Mixed Valence Perovskite Cs2Au2I6: A Potential Material for Thin‐Film Pb‐Free Photovoltaic Cells with Ultrahigh Efficiency. Issue 12 (6th February 2018)

• Record Type: Journal Article
• Authors: Debbichi, Lamjed; Lee, Songju; Cho, Hyunyoung; Rappe, Andrew M.; Hong, Ki‐Ha; Jang, Min Seok; Kim, Hyungjun
• Is Part Of: Advanced materials. Volume 30:Issue 12(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-02-06
• Subjects: first‐principles calculations -- lead‐free perovskite solar cells -- mixed valency -- multiscale simulations -- thin film solar cells; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201707001
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: New light is shed on the previously known perovskite material, Cs2 Au2 I6, as a potential active material for high‐efficiency thin‐film Pb‐free photovoltaic cells. First‐principles calculations demonstrate that Cs2 Au2 I6 has an optimal band gap that is close to the Shockley–Queisser value. The band gap size is governed by intermediate band formation. Charge disproportionation on Au makes Cs2 Au2 I6 a double‐perovskite material, although it is stoichiometrically a single perovskite. In contrast to most previously discussed double perovskites, Cs2 Au2 I6 has a direct‐band‐gap feature, and optical simulation predicts that a very thin layer of active material is sufficient to achieve a high photoconversion efficiency using a polycrystalline film layer. The already confirmed synthesizability of this material, coupled with the state‐of‐the‐art multiscale simulations connecting from the material to the device, strongly suggests that Cs2 Au2 I6 will serve as the active material in highly efficient, nontoxic, and thin‐film perovskite solar cells in the very near future. Abstract : Cs2 Au2 I6 is an interesting perovskite material having mixed‐valence Au centers. A state‐of‐the‐art multiscale simulation shows that this old‐but‐new material is highly advantageous as a lead‐free and stable material for verythin‐film perovskite solar cells (PSCs). It is hoped that this work will inspire experimentalists to realize this new concept in PSCs based on mixed‐valence perovskites.