基于吩嗪受体单元的高效近红外热激活延迟荧光  

High-efficiency Near Infrared Thermally Activated Delayed Fluorescence Based on Phenazine Acceptor

作　　者：马金珠 李阳[1] 高珊[1] 赵越 丁磊 周东营[1] 樊健[1] Ma Jinzhu;Li Yang;Gao Shan;Zhao Yue;Ding Lei;Zhou Dongying;Fan Jian(Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Institute of Functional Nano&Soft Materials,Soochow University,Suzhou 215123,China;State Key Laboratory of Coordination Chemistry,Institute of Coordination Chemistry,Nanjing University,Nanjing 210023,China;School of Chemistry and Life Sciences,Suzhou University of Science and Technology,Suzhou 215127,China)

机构地区：[1]苏州大学功能纳米与软物质研究院、江苏省碳基功能材料与器件重点实验室,苏州215123 [2]南京大学配位化学研究所配位化学国家重点实验室,南京210023 [3]苏州科技大学化学与生命科学学院,苏州215127

出　　处：《化学学报》2025年第1期17-24,共8页Acta Chimica Sinica

基　　金：国家重点研发计划(No.2020YFA0714604);国家自然科学基金(Nos.22005184,62375193);江苏省国际科技合作/港澳台科技合作项目(No.BZ2023053)资助.

摘　　要：分别以二苯并吩嗪和二吡啶并吩嗪为受体单元,三苯胺为给体单元,设计并合成了两种给体-受体-给体(D-A-D)型红色热激活延迟荧光(TADF)材料即10,13-双(4-(二苯基氨基)苯基)二苯并[a,c]吩嗪-3,6-二腈(BzPz-TPA)和10,13-双(4-(二苯基氨基)苯基)联吡啶并[3,2-a:2',3'-c]吩嗪-11,12-二腈(PyPz-TPA).将两个氰基基团分别引入到BzPz-TPA和PyPz-TPA的受体单元上,增强受体单元的吸电子能力.在分子骨架中嵌入强给体-强受体单元,并且因为二者间的空间位阻效应,使BzPz-TPA分子和PyPz-TPA分子均具有扭曲D-A分子构型,从而使其产生小的单线态-三线态能级差(ΔE_(ST)).另外,分子内给体和受体单元之间的氢键作用,可以调控D-A分子构型以及最高占据分子轨道(HOMO)和最低未占分子轨道(LUMO)之间的重叠程度.在BzPz-TPA分子中,供体和受体单元之间的二面角为44°,D-A之间存在扭曲构型,从而实现了HOMO和LUMO的有效分离,HOMO主要位于供体单元TPA上,而LUMO主要位于受体单元上;在PyPz-TPA分子中,供体和受体单元之间的二面角为52°,D-A扭曲构型有效地分离了HOMO和LUMO,HOMO主要位于供体单元TPA上,LUMO主要位于受体单元上.由于BzPz-TPA和PyPz-TPA具有相同的供体单元,因此它们具有相似的HOMO能级.由于两个发光分子均具有强的刚性骨架和较小的ΔE_(ST),将BzPz-TPA分子掺杂在主体材料4,4'-二(9-咔唑)联苯(CBP)中,该有机发光二极管(OLED)器件在638 nm发射时,其最大外量子效率(EQE)达到7.4%;PyPz-TPA分子掺杂在主体材料CBP中,其OLED器件在676 nm发射时,其最大EQE达到了22.6%;并且当其在电致发射波长为714 nm时该器件达到了16.58%的最大EQE,实现近红外发光.Two donor-acceptor-donor(D-A-D)type red thermally activated delayed fluorescence(TADF)materials 10,13-bis(4-(diphenylamino)phenyl)dibenzo[a,c]phenazine-3,6-dicarbonitrile(BzPz-TPA)and 10,13-bis(4-(diphenylamino)phenyl)-dipyrido[3,2-a:2',3'-c]phenazine-11,12-dicarbonitrile(PyPz-TPA)were designed and synthesized with dibenzophenazine and dipyridobenzazine as acceptor units and triphenylamine as donor units respectively.Two cyano groups were introduced into BzPz-TPA and PyPz-TPA to enhance the electron-withdrawing capability of the acceptor unit.Strong donor and acceptor units were introduced into the molecular skeletons of BzPz-TPA and PyPz-TPA,and steric hindrance between D and A units led to a twisted D-A configuration,thus achieving relatively small singlet-triplet energy gaps(ΔE_(ST)).In addition,the intra-molecular hydrogen bonding interaction between donor and acceptor units can modulate the D-A molecular configuration and the overlap between the highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO).In the BzPz-TPA molecule,the dihedral angle between the donor and acceptor units is 44°,and there is a twisted configura tion between D-A,thereby achieving effective separation of HOMO and LUMO.HOMO is mainly located on the donor unit TPA,while LUMO is mainly located on the acceptor unit.In PyPz-TPA molecule,the dihedral angle between the donor and acceptor units is 52°,and the D-A twisted configuration effectively separates the HOMO and LUMO.The HOMO is mainly on the donor unit TPA,and the LUMO is mainly on the acceptor unit.Since BzPz-TPA and PyPz-TPA have the same donor unit,they have similar HOMO energy levels.Due to the rigid skeleton of two molecules and the smallerΔE_(ST),the BzPz-TPA is doped into the host material 4,4'-bis(9-carbazole)biphenyl(CBP)and resulted in the maximum external quantum efficiency(EQE)of 7.4%for the organic light-emitting diode(OLED)device emitting at 638 nm.When PyPz-TPA is doped into the host material CBP,the OLED device achieved the maximum

关 键 词：热激活延迟荧光 单线态-三线态能极差 外量子效率 热稳定性 电致发光性能 

分 类 号：TN383.1[电子电信—物理电子学] TQ422[化学工程]