering represent promising approaches to improve the performance of CZGSe devices by predicting a type-II staggered band alignment with a small conduction band offset of 0.18 eV at the CZGSe/CdS interface. This journal is

Original languageEnglish (US)
Pages (from-to)9553-9560
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume23
Issue number15
DOIs
StatePublished - Apr 21 2021

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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