Adjustable giant negative electrocaloric effect in Pb1+xZrO3 thin films

Abstract

Electrocaloric effect (ECE) driven by electric field is suitable for implementation of built-in cooling in electronic devices. However, most of the known electrocaloric materials show low adiabatic temperature change ( ) near room temperature and usually require high electric field. Here, the investigation of ECE in Pb 1+x ZrO 3 (x=0, 0.1, 0.15) thin films, which were prepared on Pt/Ti/SiO 2 /Si substrates by sol-gel method, reveals that both the magnitude and the present temperature range of can be controlled by Pb concentration. Through increasing the dosage of PbO, decreased lead vacancies and enhanced interface layer are induced, which postpone the transition from antiferroelectrics to ferroelectrics of PbZrO 3 films under a given electric field ( E ), which thus controls the appearance temperature range of negative ECE. As a result, large isothermal entropy change ( and are observed in the temperature range from 260 K to 494 K, depending on the applied electric field and Pb concentration. Giant ECE ( , ~0.054) at room temperature (303 K) is obtained in Pb 1.1 ZrO 3 films under 460 kV/cm. This result provides a convenient method for modulating ECE of PbZrO 3 -based materials and will benefit its applications in cooling devices.