Influence of Plasmonic Au@Cl/N Co‐doped Carbon Dots on the Performance of Dye‐Sensitized Solar Cells

ABSTRACT The synergistic influence of the LSPR (localized surface plasmon resonance) of gold nanoparticles (Au NPs) and the effect of nitrogen and chlorine co‐doped carbon dots (Cl/N‐CQDs) on dye‐sensitized solar cells (DSSCs) performance are investigated. The gold NPs are coated with a thin layer of Cl/N‐CQDs to produce the Au@Cl/N‐CQDs structure. DSSCs are fabricated by using Au@Cl/N‐CQDs as co‐sensitizer. The focus of this work is to examine the effects of plasmonic Au NPs and carbon dots in addition to their synergistic effect by capping the Au NPs with Cl/N‐CQDs, and track their influence in DSSCs. N719 as ruthenium‐based dye, and natural dyes including betanin, crocin, carthamin, curcumin, chlorophyll, mallow, and lawsone are selected and applied in the DSSCs co‐sensitized by Au@Cl/N‐CQDs. The power conversion efficiency (PCE) of DSSCs using all of the selected dyes is enhanced upon using the Au@Cl/N‐CQDs. It is due to the improvement in V OC (open circuit voltage) and J SC (short circuit photocurrent densities) relative to the use of dyes alone. Based on computational results, Au@Cl/N‐CQDs cause a red‐shift in comparison with pure dyes. The TD‐DFT (time‐dependent density functional theory) results show that the orbitals from the Au@Cl/N‐CQDs in dye/Au@Cl/N‐CQDs have contribution in most of the absorptions. In other words, electrons from HOMO (highest occupied molecular orbital) of Au@Cl/N‐CQDs is transferred to the LUMO (lowest unoccupied molecular orbital) of dye, in most cases.