Effect of TiOx and TiO2 Layer on the Photovoltaic Property of BiOI Films

Abstract

This study aims to investigate the impact of mesoporous and compact layers, like TiO2 and TiOx on the photovoltaic performance of bismuth oxyiodide (BiOI) films. BiOI thin films were prepared using the spin-coating method for 10 cycles onto FTO glass, FTO/TiOx, FTO/TiO2, and a combination of FTO/TiOx-TiO2 layer. Then, the resulted films were characterized on their optical, structural, and photovoltaic properties. By adding the TiOx or TiO2 layer into the cell, it resulted in the shifting of UV-Visible absorbance to a longer wavelength. On the structural property analysis, Raman spectra showed an overlapping peak among TiOx, TiO2, and BiOI films. Moreover, the solar cell was successfully developed using iodine electrolyte and Pt-counter electrode. By the photovoltaic analysis, it was known that the combination of those layers of metal oxide nanomaterials could give a slight improvement on the short-current density and open-circuit voltage of BiOI thin films. Therefore, the overall BiOI photovoltaic parameter was enhanced.