Characterization of Dye-Sensitized Solar Cell with Different Nanoparticle sizes

Abstract

The Dye-sensitized Solar Cell (DSSC) has been regarded as the next-generation solar cell because of its simple and low cost fabrication process. The experiments for optimizing the cell efficiency were carried out in this work include varying the TiO₂ layer thickness on the working electrode and determining the most favorable nanoparticle size in the TiO₂ paste. The TiO₂ electrode or working electrode was fabricated using screen printing technique with the Coatema tool with thicknesses ranging from ~20 to 66 μm. It was observed that both open circuit voltage and short circuit current were found to have measurable dependence on the TiO₂ layer thickness. The open circuit voltage changed from 0.77 to 0.82 V and correspondingly the short circuit current also varied from ~19 to 23 mA/cm² depending on the TiO₂ layer thickness. Additionally, the cell with 40 μm TiO₂ thickness showed 9.06% photo conversion efficiency compared to 6.4% and 8.5% efficiency obtained for the cells with 20 μm and 66 μm TiO₂ thicknesses respectively. The second part of the experiment was conducted using three different nanoparticle sizes of 13 nm, 20 nm and 37nm in the TiO₂ layer to identify optimum nanoparticle size by maintaining the TiO₂ film thickness at 40 μm. The cell with 20 nm size nanoparticle, in combination with 40 μm TiO₂ thickness showed 11.2% efficiency that is in par or slightly better than the efficiency value reported for the DSSC in the literature as of now. The work described in this paper showed best possible values for the TiO₂ layer thickness and nanoparticle size in the TiO₂ for obtaining improved cell efficiency of 11.2%.