摘要
采用咔唑和3,3’-二甲基二苯醚共聚物作为主链,通过Suzuki聚合方法,设计合成了系列红光热活化延迟荧光(TADF)聚合物PCzDMPE-R03~PCzDMPE-R10.和基于芴和3,3’-二甲基二苯醚共聚物主链的红光TADF聚合物相比,芴到咔唑的改变,能够有效地增加主链的最高占据分子轨道(HOMO)能级,进而降低空穴注入势垒.因此,PCzDMPE-R07获得了最优的非掺杂器件性能,启亮电压从原来的9.8 V降低到5.2 V,最大电流效率和外量子效率分别为3.35 cd/A和2.03%.在此基础上,将其分散在mCP中制备了掺杂器件,电流效率和外量子效率进一步提升到7.36 cd/A和3.77%.
A series of red-emitting thermally activated delayed fluorescence(TADF)polymers based on poly(2,7-carbazole-co-3,3′-dimethyldiphenyl ether)(PCzDMPE)main chains,including PCzDMPE-R03,PCzDMPE-R05,PCzDMPE-R07,and PCzDMPE-R10,have been designed and synthesized via Suzuki polycondensation.The thermally stable polymers possessed glass transition temperatures above 90°C and decomposition temperatures above 410°C,which is beneficial to the devices of long-term services.As the content of red TADF unit increased,the maximum emission was gradually red-shifted from 577 nm(PCzDMPE-R03)to584 nm(PCzDMPE-R010),while the film photoluminescence quantum yield(PLQY)dropped correspondingly from 0.47 to 0.21 according to the energy gap law.Meanwhile,they all exhibited an obviously delayed fluorescence with the lifetime of 145–161μs,accompanied by a prompt fluorescence of 4.5–6.5 ns.For instance,the temperature-dependent transient photoluminescence spectra measured for PCzDMPE-R07 sample displayed an enhanced delayed fluorescence upon the temperature rise from 150 K to 300 K,indicative of its TADF nature.More importantly,compared with earlier reports of red TADF polymers based on poly(fluorene-co-3,3′-dimethyl diphenyl ether),fluorene being replaced by carbazole in the present work could increase the highest occupied molecular orbital(HOMO)level and thus favor the hole injection.As a consequence,the turn-on voltage of PCzDMPE-R07 nondoped device was significantly reduced from 9.8 V to 5.2 V.PCzDMPE-R07 also outperformed the other candidates in terms of a maximum current efficiency of 3.35 cd/A and a maximum external quantum efficiency(EQE)of 2.03%.For performance optimization,a doped device was then fabricated by dispersing 20 wt%of PCzDMPE-R07 into the 1,3-bis(9 H-carbazol-9-yl)benzene(mCP)matrix as an emitting layer.The corresponding current efficiency and EQE were further improved to 7.36 cd/A and 3.77%,respectively.To sum up,the copolymer containing carbazole and 3,3′-dimethyldiphenyl ether provides a favorable backbon
作者
杨云
赵磊
王淑萌
丁军桥
王利祥
Yun Yang;Lei Zhao;Shu-meng Wang;Jun-qiao Ding;Li-xiang Wang(State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022;School of Applied Chemistry and Engineering,University of Science and Technology of China,Hefei 230026)
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2019年第7期685-694,共10页
Acta Polymerica Sinica
基金
国家重点研发计划(项目号2016YFB0401301)
国家重点基础研究发展计划(973计划,项目号2015CB655001)
国家自然科学基金(基金号51873205,5157318)资助项目
关键词
咔唑
3
3’-二甲基二苯醚
热活化延迟荧光
聚合物
红光
Carbazole
3,3′-Dimethyldiphenyl ether
Thermal activated delayed fluorescence
Polymers
Red emission
