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

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 similar to 61% in comparison with a pristine TiO2 photoelectrode. (C) 2014 Elsevier Inc. All rights reserved.