Brick Shaped Vanadium Nitride/Graphene Nanocomposite as Highly Efficient Counter Electrode Catalyst for Pt Free Dye‐Sensitized Solar Cell.

A Platinum free hybrid counter electrode (CE) Vanadium nitride/graphene (VNGp) for dye‐sensitized solar cell (DSSC) was synthesized by hydrothermal method. The surface morphology and chemical composition of the as‐prepared VNGp composite were analyzed by X‐ray diffraction (XRD) analysis, Raman spectroscopy, high‐resolution electron transmission microscopy (HR‐TEM), and cyclic voltammetry (CV). The VNGp hybrid counter electrode displayed an adsorption‐controlled process towards the (I−/I3−) redox couple at CE/electrolyte interface and the value was calculated to be 3.16×10−9 mol/s by varying the scan rate. The exchange current density (Jo) was calculated as 6.59 mA/cm2 from the Tafel slope. The VNGp hybrid counter shows a maximum fill factor (FF) of 66.28 with high efficacy of 8.15 % under the illumination of 100 mW/cm2 as compared to the Pt CE for DSSC. [ABSTRACT FROM AUTHOR]