Improved solar cells efficiency with TiO₂/CuO nanocomposite as photoanode sensitized by natural dyes from scarlet eggplant, pitomba and black grapes

This study investigates the impact of CuO (p-type) incorporation into TiO₂ (n-type) photoanodes, sensitized with three different natural dyes extracted from scarlet eggplant, pitomba, and black grape fruits using ethanol, for dye sensitized solar cells (DSSCs). The natural dyes visible light absorption properties were characterized through ultraviolet–visible (UV–Vis) spectroscopy, while Fourier-transform infrared (FTIR) spectroscopy identified their functional groups. The structural and morphological features of TiO₂ and TiO₂/CuO nanocomposites were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Additionally, atomic force microscopy (AFM) was employed to evaluate the surface topographies of the photoanodes and cathode. The incorporation of CuO into the TiO₂ matrix formed an n–p junction within the TiO₂/CuO photoanode, significantly enhancing photocurrent, photovoltage, fill factor, and overall conversion efficiency. DSSCs fabricated with the TiO₂/CuO photoanode sensitized by scarlet eggplant, pitomba, and black grape fruits natural dyes achieved maximum conversion efficiencies of 2.77, 2.81, and 5.22%, compared to lower efficiencies of 0.51, 0.56, and 1.12% obtained using unmodified TiO₂ photoanodes, respectively. The results demonstrate the synergistic effect of the hybrid photoanode and natural dye sensitization in improving DSSC performance, highlighting the potential of sustainable and efficient energy solutions.