Tuning interfacial charge dynamics in 2D SnO2–MWCNT composite photoanodes for dye-sensitized solar cells

This paper presents a low-temperature, facile, and cost-effective wet chemical synthesis of two-dimensional (2D) tin oxide (SnO 2 )–multi-walled carbon nanotube (MWCNT) composites for efficient dye-sensitized solar cells (DSSCs). Incorporating varying concentrations of MWCNTs into 2D SnO 2 nanosheets significantly enhanced the overall photovoltaic performance by improving charge separation and suppressing electron–hole recombination. The 2D SnO 2 –MWCNT composites exhibited remarkable photoluminescence quenching and increased UV-vis absorbance, indicating efficient photoinduced charge transfer. The optimized 2D SnO 2 –MWCNT composite photoanode achieved a power conversion efficiency (PCE) of 3.84%, which was ~ 3.5 times higher than that of the pristine SnO 2 nanosheets (1.83%). This PCE improvement was attributed to an increase in the short-circuit current density ( J sc ) and the fill factor ( FF ). Additionally, electrochemical impedance spectroscopy (EIS) measurements confirmed the reduced charge transport resistance, increased electron diffusion length, enhanced charge collection efficiency, and enhanced electron mobility of the 2D SnO 2 –MWCNT composites. This improved photovoltaic performance is primarily attributed to the incorporation of MWCNTs, which provide efficient electron-conducting pathways that mitigate recombination. These results highlight the potential of 2D SnO 2 –MWCNT composites as efficient photoanodes for DSSCs, providing valuable insights into the interfacial charge dynamics of next-generation optoelectronic devices.