Interface-Charge Induced Giant Electrocaloric Effect in Lead Free Ferroelectric Thin-Film Bilayers

• DOI: 10.1021/acs.nanolett.9b04727
• Publication Date: 2019-12-26T18:33:00Z
• Authors: Sagar E. Shirsath; Claudio Cazorla; Teng Lu; Le Zhang; Yee Yan Tay; Xiaojie Lou; Yun Liu; Sean Li; Danyang Wang
• Keywords: Electrocaloric Effect; Interface (matter); Lead (geology)

Conventional refrigeration methods based on compression-expansion cycles of greenhouse gases are environmentally threatening and cannot be miniaturized. Electrocaloric effects driven by electric fields especially well suited for implementation built-in cooling in portable electronic devices. However, most known electrocaloric materials present poor performances near room temperature, contain toxic substances, require high fields. Here, we show that lead-free ferroelectric thin-film bilayers composed (Bi0.5Na0.5)TiO3-BaTiO3 (BNBT) Ba(Zr0.2Ti0.8)O3-(Ba0.7Ca0.3)TiO3 (BCZT) display unprecedentedly large ∼23 K temperature under moderate bias. The giant effect observed BNBT/BCZT bilayers, which largely surpasses the sum individual caloric responses measured BNBT BCZT, is originated from presence compositional bound charges at their interface. Our discovery interface charge-induced indicates multilayered oxide heterostructures hold tremendous promise developing highly efficient scalable solid-state applications.