NH3-treated WO3 as low-cost and efficient counter electrode for dye-sensitized solar cells

Abstract

A novel low-cost and efficient counter electrode (CE) was obtained by treating catalytic inert tungsten trioxide (WO 3 ) nanomaterial in NH 3 atmosphere at elevated temperatures. The formation of tungsten oxynitride from WO 3 after NH 3 treatment, as evidenced by X-ray photoelectron spectroscopy and X-ray diffraction, increases the catalytic activity of the CE. Correspondingly, the power conversion efficiency (PCE) of the DSC is significantly increased from 0.9% for pristine WO 3 CE to 5.9% for NH 3 -treated WO 3 CE. The photovoltaic performance of DSC using NH 3 -treated WO 3 CE is comparable to that of DSC using standard Pt CE (with a PCE of 6.0%). In addition, it is also shown that NH 3 treatment is more efficient than H 2 or N 2 treatment in enhancing the catalytic performance of WO 3 CE. This work highlights the potential of NH 3 -treated WO 3 for the application in DSCs and provides a facile method to get highly efficient and low-cost CEs from catalytic inert metal oxides.

Counter Electrode Impact on Quantum Dot Solar Cell Efficiencies

“…Li et al used NH 3 -treated WO 3 as a CE in a DSSC, and it delivered a PCE of 5.9%, which was comparable to the PCE of the cell with Pt as CE (6.0%). 36 Here, we observed that with WO 3 /FTO and WO 3−x /FTO as CEs in QDSCs the PCEs are higher at 2.1 and 3.66% compared to that obtained with Pt as the CE (1.69%) reiterating that other catalytic materials are better performers compared to Pt in QDSCs and thus contrasting the trends observed in DSSCs. With carbon soot as CE and TiO 2 /CdS as the photoanode, the authors in ref 15 reported a PCE of 1.16%, which is lower than the value obtained here with soot (2.95%).…”