Electrically tunable photoluminescence of liquid crystalline polyacetylene solutions

Light emission from tetrahydrofuran solutions of a liquid crystalline polyacetylene, poly(11-{[(4′-heptoxy-4-biphenylyl)carbonyl]oxy}-1-undecyne), is investigated in the electrical field. The field exerts little effect on the photoluminescence of the polymer solution with a low concentration (1.03×10−4 M). The photoluminescence of a concentrated solution (113×10−4 M) is, however, noticeably quenched under an electrical field with a field strength of >3×105 V m−1. When the field strength is increased to ⩾3.67×105 V m−1, the bimodal emission spectrum of the solution changes to a monomodal one. Thus, both the emission intensity and spectral profile of the photoluminescence of the concentrated solution can be tuned by the electrical field, which is probably caused by the aggregate dissociation and mesogen realignment induced by the external stimulus.