Synthesis and Electroluminescent Properties of New Conjugated Bithiazole-Containing Polymers

Three new bithiazole-based conjugated copolymers were synthesized and characterized. The EL device using PNBTV as the emitting layer showed red electroluminescence at 641 nm with a peak luminance of ca. 160 cd/m(2) (0.008 cd/A). The red electroluminescence was attributed to the formation of excimers between the polymer chains. An EL device using PNBTV6 as the emitting material, which had two n-hexyl groups introduced to the phenylene in the main chain of PNBTV, showed a reddish orange emission that was blue shifted by approximately 52 nm compared with that observed with PNBTV. This observation was attributed to the significant decrease in interactions between the chains of the polymers due to the two bulky n-hexyl groups. On the other hand, PNBTV6 was found to have superior hole transporting ability compared with its electron transporting ability.