Quantum chemical investigations on a supramolecular porphyrin-fulleropyrrolidine dyads for photovoltaic devices

Abstract

The present paper deals with the estimation of conformational stability and determination of electronic structures of H2-porphyrin-fulleropyrrolidine (1) and zincporphyrin–fulleropyrrolidine (2) dyads by ab initio (HF)and density functional theory (DFT) calculations in vacuo. In dyads 1 and 2, fulleropyrrolidine is directly linked to the tetrapyrrolic rings by ethylene subunits. Both HF and DFT calculations establish that possibility of photoinduced electron transfer (PET) phenomenon is higher in case of 2 compared to 1. Investigation on frontier molecular orbitals at different electronic states reveal that the highest occupied molecular orbital and the lowest unoccupied molecular orbital of these supramolecules is delocalized due to PET phenomenon. Generation of molecular electrostatic potential (MEP) maps by both HF and DFT calculations substantiate the PET phenomenon (as stated above) and establish that the direction of electron transfer occurs from the porphyrin subunits to the fulleropyrrolidine in dyads 1 and 2.