Novel Efficient Light-Emitting Polyfluorene Derivatives Modified by Electron-Deficient Moieties with Nonlinear Structure  

作　　者：彭强 黄艳 卢志云 秦圣英 谢明贵 高维先 彭俊彪 曹镛 

机构地区：[1]Department of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China [2]Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, Guangdong 510640, China

出　　处：《Chinese Journal of Chemistry》2004年第6期599-604,共6页中国化学（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (No. 20102004).

摘　　要：Two novel fluorene-based copolymers (PFSD and PFMD) containing squaric acid or maleimide unit in the main chain were synthesized in good yields by Suzuki coupling reaction. The resulting polymers possess excellent thermal stability, high electron affinity and high photoluminescence (PL) quantum yields. They can fluoresce in yellow-light range due to either the charge transfer between a fluorene segment and an electron-deficient containing squaric acid/maleimide segment of the polymers or the Forster energy transfer between different polymer chains. The results from PL measurements of the isothermally heated polymer thin films show that the commonly observed aggregate excimer formation in polyfluorenes is very effectively suppressed in these two polymers due to the nonlinear structures of maleimide and squaric acid moieties. Double-layer polymer light-emitting diodes (PLED) were fabricated using the resulting polymers as the emitting layers and Ba or Mg : Ag (V : V= 10 : 1) as cathodes. All the devices show bright yellow emission (562-579 nm) with different maximum external quantum efficiencies (0.006%-1.13%). Compared with the other devices, indium-tin oxide (ITO)/polyethylenedioxythiophene (PEDOT) : polystyrene sulfonic acid (PSS)PFMD/Mg : Ag has the higher maximum external quantum efficiency of 1.13% at 564 cd/m2 with a bias of 8.4 V.Two novel fluorene-based copolymers (PFSD and PFMD) containing squaric acid or maleimide unit in the main chain were synthesized in good yields by Suzuki coupling reaction. The resulting polymers possess excellent thermal stability, high electron affinity and high photoluminescence (PL) quantum yields. They can fluoresce in yellow-light range due to either the charge transfer between a fluorene segment and an electron-deficient containing squaric acid/maleimide segment of the polymers or the Forster energy transfer between different polymer chains. The results from PL measurements of the isothermally heated polymer thin films show that the commonly observed aggregate excimer formation in polyfluorenes is very effectively suppressed in these two polymers due to the nonlinear structures of maleimide and squaric acid moieties. Double-layer polymer light-emitting diodes (PLED) were fabricated using the resulting polymers as the emitting layers and Ba or Mg : Ag (V : V= 10 : 1) as cathodes. All the devices show bright yellow emission (562-579 nm) with different maximum external quantum efficiencies (0.006%-1.13%). Compared with the other devices, indium-tin oxide (ITO)/polyethylenedioxythiophene (PEDOT) : polystyrene sulfonic acid (PSS)PFMD/Mg : Ag has the higher maximum external quantum efficiency of 1.13% at 564 cd/m2 with a bias of 8.4 V.

关 键 词：Light-emitting diode POLYFLUORENE ELECTRON-DEFICIENT aggregate excimer external quantum efficiency 

分 类 号：O631[理学—高分子化学]