Recent Advances on Thermally Activated Delayed Fluorescence Dendrimers Enhanced Publication

树枝状热活化延迟荧光材料研究进展 Recent Advances on Thermally Activated Delayed Fluorescence Dendrimers 1 first-author 马志华(1982-)，女，河北秦皇岛人，博士，讲师，2011年于中国科学院长春应用化学研究所获得博士学位，主要从事溶液加工型有机发光材料方面的研究。E-mail: mazhihua@cust.edu.cn http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351681&type= http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351686&type= http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351691&type= 马志华 (1982-)，女，河北秦皇岛人，博士，讲师，2011年于中国科学院长春应用化学研究所获得博士学位，主要从事溶液加工型有机发光材料方面的研究。E-mail: mazhihua@cust.edu.cn mazhihua@cust.edu.cn 1 1 1 2 corresp * Corresponding Author, E-mail: ssyang@ciac.ac.cn * Corresponding Author, E-mail: ssyang@ciac.ac.cn 邵世洋(1985-)，男，湖北洪湖人，博士，副研究员，2012年于中国科学院长春应用化学研究所获得博士学位，主要从事有机高分子发光材料的合成化学与性能的研究。E-mail: ssyang@ciac.ac.cn http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351698&type= http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351703&type= http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351711&type= 邵世洋 (1985-)，男，湖北洪湖人，博士，副研究员，2012年于中国科学院长春应用化学研究所获得博士学位，主要从事有机高分子发光材料的合成化学与性能的研究。E-mail: ssyang@ciac.ac.cn ssyang@ciac.ac.cn 长春理工大学　材料科学与工程学院，吉林 　 长春 　 130022 长春理工大学　材料科学与工程学院，吉林 　 长春 　 130022 School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, China School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, China 中国科学院长春应用化学研究所　高分子物理与化学国家重点实验室，吉林 　 长春 　 130022 中国科学院长春应用化学研究所　高分子物理与化学国家重点实验室，吉林 　 长春 　 130022 State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China 树枝状发光材料是一类由中心核和外围树枝构成的具有三维空间结构的发光功能材料，既具有有机小分子发光材料明确的化学结构和确定的分子量，又具有高分子发光材料的良好溶液加工性能，是发展低成本、高效率有机电致发光器件的重要材料体系。具有热活化延迟荧光效应的树枝状发光材料能够通过反向系间窜越过程将三线态激子转变为单线态激子而发出荧光，其器件理论内量子效率可以达到100%，是开发设计高效树枝状发光材料的有效途径。近年来，在分子设计方面，树枝状热活化延迟荧光材料取得了重要进展，形成了种类丰富的材料体系，同时其器件性能得到了大幅提升。本文根据树枝状热活化延迟荧光材料的中心核进行分类，围绕其分子设计、光物理特性和器件性能，总结和评述了国内外研究者在该领域的主要研究进展，并分析了其未来发展所面临的机遇和挑战。 Dendritic luminescent materials are a kind of three-dimensional(3D) organic optoelectrical functional materials composed of the central core and the dendrons. They are regarded as an important category of organic luminescent materials for the development of cost-effective and high-efficiency organic light emitting devices(OLEDs) because they possess well-defined molecular structure like small molecules and excellent solubility like polymers. Thermally activated delayed fluorescence(TADF) dendrimers-based OLEDs can realize 100% internal quantum efficiency by utilizing triplet excitons through enhanced reverse intersystem crossing process from the lowest triplet state to singlet state. Thus, TADF dendrimers represent a promising approach towards highly efficient dendritic luminescent materials. During these years, significant progress has been made on the molecular design and device performance of TADF dendrimers. In this review, we classify the TADF dendrimers according to their core structure and summarize their research progress with the emphasis on molecular structure, photophysical properties and device performances. Finally, the perspectives and the key challenges on developing TADF dendrimers are discussed. 热活化延迟荧光 树枝状发光材料 溶液加工 有机电致发光 thermally activated delayed fluorescence dendritic luminescent materials solution processible organic light-emitting diodes 1　引言 1 有机电致发光二极管(Organic light emitting diodes,OLEDs)具有色彩丰富、视角广、能耗低等特点，近年来在彩色显示和固体照明等领域取得了快速发展。根据制备工艺不同，OLEDs主要可分为两种，即真空蒸镀型OLEDs和溶液加工型OLEDs。前者是在真空环境下利用热蒸镀技术制备器件;而后者则是在常压下采用喷墨打印、旋涂、刮涂等湿法工艺制备器件，其材料利用率高，且适用于大面积显示器件的制备，受到学术界和产业界的广泛关注。目前，OLEDs材料主要包括三类:小分子发光材料、树枝状发光材料和高分子发光材料 [ 1 1 - 6 6 1-6 ] 。