Abstract: This invention relates to an optoelectronic and/or photovoltaic device comprising a compound used as crystal defect mitigating agent or passivating agent, the compound being selected from a compound of formula (I), a compound of formula (II), a mixture thereof, or a compound of formula (II) being selected from anyone of the disclosed formulae (III.1), (III.2), (II.3), (III4) and (III.5).

Abstract: The present invention relates to an optoelectronic device including an electron transport layer (ETL) and a light harvesting layer, wherein the light harvesting layer includes a metal halide perovskite and is provided on the ETL being a multilayer structure having at least two layers of metal oxide, at least one layer of which includes a crystalline mesoporous metal oxide and at least one layer of which includes an amorphous metal oxide or metal oxide nanocrystals, and wherein the layer being in contact with the light harvesting layer includes the amorphous metal oxide or the metal oxide nanocrystals and is provided on the layer including the crystalline mesoporous metal oxide.