Photovoltaic Properties of an rGO/Pt Counter Electrode With AZO Photoanode for Dye-Sensitized Solar Cells Under Low Light Intensity

Abstract

This study used reduced graphene oxide (rGO) applied to a platinum (Pt) counter electrode to improve light conversion efficiency. The study also used an Al-doped Zinc Oxide (AZO) nanosheet/TiO2 photoanode for the dye-sensitized solar cell (DSSC). Photovoltaic characteristics, electrochemical impedance spectroscopy (EIS), field-emission scanning electron microscopy (FE-SEM) and Raman spectroscopy were used to analyze DSSC. The different light intensities and photovoltaic characteristics were analyzed to determine optimal light intensity conditions. The unmodified Pt counter electrode was compared with the rGO/Pt counter electrode, photovoltaic conversion efficiency ( ${\eta }$ ) increased from 3.60% to 4.04% due to the rGO modification as it possesses a higher specific surface area. Its low cost also makes it suitable for mass production. In addition, an AZO nanosheet/TiO2 photoanode was fabricated to form a double-layer structure in which photovoltaic conversion efficiency was 4.47 %. Finally, a DSSC with an AZO/TiO2 photoanode and rGO/Pt counter electrode was fabricated and had an photovoltaic conversion efficiency of 5.05 %. This study also analyzed the photovoltaic parameters of DSSC under different light intensities, which shows the optimal photovoltaic conversion efficiency of 5.54% under 30mW/cm2.