Poly(2,3-diphenyl-1,4-phenylenevinylene) (DP-PPV) derivatives: Synthesis, properties, and their applications in polymer light-emitting diodes

Poly(1,4-phenylene vinylene) (PPV) has drawn a great deal of attention in the last two decades because of their applications in areas such as light-emitting diodes. To improve the solubility and optoelectronic properties, various PPV derivatives have been synthesized and investigated for their light-emitting performance. Among PPV derivatives, poly(2,3-diphenyl-1,4-phenylenevinylene) (DP-PPV) and its derivatives have been widely studied because of their promising electronic properties. Here, we review the synthesis, properties, and device performances of DP-PPV derivatives, which exhibit high external efficiency and brightness in polymer light-emitting diodes. For example, long alkyl chains were introduced to increase the solubility of DP-PPV. DP-PPV derivatives having liquid crystalline side groups were also synthesized and polarized emissions were obtained. In addition, bulky dendritic side groups were incorporated on the pendant phenyl ring and quantum efficiency of the device was significantly enhanced with increasing the generation of dendrons. By introducing methoxy or long branched alkoxy chains into DP-PPV, a maximum brightness of 78050 cd/m2 with a low turn-on voltage of 4.0 V was also achieved by fabricating a multilayer electroluminescent device. In addition, the self-assembly behaviors and optical properties of different DP-PPV derivatives in solution and in confined environment are also discussed.