The effect of photo-anode surface morphology and gel-polymer electrolyte on dye-sensitized solar cells with natural dyes

There is increasing demand for highly stable and solid-state dye-sensitized solar cells (DSSCs) for renewable energy resources. Following this concern, we have fabricated DSSCs using different thicknesses thin films of TiO2 photo-anode, graphite film as cathode and extracted natural dyes from fruits and vegetables as sensitizers. The effect of natural dye molecules on TiO2 particles and photon-electron conversion efficiencies were studied. Microstructures of photo-anodes, cathodes and the functional groups of the extracted dye molecules and their conjunction with TiO2 films were analyzed using scanning electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy, respectively. A mixture of polyvinylpyrrolidone and iodine has been used to prepare a polymer-gel electrolyte, and it confirms the promising behavior of highly stable and solid-state DSSCs. Amongst a variety of natural dyes extracted from fruits, jabuticaba skin dye shows better performance of the DSSCs in this work. The obtained results show that the thickness of the photo-anode thin film influences directly on the photovoltaic performance.