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.