Facile synthesis of Au@TiO2 nanocomposite and its application as a photoanode in dye-sensitized solar cells

Abstract

In the present investigation, gold-decorated TiO₂ (Au@TiO₂) plasmonic nanocomposite materials were successfully prepared through a simple one-step chemical reduction method without using any stabilizer or surfactant. These materials were then used as efficient photoanodes in dye-sensitized solar cells (DSSC). The prepared nanocomposite materials were characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) mapping, X-ray diffraction (XRD), photoluminescence (PL) and Raman analyses. The DSSC assembled with the Au@TiO₂-modified photoanode demonstrated an enhanced solar-to-electrical energy conversion efficiency of 5.61%, which was higher than the unmodified TiO₂ photoanode (2.55%) under full sunlight illumination (100 mW cm⁻², AM 1.5 G). This enhanced efficiency is mainly attributed to the plasmonic effect, reduction in the band gap energy, improved interfacial charge transfer, and retarded charge recombination process. The influence of the Au content on the overall efficiency was also investigated, and the optimum Au content with TiO₂ was found to be 2.5 wt%. The significant improvement in the solar energy conversion efficiency with the Au@TiO₂-plasmonic nanocomposite showed its potential as a photoanode for high-efficiency DSSC.