Theoretical investigation of electronic structure and spectroscopic properties of functionalized bis-silicon-bridged stilbene homologue

Electronic structures of bis-sillicon-bridged trans-stilbene homologues were theoretically analyzed from the viewpoint of electronic effect occurring from geometrical difference in the vicinity of the stilbene bridged moiety using DFT B3LYP method. Absorption and emission energies were reported on the basis of TD-DFT and ZINDO approaches, establishing good agreement with experimental data. As compared with the carbon analogue, the absorption and emission maxima of silicon-bridged stilbene analogues have substantial red shifts. These significant red shifts are attributable to the electronic contribution of the silicon bridges. EL peak was predicted to be about 393 and 483 nm for them. The effects of hole and electron injection are clarified by the ionization potentials (IPs) and electron affinities (EAs) calculations. It is suggested that bis-sillicon-bridged trans-stilbene homologue should be more efficient at trapping the electron than carbon species.