Sb2S3-Sensitized Photoelectrochemical Cells: Open Circuit Voltage Enhancement through the Introduction of Poly-3-hexylthiophene Interlayer

The Sb 2 S 3 -sensitized photoelectrochemical cells (Sb 2 S 3 –SPECs) in cobalt electrolyte were fabricated by depositing Sb 2 S 3 on the macroporous TiO 2 nanorods electrodes and consecutively spin-coating P3HT (Poly-3-hexylthiophene) interlayer to relieve the mass transport problem at vicinity of Sb 2 S 3 and cobalt redox couples and reduce the backward recombination. Through the introduction of P3HT interlayer, we could greatly enhance the power conversion efficiency of Sb 2 S 3 –SPEC to 4.2% at 1 sun illumination, whereas the Sb 2 S 3 –SPEC without P3HT interlayer exhibits 3.2% of device efficiency. The electrochemical impedance analysis let us know that the improved device performance was mainly attributed to the reduced backward recombination building up the higher open circuit voltage.