Design and photovoltaic studies of W@TiO2/rGO nanocomposites with polymer gel electrolyte

Abstract

The present research endeavor is focused on designing tungsten(VI) ion-doped TiO₂/rGO nanocomposites (TR NCs) via a single-step in situ wet chemical route for Co²⁺/Co³⁺-based PEO–PEG polymer gel electrolyte-assisted D–π–A carbazole dye (SK3) sensitized solar cells (DSSCs). After the synthesis of the desired W@TiO₂/rGO (WTR) NCs, their physicochemical (viz., optoelectrical, structural, morphological, electrochemical, etc.) properties are studied. BET reveals a higher surface area with improved pore volumes up to 344.04 m² g⁻¹ and 0.918 cm³ g⁻¹, respectively, for W_0.020@Ti_0.980/rGO (WTR-2) NCs as compared to others. The doctor blade technique is deployed for depositing photoanodes. EIS and M–S analysis showed improved photogenerated charge transfer and a higher carrier density, respectively, for WTR-2 NCs. Thereafter, WTR-2 NCs were further sensitized with SK3 dye and sandwiched with a Pt-counter electrode for making DSSCs, and then photovoltaic performance was studied and compared to that of bare TiO₂ NPs under an AM 1.5 solar simulator. The WTR-2 NC-based DSSCs exhibited the highest conversion efficiency (η) of 6.95%, which is 3.7 and 5.2 times greater than that of TR NC-based (1.84%) and bare TiO₂ NP-based (1.32%) DSSCs, respectively. Hence, the present investigation validates the effectual photovoltaic performance of the DSSCs comprising TiO₂ NP-based hybrids and SK3 dye and the utilization of Co²⁺/Co³⁺-based PEO–PEG polymer gel electrolyte.