Electronic Structures and Spectroscopy of Luminescent para‐Phenylenevinylene Oligomers

The computational models for a series of PPV (para-phenylenevinylene) oligomers were formed based on the biphenyl and stilbene structures. These oligomers were optimized using DFT at B3LYP/6-31G (d) level. On the basis of the optimized geometries, the electronic spectra and 13C NMR spectra were calculated by the INDO/CIS and B3LYP/6-31G(d) methods, respectively. It indicates that the main absorptions in the electronic spectra are red-shifted when the oligomer length is increased. The main absorptions in the electronic spectra and the 13C chemical shifts are altered obviously when the substituents on the matrix are changed.