BaCu2Sn(S,Se)4: Earth-Abundant Chalcogenides for Thin-Film Photovoltaics

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• 作者：Donghyeop Shin ; Bayrammurad Saparov ; Tong Zhu ; William P. Huhn ; Volker Blum ; David B. Mitzi
• 刊名：Chemistry of Materials
• 出版年：2016
• 出版时间：July 12, 2016
• 年：2016
• 卷：28
• 期：13
• 页码：4771-4780
• 全文大小：583K
• 年卷期：0
• ISSN：1520-5002

文摘

Chalcogenides such as CdTe, Cu(In,Ga)(S,Se)b>2b> (CIGSSe), and Cub>2b>ZnSn(S,Se)b>4b> (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 BaCub>2b>SnSeb>xb>Sb>4–xb> (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 BaCub>2b>SnSb>4b>-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 BaCub>2b>SnSeb>xb>Sb>4–xb> as a thin-film solar cell absorber.