其中，小分子发光材料具有结构明确和易于提纯等优点，但是一般需要采用真空蒸镀工艺制备器件;而高分子发光材料具有良好的成膜能力，能够用于组装溶液加工型器件，但缺点是其分子量具有多分散的特点，导致批次稳定性较差。不同于小分子发光材料和高分子发光材料，树枝状发光材料是一类由中心核和外围树枝构成的具有三维空间结构的有机电光转换材料，既具有有机小分子发光材料明确的化学结构和确定的分子量，又具有高分子发光材料的良好溶液加工性能，是发展低成本、高效率有机电致发光器件的重要材料体系 [ 2 2 , 4 4 ] 。 依据发光机制不同，树枝状发光材料可以分为三类:树枝状荧光材料，树枝状磷光材料和树枝状热活化延迟荧光(Thermally activated delayed fluorescence,TADF)材料。其中，树枝状荧光材料受到自旋量子统计规律的限制，在OLEDs器件中仅能利用25%的单线态激子，其余75%的三线态激子通过非辐射跃迁的方式失活，因此其器件内量子效率(Internal quantum efficiency,IQE)的极限值为25%。树枝状磷光材料能够利用重金属原子的旋轨耦合作用实现对三线态激子的利用，从而达到100%的内量子效率，但是面临贵金属成本偏高和蓝光磷光配合物稳定性较差的问题。树枝状热活化延迟荧光材料由于其单线态-三线态能级差(Singlet-triplet energy gap,Δ E ST )较小，能够利用反向系间窜越(Reverse intersystem crossing,RISC)过程将三线态激子转变为单线态激子而产生延迟荧光发射( 图1 图1 )，因而无需贵金属也能实现100%的器件内量子效率，成为开发设计低成本高效发光材料的有效途径，受到了国内外研究者的广泛关注 [ 7 7 - 24 24 7-24 ] 。近年来，在分子设计方面，树枝状热活化延迟荧光材料取得了重要进展，形成了种类丰富的材料体系，同时其器件性能得到了大幅提升。本文根据树枝状热活化延迟荧光材料的中心核进行分类，围绕其分子设计、光物理特性和器件性能，总结和评述了国内外研究者在该领域的主要研究进展，并分析了其未来发展所面临的机遇和挑战。 2　树枝状热活化延迟荧光材料 1 树枝状热活化延迟荧光材料一般是由中心核(如电子受体单元)和外围功能树枝(如具有空穴传输能力的电子给体单元)构成，其分子结构如 图1 图1 所示。其中心核通常采用三嗪、硫砜、二苯甲酮等电子受体单元，而树枝通常由咔唑、吖啶及其杂化单元组成。通过调控中心核的吸电子能力，以及调控树枝单元连接方式、数目和给电子能力可以调控材料的发光性能，同时，外围树枝对发光中心核的包裹作用还可以有效抑制浓度猝灭、提高发光效率。本节根据树枝状热活化延迟荧光材料的中心核不同进行分类，对树枝状TADF材料的结构设计、光物理性质及器件性能等方面的研究进展进行了总结。 2.1　以三嗪为中心核的树枝状TADF材料 2 三嗪单元具有较强的吸电子能力，是一类广泛用于构建蒸镀型小分子热活化延迟荧光材料的电子受体单元。2015年，Yamamoto等首次报道了以三嗪为核和1~4代齐聚咔唑为树枝的TADF材料DT-1~DT-4( 图2 图2 ) [ 25 25 ] 。研究表明，第2~4代树枝状TADF材料由于最高占据轨道(Highest occupied molecular orbital,HOMO)和最低未占轨道(Lowest unoccupied molecular orbital, LUMO)重叠程度较小，表现出明显的TADF特性，Δ E ST 分别为0.03,0.06,0.06 eV，并且溶液态的荧光量子效率(Photoluminescence quantum yields,PLQY)均大于0.94。但是其薄膜态的PLQY却随着代数的增加而降低(DT-2: 0.52; DT-3: 0.31; DT-4: 0.08)，这可能是由激发态寿 命变长使得非辐射跃迁途径增多导致。基于该系列材料制备的溶液加工型非掺杂器件的外量子效率(External quantum efficiency,EQE)分别为2.4%、3.4%和1.5%。同时，该研究组在第2代树枝状分子上引入不同的外围基团，报道了具有更好溶解性的树枝状TADF材料DT-5~DT-7，其Δ E ST 分别为0.10,0.12,0.09 eV，薄膜态PLQY大于0.40。其中，以叔丁基为外围基团的DT-6为发光层、采用全溶液加工工艺制备的非掺杂器件的最大EQE达到9.5% [ 26 26 ] 。进一步将DT-6掺杂到树枝状主体材料中，通过抑制分子间浓度猝灭将PLQY提升至0.76，相应的全溶液加工工艺器件的最大EQE提升至16.1% [ 27 27 ] 。 Choi等将叔丁基咔唑树枝通过亚甲基连接到TADF中心核上，设计合成了树枝状TADF材料DT-8和DT-9。非共轭亚甲基间隔基团的引入能够打断发光中心核与具有主体作用的树枝之间的电子相互作用，保持中心核的发光特性。二者的薄膜态PLQY分别为0.69和0.56,Δ E ST 分别为0.079 eV和0.134 eV，延迟荧光寿命分别为2.9 μs和25.2 μs。将DT-8和DT-9应用于不含空穴注入/传输层的非掺杂器件中，其最大EQE分别为9.5%和8.1%，相比于不含树枝的中心核(EQE=1.2%)，器件效率提升约7倍 [ 28 28 ] 。 Jiang等将咔唑树枝通过饱和脂肪链连接到三苯基三嗪/咔唑TADF中心核上，发展了树枝状TADF材料DT-10和DT-11 [ 29 29 ] 。DT-10和DT-11的膜态发射峰分别位于490 nm和487 nm，与中心核TADF单元的发光峰位(502 nm)相比，表现出一定程度的蓝移。并且DT-10和DT-11的PLQY分别为0.58和0.76，相比于中心核分子(0.32)明显提升。此外，这种非共轭的连接方式能够很好地保持中心核的发光特性，且树枝的包裹作用能够有效抑制发光中心核的浓度猝灭。以DT-11为发光层制备的非掺杂器件的最大EQE为10.1%。基于这一设计思路，他们还发展了以三苯基三嗪/三苯胺为TADF中心核的黄光树枝状发光材料DT-12和DT-13，其Δ E ST 分别为0.17 eV和0.20 eV。由于树枝的包裹对浓度猝灭的抑制作用，PLQY由中心核分子的0.44提升至0.56(DT-12)和0.71(DT-13)，用DT-13制备的非掺杂器件的最大EQE为11.8% [ 30 30 ] 。 除了树枝的种类与尺寸之外，树枝外围的表面基团对发光性能也有重要影响。我们采用具有给电子能力的正丁氧基作为外围基团代替常用的叔丁基致溶基团，设计合成了树枝状TADF材料DT-14及DT-15( 图3 图3 ) [ 31 31 ] 。如 图3(a) 图3(a) 及 图3(b) 图3(b) 所示，其在甲苯溶液中的发光峰位分别位于495 nm和509 nm，并且表现出显著的热活化延迟荧光性质。对比叔丁基为外围基团的材料(Δ E ST =0.21 eV;延迟荧光寿命为0.71 μs),DT-14和DT-15表现出更小的Δ E ST (0.09 eV和0.02 eV)及更长的延迟荧光寿命(0.82 μs和1.43 μs)。基于 DT-15制备的溶液加工型器件的最大EQE达到20.6%，是含有叔丁基外围基团的树枝状TADF材料的2倍。 2.2　以二苯砜/二苯并噻吩砜为中心核的树枝状TADF材料 2 二苯砜/二苯并噻吩砜单元是一类较弱的电子受体单元，常用于构建蓝光TADF材料。Yang等报道了基于二苯砜中心核和咔唑/吖啶杂化树枝的蓝光树枝状TADF材料DT-16和DT-17( 图4 图4 ) [ 32 32 ] 。二者的Δ E ST 分别为0.09 eV和0.20 eV，由于树枝的包裹作用，DT-16和DT-17在纯膜态下的PLQY分别维持在0.68和0.48。以DT-16为发光层制备的非掺杂器件的最大EQE达到了12.2%。 Jiang等报道了含有二苯砜中心核和咔唑/二苯基氧膦双极树枝的树枝状TADF材料(DT-19)，通过将双极性树枝以柔性链连接到二苯砜中心核，能够保证树枝与发光中心的性质互不影响 [ 33 33 ] 。该树枝状TADF材料的Δ E ST 为0.11 eV。单载流子器件研究表明，相比于含有单极性叔丁基咔唑树枝的分子DT-18，含双极性树枝的DT-19表现出更加平衡的载流子传输能力。