Influence of electric field on the photoluminescence of a liquid crystalline monosubstituted polyacetylene

It has been shown recently that strong photoluminescence (PL) can occur in monosubstituted polyacetylenes (PAs). In this letter, we investigate the PL of tetrahydrofuran solutions of a highly luminescent liquid crystalline PA , poly(11-{[4'-heptoxy-4-biphenylyl)carbonyl]oxy}-1-undecyne) (PBU), under the influence of direct current electric fields. The applied electric field s can dramatically tune the PL structures of a moderately concentrated PBU solution (similar to 11.3 mM) at and above an electric field threshold of a bout 3x10(5) V/m. Combined with the director simulations, our results indic ate that the electrically induced molecular reorientation and intermolecula r interaction are responsible for the observed spectral changes. (C) 2001 A merican Institute of Physics.