Enhanced electronic contacts in SnO2–dye–P3HT based solid state dye sensitized solar cells

Abstract

We present an investigation on the optimisation of solid-state dye sensitized solar cells (SDSCs) comprising mesoporous tin oxide photoanodes infiltrated with poly(3-hexylthiophene-2,5-diyl) (P3HT) hole conductor and sensitized with an organic dye. We chose both the SnO₂ and P3HT for their high charge carrier mobilities and conductivities, but as a result preclude conventional device configurations because of high leakage current and low shunt-resistance. To minimize the “hole leakage current” through the FTO anode, we employed a double compact layer structure, and to minimize “electron leakage current” at the silver cathode, we developed a protocol for depositing an optimal P3HT “capping layer”. After optimisation of cell fabrication, the electron lifetime is increased considerably and the solar cells exhibited simulated AM1.5 full sun solar power conversion efficiencies in excess of 1%.