Flexible Piezoelectric Energy Harvesters with Mechanoluminescence for Mechanical Energy Harvesting and Stress Visualization Sensing

Abstract Flexible piezoelectric energy harvesters (FPEHs) have wide applications in mechanical energy harvesting, portable device driving, and piezoelectric sensors. However, the poor output performance of piezoelectric energy harvesters and the intrinsic shortcoming of piezoelectric sensors that can only detect dynamic pressure limit their further applications. BaTiO 3 (BT) and PVDF are deposited on the glass fiber electronic cloth (GFEC) by impregnation and spin‐coating methods, respectively, to form BT‐GFEC/PVDF piezoelectric composite films. A mixed solution of mechanoluminescence (ML) particles ZnS:Cu and PDMS are used as the encapsulation layer to construct a high‐performance ML‐FPEH with self‐powered electrical and optical dual‐mode response characteristics. Due to the interconnection structure of the piezoelectric films, the prepared ML‐FPEH illustrates a high effective energy harvesting performance (≈58 V, ≈43.56 µW cm −2 ). It can also effectively harvest mechanical energy from human activities. More importantly, ML‐FPEH can sense stress distribution of hand‐writing via ML to achieve stress visualization, making up for the shortcomings of piezoelectric sensors. This work provides a new strategy for endowing FPEH with dual‐mode sensing and energy harvesting.