Ferroelectric Thin Films for Energy Conversion Applications

Abstract

The chapter attempts to describe the potential of sol-gel derived ferroelectric thin films in energy conversion applications in two fields, namely in cooling by exploiting the electrocaloric effect and in energy harvesting. First, the basics of the sol-gel processing of ferroelectric thin films with the Pb(Zr,Ti)O3 solid solution as the representative material are described. The electrocaloric effect is described as a reversible temperature change in a material under an applied electric field at adiabatic conditions. Sol-gel derived relaxor ferroelectric thin films demonstrate a giant electrocaloric effect and they could be applied for solid-state cooling devices in microelectronics. In energy harvesting, the energy is derived from external sources, captured, stored and used, for example in small autonomous devices. In ferroelectric thin films, the piezoelectric effect, i.e. the generation of an electric charge upon applied stress, is exploited. Due to the miniaturization of electronic components, thin films with lateral dimensions in nanometer to micrometer range are appropriate candidates for future miniature applications related to energy.