Photovoltaic Performance of Dye-Sensitized Solar Cells under Low Illumination by Modification of a Photoanode with ZnFe2O4/TiO2 Nanofibers

In this study, the content of ZnFe 2 O 4 /TiO 2 nanofibers were synthesized by electrospinning technology with various ratios of 1%, 3% and 5%. Then ZnFe 2 O 4 /TiO 2 nanofibers were applied to modify photoanodes of dye-sensitized solar cells (DSSCs). This study demonstrates that the conversion efficiency under different light intensities of the DSSC modified by 3% ZnFe 2 O 4 /TiO 2 nanofibers is superior to that of the other DSSCs. At a light intensity of 100 mW/cm 2 , the efficiency is 5.78%, which is 69.5% improvement over the pure TiO 2 -based DSSC (3.41%). The conversion efficiency of the DSSC modified by 3% ZnFe 2 O 4 /TiO 2 nanofibers is the highest about 7.92% at a light intensity of 30% mW/cm 2 . The critical role of ZnFe 2 O 4 in promoting photovoltaic performance is demonstrated by use of incident photocurrent conversion efficiency (IPCE) and electrochemical impedance spectroscopy (EIS). EIS analysis confirms that the DSSC modified by 3% ZnFe 2 O 4 /TiO 2 nanofibers possesses superior photoelectrochemical performance with a maximum IPCE value of 49% at a wavelength of 530 nm. The DSSC modified by 3% ZnFe 2 O 4 /TiO 2 nanofibers does not only have high efficiency, but also improve the dye adsorption performance.