Photovoltaic Characteristics of a Dye-Sensitized Solar Cell (DSSC) Fabricated by a Nano-Particle Deposition System (NPDS)

Abstract

Nano particle deposition system (NPDS) was evaluated for the potential photoelectrode fabrication method for dye-sensitized solar cell (DSSC). TiO₂ powders as a photoelectrode for DSSC, were fabricated via NPDS and screen printing methods to compare its photovoltaic characteristics. The NPDS is a novel system for depositing ceramic and metallic powders on substrates at room temperature without using solvents by accelerating particles to supersonic velocity. The conventional method for preparing working electrodes uses TiO₂ paste where poor adhesion to the substrate and numerous steps to properly disperse the powders are the main problems. To overcome these issues, TiO₂ powders were directly sprayed onto ITO glass using the NPDS. The nano-sized TiO₂ particles were densely deposited, no adhesion problems were noted and the solar-cell properties were improved. The photovoltaic performance of a cell having TiO₂ layers first deposited by the NPDS method and then deposited by the paste method was compared to a cell fabricated only using the NPDS and only using the paste. A light conversion efficiency of 3.5% was obtained for the former cell, which indicates synergy effect of using these two methods. The screen-printing step right after NPDS deposition served to densify the TiO₂ film, which decreased the series resistance. Therefore, NPDS was found to be a promising approach for improving DSSC properties and efficiencies.