Hybrid energy harvester integrating ZnO piezoelectric nanogenerator with perovskite solar cell demonstrating the piezo-phototronic effect

As portable devices and wireless sensors become more ubiquitous and power hungry, new methods are required to power them to avoid an overreliance on batteries. Materials that combine multiple functionalities, such as semiconducting and piezoelectric properties, offer an excellent opportunity to harvest energy from multiple sources in a single device. As such, we report a hybrid energy harvester (HEH) combining a piezoelectric nanogenerator and a perovskite solar cell to simultaneously harvest mechanical and solar energy. The HEH exhibited the piezo-phototronic effect, where strain-induced shifts in the energy bands of ZnO nanorods modulated the photovoltaic (PV) output under mechanical deformation. The output of the HEH under light and oscillation conditions combined PV variations driven by the piezo-phototronic effect and piezoelectric signals generated by the ZnO nanorods. Furthermore, the piezoelectric output showed distinct variations between dark and illuminated conditions, attributed to differences in the electrical conductivity of ZnO and perovskite, which influenced charge screening. Additionally, morphological variations in ZnO nanorods were found to significantly impact performance. Overall, these findings provide guidance for optimizing nanostructures and device designs to enhance multi-source energy harvesting efficiency and further explore the piezo-phototronic effect.