Voltage Generation in Optically Sensitive Supercapacitor for Enhanced Performance

An optically sensitive solid-state supercapacitor (SSC) is presented for direct utilization of optical energy for charge storage in a compact opto-electrochemical system. Optically and electrochemically active, energy efficient heterostructure nanomaterials of zinc cobalt oxide and zinc oxide (ZCZO) nanorods (NRs) were used as electrodes for the SSC, where the energy storage performance of the as-fabricated SSC displays highly sensitive behavior toward ultraviolet (UV) illumination, where the photoinduced electrons under UV radiation notably participate in the energy storage process that boosts the overall charge storage capacity (174%) of the SSC. The photogenerated areal capacitance and energy density under UV were found to be 150 μF/cm2 and 11.8 × 10–3 μWh/cm2. Moreover, SSC can be charged by exposure to UV radiation without any integration of an external electrical power source, where the self-generated voltage in the SSC was measured to be 350 mV under the UV illumination, which is much higher than so-far-presented self-powered SSCs.