采用DT-19为发光层的非掺杂器件表现出优良的器件性能，最大EQE为6.2%。在此基础上，他们进一步发展了四臂结构的树枝状TADF材料DT-20 [ 34 34 ] 。由于树枝的包裹作用有效抑制了发光中心核之间的浓度猝灭，其膜态的PLQY达到0.61。采用DT-20为发光层制备的非掺杂器件的最大EQE为7.3%，色坐标为(0.18,0.30)。 Li等设计合成了以二苯砜为中心核、以不同代数叔丁基咔唑为树枝的树枝状TADF材料DT-21~DT-23 [ 35 35 ] 。随着树枝代数的增加，3个分子的Δ E ST 逐渐降低，分别为0.33,0.25,0.17 eV。DT-21~DT-23在薄膜态的PLQY分别为0.42,0.58,0.22。器件结果表明，以二代叔丁基咔唑为树枝的DT-22为发光层的非掺杂器件表现出深蓝光发射，发光峰位于428 nm，色坐标为(0.15,0.12)，电流效率为4.1 cd·A -1 。该研究组还以DT-22作为主体和蓝光发光单元，以橙光铱配合物作为掺杂剂，组装了溶液加工型白光器件，最大EQE达到10.1%，色坐标为(0.32,0.33) [ 36 36 ] 。 Yang等采用二苯并噻吩砜为中心核，将一代到四代咔唑树枝连接到中心核单元的2,8-位，合成了树枝状TADF分子DT-24~DT-26( 图4 图4 ) [ 37 37 ] 。由于树枝状给体单元与中心核受体单元之间存在较大的扭曲角，因此，其Δ E ST 降低，三者的Δ E ST 分别为0.35,0.16,0.08 eV。器件结果表明，以DT-25为发光层的非掺杂器件的最大EQE为10.7%。同时，他们报道了基于不同代数咔唑/吖啶杂化树枝的TADF材料DT-27和DT-28 [ 38 38 ] 。二者的Δ E ST 分别为0.02 eV和0.04 eV,PLQY分别为0.41和0.54。以DT-27和DT-28为发光层的非掺杂器件的最大EQE分别为3.9%和4.5%，相比于不含咔唑树枝的中心核TADF分子(EQE:0.2%)，分别提升了19.5倍和22.5倍。将DT-28与TADF小分子敏化剂掺杂到主体材料1,3-二咔唑基苯(N,N'-dicarbazolyl-3,5-benzene, mCP)中，当三者比例为20∶10∶70时，器件的电致发光峰位于538 nm，最大EQE达到7.9%。 2.3　以二苯甲酮/蒽醌为中心核的树枝状TADF材料 2 二苯甲酮/蒽醌的羰基具有吸电子特性，能够降低与之相邻苯环的电子密度，因而能够用作构建TADF材料的电子受体单元。Yang等发展了以二苯甲酮为中心核、外围连接有咔唑/吖啶杂化树枝的绿光树枝状TADF材料DT-29和DT-30( 图5 图5 ) [ 39 39 ] 。由于二苯甲酮的吸电子能力较强，其发光波长分别位于520 nm和499 nm,Δ E ST 分别为0.11 eV和0.15 eV，纯膜态的PLQY分别为0.77和0.75。采用DT-29为发光层的非掺杂器件的最大EQE达到了13.8%。同时，DT-29还表现出非常小的效率滚降，在亮度为1 000 cd·m -2 时，EQE仍然维持在13.3%。 Fujita等设计合成了以二苯甲酮为中心核，以齐聚咔唑为树枝的树枝状TADF材料DT-31~DT-33 [ 40 40 ] 。其中含有第二代和第三代咔唑树枝的分子DT-32和DT-33在纯膜状态下的PLQY分别为0.33和0.21，其Δ E ST 分别为0.12 eV和0.10 eV，且均表现出TADF效应，延迟荧光寿命为0.7~0.75 μs。以DT-32为发光层的非掺杂器件的最大EQE为5.7%。该研究组还进一步研究了在DT-32中引入不同的外围基团(如叔丁基(DT-34)、甲基(DT-35)、甲氧基(DT-36)和苯基(DT-37)等)对材料发光性能和聚集诱导荧光增强(Aggregation-Induced emission enhancement,AIEE)特性的影响 [ 41 41 ] 。研究表明，DT-34~DT-37的Δ E ST 分别为0.08,0.09,0.11,0.14 eV,PLQY分别为0.74,0.34,0.17,0.41。以DT-34为发光层的非掺杂全溶液加工器件的最大EQE达到了17.0%。 Jiang等报道了含有蒽醌/芳胺发光中心核和一代或二代咔唑树枝的树枝状TADF材料DT-38和DT-39( 图5 图5 ) [ 42 42 ] 。由于蒽醌的吸电子能力较强，所得材料在甲苯溶液中的发光光谱均位于667 nm,PLQY分别为0.06和0.08，延迟荧光寿命分别为0.56 μs和0.93 μs。以DT-39为发光层制备的非掺杂器件的最大EQE为0.254%，电致发光峰位于715 nm，色坐标为(0.69,0.30)。同时，他们将具有主体功能的4,4'-二(9-咔唑)联苯(4,4'-N,N'-dicarbazole-biphenyl,CBP)通过烷基链连接到TADF中心核上，合成了树枝状TADF材料DT-40，其Δ E ST 为0.17 eV，延迟荧光寿命为0.67 μs，非掺杂器件的最大EQE为0.62%，发光峰位于698 nm，色坐标(0.67,0.31) [ 43 43 ] 。 2.4　以苯甲腈为中心核的树枝状TADF材料 2 Jiang等报道了以苯甲腈为中心核、苯环的2,3,4,5,6-位连接5个咔唑树枝的树枝状TADF材料DT-41( 图6 图6 ) [ 44 44 ] 。该分子中发光核与树枝间采用烷基链的连接方式，能够对发光单元起到有效的包裹作用而抑制浓度猝灭，其薄膜态的PLQY为0.52。采用该材料为发光层的非掺杂全溶液加工器件的最大EQE达到了15.5%。此外，他们通过改变树枝与TADF中心核的连接方式(烷氧基链连接或烷基链连接)和树枝的数目，设计合成了树枝状TADF材料DT-42~DT-44 [ 45 45 ] 。连接方式和树枝数目的改变实现了材料电致发光从蓝绿光到黄绿光的颜色调控，其非掺杂器件的电致发光峰位分别为541,516,515 nm，最大EQE分别为17.38%、14.36%和20.41%。他们还将具有空穴传输特性和主体功能的4,4',4″-三(N-咔唑基)三苯胺(4,4',4″-tris(N-carbazolyl)-triphenylamine,TCTA)及mCP通过烷基链连接到间苯二腈/咔唑基TADF发光单元上，合成了树枝状TADF材料DT-45和DT-46 [ 46 46 ] 。研究表明，DT-45的TCTA树枝可以与TADF中心单元形成分子内激基复合物，其膜态PLQY较低，为0.08;而DT-46的mCP树枝则不与中心单元形成激基复合物，其PLQY提高至0.90。器件结果表明，采用DT-46为发光层制备的非掺杂器件的最大EQE达到16.5%。 2.5　以苯环为中心核的树枝状TADF材料 2 我们设计合成了以苯为中心核、外围含有树枝状吖啶单元为给体和三嗪单元为受体的空间电荷转移树枝状TADF材料DT-47( 图7 图7 ) [ 47 47 ] 。该分子的六苯基苯中心核作为空间限制单元，能够使得树枝状吖啶给体和三嗪受体在苯环外围形成交替排列结构，从而产生给体到受体的空间电荷转移(Through-space charge transfer,TSCT)发光 [ 18 18 , 48 48 - 53 53 48-53 ] 。如 图7 图7 所示，相对于仅含有给体树枝(Ac6)及仅含有受体树枝(TRZ6)的对比材料，DT-47表现出显著红移的电荷转移发射峰。同时，由于DT-47的给体和受体在空间上发生物理分离，电子云重叠程度较小，有利于降低交换能，其Δ E ST 仅为0.04 eV。将DT-47以10%掺杂到主体材料中制备薄膜，其PLQY达到0.63。此外，DT-47还表现出聚集诱导发光(Aggregation-induced emission,AIE)特性，其在四氢呋喃/水的混合溶剂中形成的聚集态的荧光强度相比四氢呋喃溶液提升17倍。基于DT-47为发光材料制备的掺杂器件的最大EQE为14.2%。 Yang等通过将3个叔丁基咔唑给体单元和3个二氟苯甲腈受体单元连接到苯环中心核外围，设计合成了TADF材料DT-48( 图8 图8 ) [ 54 54 ] 。理论计算表明，该分子的最高已占轨道(HOMO)和最低未占轨道(LUMO)在中心苯环单元及给/受体树枝之间都存在着交叠，能够同时实现空间电荷转移发光和化学键电荷转移发光。