Comparison of chitosan and chitosan nanoparticles on the performance and charge recombination of water-based gel electrolyte in dye sensitized solar cells

In commercialization of liquid dye-sensitized solar cells (DSSCs), whose leakage, evaporation and toxicity of organic solvents are limiting factors, replacement of organic solvents with water-based gel electrolyte is recommended. This work reports on utilizing and comparison of chitosan and chitosan nanoparticle as different gelling agents in preparation of water-based gel electrolyte in fabrication of dye sensitized solar cells. All photovoltaic parameters such as open circuit voltage (Voc), fill factor (FF), short circuit current density (Jsc) and conversion efficiency (η) were measured. For further characterization, electrochemical impedance spectroscopy (EIS) was used to study the charge transfer at Pt/electrolyte interface and charge recombination and electron transport at TiO2/dye/electrolyte interface. Significant improvements in conversion efficiency and short circuit current density of DSSCs fabricated by chitosan nanoparticle were observed that can be attributed to the higher mobility of I3−due to the lower viscosity and smaller size of chitosan nanoparticles.