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Polymer Science Series B, 2014, Volume 56, Issue 1, pp 59-76.
I. Nosova, D. A. Lypenko, R. Yu. Smyslov, I. A. Berezin, E. V. Zhukova, E. I. Mal’tsev, V. Dmitriev, L. S. Litvinova, N. A. Solovskaya, O. V. Dobrokhotov, I. G. Abramov, A. V. Yakimanskii
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bol’shoi pr. 31 (V.O.), St. Petersburg, 199004, Russia and
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow, 119991, Russia and
- Yaroslavl State Technical University, Moskovskii pr. 88, Yaroslavl, 150023, Russia.
Abstract
New copolyfluorenes containing units of 4,7-dibromo-2,1,3-benzothiadiazole (green luminophore) and 3,6- or 2,7-dibromocarbazole derivatives with side-chain fragments of green (4-pyrrolidinyl-1,8-naphthalimide) and red (Nile red) luminophores and additional carbazole or diphenyloxadiazole groups are synthesized via the Suzuki copolycondensation reaction. The structure of the polymers is modified via insertion of triphenylamine, aryloxadiazole, and quinoxaline units in the backbone of copolyfluorenes and via introduction of triphenylamine, fluorene, and benzene terminal groups. The molecular-weight characteristics of the polycondensation products and the specific features of the transfer of polyfluorene emission energy to the indicated luminophores in solutions and films are studied. Coating the emissive copolyfluorene layer with electron-conducting and hole-blocking layers of poly[9,9-bis(6′-diethoxyphosphorylhexyl)fluorene] makes it possible to increase the brightness of light-emitting diodes (to 2380–3900 cd/m2) and their current and luminance efficiencies.
