Transparent Photovoltaics with Array ZnO/NiO Structure for Energy Harvesting and Human Interface Applications

In this study, a proof of concept for seamless energy flow is demonstrated by converting light energy into electrical energy and then storing it. A simple heterojunction structure of an FTO/ZnO/NiO/AgNWs/ZnO array transparent photovoltaic (TPV) device is employed to ensure an excellent average visible transmittance value of 67.7% while storing light energy as electrical energy in a capacitor bank. By simple and stable array connection of unit cell devices, the power leakage is minimized while maximizing output voltage. In the array TPV device, an open-circuit voltage of 1.4 V is achieved under 365 nm illumination, with a voltage of 1.26 V stored in the capacitor bank, accumulating to over 6 V. The stored electrical energy is successfully converted for use by an light-emitting diode (LED) light source, demonstrating sustained light-up for over 30 s. This work explores facile energy generation, storage and utilization through TPVs, with a good potential for transparent energy harvesting and human interface applications.