Lead iodide nanosheets for piezoelectric energy conversion and strain sensing

Flexible piezoelectric devices are attractive for energy conversion and strain sensing applications, including in the area of wearable electronics and self-powered sensors. Here, we report a piezoelectric nanogenerator/strain sensor based on lead (II) iodide (PbI2) nanosheets with the shape of two-dimensional (2D) structures, of which the piezoelectricity is not affected by the number of layers. A typical 2D piezoelectric device fabricated with 3 layers PbI2 nanosheets has recorded peak values of open-circuit voltage, short-circuit current and loading power as 29.4 mV, 20 pA, and 0.12 pW, respectively, and also possess good charging and integration capabilities. Moreover, these devices can be applied as self-powered strain sensors, with high sensitivity and excellent stability. As such, this study provides new knowledge and strategy for flexible energy harvesting or strain sensing devices based on 2D structures.