Enhanced piezo-response in copper halide perovskites based PVDF composite films.

In-situ fabricated perovskite nanocrystals in polymeric matrix provide new generation composite materials for plenty of cutting edge technology. In this work, we report the in-situ fabrication of copper halide perovskite (MACuCl, MA:CHNH) embedded poly(vinylidene fluoride) (PVDF) composite films. The optimized MACuCl/PVDF composite films exhibit greatly enhanced piezo-response in comparasion with pure PVDF films. The enhancements were invesitgated and explained by applying piezo-response force microscopy (PFM) measurements and density functional theory (DFT) caculations. We proposed that the high piezoelectric properties of MACuCl/PVDF composite films could be related to the large Cu off-centering displacement, the strong interactions between MACuCl and PVDF as well as large stress concentration around the MACuCl particles in the films. These piezoelectric composite films are expected to be suitable functional materials for flexible and/or wearable piezoelectrics.