Human motion interactive mechanical energy harvester based on all inorganic perovskite-PVDF

Benefited with the advantage of easy assembly and conformal structure, flexible and self-powered piezoelectric nanogenerators (PNGs) have become a sustainable and accessible energy alternative. Here, novel piezoelectric sensor is fabricated by a composite of room temperature processed all-inorganic cesium lead bromide (CsPbBr3) perovskite rod and polyvinylidene fluoride (PVDF) nanofiber. CsPbBr3 enables nucleation of electroactive beta phase in PVDF >90% and makes it suitable for piezoelectric energy harvesting. Piezoelectric energy generation from the devices has been investigated under several simple human movements like hammering by hand, finger touch, toe pressing, bending by arm, etc. Optimized CsPbBr3-PVDF composite (with 5 wt% of CsPbBr3 loading) based PNG delivered an output power 4.24 mW with high open-circuit voltage of 120 V and short-circuit current of 35 mu A. Such high output value for the composite sample suggests much improved energy conversion efficiency as compared to the building blocks separately. Fatigue test of the PNG under continuous mechanical impact (over 4 months) showed its possibilities as a robust wearable mechanical energy harvester. This device is also able to light up several commercial LEDs. Increase in output values is attributed to the improved polarization in PVDF by CsPbBr3 incorporation. Additionally, photosensitivity of the composite is demonstrated under light, which indicates its potential as photodetector. Considering the photoresponse and electroactive features, a new class of self-powered photoactive piezoelectric energy harvester has also been fabricated. Such results highlight the rational design of all inorganic perovskite based nanoforms in maximizing device performance and thereby providing a useful pathway to develop new materials for piezo-phototronics.