Potential-reversal electrodeposited MoS2 thin film as an efficient electrocatalytic material for bifacial dye-sensitized solar cells

Seeking inexpensive, cost-effective fabrication, and highly effective Pt-free counter electrode (CE) electrocatalysts to replace the conventional Pt CE for dye-sensitized solar cells (DSSCs) is of great challenge. Here, molybdenum disulfide (MoS2) thin films were directly electrodeposited on F-doped tin oxide (FTO) glass substrates via facile one-step potentiostatic (PS) and potential-reversal (PR) methods, which were exploited as the CE electrocatalysts for DSSC application. According to series of the electrochemical tests, the MoS2 CE electrodeposited by PR mode (PR-MoS2) had a superior electrocatalytic property for I-3(-) reduction in DSSCs to that by PS mode (PS-MoS2). When PR-MoS2 was employed as a CE in a DSSC, the device achieved a satisfactory photoelectric conversion efficiency (PCE) of 8.77%, which is comparable to that based on the conventional Pt CE (9.01%). Meanwhile, the rear side illumination studies showed that the PCE of the DSSC using PR-MoS2 as a CE reached 4.82% and was equivalent to that using the Pt CE (5.67%), which is attributed to their similar transmittance property. This work provides a novel insight into preparing an electrodeposited PR-MoS2-based CE for bifacial DSSCs application.