Enhancing Efficiency in Dye-Sensitized Solar Cells: Incorporation of Cu₃VSe₄ Nanocrystals into TiO₂ Photoanodes

In the quest for sustainable energy solutions to meet the growing energy demands, third-generation solar photovoltaic (PV) technologies, specifically dye-sensitized solar cells (DSSCs), have gained considerable attention for their cost-effectiveness, ease of manufacture, and operability under dim-light conditions. However, the limited light-harvesting capability of mesoporous titanium dioxide (m-TiO 2 ) photoanodes presents a significant hurdle, constraining the power conversion efficiency (PCE) of the DSSCs. The present work introduces a class of semiconducting materials known as sulvanites, with a particular focus on Cu 3 VSe 4, which is aimed at addressing the light-harvesting issues encountered with m-TiO 2 . Cu 3 VSe 4 exhibits a broad absorption across the visible range of solar spectrum, which substantially enhances light absorption in DSSCs, when incorporated into m-TiO 2 photoanodes. Cu 3 VSe 4 nanocrystals, synthesized via a hot injection, one-pot synthesis method, are incorporated in m-TiO 2 (Cu 3 VSe 4 /m-TiO 2 ) via direct chemical mixing. To understand the induced changes in the structural and optical properties of m-TiO 2 by incorporating Cu 3 VSe 4 nanocrystals, the prepared thin films are characterized using scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), attenuated total reflectance (ATR), UV–vis, and Raman spectroscopy. DSSCs employing Cu 3 VSe 4 /m-TiO 2 photoanodes demonstrated a noteworthy 14.28% increase in PCE (reaching 7.38%) compared to that of reference m-TiO 2 DSSCs (6.37%). The enhanced PCE is attributed to the improved light absorption of photoanodes resulting from enhanced porosity and dye-loading content of Cu 3 VSe 4 /m-TiO 2 photoanodes and improved charge-transfer processes. The improved charge-transport kinetics of fabricated DSSCs is confirmed from the reduced resistances at different interfacial layers estimated from the electrochemical impedance spectroscopy (EIS) spectra. Furthermore, external quantum efficiency (EQE) spectra indicate an improved spectral response of Cu 3 VSe 4 /m-TiO 2 photoanodes in DSSCs. Hence, the incorporation of sulvanites offers a promising strategy to enhance the light-harvesting efficiency not only in DSSCs but also in various cutting-edge optoelectronic devices.