Influence of annealing temperature on In2O3 – SWCNTs (0.1 wt%) in DSSCs

Abstract

In2O3 is a n – type semiconductor material with excess indium and oxygen atoms that serve as donors by implemented a host electrode in photoanode layer. In this research, Indium oxide – single wall carbon nanotubes (In2O3 – SWCNTs) as a photoanode in DSSCs was successfully fabricated using sol – gel spin coating method. The objective of this work is to determine the optimum annealing temperature vary at 400 C, 450 C, 500 C, 550 C, and 600 C for SWCNTs doping 0.1 wt. % in In2O3 – based DSSCs. The changes in the structural properties were analyzed by means of X-ray diffraction (XRD) and atomic force microscopy (AFM) analysis. X – ray diffraction analysis proved the In2O3 - SWCNTs have a formation of a body center cubic structure. While AFM results indicate the grain have a decrease in rough surface (RMS) from 26.21 nm to 15.17 nm as the annealing temperature increase from 400C to 500C. Above 500 °C, the grain size of In2O3 will back to normal size due to the loss of carbon element from CNTs compound. The optimum annealed temperature was found at 450 C by produced the highest photovoltaic performance with power conversion efficiency (η), photocurrent density (Jsc), open circuit voltage (Voc), and fill factor (FF) of 0.0131 %, 0.29 mA/cm2 , 0.15 V, and 0.302, respectively. The result showed, by increasing the annealing temperature, the carbon element in the CNTs tend to burn out and consequently the thin films remain is the In2O3 nanoparticles without the presence of SWCNTs on the substrate and dropped the photovoltaic efficiency of the cell. The study shows the incorporation of SWCNTs play a role in In2O3 - based DSSCs by enhancing the performance and the efficiency.