Highly efficient pure white polymer light-emitting devices based on poly(N-vinylcarbazole) doped with blue and red phosphorescent dyes  

作　　者：HU SuJun ZOU JianHua ZHOU GuiJiang LI DongYun WU HongBin SU ShiJian WONG Wai-Yeung YANG Wei PENG JunBiao CAO Yong 

机构地区：[1]1Key Laboratory of Specially Functional Materials,Ministry of Education Institute of Polymer Optoelectronic Materials and Devices,South China University of Technology,Guangzhou 510640,China [2]Department of Chemistry and Centre for Advanced Luminescence Materials,Hong Kong Baptist University,Waterloo Road,Kowloon Tong,Hong Kong,China [3]Ministry of Education Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter and Department of Chemistry,Faculty of Science,Xi'an Jiaotong University,Xi'an 710049,China

出　　处：《Science China Chemistry》2011年第4期671-677,共7页中国科学（化学英文版）

基　　金：Fund of Ministry of Education of China (20090172120012);the National Basic Research Program of Chima (2009CB623602);the National Natural Science Foundation of China (60906032);the Fundamental Research Funds for the Central Universities for the financial support. Wong W.-Y. thanks the Hong Kong Research Grants Council (HKBU202709);the University Grants Committee of HKSAR,China (AoE/P-03/08);Hong Kong Baptist University (FRG2/08-09/111);the Croucher Foundation for the Croucher Senior Research Fellowship

摘　　要：Efficient white-polymer-light-emitting devices (WPLEDs) have been fabricated with a single emitting layer containing a hole-transporting host polymer,poly(N-vinylcarbzole),and an electron-transporting auxiliary,1,3-bis[(4-tert-butylphenyl)-1,3,4-oxadiazolyl]-phenylene,codoped with two phosphorescent dyes:Iridium(III)bis (2-(4,6-difluorophenyl)-pyridinato-N,C2') picolinate (FIrpic) and home-made Ir-G2 for blue and red emission,respectively.With the structure of ITO/PEDOT:PSS 4083(40 nm)/emission layer(80 nm)/Ba(4 nm)/Al(120 nm),the device showed a maximal luminous efficiency (LE) of 13.5 cd A-1(corresponding to an external quantum efficiency (EQE) of 6.8%),and a peak power efficiency (PE) of 6.5 lm W-1 at 6.0 V.Meanwhile,the device exhibited pure white emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.34,0.35) at a current density of 12 mA cm-2,which is very close to the equi-energy white point with CIE coordinates of (0.33,0.33).The device performance can be further optimized when more balanced hole/electron injection is achieved by incorporating a lower conducting type anode buffer layer (PEDOT:PSS) and incorporating poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorenene)-alt-2,7-(9,9-dioctyfluorene)] (PFN) as an electron injection layer at the cathode.The optimized device showed an LE of 24.6 cd A-1 (with an EQE of 14.1%),while the peak power efficiency reached 12.66 lm W-1.Moreover,the WPLEDs showed good electroluminescence (EL) stability over a wide range of operating current density and luminance.Efficient white-polymer-light-emitting devices （WPLEDs） have been fabricated with a single emitting layer containing a hole-transporting host polymer,poly（N-vinylcarbzole）,and an electron-transporting auxiliary,1,3-bis[（4-tert-butylphenyl）-1,3,4-oxadiazolyl]-phenylene,codoped with two phosphorescent dyes：Iridium（III）bis （2-（4,6-difluorophenyl）-pyridinato-N,C2＇） picolinate （FIrpic） and home-made Ir-G2 for blue and red emission,respectively.With the structure of ITO/PEDOT：PSS 4083（40 nm）/emission layer（80 nm）/Ba（4 nm）/Al（120 nm）,the device showed a maximal luminous efficiency （LE） of 13.5 cd A-1（corresponding to an external quantum efficiency （EQE） of 6.8%）,and a peak power efficiency （PE） of 6.5 lm W-1 at 6.0 V.Meanwhile,the device exhibited pure white emission with Commission Internationale de l＇Eclairage （CIE） coordinates of （0.34,0.35） at a current density of 12 mA cm-2,which is very close to the equi-energy white point with CIE coordinates of （0.33,0.33）.The device performance can be further optimized when more balanced hole/electron injection is achieved by incorporating a lower conducting type anode buffer layer （PEDOT：PSS） and incorporating poly[（9,9-bis（3＇-（N,N-dimethylamino）propyl）-2,7-fluorenene）-alt-2,7-（9,9-dioctyfluorene）] （PFN） as an electron injection layer at the cathode.The optimized device showed an LE of 24.6 cd A-1 （with an EQE of 14.1%）,while the peak power efficiency reached 12.66 lm W-1.Moreover,the WPLEDs showed good electroluminescence （EL） stability over a wide range of operating current density and luminance.

关 键 词：white polymer light-emitting device phosphorescent iridium complex anode buffer layer water-/alcohol-soluble conjugated polymer 

分 类 号：TN383[电子电信—物理电子学] TN383.1