Lead free halide perovskite embedded PVDF based efficient mechanical energy harvester: Self-driven respiratory sensor

Lead-free inorganic perovskites have emerged as a promising material for energy harvesting applications, owing to their superior optoelectronic properties. This enables the insertion of lead-free halide perovskites into polyvinylidene difluoride (PVDF) to feasibly enhance its piezoelectric coefficient. Consequently, piezoelectric nanogenerators based on PVDF composite have evolved as a futuristic, sustainable, and renewable energy alternative due to their flexible, durable, and nontoxic behavior. Herein, we realized a novel composite by incorporating different mass-fractions of pre-synthesized CsCuCl3 particles in the polymer matrix. Notably, the composite containing 4 wt% CsCuCl3 perovskite nucleates an optimum electroactive phase fraction of about ∼93 %. A first-principles investigation is also carried out in order to fully comprehend the interfacial interaction of the PVDF dipole with the CsCuCl3 system. Thereafter, the piezo-sensors are fabricated utilizing the composites, where the 4 wt% CsCuCl3/PVDF- based device delivered optimal output performance owing to its highest electroactive phase. This optimized device, viz., PNG 4 achieves an open-circuit voltage and short-circuit current of ∼73.2 V and ∼5.44 μA, respectively. Besides, the optimized device could operate as a piezo-resistive sensor as well as a pressure sensor. An excellent sensing performance was achieved from the PNG 4 device, where the sensing parameter (∆II0) reached values as high as ∼98.7. The optimized device is efficient in the low-pressure region and exhibits a high sensitivity of 13.8 kPa−1 with notable response ≤26ms and recovery time≤75ms. Furthermore, the device is capable of sensing different bending states with a sensitivity of 0.5/degree, which proves its potential for applications in human health care monitoring regarding self-powered real-time respiratory monitoring systems.