Synthesis of benzothiadiazole-based liquid crystalline polyacrylates for polarized light emitting diodes

Abstract

Two benzothiadiazole-based liquid crystalline polyacrylates were synthesized. These polymers revealed a nematic liquid crystal phase and exhibited photoluminescence as well as polarized electroluminescence when incorporated into light-emitting diode applications. The polymers showed-dichroic ratios of about 8.3-8.8 in UV-vis absorption and photoluminescence emission. The polymer with vinylene linkages (P2) showed better electroluminescence device performance than that with acetylene linkages (P1). The P2 device emitted red light at 604 nm with a turn-on voltage at 6 V, and a maximum polarized luminance of 235 cd/m(2) at 12 V, with an efficiency of 0.09 cd/A and a polarization ratio of 6.5.