Synthesis and optical properties of light-emitting π-conjugated polymers containing biphenyl and dithienosilole

• Published in: Journal of polymer science. Part A, Polymer chemistry Polymer chemistry, 2007-05, Vol.45 (10), p.2048-2058
• Main Authors: Liao, Liang, Cirpan, Ali, Chu, Qinghui, Karasz, Frank E., Pang, Yi
• Format: Article
• Language: English
• Subjects: Applied sciences; conjugated polymers; Electronics; Exact sciences and technology; light-emitting diodes; luminescence; Optoelectronic devices; Organic polymers; Physicochemistry of polymers; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.21970

Copolymers containing oligo(phenylene vinylene) (2.5), fluorene, and 4,4‐dihexyldithienosilole (DTS) units were synthesized and characterized. The π‐conjugated monomers were joined with the palladium(0)‐catalyzed Suzuki–Miyaura coupling reaction, thus forming either biphenyl– or phenyl–thiophene linkages. These polymers were photoluminescent, with the fluorescent quantum efficiency between 54 and 63% and with λmax for fluorescence at ∼448 nm in tetrahydrofuran. The presence of 5% DTS in the copolymers had little influence on the optical absorption and emission wavelengths. Double‐layer light‐emitting‐diode devices using these polymers as emissive layers had low turn‐on voltages (3.5–4 V) and moderate external quantum efficiencies (0.14–0.30%). The results show that DTS plays a positive role in improving the charge‐injection characteristics of poly(phenylene vinylene) materials. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2048–2058 Copolymers containing oligo(phenylene vinylene), fluorene, and dithienosilole units were synthesized and characterized. Double‐layer light‐emitting‐diode devices using these polymers had relatively low turn‐on voltages (3.5–4 V). The results show that dithienosilole plays a positive role in improving the charge‐injection characteristics of poly(phenylene vinylene) materials.