Improved performance of dye-sensitized solar cells using gallium nitride–titanium dioxide composite photoelectrodes

• About 60% increase in power conversion efficiency has been achieved.
• Charge transfer resistance is reduced with GaN–TiO2 composite photoelectrode.
• This method is potential to develop high-performance DSSCs.

Dye-sensitized solar cells (DSSCs) are fabricated with gallium nitride–titanium dioxide (GaN–TiO2) composite photoelectrodes to enhance the power conversion efficiency. The value of power conversion efficiency increases with the incorporation of GaN in TiO2 matrix and reaches a maximum at 0.05 wt% GaN. Internal resistance in the DSSC is characterized by electrochemical impedance spectroscopy (EIS). From the EIS of electrolyte/dye/GaN–TiO2 interface resistances under illumination and in the dark, a decrease in the charge transfer resistance and an increase in the charge recombination resistance of the DSSCs are obtained after the inclusion of GaN (0.01–0.05 wt%) in the TiO2 matrix. The power conversion efficiency of the DSSC based on the GaN (0.05 wt%)-TiO2 composite photoelectrode is enhanced by ∼61% in comparison with a pristine TiO2 photoelectrode.

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