Series Circuit of Organic Thin-Film Solar Cells for Electrochemical Conversion of Water into Hydrogen

Series circuit of organic thin-film solar cells (OSCs), which are bulk hetero-junction (BHJ) solar cell composed of poly(3-hexylthiophene) (P3HT) as a donor and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as an acceptor, has been investigated for electrolyzing water to hydrogen and oxygen gases. The cell performance parameters of OSC, such as the annealing time, P3HT/PCBM film thickness and the conductivity of PEDOT/PSS film were optimized. The series circuit of 6 unit OSCs shows the open circuit voltage (Voc) of 3.48 V, which is enough for electrolyzing water. By combination of water electrolysis cell using carbon supported Pt nanoparticles cathode and Ni anode, and the series circuit solar cells, the electrolyzing current and voltage are obtained to be 2.7 mA/cm2 and 2.2V, respectively under the simulated solar light irradiation. Hydrogen is generated to 0.5 mL after an hour irradiation.