Process for making multicomponent perovskites

Abstract

The invention provides a method of forming a perovskite material from a plurality of evaporation sources comprising co-subliming from: (i) a first evaporation source comprising a mixture of co-sublimable organic halides, wherein the organic halides comprise: a. a first organic halide comprising an organic cation A; b. a second organic halide comprising an organic cation A' which is different to A and has a larger ionic radius than the first organic cation A; and (ii) a second evaporation source comprising one or more metal halides having the formula (I): B(XX′)2 (I) wherein B is a divalent metal cation, X and X′ are different halides and 0≤y<1; and (iii) one or more further organic halides from one or more further evaporation sources; and/or (iv) one or more inorganic halides from one or more further evaporation sources; to form the perovskite material, wherein the perovskite material comprises three or more different cations in the A site. Perovskite materials and semiconductor devices, typically photovoltaic devices, are also provided.