The effect of TiO2 photo anode film thickness on photovoltaic properties of dye-sensitized solar cells

Nanocrystalline titanium dioxide (TiO₂) photoanodes with four different film thicknesses from 5.57μm to 20.65μm were prepared by doctor-blade technique. Performance of dye sensitized solar cells (DSSCs) fabricated with these photoanodes were studied using current-voltage characteristics and incident photon-to-current conversion efficiency (IPCE) measurements. Electrochemical impedance spectroscopy (EIS) was used to analyze the effect of TiO₂ film thickness on the charge transfer resistance and electron life time in the solar cells. Voltage decay measurements were used to study the recombination process of photo generated charge carriers. These studies revealed that the photovoltaic properties of DSSCs largely depend on the film thickness of TiO₂ photoanode. Further, the DSSCs fabricated using a TiO₂ film of 12.73 μm thickness exhibited the best photovoltaic performance with highest incident photon-to-current conversion efficiency, highest short-circuit photocurrent, lowest charge transfer resistance, highest electron life time and lowest recombination life time.