Ferroelectric oxides for solar energy conversion, multi-source energy harvesting/sensing, and opto-ferroelectric applications

Photoferroelectrics belong to a unique material family that exhibits both photovoltaic and ferroelectric effects simultaneously. The photovoltaic effect is the only known direct method of converting light into electricity and is the basis of solar cells. The ferroelectric effect can induce piezoelectric and pyroelectric effects, which are the working principles of widely used kinetic and thermal sensors, transducers, actuators, and energy harvesters. For a long time, photoferroelectric research was restricted to theoretical investigations only because of either the wide band gap (E_g), which is not able to effectively absorb visible light, or to the weak ferroelectricity caused by a narrow E_g. Recent scientific breakthroughs, however, have opened doors for the development of practical applications. In this article, emerging concepts of creating balanced photovoltaic and ferroelectric properties for photoferroelectrics, as well as those of novel applications in future devices, are presented.