Charge transfer and recombination kinetics in dye-sensitized solar cell using static and dynamic electrical characterization techniques

• An impedance-based electrical model incorporates charge transfer and recombination.
• Validation of model with actual performance of DSSC fabricated in our laboratory.
• Effect of illumination and temperature on the performance of DSSC is studied.
• Influence of recombination during electrolytic charge diffusion is evaluated.

This study investigates the steady-state current–voltage characteristics, electronic and ionic processes and dynamic response of a TiO2 nanoparticle based dye-sensitized solar cell (DSSC) using impedance spectroscopy and current–voltage measurements. A dye-sensitized solar cell is fabricated with 12.26 μm thick TiO2 layer, having power conversion efficiency of 2.9% under AM1.5 spectrum with photo-generated current density (JSC) of 7.2 mA cm−2 and open-circuit voltage (VOC) of 672 mV. The observed electrochemical phenomenon at the TiO2–electrolyte interface, in diffusion of electrolyte and in charge transfer at the counter electrode is mathematically modeled using alternating current (AC) electrical equivalent circuit. The effect of temperature and illumination on the steady state and dynamic parameters of dye-sensitized solar cells is also studied. The dynamic resistance of DSSC decreases from 440.7 Ω to 78.6 Ω with increase in illumination level from 20 mW cm−2 to 100 mW cm−2.