Electrically tunable photoluminescence of liquid crystalline polyacetylenesolutions

Light emission from tetrahydrofuran solutions of a liquid crystalline polya cetylene, 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 X 10(-4) M). The photoluminescence of a concentrated solution (113 x 10(-4) M) is, however, noticeably quenched under an electrical field with a field strength of > 3 x 10(5) V m(-1). When the field strength is increased to gr eater than or equal to 3.67 x 10(5) V m(-1), the bimodal emission spectrum of the solution changes to a monomodal one. Thus, both the emission intensi ty and spectral profile of the photoluminescence of the concentrated soluti on can be tuned by the electrical field, which is probably caused by the ag gregate dissociation and mesogen realignment induced by the external stimul us. (C) 2001 Elsevier Science B.V. All rights reserved.