Dye - Sensitized Solar Cell Photoanode Based on Silver – Doped Titanium Dioxide Nanoparticles

Abstract

Silver - doped titanium dioxide (Ag-TiO2) nanoparticles were prepared from TiO2 (P25, Degussa) and silver nitrate (AgNO3) by gamma Co-60 irradiation method with various initial concentration of AgNO3 (0.1 – 0.75%, w/w). The formed silver nanoparticles and optical band gap of Ag-TiO2 films were investigated by XRD, XRF, TEM and UV-Vis spectrocopy. The silver nanoparticles with grain size about 17 – 20 nm are woven on TiO2 nanoparticles and decrease the optical bandgap of TiO2 film. Ag-TiO2 nanoparticles were used to fabricate photoanode in N719-dye-sensitized solar cells (DSCs). Under full sunlight illumination (1000 W/m2, 1.5 AM) the DSC assembled with Ag-TiO2 (0.75% AgNO3) photoanode has shown a 25% increase in energy conversion efficiency compared with the DSC using undoped TiO2 photoanode. The improvement of energy conversion efficiency was attributed to enhanced photocurent of the cell. The effect of silver dopant content on DSC performance was also studied by electrochemical impedance spectrocopy. The impedance arc at intermediate frequency region in Nyquist plots are reduced with the concentration of AgNO3 precursor, demonstrating that charge transfer at TiO2/dye interface was improved in the presence of silver dopant. The Ag- TiO2 nanoparticles synthesized by gamma Co-60 irradiation method have shown themselves as promising photoanode materials for DSCs. This work may inspire new ideas for constructing high-performance photoanodes for large scale DSCs