Hybrid Energy Harvester Based on Perovskite Solar Cell and ZnO Piezoelectric Nanogenerator

With the consumption of fossil fuels and the increasing awareness of environmental protection, more and more efforts are being put into the development of renewable and clean energy. Mechanical energy is the one of the most abundant and accessible energy sources, and has been widely harvested by large-scale technologies such as wind power or tidal stream generators. Piezoelectric nanogenerators (PENGs) provide a potential way to convert small mechanical energy such as body motion or vibration into electricity, which can be used to power small portable electronics, medical bio implants, remote wireless sensors etc. Also, solar energy offers the potential to provide much higher power levels than motion since the sun delivers more energy to the earth in 1 h than the entire planet consumes in one year. However, light is not always available, nor is movement, therefore a hybrid energy harvester that can make use of both sources provide a more reliable and high-level of power for small, portable or self-powered devices.<br/>Here, a combined solar and piezoelectric hybrid energy harvester (HEH) was designed, fabricated and tested, which combined a PENG and perovskite solar cell with the structure of PET/ITO/ZnO seed layer/ZnO nanorods/perovskite/hole transport layer/Au. Oscillation (NG) and illumination (PV effect) testing indicated that HEHs operated as kinetic and solar energy harvesters both separately and simultaneously. The length and diameter of ZnO nanorods, and the composition of perovskite were optimised to achieve the enhancement of both PV and NG output performance. The coupling effect between perovskite and piezoelectric ZnO nanorods, as known as the piezo-phototronic effect, was also investigated.