Enhancing charge transfer in hybrid solar cells: the role of pulse laser-assisted hydrothermally synthesized Au@N-S-doped fluorescent carbon quantum dots as Forster Resonance Energy Transfer antennas

The strategic selection and design of antenna materials can significantly improve the light-harvesting efficiency of acceptor dye in Forster Resonance Energy Transfer (FRET)-based hybrid solar cells. This study uses innovative pulse laser-assisted hydrothermally synthesized Au-decorated nitrogen and sulphur-doped fluorescent carbon quantum dots (Au@NSCDs) as FRET relay antennas. They have unique properties, such as large surface areas for biomolecule attachment, broad spectral absorption, efficient charge carrier extraction, and rapid charge transport. We investigate hybrid solar cell integration with N3 dyes as energy acceptors and Au@NSCDs as donors. The study reveals the existence of FRET and the interaction between Au@NSCDs and the N3 dye. The FRET efficiency is 22.17%, while the Radiative Energy Transfer (RET) efficiency is 20%. Co-sensitization of Au@NSCDs with N3 dye in DSSCs leads to a 1.29% power conversion efficiency (PCE), 0.45 V open circuit voltage, a 1.77 mA/cm² short-circuit current density, and a 30% improvement compared to TiO₂/BaTiO₃/N3-based DSSCs. Au@NSCDs also mitigate charge recombination, increasing open-circuit voltage to 670 mV. The TiO₂/BaTiO₃/N3-Au@NSCD configuration had an effective lifetime (17.57 ms), excellent charge carrier retention, and the highest charge collection efficiency (0.99). Au@NSCD antenna material can reduce charge recombination, indicating potential for future hybrid solar cell technology advancements.