Copolyfluorenes containing carbazole or triphenylamine and Diethoxylphosphoryl groups in the side chains as white-light-emitting polymers. (1st December 2020)

• Record Type: Journal Article
• Authors: Nosova, Galina I.; Lypenko, Dmitry A.; Smyslov, Ruslan Yu.; Zhukova, Elena V.; Berezin, Ivan A.; Litvinova, Larisa S.; Maltsev, Eugene I.; Yakimansky, Alexander V.
• Is Part Of: Polymer. Volume 210(2020)
• Publication Date: 2020-12-01
• Subjects: Copolyfluorenes -- Microwave heating -- Thermal annealing treatment -- Photoluminescence -- Electroluminescent properties; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2020.122978
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: New copolyfluorenes containing 4, 7-di-2-thienyl-2, 1, 3-benzothiadiazole and 2, 1, 3-benzothiadiazole or derivatives of naphthalimide as luminophores were synthesized under microwave heating. Charge-transporting carbazole, triphenylamine, or diphenyloxadiazole groups were introduced into the side chains of polymers through 9, 9-bis-(4-phenoxy)-2, 7-fluorene units. Copolyfluorenes were also modified via insertion of 10 mol% of 2, 7-[9, 9-bis-(6′-diethoxyphosphorylhexyl)]fluorene or dibenzothiophene-S, S-dioxide comonomer units into the polymer backbone. This study demonstrates the influence of chemical compositions, molecular masses of the polymers under investigation, and thermal treatment on microstructures of their films. Photo- and electroluminescent characteristics of the synthesized copolyfluorenes were determined. The best samples of devices manifested the luminance of 5110 cd m⁻ 2, the current efficiency of 1.33 cd A⁻ 1, and the CIE 1931 xy chromaticity coordinates of (0.339 0.364), or 7930 cd m⁻ 2, 2.18 cd A⁻ 1, and of (0.300 0.369) respectively. The effect of active layer thickness on the white emission color of polymer light-emitting diodes was revealed. Graphical abstract: Image 1 Highlights: Light-emitted copolyfluorenes were obtained by microwave synthesis with Suzuki method. Copolyfluorene structure modified by green, conducting and polar groups in side chain. Film morphology depends on structural units, molecular mass and temperature treatment. Embedding end-groups affect films' morphology and their photophysical properties. Polar groups interact with donor-acceptor units and allow getting PLED white emission.