Enhanced photoanode efficiency in DSSCs using CNT-doped Zn_0.5Ce_0.5 O₂: a comparative study with CeO₂-based materials

This study investigates the synthesis and characterization of cerium oxide (CeO₂) quantum dot-based photoanodes, enhanced by doping with carbon nanotubes (CNTs) and metals such as Zn and Co, for dye-sensitized solar cells (DSSCs). CeO₂-based quantum dots were prepared using the successive ionic layer adsorption and reaction (SILAR) method and deposited on fluorine-doped tin oxide (FTO) plates. X-ray diffraction (XRD) confirmed the cubic fluorite structure, while photoluminescence (PL) analysis revealed modified electronic transitions due to doping. AFM analysis showed that the CNT-doped Zn_0.5Ce_0.5O₂ film exhibited the maximum surface roughness with 70 nm along the x-direction and 72.65 nm along the y-direction. UV–Vis results showed that the indirect band gap of CNT-doped Zn_0.5Ce_0.5O₂ was calculated to be 3.66 eV, which is the same as that of CNT-doped Co_0.5Ce_0.5O₂ and greater than that of undoped CeO₂. The DSSCs fabricated with CNT-doped Zn_0.5Ce_0.5O₂ exhibited the highest photon conversion efficiency (PCE) of 8.85%, surpassing other configurations. This improved performance is attributed to an optimized band gap, enhanced electron transport, and suppressed charge recombination. The results suggest that doped CeO₂ quantum dots hold significant potential for advanced solar cell applications.