Bi- and tri-layer interfacial layers in perovskite material devices

A photovoltaic device comprising:

• a first electrode;
• a second electrode;
• and
• an active layer disposed at least partially between the first and second electrodes, the active layer comprising:
• a perovskite material;
• and
• three or more adjacent interfacial layers;
• wherein each interfacial layer is in contact with at least one adjacent interfacial layer and comprises a different material than the adjacent interfacial layers that it is in contact with;
• wherein the perovskite material has the formula CMX3;
• wherein C comprises one or more cations each selected from the group consisting of Group 1 metals, Group 2 metals, organic cations, and combinations thereof;
• wherein M comprises one or more metals each selected from the group consisting of Fe, Co, Ni, Cu, Sn, Pb, Bi, Ge, Ti, Zn, and combinations thereof;
• and
• wherein X comprises one or more anions each selected from the group consisting of halides, pseudohalides, sulfide, selenide, and combinations thereof.