BaCu2Sn(S,Se)4: Earth-abundant chalcogenides for thin-film photovoltaics


Journal Article

© 2016 American Chemical Society. Chalcogenides such as CdTe, Cu(In,Ga)(S,Se)2 (CIGSSe), and Cu2ZnSn(S,Se)4 (CZTSSe) have enabled remarkable advances in thin-film photovoltaic performance, but concerns remain regarding (i) the toxicity (CdTe) and (ii) scarcity (CIGSSe/CdTe) of the constituent elements and (iii) the unavoidable antisite disordering that limits further efficiency improvement (CZTSSe). In this work, we show that a different materials class, the BaCu2SnSexS4-x (BCTSSe) system, offers a prospective path to circumvent difficulties (i-iii) and to target new environmentally friendly and earth-abundant absorbers. Antisite disordering and associated band tailing are discouraged in BCTSSe due to the distinct coordination environment of the large Ba2+ cation. Indeed, an abrupt absorption edge and sharp associated photoluminescence emission demonstrate a reduced impact of band tailing in BCTSSe relative to CZTSSe. Our combined experimental and computational studies of BCTSSe reveal that the compositions 0 ≤ x ≤ 4 exhibit a tunable nearly direct or direct bandgap in the 1.6-2 eV range, spanning relevant values for single- or multiple-junction photovoltaic applications. For the first time, a prototype BaCu2SnS4-based thin-film solar cell has been successfully demonstrated, yielding a power conversion efficiency of 1.6% (0.42 cm2 total area). The systematic experimental and theoretical investigations, combined with proof-of-principle device results, suggest promise for BaCu2SnSexS4-x as a thin-film solar cell absorber.

Full Text

Duke Authors

Cited Authors

  • Shin, D; Saparov, B; Zhu, T; Huhn, WP; Blum, V; Mitzi, DB

Published Date

  • July 12, 2016

Published In

Volume / Issue

  • 28 / 13

Start / End Page

  • 4771 - 4780

Electronic International Standard Serial Number (EISSN)

  • 1520-5002

International Standard Serial Number (ISSN)

  • 0897-4756

Digital Object Identifier (DOI)

  • 10.1021/acs.chemmater.6b01832

Citation Source

  • Scopus