Abstract: The invention provides a material with perovskite-type structure having a formula selected from Formula I and Formula II. in which A? represents one or more monovalent cations that can be selected from alkali metal ions, (organo)ammonium and (organo)phosphonium ions; A? represents one or more divalent cations that can be selected from alkaline earth metal cations; A?? represents one or more trivalent cations that can be selected from lanthanide ions; a, b and c are each in the range of from 0 to 1, a+b+c=1; x=a+2b+3c; d is in the range of from 1 to 5, each of e, f and g are in the range of from 0 to 1. with the proviso that g is less than 1 in Formula I; e+f+g?1; y=2(e+f)+3g; each X in “X” and “X2” is independently selected from the halogens; and h is in the range of from 0.0001 to 0.2. X2 is a dihalogen moiety, and can be the source of a valence band “hole” in the photovoltaic semiconducting material. The invention also relates to photovoltaic devices or a surface coating that comprises the material.