Nanocomposites of Bi 5 FeTi 3 O 15 with MoS 2 as novel Pt-free counter electrode in dye-sensitized solar cells

Abstract Bi 5 FeTi 3 O 15 (BFTO) nanofibers with diameters in the range of 40–100 nm have been fabricated by sol-gel based electrospinning technique. The structure and morphology of the nanofibers were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The MoS 2 nanoparticles are uniformly dispersed into the BFTO, forming nanocomposites. The optical bandgap of the nanocomposites decreases as MoS 2 content increases. The nanocomposites with different MoS 2 contents serve as low-cost counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). Through photocurrent–voltage curves, electrochemical impedance spectroscopy and Tafel curves, the performance of the CEs indicates that the charge transfer resistance on the electrolyte-electrode interface lower and the catalytic activity for reduction of triiodide to iodide enhance with the increase of MoS 2 concentration. The DSSC with the CE exhibits a power conversion efficiency of 5.20% after the optimization of the content of MoS 2 , which is almost 24 times larger than that of the pure BFTO CE.