A comparative study of one- and two-photon absorption properties of meso-meso singly, meso-β doubly and meso-meso β-β β-β triply linked ZnII-porphyrin oligomers

The electronic structures, one-photon absorption (OPA) and two-photon absorption (TPA) properties of the meso-meso singly, the meso-β doubly and the meso-meso β-β β-β triply linked ZnII-porphyrin dimers and trimers have been comparatively studied by using the hybrid B3LYP functional combined with the 6-31G basis set and ZINDO-SOS methods. The results show that on going from the dimers to the trimers, due to the increased conjugation chain, the maximum TPA positions are red-shifted and the maximum TPA cross sections produce a remarkable enhancement. The calculated maximum TPA cross sections of the studied molecules are in the range of 25.4-616.3 × 10−48 cm4 s/photon. Compared with the meso-meso singly linked ZnII-porphyrin derivatives, the meso-β doubly and the meso-meso β-β β-β triply linked ZnII-porphyrin derivatives have larger TPA cross sections at 700-1000 nm. They are promising candidates for TPA materials.