Density functional theory study on photophysical properties of the porphyrins derivatives with through-bond energy transfer characters

Density functional theory (DFT) calculations have been carried out on the electronic structures, electronic spectra, carrier injection and transport properties of a series of porphyrin derivatives, 5,15-di(R) porphyrin, 5,10,15,20-tetra(R) porphyrin, and Zn-5,10,15,20-tetra(R)porphyrin, namely, DCP, TCP, and ZCP (where R = carbazole); DMP, TMP, and ZMP (where R = N,N-dimethyl-phenyl); DQP, TQP, and ZQP (where R = 2,3,6,7-tetrahydro-1H,5H-benzo[ij]puinolizine). The through-bond (TB) energy transfer process in these porphyrin derivatives has been verified by three aspects of characters, i.e. electronic structures, Dexter-type and Forster-type energy transfer. Moreover, the reasons for their high efficiency as red emitting materials have been revealed by the investigations of the ionization potential (IP), electron affinity (EA), reorganization energy (lambda), and exciton binding energy (E(b)). These structure-property relationships provide a valuable guide for the design and synthesis of highly efficient red light-emitting materials based on porphyrin derivatives. (C) 2010 Elsevier B.V. All rights reserved.