Synthesis and structural, optical and photovoltaic characteristics of pure and Ag doped TiO2 nanoparticles for dye sensitized solar cell application

Abstract

The Pure titanium oxide (TiO2) and Ag doped (0.04 mol%) TiO2nanoparticles (NPs) were prepared by microwave-assisted method, and were characterized by various techniques. The XRD patterns of both samples suggested the presence of anatase tetragonal structure. The Rietveldrefinements on XRD plots of both samples by GSAS package confirmed the proper incorporation of Ag at TiO2 lattice. The SEM-EDS analysis revealed that the presence of spherical-shaped NPs with the expected elements in proper ratio. The Raman spectroscopy analysis also confirmed the incorporation of Ag nanoparticles at TiO2lattice by showing the drastically decreased intensity while comparing with pure TiO2NPs. The UV–Vis spectroscopy results confirmed the presence of direct band gap in both the samples; however Ag doping reduces the optical band gap but increases Urbach energy, which is the clear indication of red shift in Ag doped TiO2 NPs. The Photoluminescence spectra confirmed the presence of the defects like oxygen vacancies, however, these defects are increased in Ag doped TiO2 system. So, as expected, the photovoltaic measurements showed very slight increase in power conversion efficiency of Ag doped TiO2 NPs. These optical and photovoltaic results of Ag doped TiO2 NPs were correlatively discussed to bring the broad understanding for device fabrications successfully.