Charge transfer dynamics in graphene quantum dot-porphyrin derivative nanohybrids appraised via experimental and theoretical calculations

Abstract

This article is designed to unveil the electronic and spectroscopic property changes of electron withdrawing/releasing group substituted porphyrins, in porphyrin-graphene quantum dot nanohybrids via experimental and computational calculations. Herein, amino, methyl, fluoro & nitro derivatives of meso substituted Tetraphenylporphyrin referred as TAPP, TMPP, TFPP & TNPP respectively, are synthesized from the corresponding benzaldehydes. Charge transfer dynamics of their nanohybrid systems with graphene quantum dots are investigated by electronic spectroscopy, steady state fluorescence and lifetime decay analysis. Negative Gibb's free energy change and dynamic quenching constants stipulate a photoinduced electron transfer with dynamic quenching mechanism within the nanohybrids under scrutiny. Further the computational calculations with the aid of optimized geometries, scatter plots and energy decomposition analysis reflect the same experimental observations. Both experimental and computational studies show that the electron withdrawing group substituted porphyrins have higher interaction with GQD than the electron releasing group substituted porphyrins.