A dual-functional Pt/CNT TCO-free counter electrode for dye-sensitized solar cell

Abstract

A nanohybrid of platinum and carbon nanotubes (Pt/CNT) with dual functions of catalytic activity and conductivity was synthesized. The selection of the poly(oxyethylene)-backboned polyimide dispersant was essential for preparing the dispersion with the de-bundled CNTs and platinum salts in ethanol/water. Subsequent solution casting and annealing at the optimized temperature of 390 °C led to the in situ reduction of platinum salts and the formation of a thin film of Pt/CNT nanohybrids on the glass substrate. The film was used directly as the counter electrode (CE) in a dye-sensitized solar cell (DSSC), which exhibited a short-circuit current density of 16.6 ± 0.2 mA cm⁻² and a power conversion efficiency of 6.96 ± 0.09% at 100 mW cm⁻² illumination. This performance is comparable with a DSSC with a conventional Pt-CE, and feasible for replacing the conventional transparent conductive oxide (TCO) conductive layer in DSSCs.