Abstract:
This study explored the effects of Neodymium-doped graphene quantum dots (NdGQDs) on
improving the performance efficiency of TiO2 based dye-sensitized solar cells (DSSCs). By
employing in-situ physical assisted mixing, DSSCs with optimized NdGQDs in
TiO2 photoanodes showed a power conversion efficiency of 8.76 %, a significant improvement
compared to the 6.01 % efficiency of pristine TiO2-based DSSCs under 100 mW cm⁻2 illumination
(AM 1.5). Notably, the short-circuit current density increased by 74 %. HRTEM analysis revealed
that the NdGQDs have a size range of approximately 7–9 nm. UV–visible spectroscopy and Mott
Schottky analysis revealed a positive shift in the Fermi level, promoting better electron transfer
and increased photocurrent density at the expenses of the open circuit voltage. Electrochemical
impedance spectroscopy characterization of DSSCs incorporating NdGQD-modified
photoanodes revealed a reduction in electron transfer resistance at the
photoanode|dye|electrolyte interface, accompanied by an increase in recombination resistance
within the device suppressing the electron recombination rate.
