Synthesis, characterization, and electroluminescence of new conjugated PPV derivatives bearing triphenylamine side-chain through a vinylene bridge

Abstract

Three new conjugated poly(p-phenylene vinylene) (PPV) derivatives bearing triphenylamine side-chain through a vinylene bridge, poly(2-(4′-(diphenylamino)phenylenevinyl) -1,4-phenylenevinylene)(DP-PPV), poly(2-(3′- (3″,7″-dimethyloctyloxy)phenyl)-1, 4-phenylenevinylene-alt-2-(4′-(diphenylamino)phenylenevinyl)-1, 4-phenylenevinylene) (DODP-PPV), and poly(2-(4′- (diphenylamino)phenylenevinyl)-1,4-phenylenevinylene- co-2-(3′,5′-bis(3″,7″-dimethyloctyloxy)- 1,4-phenylenevinylene) (DP-co-BD-PPV), were synthesized according to the Gilch or Wittig method. Among the three polymers, the copolymer DP-co-BD-PPV is soluble in common solvents with good thermal stability with 5% weight loss at temperatures higher than 386°C. The weight-average molecular weight (Mw) and polydispersity index (PDI) of DP-co-BD-PPV were 1.83 × 105 and 2.33, respectively. The single-layer polymer light-emitting diodes (PLEDs) with the configuration of Indium tin oxide (ITO)/poly (3,4-ethylenedioxythiophene) : poly(4-styrene sulfonate)(PEDOT:PSS)/DP-co-BD-PPV/Ca/Al were fabricated. The PLED emitted yellow-green light with the turn-on voltage of ca. 4.9 V, the maximum luminance of ca. 990 cd/m2 at 15.8 V, and the maximum electroluminescence (EL) efficiency of 0.22 cd/A. Copyright © 2007 John Wiley & Sons, Ltd.