Ultraviolet-protecting, flexible and stable photovoltaic-assisted piezoelectric hybrid unit nanogenerator for simultaneously harvesting ultraviolet light and mechanical energies

Abstract

Owing to the ecological destruction and the energy crisis, harvesting green energy from the environment has become a hot issue in modern times. Here, a facile, flexible and stable hybrid unit nanogenerator (NG) with ultraviolet (UV) protection based on poly(vinylidene fluoride) (PVDF) piezoelectric nanogenerator (PENG) unit and ultraviolet photovoltaic (SC) unit is fabricated. Specially, self-made thiophenyl soluble conjugated polymer (scp)/zinc oxide (ZnO) quantum dots nanocomposite film was prepared by spin-coating in ambient air condition as UV photoelectric and UV-protective thin film. The flexible photovoltaic films were found to exhibit good photovoltaic performance with a dominating fraction of UV absorption. Under external mechanical forces and UV LED illumination, and the open-circuit output voltage and short-circuit current of the device were significantly enhanced by UV LED constant light exposure. To specify this device performance, the effects of different external mechanical forces and UV illumination on the output of hybrid unit are also analyzed, the open-circuit output voltage of the device was significantly influenced by UV illumination. To demonstrate the practical applications of flexible hybrid unit NG, it exhibits high performance with a maximum power density of 0.97 mW/cm3. The device is able to charge a 33-μF capacitor to 3.6 V within a short time span (60 s) and drive a red LED for a few seconds. This work explores new prospects for UV-protective energy harvesting which can eventually boost up the self-powered electronic robotics and wearable systems based on renewable energy.