Unconventional Photocapacitor Utilizing Metal–Organic Dye Capable of Operating in Low Intensity Light

The development of devices capable of storing energy harnessed from photons is on the rise, owing to the increasing global energy demand for smart systems. The majority of reports in this field cover the use of integrated type devices, which houses a separate photovoltaic module and supercapacitor or battery. Herein, we are reporting a photocapacitor with a simple two-electrode design, capable of operating without a conventional electrolyte or metal ions. The device prepared using a layered architecture of reduced graphene oxide (rGO) and TiO 2 on both electrodes and N719 dye as a photoactive material resulted in a capacitance of 20.3 F/g. Optimizing the number of rGO and TiO 2 layers led to an enhanced diffusion of photons to the N719 dye, thus leading to better absorption characteristics. Interestingly, the developed photocapacitor could also be recharged with low intensity light (<300 lx). The capacitance was further improved by more than twice (43.5 F/g) upon substituting the back electrode with conducting carbon and the capacity retention was over 93% after 50 cycles. The current work opens wide possibilities for developing efficient two-electrode photocapacitors.