Random terpolymers for electroluminescent devices: Synthesis and characterization of new cyano‐containing poly(fluorenylene‐vinylene)s |
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Authors: | Roberto Grisorio Claudia Piliego Paola Fini Pinalysa Cosma Piero Mastrorilli Giuseppe Gigli Gian Paolo Suranna Cosimo Francesco Nobile |
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Affiliation: | 1. Dipartimento di Ingegneria delle Acque e di Chimica (DIAC) – Politecnico di Bari, via Orabona, 4 I‐70125 Bari, Italy;2. National Nanotechnology Laboratories (NNL) of CNR – INFM, Lecce, Italy;3. Istituto Superiore Universitario di Formazione Interdisciplinare (ISUFI)‐Sezione Nanoscienze, Lecce, Italy;4. IPCF – CNR c/o Dipartimento di Chimica, Bari, Italy;5. Dipartimento di Chimica dell'Università di Bari, Campus Universitario‐Bari, Italy;6. Dipartimento di Ingegneria dell'Innovazione, Università del Salento, Lecce, Italy |
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Abstract: | The synthesis of new random poly(2,7‐fluorenylene‐vinylene)s was achieved by a Suzuki–Heck cascade polymerization reaction. The poly(fluorenylene‐vinylene) base structure was modified by the regio‐random incorporation of 1‐cyano‐2,5‐phenylene as electron withdrawing unit ( CN‐PFV1 ) and its properties were compared with terpolymers also embodying 1,4‐dioctyloxy‐2,5‐phenylene ( CN‐PFV2 ) or 3,6‐N‐octylcarbazole ( CN‐PFV3 ) as electron‐donating moieties. Thermal analysis revealed a high thermal stability (Td > 389 °C) and the absence of glass transitions for all polymers. Cyclic voltammetry indicated a high electron affinity of the materials (2.96–3.21 eV) attributed to the presence of the cyano‐containing comonomer. In dilute solutions, the copolymers showed a broad green fluorescence with quantum yields ranging from 0.42 to 0.79, while in the solid state, a relatively narrow emission centered at ~ 560 nm, governed by the low‐energy segments within the π‐conjugated backbone, was observed. The electroluminescence properties of the materials were tested in OLED devices of ITO/PEDOT‐PSS/ CN‐PFV1‐3 /Ca/Al or ITO/PEDOT‐PSS/ CN‐PFV1‐3 /Alq3/Ca/Al configurations, showing a bright green‐yellow emission that, in the case of CN‐PFV2 , reached 1403 cd/m2 with efficiencies as high as 0.13 cd/A. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6051–6063, 2008 |
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Keywords: | conjugated polymers copolymerization electroluminescence fluorene light‐emitting diodes (LED) poly(arylene‐vinylene) potassium vinyl‐trifluoroborate Suzuki– Heck cascade terpolymers |
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