Energy Transfer in a pi-Conjugated Liquid Crystalline Molecule with Two Chromophores of Rigid Biphenyl Core and Pyrene Head Moieties

Abstract

We investigate the energy transfer of a highly ordered pi-conjugated liquid crystalline molecule containing two chromophores of biphenyl and pyrene moiety, in which the molecule was prepared by esterification of fluorinated biphenyl compound and 1-pyrenebutanol. DSC, POM and XRD results show that this molecule forms a highly ordered smectic liquid crystalline mesophase, in which the pi-conjugated molecule was strongly packed together over large-areas. We show that the liquid crystalline bi-chromophoric systems with highly ordered structure exhibit the energy hopping and transfer to the chromophore with the energetically lowest S(1) state. From the single-molecule spectroscopy of the biphenyl and pyrene chromophore in solution, we show an intramolecular energy transfer from biphenyl to pyrene moieties. In solid thin film, highly ordered structure of the liquid crystal plays a significant role in the formation of the excimer and perfect energy transfer between the chromophores.