Optical, morphology and electrical properties of In2O3 incorporating acid-treated single-walled carbon nanotubes based DSSC

Abstract

This study focuses on the influence of an acid treatment process of single-walled carbon nanotubes (SWCNTs) in In2O3-based dye-sensitized solar cells (DSSCs). Pure In2O3, In2O3-SWCNTs with acid treatment and In2O3-SWCNTs without acid treatment were prepared using the sol–gel method via a spin coating technique annealed at 450 °C. The optical, morphology and electrical properties of the photoanodes were characterized by means of UV–Vis analysis, atomic force microscopy and field-emission scanning electron microscopy, and J–V curve measurements, respectively. The optical band gap obtained through UV–Vis analysis showed that the acid treatment process modified the band gap of the photoanode, which enhances the Voc of the DSSCs. In addition, In2O3-SWCNTs with acid treatment possess a porous structure that improves the power conversion efficiency (PCE) of the DSSCs. In addition, the diameter of acid-treated SWCNTs was reduced compared to pristine SWCNTs. In2O3-SWCNTs with acid treatment exhibited the highest PCE of 1.40% with Jsc of 7.6 mA cm−2, Voc of 0.51 V, and fill factor of 0.36. The increment in Voc is due to the higher band gap obtained through the UV–Vis absorption spectrum. Moreover, In2O3-SWCNTs with acid treatment has a higher electron lifetime with a higher effective diffusion coefficient that slows down the recombination rate and speeds up the electron transport process.