Enhanced Photoelectrochemical Activity of Green‐Capped TiO ₂ Photoelectrodes for DSSC Application

Abstract The dye‐sensitized solar cell (DSSC) is a favourable option for solving the global energy challenge, but its efficiency is still low. The improvement of its efficiency will depend on the development of new TiO 2 photoelectrodes, amongst others. We report herewith the green‐capping of TiO 2 through a straightforward sol‐gel method at a minimal temperature (45 °C), with extracts from three plants, Hibiscus Sabdariffa (HS), Lawsonia inermis (LI), and Lonchocarpus cyanescens (LC). UV‐visible spectroscopy (UV–vis), Raman spectroscopy, Photoluminescence spectroscopy (PL), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy with energy dispersive X‐ray spectroscopy (SEM‐EDX) were applied to characterize the samples. The photoefficiency of the green‐capped TiO 2 Photoelectrodes was investigated through Cyclic voltammetry (CV). Calcinations at 450 °C revealed an anatase stabilization in the order: LC‐TiO 2 > HS‐TiO 2 > LI‐TiO 2, with LC‐TiO 2 being 100% anatase. Capped TiO 2 has better crystallites, possesses suppressed recombination, and exhibits a higher rate of electron transfer. LC and LI‐capped TiO 2 have anodic to cathodic peak difference (ΔE) of 0.32 and 0.46 V, respectively, compared to 0.64 V for the uncapped TiO 2 . These newly stabilized TiO 2 can find applications in DSSC as photoelectrodes. This study opens a new way for harnessing affordable and clean energy using green‐synthesized nanomaterials alternatives.