Energy conversion into hydrogen gas using series circuit of organic thin-film solar cells

Series circuit of six organic thin-film solar cells (OSCs) consisting of poly(3-hexylthiophene) and PCBM has been fabricated in order to electrolyze water into hydrogen and oxygen gases. The open circuit voltage increases linearly with the number of unit cells and becomes 2.9V at the six unit cells. On the other hand, the short circuit current, the fill factor and the energy conversion efficiency are almost constant, independent of the number of unit cells. The series circuit of six OSCs was combined with the water electrolysis cell with two platinum electrodes. Hydrogen and oxygen gases were generated at each platinum electrodes of the electrolysis cell under illumination. The operating current and voltage was determined to be 1.3mA/cm² and 2.6V, respectively.