此外，由于外围树枝的扭曲排列能够有效抑制分子间堆积，该分子在纯膜态的PLQY达到了0.76。以该分子为 发光层制备的非掺杂器件表现出天蓝光发射，发光峰位于484 nm，最大EQE达到21.0%。 a光致发光峰位;b最大电流效率;c最大外量子效率;d色坐标。 1 1 Materials 1 1 http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351856&type= http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351866&type= http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351862&type= /nm(test condition) 1 1 PLQY/%(test condition) 1 1 Δ E ST /eV 1 1 L http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351871&type= http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351881&type= http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351876&type= /(cd·A -1 ) 1 1 EQ http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351886&type= http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351896&type= http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=21351891&type= /% 1 1 CIE d ( x , y ) 1 1 Ref. 1 1 DT-3 1 1 473 (toluene) 1 1 100 (toluene) 1 1 0.06 1 1 — 1 1 3.4 1 1 (0.266,0.485) 1 1 [ 25 25 ] 1 1 DT-6 1 1 500 (doped film) 1 1 76 (doped film) 1 1 0.07 1 1 42.7 1 1 16.1 1 1 (0.28,0.49) 1 1 [ 27 27 ] 1 1 DT-8 1 1 52 0 (neat film) 1 1 69 (neat film) 1 1 0.079 1 1 30.8 1 1 9.5 1 1 (0.32,0.57) 1 1 [ 28 28 ] 1 1 DT-10 1 1 490 (neat film) 1 1 58 (neat film) 1 1 0.20 1 1 30.5 1 1 10.1 1 1 (0.24,0.51) 1 1 [ 29 29 ] 1 1 DT-13 1 1 541 (neat film) 1 1 71 (neat film) 1 1 0.20 1 1 39.0 1 1 11.8 1 1 (0.39,0.56) 1 1 [ 30 30 ] 1 1 DT-15 1 1 509 (toluene) 1 1 74 (toluene) 1 1 0.02 1 1 63.3 1 1 20.6 1 1 (0.30,0.52) 1 1 [ 31 31 ] 1 1 DT-16 1 1 492 (neat film) 1 1 68 (neat film) 1 1 0.09 1 1 30.6 1 1 12.2 1 1 (0.22,0.44) 1 1 [ 32 32 ] 1 1 DT-19 1 1 458 (neat film) 1 1 — 1 1 0.11 1 1 10.5 1 1 6.2 1 1 (0.18,0.27) 1 1 [ 33 33 ] 1 1 DT-20 1 1 460 (neat film) 1 1 61 (neat film) 1 1 0.23 1 1 12.6 1 1 7.3 1 1 (0.18,0.30) 1 1 [ 34 34 ] 1 1 DT-22 1 1 438 (neat film) 1 1 58 (neat film) 1 1 0.25 1 1 4.1 1 1 — 1 1 (0.15,0.12) 1 1 [ 35 35 ] 1 1 DT-25 1 1 499 (neat film) 1 1 57 (neat film) 1 1 0.16 1 1 — 1 1 10.7 1 1 — 1 1 [ 37 37 ] 1 1 DT-28 1 1 540 (neat film) 1 1 54 (neat film) 1 1 0.04 1 1 24.7 1 1 7.9 1 1 (0.35,0.54) 1 1 [ 38 38 ] 1 1 DT-29 1 1 520 (neat film) 1 1 77 (neat film) 1 1 0.11 1 1 — 1 1 13.8 1 1 (0.40,0.54) 1 1 [ 39 39 ] 1 1 DT-32 1 1 493 (neat film) 1 1 33 (neat film) 1 1 0.12 1 1 14.0 1 1 5.7 1 1 (0.26,0.48) 1 1 [ 40 40 ] 1 1 DT-34 1 1 501 (neat film) 1 1 74 (neat film) 1 1 0.08 1 1 46.6 1 1 17.0 1 1 (0.27.0.52) 1 1 [ 41 41 ] 1 1 DT-39 1 1 667 (toluene) 1 1 8 (toluene) 1 1 0.16 1 1 — 1 1 0.254 1 1 (0.69,0.30) 1 1 [ 42 42 ] 1 1 DT-40 1 1 667 (toluene) 1 1 — 1 1 0.17 1 1 — 1 1 0.62 1 1 (0.67,0.31) 1 1 [ 43 43 ] 1 1 DT-41 1 1 — 1 1 52 (neat film) 1 1 0.17 1 1 46.3 1 1 15.5 1 1 (0.25,0.52) 1 1 [ 44 44 ] 1 1 DT-44 1 1 477 (toluene) 1 1 89 (toluene) 1 1 0.18 1 1 63.02 1 1 20.41 1 1 (0.25,0.52) 1 1 [ 45 45 ] 1 1 DT-46 1 1 548 (neat film) 1 1 90 (neat film) 1 1 0.08 1 1 44.5 1 1 16.5 1 1 (0.42,0.55) 1 1 [ 46 46 ] 1 1 DT-47 1 1 518 (toluene) 1 1 63 (doped film) 1 1 0.04 1 1 40.6 1 1 14.2 1 1 (0.25,0.47) 1 1 [ 47 47 ] 1 1 DT-48 1 1 477 (neat film) 1 1 76 (neat film) 1 1 0.03 1 1 46.4 1 1 21.0 1 1 (0.19,0.35) 1 1 [ 54 54 ] 3　结论 1 树枝状热活化延迟荧光材料结合了树枝状分子结构明确、可溶液加工的优点和热活化延迟荧光材料高激子利用率的优势，近年来受到了研究者的广泛关注，目前在材料体系方面已经较为丰富，器件性能也得到较大改善，特别是在溶液加工型非掺杂器件以及全溶液加工型器件中表现出了较高的发光效率，这对于未来采用湿法工艺发展低成本和大面积显示与照明器件具有重要意义。尽管如此，树枝状热活化延迟荧光材料的发展仍然面临诸多挑战，在分子设计和器件性能优化等方面需要持续加强研究。从分子设计角度，一是要进一步明确分子结构与其发光性能之间的关系，包括中心核的类型、树枝结构单元的能级结构、树枝数目与连接方式等因素与发光特性之间的内在关联，特别需要关注利用树枝与载流子传输层之间形成激基复合物来增加激子利用通道和提升器件效率的分子设计策略 [ 46 46 ] ;二是需要面向溶液加工型非掺杂发光器件，发展集多种功能于一体的树枝状热活化延迟荧光材料，特别是同时具有主体功能、发光功能、电子和空穴注入/传输功能的树枝状热活化延迟荧光材料。