Elucidating the factors limiting the photovoltaic performance of mixed Sb-Bi double perovskite absorbers

Authors: Z. Li, Y.-T. Huang, L. Mohan, S. J. Zelewski, R. H. Friend, J. Briscoe, R. L. Z. Hoye* Sb-alloying has been proposed as a strategy to improve the visible light absorption of Cs2AgBiBr6 elpasolites by reducing the bandgap, but this approach has not so far led to improvements in photovoltaic performance. Herein, we show that this is due to the introduction of a sub-bandgap loss channel, which may arise from an increase in film strain.