Piezoelectric nanocomposites have been a rapidly growing field in energy harvesting, with applications in wearable electronics, strain sensors, mechanical actuators, and electromechanical membranes. Flexible wearable piezoelectric sensors are made by Poly (vinylidene fluoride) (PVDF)-based nanofibers with different types of nano-fillers, such ZnO, Ag:ZnO, graphene, MXene, providing high sensitivity response to applied mechanical strain and converting into electric signals[1-3]. This research reports the use of three-dimensional polymer photonic crystals (PC) with varying ratios grafting onto the piezoelectric fibers to enhance the photosensitivity. Due to its superior elasticity, thermoplastic polyurethane (TPU) was blended with PVDF to obtain high flexibility nanofibers processed by electrospinning. Photonic crystals were synthesized by a chemical reduction method and grafted onto the PVDF/TPU fibers, and photonic piezoelectric sensor devices were fabricated. The piezoelectric responses of different blending ratios of PC@PVDF/TPU were investigated. It was found that PC grafted fibers give higher output voltage at different stress conditions and higher photosensitivity. This work evidenced that PCs help increasing the strain sensitivity and mechanical elasticity of piezoelectric sensors, making it a unique contribution in a new research direction and valuable for future devices. 

Piezoelectric, Wearable sensors, energy harvesting, 3D photonic crystals