Journal of Polymer Science Part A: Polymer Chemistry, Vol.46, No.7, 2367-2378, 2008
Bipolar poly(p-phenylene vinylene)s bearing electron-donating triphenylamine or carbazole and electron-accepting quinoxaline moieties
Two new poly(phenylene vinylene)s (PPVs) carrying electron-donating tri-phenylamine or carbazole and electron-deficient quinoxaline units were synthesized and characterized. Their properties were compared with those of PPV containing only quinoxaline unit. The two polymers showed PL maximum at 501-510 in solution and 533-540 in thin film. Because of the presence of electron donor and acceptor units they displayed strong intramolecular charge transfer (ICT) effects; hence, low-photoluminescence quantum yields. The polymers showed reversible electrochemical reduction with electron affinity of 2.75 eV and irreversible oxidation with ionization potential of 5.10-5.24 eV. Single-layer LED of configuration ITO/PEDOT/polymer/Al showed low turn-on voltage at 5 V, but limited brightness of 50-60 cdm(-2). The electroluminescence maximum was voltage-tunable varying from 500 to 542 nm. (C) 2008 Wiley Periodicals, Inc.
Keywords:carbazole;conjugated polymers;donor-acceptor copolymers;light-emitting diodes (LED);organic light-emitting diodes;PPV;quinoxaline;synthesis;triphenylamine