Probing the Photophysics of Covalently and Non‐covalently Bonded Graphene Quantum Dots‐Tetraaminophenylporphyrin Nanohybrids

Abstract

AbstractHerein, we scrutinize the photophysical and electronic changes on graphene quantum dots (GQDs) which occurs as a consequence of both type of covalent and non‐covalent functionalization using Tetraaminophenylporphyrin (TAPP). Covalent functionalization resulted in amide bond between GQD and TAPP (GQD‐CONH‐TAPP), while electrostatic interactions, hydrogen bonding and π‐π interactions together contribute to the binding in non‐covalent functionalization. Outstanding difference between both of the functionalized GQDs were observed in their UV‐Visible absorption spectra, photoluminescence (PL) spectra and time‐correlated single photon counting (TCSPC) measurements. GQD‐CONH‐TAPP acts as a charge separated system having C1 point group. In case of GQD‐TAPP, the non‐covalent nanohybrid system, photoinduced electron transfer from TAPP to GQD occurs with a dynamic quenching constant of 21.89×103 M−1 and bimolecular rate constant of 2.77×1014 M−1s−1. Feasibility of this electron transfer is reinforced by the negative ΔGPET value and the theoretical studies.