The photocapacitor: An efficient self-charging capacitor for direct storage of solar energy

A light-driven self-charging capacitor was fabricated as an efficient solar energy storage device. The device, which we name the photocapacitor, achieves in situ storage of visible light energy as an electrical power at high quantum conversion efficiency. The photocapacitor was constructed on a multilayered photoelectrode comprising dye-sensitized semiconductor nanoparticles/hole-trapping layer/activated carbon particles in contact with an organic electrolyte solution, in which photogenerated charges are stored at the electric double layer. Repeated charge-discharge cycles with a charging voltage of >0.45V yielded a capacitance of 0.69Fcm−2.