从器件性能优化的角度，针对溶液加工工艺在组装多层器件时面临的层间互溶问题，需要发展具有抗溶剂侵蚀能力的树枝状热活化延迟荧光材料，例如通过发展高代数的树枝状分子或者引入交联基团降低其在特定溶剂(如醇类溶剂)中的溶解性，保证发光层不被加工相邻层使用的溶剂所破坏。相信随着材料和器件两个方面的不断深入研究，树枝状热活化延迟荧光材料的综合性能将得到进一步提升，从而成为发展低成本和大面积平板显示与固体照明器件的重要材料体系。 本文专家审稿意见及作者回复内容的下载地址:http://cjl.lightpublishing.cn/thesisDetails#10.37188/CJL.202100899. 参考文献: BYEON S Y , LEE D R , YOOK K S , et al . Recent progress of singlet-exciton-harvesting fluorescent organic light-emitting diodes by energy transfer processes [J]. Adv. Mater. , 2019 , 31 ( 34 ): 1803714-1-15 . Recent progress of singlet-exciton-harvesting fluorescent organic light-emitting diodes by energy transfer processes LO S C , BURN P L . Development of dendrimers:macromolecules for use in organic light-emitting diodes and solar cells [J]. Chem. Rev. , 2007 , 107 ( 4 ): 1097 - 1116 . Development of dendrimers:macromolecules for use in organic light-emitting diodes and solar cells 邵世洋 , 丁军桥 , 王利祥 . 高分子发光材料研究进展 [J]. 高分子学报 , 2018 , ( 2 ): 198 - 216 . 高分子发光材料研究进展 SHAO S Y , DING J Q , WANG L X . Research progress on electroluminescent polymers [J]. Acta Polym. Sinica , 2018 , ( 2 ): 198 - 216 . (in Chinese) Research progress on electroluminescent polymers HECHT S , FRÉCHET J M J . Dendritic encapsulation of function:applying nature's site isolation principle from biomimetics to materials science [J]. Angew. Chem. Int. Ed. , 2001 , 40 ( 1 ): 74 - 91 . Dendritic encapsulation of function:applying nature's site isolation principle from biomimetics to materials science GRIMSDALE A C , CHAN K L , MARTIN R E , et al . Synthesis of light-emitting conjugated polymers for applications in electroluminescent devices [J]. Chem. Rev. , 2009 , 109 ( 3 ): 897 - 1091 . Synthesis of light-emitting conjugated polymers for applications in electroluminescent devices 曲波 , 陈志坚 , 李福山 , 等 . 聚芴类有机电致发光的材料和器件 [J]. 发光学报 , 2007 , 28 ( 5 ): 683 - 692 . 聚芴类有机电致发光的材料和器件 QU B , CHEN Z J , LI F S , et al . Materials and devices in the field of polyfluorene derivatives organic electroluminescence [J]. Chin. J. Lumin. , 2007 , 28 ( 5 ): 683 - 692 . (in Chinese) Materials and devices in the field of polyfluorene derivatives organic electroluminescence UOYAMA H , GOUSHI K , SHIZU K , et al . Highly efficient organic light-emitting diodes from delayed fluorescence [J]. Nature , 2012 , 492 ( 7428 ): 234 - 238 . Highly efficient organic light-emitting diodes from delayed fluorescence TAO Y , YUAN K , CHEN T , et al . Thermally activated delayed fluorescence materials towards the breakthrough of organoelectronics [J]. Adv. Mater. , 2014 , 26 ( 47 ): 7931 - 7958 . Thermally activated delayed fluorescence materials towards the breakthrough of organoelectronics IM Y , KIM M , CHO Y J , et al . Molecular design strategy of organic thermally activated delayed fluorescence emitters [J]. Chem. Mater. , 2017 , 29 ( 5 ): 1946 - 1963 . Molecular design strategy of organic thermally activated delayed fluorescence emitters WONG M Y , ZYSMAN-COLMAN E . Purely organic thermally activated delayed fluorescence materials for organic light-emitting diodes [J]. Adv. Mater. , 2017 , 29 ( 22 ): 1605444-1-54 . Purely organic thermally activated delayed fluorescence materials for organic light-emitting diodes XIE Y J , LI Z . Thermally activated delayed fluorescent polymers [J]. J. Polym. Sci. Part A: Polym. Chem. , 2017 , 55 ( 4 ): 575 - 584 . Thermally activated delayed fluorescent polymers YANG Z Y , MAO Z , XIE Z L , et al . Recent advances in organic thermally activated delayed fluorescence materials [J]. Chem. Soc. Rev. , 2017 , 46 ( 3 ): 915 - 1016 . Recent advances in organic thermally activated delayed fluorescence materials BUI T T , GOUBARD F , IBRAHIM-OUALI M , et al . Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs) [J]. Beilstein J. Org. Chem. , 2018 , 14 : 282 - 308 . Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs) LIU Y C , LI C S , REN Z J , et al . All-organic thermally activated delayed fluorescence materials for organic light-emitting diodes [J]. Nat. Rev. Mater. , 2018 , 3 ( 4 ): 18020-1-20 . All-organic thermally activated delayed fluorescence materials for organic light-emitting diodes WEI Q , GE Z Y , VOIT B . Thermally activated delayed fluorescent polymers:structures, properties, and applications in OLED devices [J]. Macromol. Rapid Commun. , 2019 , 40 ( 1 ): 1800570 . Thermally activated delayed fluorescent polymers:structures, properties, and applications in OLED devices 邵世洋 , 丁军桥 , 王利祥 . 高分子热活化延迟荧光材料研究进展 [J]. 应用化学 , 2018 , 35 ( 9 ): 993 - 1004 . 高分子热活化延迟荧光材料研究进展 SHAO S Y , DING J Q , WANG L X . Recent advances on thermally activated delayed fluorescence polymers [J]. Chin. J. Appl. Chem. , 2018 , 35 ( 9 ): 993 - 1004 . (in Chinese) Recent advances on thermally activated delayed fluorescence polymers JIANG T C , LIU Y C , REN Z J , et al . The design, synthesis and performance of thermally activated delayed fluorescence macromolecules [J]. Polym. Chem. , 2020 , 11 ( 9 ): 1555 - 1571 . The design, synthesis and performance of thermally activated delayed fluorescence macromolecules SHAO S Y , WANG L X . Through-space charge transfer polymers for solution-processed organic light-emitting diodes [J]. Aggregate , 2020 , 1 ( 1 ): 45 - 56 . Through-space charge transfer polymers for solution-processed organic light-emitting diodes ZOU Y , GONG S L , XIE G H , et al . Design strategy for solution-processable thermally activated delayed fluorescence emitters and their applications in organic light-emitting diodes [J]. Adv. Opt. Mater. , 2018 , 6 ( 23 ): 1800568-1-25 . Design strategy for solution-processable thermally activated delayed fluorescence emitters and their applications in organic light-emitting diodes 蒋云波 , 李欢欢 , 陶冶 , 等 . 热活化延迟荧光聚合物及其电致发光器件 [J]. 化学进展 , 2019 , 31 ( 8 ): 1116 - 1128 . 热活化延迟荧光聚合物及其电致发光器件 JIANG Y B , LI H H , TAO Y , et al . Thermally activated delayed fluorescence polymers and applications in organic light emitting devices [J]. Progr. Chem. , 2019 , 31 ( 8 ): 1116 - 1128 . (in Chinese) Thermally activated delayed fluorescence polymers and applications in organic light emitting devices 华磊 , 闫寿科 , 任忠杰 . 聚合物热激活延迟荧光材料的分子设计与器件性能 [J]. 高分子学报 , 2020 , 51 ( 5 ): 457 - 468 . 聚合物热激活延迟荧光材料的分子设计与器件性能 HUA L , YAN S K , REN Z J . Molecular design and device performance of thermally activated delayed fluorescent polymer materials [J]. Acta Polym. Sinica , 2020 , 51 ( 5 ): 457 - 468 . (in Chinese) Molecular design and device performance of thermally activated delayed fluorescent polymer materials XIE G H , LUO J J , HUANG M L , et al . Inheriting the characteristics of TADF small molecule by side-chain engineering strategy to enable bluish-green polymers with high PLQYs up to 74% and external quantum efficiency over 16% in light-emitting diodes [J]. Adv. Mater. , 2017 , 29 ( 11 ): 1604223-1-7 . Inheriting the characteristics of TADF small molecule by side-chain engineering strategy to enable bluish-green polymers with high PLQYs up to 74% and external quantum efficiency over 16% in light-emitting diodes LI X , WANG K , SHI Y Z , et al . Efficient solution-processed orange-red organic light-emitting