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• Negative electrocaloric effect (ECE) could be obtained in PLZ thin films within wide temperature range (213–493 K). • Giant negative ECE (Δ T ≈ −13.2 K) and entropy change (Δ S ≈ −11.5 J K−1 kg−1) could be obtained in PLZ thin films. • The combination between negative and positive ECE promotes cooling efficiency during electrical bias processing. Antiferroelectric thin films have exhibited outstanding negative electrocaloric effect (ECE), which are potential candidate regarding to the solid-state refrigeration technology. In this work, Pb 0.97 La 0.02 ZrO 3 (PLZ) antiferroelectric thin films were prepared on LaNiO 3 (LNO)/Pt electrode and LNO electrode by sol-gel method. Giant negative electrocaloric effect (Δ T ~ −13.2 K) can observed in wide temperature range (213–493 K) that deposited on composite electrode, which can be attributed to better electric conductivity of LNO/Pt composite electrode than LNO electrode. In addition to outstanding negative ECE, positive ECE also can be obtained near curie temperature, which is caused by phase transition from ferroelectric (FE) to paraelectric (PE) state. The optimized ECE property contributed to the phase transition and introduction of composite electrode, which pave the giant prospect considering high-efficiency solid-state refrigeration devices through combination of positive and negative ECE. [ABSTRACT FROM AUTHOR]

Because of high temperature process, it has been a challenge to fabricate flexible piezoelectric or ferroelectric devices based on PbZr 0.53 Ti 0.47 O 3 (PZT). In this work, a high-quality flexible PZT film is successfully fabricated by the controlled spalling technology (CST). The PZT film deposited on sapphire substrate using sol-gel method is transferred onto a flexible polyimide (PI) substrate through electroplating Ni stressor layer, realizing the flexible heterogeneous integration of PZT film and PI substrate. The obtained PZT film exhibits a good crystalline perovskite structure and a smooth surface before and after spalling process. The ferroelectric response of the spalled PZT film based on Au/PZT/Au structure does not show obvious deterioration under different mechanical deformation, which indicates good ferroelectric property and stable mechanical performance. Further, the film on flexible Ni layer has the better piezoelectric property compared with that on conventional rigid Pt/Ti/SiO 2 /Si substrate. This work has the important significance for the development of flexible ferroelectric and piezoelectric devices like sensors, memorizers and nanogenerators. • High-quality PZT film on sapphire is successfully transferred onto flexible PI by CST. • Ferroelectric performance of spalled PZT film does not deteriorate after deformation. • The spalled PZT film on flexible Ni layer has a better piezoelectric property. [ABSTRACT FROM AUTHOR]