New bithiophene-containing electroluminescent polymer: Synthesis, characterization, optical and electrical properties

• Semi-conducting polymer based on distyryl-bithiophene π-conjugated system.
• Synthesis, structural, thermal, morphological and electrochemical characterization.
• Absorption and photoluminescence properties in dilute solution and as thin solid film.
• Electrical characteristic modeled by the current space-charge-limited mechanism.
• Yellow-green electroluminescence from multilayer organic light-emitting diode.

A semi-conducting polymer, P-DSBT, based on distyryl-bithiophene π-conjugated sequences has been synthesized and characterized. The macromolecular material was soluble in volatile solvents and showed a good film quality; it exhibited an amorphous morphology with relatively high glass transition temperature. The absorption and photoluminescence properties of the polymer were studied in solution and as thin solid film, which showed an optical gap of 2.6 eV. The HOMO/LUMO energy levels were evaluated by cyclic voltammetry measurements and indicate a p-type semi-conducting material. The electrical properties of P-DSBT were investigated by the current-tension characteristic and modeled by the current space-charge-limited (SCLC) mechanism; charge carrier mobility higher than 10−6 cm2 V−1 s−1 was evaluated. A yellow-green electroluminescence was evidenced in a multilayer organic light-emitting diode with an [ITO/PEDOT:PPS/P-DSBT/BCP/Al] configuration.

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