Electron Donating Chlorophyll-a on Graphene: A Way toward Tuning Fermi Velocity in an Extended Molecular Framework of Graphene/Chlorophyll-a Nanohybrid

We aimed to synthesize graphene/chlorophyll-a nanohybrids with an extended interface via the LB method, through which charge and energy-transfer processes can create synergistic effects resulting in unique properties and superior performance with regard to photovoltaic and advanced electronics applications. The reduced lifetime of excited-state chlorophyll-a molecules, evident from time-resolved fluorescence decay (TCSPS) data, is accounted for by the effect of two phenomena that are intermolecular exciton migration through packed chlorophyll-a molecules [radiative] and electron transfer from chlorophyll-a to the graphene surface [nonradiative]. The G band in the Raman spectra gradually shifts to lower frequency with decreasing layer numbers, implying electron transfer from porphyrin to graphene is prominent due to the doping induced change of the equilibrium lattice parameter along with nonadiabatic removal of the Kohn anomaly. The lattice relaxation effect is also evident from the decrease in symmetric ...