diodes based on a novel thermally activated delayed fluorescence emitter [J]. J. Mater. Chem. C , 2018 , 6 ( 34 ): 9152 - 9157 . Efficient solution-processed orange-red organic light-emitting diodes based on a novel thermally activated delayed fluorescence emitter YANG H Y , ZHENG C J , ZHANG M , et al . Green solution-processed thermally activated delayed fluorescence OLEDs with improved performance by using interfacial exciplex host [J]. Org. Electron. , 2019 , 73 : 36 - 42 . Green solution-processed thermally activated delayed fluorescence OLEDs with improved performance by using interfacial exciplex host ALBRECHT K , MATSUOKA K , FUJITA K , et al . Carbazole dendrimers as solution-processable thermally activated delayed-fluorescence materials [J]. Angew. Chem. Int. Ed. , 2015 , 54 ( 19 ): 5677 - 5682 . Carbazole dendrimers as solution-processable thermally activated delayed-fluorescence materials ALBRECHT K , MATSUOKA K , YOKOYAMA D , et al . Thermally activated delayed fluorescence OLEDs with fully solution processed organic layers exhibiting nearly 10% external quantum efficiency [J]. Chem. Commun. , 2017 , 53 ( 16 ): 2439 - 2442 . Thermally activated delayed fluorescence OLEDs with fully solution processed organic layers exhibiting nearly 10% external quantum efficiency ALBRECHT K , MATSUOKA K , FUJITA K , et al . A dendrimer emitter doped in a dendrimer host:efficient thermally activated delayed fluorescence OLEDs with fully-solution processed organic-layers [J]. Mater. Chem. Front. , 2018 , 2 ( 6 ): 1097 - 1103 . A dendrimer emitter doped in a dendrimer host:efficient thermally activated delayed fluorescence OLEDs with fully-solution processed organic-layers GODUMALA M , CHOI S , KIM H J , et al . Novel dendritic large molecules as solution-processable thermally activated delayed fluorescent emitters for simple structured non-doped organic light emitting diodes [J]. J. Mater. Chem. C , 2018 , 6 ( 5 ): 1160 - 1170 . Novel dendritic large molecules as solution-processable thermally activated delayed fluorescent emitters for simple structured non-doped organic light emitting diodes BAN X X , JIANG W , LU T T , et al . Self-host thermally activated delayed fluorescent dendrimers with flexible chains:an effective strategy for non-doped electroluminescent devices based on solution processing [J]. J. Mater. Chem. C , 2016 , 4 ( 37 ): 8810 - 8816 . Self-host thermally activated delayed fluorescent dendrimers with flexible chains:an effective strategy for non-doped electroluminescent devices based on solution processing SUN K Y , SUN Y B , HUANG T Y , et al . Design strategy of yellow thermally activated delayed fluorescent dendrimers and their highly efficient non-doped solution-processed OLEDs with low driving voltage [J]. Org. Electron. , 2017 , 42 : 123 - 130 . Design strategy of yellow thermally activated delayed fluorescent dendrimers and their highly efficient non-doped solution-processed OLEDs with low driving voltage MA Z H , WAN Y C , DONG W Y , et al . Alkoxy encapsulation of carbazole-based thermally activated delayed fluorescent dendrimers for highly efficient solution-processed organic light-emitting diodes [J]. Chin. Chem. Lett. , 2021 , 32 ( 2 ): 703 - 707 . Alkoxy encapsulation of carbazole-based thermally activated delayed fluorescent dendrimers for highly efficient solution-processed organic light-emitting diodes LUOJ J , GONG S L , GU Y , et al . Multi-carbazole encapsulation as a simple strategy for the construction of solution-processed, non-doped thermally activated delayed