Click-assembled N-graphene–C60 hybrids for ultrafast electron transfer

Abstract

A novel donor–acceptor hybrid derived from N-doped graphene (NG) and an electron acceptor, C₆₀, has been newly synthesized using click chemistry and characterized by a suite of physico–chemical techniques. The usage of click chemistry resulted in a relatively high degree of functionalization. Due to the presence of two C₁₂ alkyl chains on the fulleropyrrolidine moiety, the NG-C₆₀ hybrid was found to be relatively soluble in most organic solvents, facilitating both spectroscopic and electrochemical characterization. Fluorescence studies revealed quenching of the fulleropyrrolidine emission, indicating the occurrence of excited-state events. While DFT studies provided insights into the geometry and localization of the frontier orbitals, the TD-DFT studies performed at the B3LYP/6-311G(d,p) level suggested the possibility of excited-state charge transfer from several excited states. Subsequent femtosecond transient absorption studies performed in DMF confirmed electron transfer, wherein the material could be characterized. The charge transfer state persisted for approximately 12 ps before populating the low-lying ³C₆₀*, highlighting the material's potential for light energy harvesting applications.