Integration of solid-state dye-sensitized solar cell with metal oxide charge storage material into photoelectrochemical capacitor

A solid-state photo-rechargeable capacitor (photocapacitor) is obtained here by coupling a dye-sensitized solar cell and a ruthenium oxide based electrochemical capacitor. This integrated system permits direct storage of energy generated by sunlight within a single optoelectronic microelectrochemical device. It utilizes three planar electrodes arranged sequentially to include a polymer hole conductor (poly-(3-hexylthiophene-2,5-diyl)), between the titanium oxide photoanode modified with dye (E)-3-(5-(4-(Bis(20,40-dibutoxybiphenyl-4-yl)amino)phenyl)thiophen-2-yl)-2-cyanoacrylic acid (D35) and the intermediate silver electrode as well as two hydrous ruthenium oxide layers (separated by protonically conducting Nafion™ membrane) between the intermediate (silver) and the external (counter) electrode. Upon integration of the capacitor and dye-sensitized solar cell into a single photocapacitor hybrid device, the following parameters were obtained under simulated 100 mW cm−2 solar illumination: specific capacitance, 407 F g−1 (3.26 F cm−2); energy and power densities, 0.17 mWh cm−2 and 0.34 mW cm−2 and coulombic efficiency, 88%. These data together with results of experiments performed at different light intensities (10–100 mW cm−2) are consistent with very good performance of the optoelectronic device under various light conditions.

► An integrated microelectrochemical device for solar energy storage is reported here. ► The system defined as photocapacitor consists of dye solar cell and supercapacitor. ► The device operates under various light conditions including low light intensity. ► Energy conversion efficiency (including storage) of 0.8% has been obtained.