The invention provides an optoelectronic device comprising a porous material, which porous material comprises a semiconductor comprising a perovskite. The porous material may comprise a porous perovskite. Thus, the porous material may be a perovskite material which is itself porous. Additionally or alternatively, the porous material may comprise a porous dielectric scaffold material, such as alumina, and a coating disposed on a surface thereof, which coating comprises the semiconductor comprising the perovskite. Thus, in some embodiments the porosity arises from the dielectric scaffold rather than from the perovskite itself. The porous material is usually infiltrated by a charge transporting material such as a hole conductor, a liquid electrolyte, or an electron conductor. The invention further provides the use of the porous material as a semiconductor in an optoelectronic device. Further provided is the use of the porous material as a photosensitizing, semiconducting material in an optoelectronic device. The invention additionally provides the use of a layer comprising the porous material as a photoactive layer in an optoelectronic device. Further provided is a photoactive layer for an optoelectronic device, which photoactive layer comprises the porous material.