Semiconducting thienylene–biphenylenevinylene hybrid polymers: Synthesis, characterization and application prospects in polymer LEDs.

Two novel, highly soluble and semiconducting thienylene–biphenylenevinylene hybrid polymers with excellent photoluminescence and thermal stability were synthesized via Stille coupling polymerization of two novel monomers 5,5′-(1 E ,1′ E )-2,2′-(4,4′-bis(octyloxy)biphenyl-3,3′-diyl)bis(ethene-2,1-diyl)bis(2-bromothiophene) and 5,5′-(1 E ,1′ E )-2,2′-(6,6′-bis(octyloxy)biphenyl-3,3′-diyl)bis(ethene-2,1-diyl)bis(2-bromothiophene), respectively. The structural, thermal, optical and electrical characteristics of the synthesized monomers and polymers were studied in detail. Both polymers exhibit good solubility in common organic solvents, high thermal stability and desirable photophysical characteristics. Slight differences in the optical and electrical properties were observed for both the polymers which arise as a result of the positional change introduced to the functional groups attached in the polymer backbones. Hybrid density functional theory was used to study the band structure of the polymers and the values agree with the experimental results. Polymer light emitting diodes (PLEDs) were assembled based on these hybrid polymers as emissive layers and characterized to establish the suitability of these materials for PLED application. The assembled PLEDs show excellent diode characteristics and good emission in the orange red region. [ABSTRACT FROM AUTHOR]