An efficient photoanode for dye sensitized solar cells using naturally derived S/TiO₂ nanoparticles

Natural mineral rutile sand is used for preparing titania (TiO₂) nanoparticles employing a cost-effective simple chemical method and mass production technology. Further the sulfur doped (S/TiO₂) and pure TiO₂ are produced from chemical precursor also. Different techniques are used to analyse the effect of sulfur dopant like x-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, x-ray photoelectrons spectroscopy, ultraviolet–visible spectra, photoluminescence, Brunauer–Emmett–Teller analyser, field emission scanning electron microscopy with energy-dispersive x-ray analysis, and high-resolution transmission electron microscopy. Under visible light, a useful procedure is followed on the sulfur-doped samples preparation, enhancing the charge carrier recombination, and reducing crystallite size. In the improvement of the efficiency of dye-sensitized solar cells, this dopant could open up vast opportunities; consequently, our work is extended to apply these prepared samples in standard dye-sensitized solar cells. The photoanode of dye-sensitized solar cells are made up of these prepared materials (S-doped TiO₂ and pure TiO₂) and compared with both commercial TiO₂ (P-25) powder, as well as commercially available paste (Dyesol). The S/TiO₂ nanoparticles on dye-sensitized solar cells exhibit enhanced ultra-violet visible light absorbance with increased photogenerated electrons and holes meanwhile reduce the recombination rate of charge carriers in dye-sensitized solar cells. Further, the overall power-conversion efficiency ( η ) and external quantum efficiency of the S/TiO₂ cells ( η   =  4.32% and EQE  =  32%) is two times higher than that of pure TiO₂ cells ( η   =  2.75% and EQE  =  16%). (paper)