Route to stable lead-free double perovskites with the electronic structure of CH3NH3PbI3: a case for mixed-cation [Cs/CH3NH3/CH(NH2)2]2InBiBr6

Journal article

During the past year, halide double perovskites attracted attention as potential lead-free alternatives to Pb-based halide perovskites. However, none of the compounds discovered so far can match the optoelectronic properties of MAPbI3 (MA = CH3NH3). Here we argue that, from the electronic structure viewpoint, the only option to make Pb-free double perovskites retaining the remarkable properties of MAPbI3 is to combine In and Bi as B(+) and B(3+) cations, respectively. While inorganic double perovskites such as Cs2InBiX6 were found to be unstable due to In(+) oxidizing into In(3+), we show that the +1 oxidation state of In becomes progressively more stable as the A-site cation changes from K to Cs. Hence, we propose the use of MA and FA [FA = CH(NH2)2] to stabilize A2InBiBr6 double perovskites. We show that the optoelectronic properties of A2InBiBr6 are remarkably similar to those of MAPbI3, and explore the mixed-cation (Cs/MA/FA)2InBiBr6 halide double perovskites.

Authors: Volonakis, G; Haghighirad, A; Snaith, H; Giustino, F

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Chemical Society
• Journal: Journal of Physical Chemistry Letters
• Volume: 8
• Pages: 3917–3924
• Publication date: 2017-07-26
• Acceptance date: 2017-07-26
• DOI: 10.1021/acs.jpclett.7b01584
• ISSN: 1948-7185
• Language: English