Assessment of polyanion (BF₄⁻ and PF₆⁻) substitutions in hybrid halide perovskites

Christopher H. Hendon, Ruoxi Yang, Lee A. Burton, Aron Walsh

OAI: oai:purehost.bath.ac.uk:publications/63d2b0fb-2aed-47a0-9448-95d95cd62a47 • DOI: https://doi.org/10.1039/C4TA05284F

Halide perovskites have attracted attention for light-to-electricity conversion in solar cells due to their favorable optoelectronic properties. In particular, the replacement of the A cation by an isovalent molecule has proven highly successful. We explore the substitution of the X anion, producing polyanion perovskites based on hexafluorophosphate and tetrafluoroborate. Starting from CsPbI3, the effect of partial and complete substitution is investigated using relativistic electronic structure calculations. BF4− results in a larger perturbation to the electronic structure than PF6−; however, both localise the band edge states, and the end member compounds are predicted to be wide band gap dielectrics.