Fabrication and piezoelectric analysis based on nanogrid architecture composed of ZnO ultrathin nanosheets grown on fiber paper substrates for wearable energy harvesting

Abstract

In this work, three-dimensional (3D) nanogrid architecture composed of two-dimensional (2D) ZnO ultrathin nanosheets (ZUNSs) is grown on fiber paper substrates by a two-step low-temperature hydrothermal process, and a flexible piezoelectric nanogenerator (PENG) is also developed based on the as-grown ZUNS-paper. Piezoelectric signals were also measured under compressive forces that can harvest energy up to 30 nA and 120 mV. In order to exploit the piezoelectric properties of the unique ZnO nanostructure, a series of simulation experiments based on ZUNSs were conducted systematically through the finite element method (FEM, COMSOL). The size-dependent simulation analysis (including thickness, length, and height) under two different force modes manifests that the ZUNSs possess tremendous merits for optimizing the output performance of piezoelectric nanogenerators, especially in the case of lateral bending. Besides, the anisotropic electricity generation has been investigated and analyzed within the ZUNSs via applying force with various orientations. Our results may provide guidance for the design and performance optimization of wearable self-powered micro/nanoelectric devices.