Synergetic effect of 2D/2D Co-SnS2 with reduced graphene oxide heterostructure for Pt-free counter electrode. (March 2023)

• Record Type: Journal Article
• Authors: Raveena, J.; Chandrapal, R. Roshan; Bakiyaraj, G.; Manikandan, V.S.; Athitya, S.; Archana, J.; Navaneethan, M.
• Is Part Of: Materials today communications. Volume 34(2023)
• Publication Date: 2023-03
• Subjects: 2D/2D heterostructure -- Nanoflakes -- DSSC -- Pt free counter electrode; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2022.105204
• Languages: English
• ISSNs: 2352-4928

Abstract

Abstract: 2D Layered transition metal dichalcogenides (TMDs) have great attention concerning their unique electrical and optical properties. Counter electrodes (CEs) are crucial to creating low-cost and high power conversion efficiency (PCE) dye-sensitized solar cells (DSSCs); thereby, the development of high-performance CEs utilizing non platinum (Pt) materials is essential. This study reports on new highly electrochemically active 2D/2D cobalt substituted SnS2 /rGO (reduced graphene oxide) heterostructure that had been successfully synthesized by a two-step hydrothermal method with different weight percentages (1, 3 and 5 wt. %) of rGO. The fabricated 2D/2D heterostructure acts as a Pt-free counter electrode in a dye-sensitized solar cell. The crystalline structure, morphology, and chemical state were confirmed by X-ray diffraction (XRD), RAMAN, High resolution scanning electron microscopy (HRSEM), High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). Among all these, Co-SnS2 /rGO (5 wt. %) counter electrode delivers the highest power conversion efficiency of 5.54 % with a short circuit current density (JSC ) of 11.85 mA cm −2, open circuit voltage (VOC ) of 0.77 V and fill factor (FF) of 60.13. High surface area (59.202 → 69.148 m 2 /g), facilitating more active sites via increasing rGO content was analyzed through Brunauer-Emmett-Teller (BET) analysis. Lower peak-to-peak separation (Epp) and charge transfer resistance (RCT ) are responsible for the observed improvement in the electrolyte and counter electrode interface. Notably, rGO with Co-SnS2 creates a synergetic effect through fast electron transporting capability. Furthermore, the Co-SnS2 /rGO (5 wt. %) CE shows excellent electrochemical stability over 100 cycles in an iodine-based electrolyte. The superior electrocatalytic activity and photovoltaic output highlight the promise of Co-SnS2 /rGO (5 wt. %) for DSSCs CE. This efficiency is comparable to the expensive Pt CE (6.0 %). Graphical Abstract: ga1