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.