| Summary: | This study highlights the photovoltaic and electron transport properties of TiO2-SiO2-nickel-graphene oxide (GO) composite thin films annealed at various annealing temperatures. (SiO2)100-x-Nix (x = 7.5 wt.%) was synthesized using sol–gel method. The TiO2-(SiO2)-Ni-GO composite photoanodes were fabricated using doctor-blade technique for the usage of dye-sensitized solar cells (DSSCs). The objective of this research is to enhance the photovoltaic conversion efficiency of TiO2-SiO2-nickel-GO thin films by finding the optimum annealing temperature. Gel polymer from PAN-based is used as the electrolyte in this research. The crystalline structure, morphology, and the chemical properties of the thin films with various annealing temperatures will be reported. X-ray diffraction, field-emission scanning electron microscopy, and mapping analyses revealed that the synthesized nanoparticles had uniform nanometer grains with different phase composition and the crystallite sizes increase with annealing temperature from 30.14 to 42.43 nm. Energy dispersion X-ray and Fourier transform infrared spectroscopy also identified the elements and bonding that are associated with TiO2, SiO2, and other additional dopants. The performances of the photovoltaic were analyzed using J–V measurement and electrochemical impedance spectroscopy. The annealing treatment was able to modify the surface morphology whereby necks were developed on the surface due to high surface diffusions. The fine nanoparticles of thin films annealed at 350 °C showed more porosity with a high effective electron chemical diffusion coefficient that helped to improve the short-circuit current density in DSSC. The annealing treatment shows that the sheet resistance (Rs) increases with the increase in annealing temperature. It was also observed that the particle grains increased in numbers with the annealing temperature. It can be concluded that the photoanode annealed at 350 °C exhibited better photovoltaic performance at the highest power conversion efficiency of 3.40% due to having more porous structure, low recombination effect, and a large diffusion rate.
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