Hybrid organic-inorganic perovskites: Polar properties and applications

Inorganic perovskite materials such as SrTiO ₃ , BaTiO ₃ , and Pb(Zr,Ti)O ₃ have been widely used in the past because of their excellent dielectric, ferroelectric, piezoelectric and pyroelectric properties used in numerous applications. Recently, hybrid organic- inorganic perovskites (HOIPs) have emerged as a promising class of materials for photovoltaic (and more generally optoelectronic) applications. With their help, photovoltaic solar cells have achieved large power conversion efficiencies, in excess of 20%, within a very short time due to unique combinations of materials parameters. On the other hand, many of these materials are polar and, thus, viable substitutes for classical inorganic perovskites. In this Review we describe the origin of polar properties in several classes of HOIPs (both single crystals and thin films), present a comprehensive account of their piezo-, ferro- and pyroelectric responses, and discuss their possible applications as capacitors, memory elements, piezoelectric transducers and pyroelectric sensors.