V₂O₅ Nanosheets as an Efficient, Low‐cost Pt‐free Alternate Counter Electrode for Dye‐Sensitized Solar Cells

Abstract The search for cost‐effective and efficient counter electrode finds its way in choosing vanadium pentoxide, an abundant and low‐cost material with good electrocatalytic property and stability. Two‐dimensional vanadium pentoxide nanosheets (V₂O₅ NS) were prepared by a simple hydrothermal method followed by calcination at 350 °C. The morphology of the synthesized material provides an excellent surface property with good surface area and a wide range of porosity distribution helps in enhancing the electrocatalytic active sites for effective reduction of I₃⁻. The electrochemical studies performed with V₂O₅ NS showed good electrocatalytic activity with high current density, low series and charge transfer resistance. The electrochemical techniques CV, EIS and Tafel polarization performed with V₂O₅ NS gave an enhanced electrocatalytic activity and charge transfer kinetics with a low value of R_s and R_ct. Furthermore, the photocurrent voltage studies done with V₂O₅ NS CE DSSC achieved a PCE of 5.1% ( Open circuit voltage (V_oc)=0.65 V, short ciruit photocurrent density (J_sc)=11.67 mA/cm² and fill factor (FF)=66.46%) and the conventional thermal decomposed Pt CE DSSC reached the PCE of 7.4% (Open circuit voltage (V_oc)=0.78 V, short circuit photocurrent density (J_sc)=15.03 mA/cm² and fill factor (FF)=57.39%) under similar test conditions, appreciably good performance than previous reports on V₂O₅ CE DSSC. The present work encourages further extensive research to develop nanostructures of V₂O₅ as a low‐cost alternate counter electrode to Pt CE for large‐scale production.