fluorescence emitters [J]. J. Mater. Chem. C , 2016 , 4 ( 13 ): 2442 - 2446 . Multi-carbazole encapsulation as a simple strategy for the construction of solution-processed, non-doped thermally activated delayed fluorescence emitters BAN X X , LIN B P , JIANG W , et al . Constructing a novel dendron for a self-host blue emitter with thermally activated delayed fluorescence:solution-processed nondoped organic light-emitting diodes with bipolar charge transfer and stable color purity [J]. Chem. Asian J. , 2017 , 12 ( 2 ): 216 - 223 . Constructing a novel dendron for a self-host blue emitter with thermally activated delayed fluorescence:solution-processed nondoped organic light-emitting diodes with bipolar charge transfer and stable color purity BAN X , JIANG W , SUN K Y , et al . Self-host blue dendrimer comprised of thermally activated delayed fluorescence core and bipolar dendrons for efficient solution-processable nondoped electroluminescence [J]. ACS Appl. Mater. Interfaces , 2017 , 9 ( 8 ): 7339 - 7346 . Self-host blue dendrimer comprised of thermally activated delayed fluorescence core and bipolar dendrons for efficient solution-processable nondoped electroluminescence LI J , LIAO X Q , XU H X , et al . Deep-blue thermally activated delayed fluorescence dendrimers with reduced singlet-triplet energy gap for low roll-off non-doped solution-processed organic light-emitting diodes [J]. Dyes Pigm. , 2017 , 140 : 79 - 86 . Deep-blue thermally activated delayed fluorescence dendrimers with reduced singlet-triplet energy gap for low roll-off non-doped solution-processed organic light-emitting diodes LIAO X Q , YANG X , ZHANG R , et al . Solution-processed small-molecular white organic light-emitting diodes based on a thermally activated delayed fluorescence dendrimer [J]. J. Mater. Chem. C , 2017 , 5 ( 38 ): 10001 - 10006 . Solution-processed small-molecular white organic light-emitting diodes based on a thermally activated delayed fluorescence dendrimer LI Y F , CHEN T H , HUANG M L , et al . Tuning the twist angle of thermally activated delayed fluorescence molecules via a dendronization strategy:high-efficiency solution-processed non-doped OLEDs [J]. J. Mater. Chem. C , 2017 , 5 ( 14 ): 3480 - 3487 . Tuning the twist angle of thermally activated delayed fluorescence molecules via a dendronization strategy:high-efficiency solution-processed non-doped OLEDs HUANG M L , LI Y F , WU K L , et al . Carbazole-dendronized thermally activated delayed fluorescent molecules with small singlet-triplet gaps for solution-processed organic light-emitting diodes [J]. Dyes Pigm. , 2018 , 153 : 92 - 98 . Carbazole-dendronized thermally activated delayed fluorescent molecules with small singlet-triplet gaps for solution-processed organic light-emitting diodes LI Y F , XIE G H , GONG S L , et al . Dendronized delayed fluorescence emitters for non-doped, solution-processed organic light-emitting diodes with high efficiency and low efficiency roll-off simultaneously:two parallel emissive channels [J]. Chem. Sci. , 2016 , 7 ( 8 ): 5441 - 5447 . Dendronized delayed fluorescence emitters for non-doped, solution-processed organic light-emitting diodes with high efficiency and low efficiency roll-off simultaneously:two parallel emissive channels MATSUOKA K , ALBRECHT K , YAMAMOTO K , et al . Mulifunctional dendritic emitter:aggregation-induced emission enhanced, thermally activated delayed fluorescent material for solution-processed multilayered organic light-emitting diodes [J]. Sci. Rep. , 2017 , 7 : 41780-1-9 . Mulifunctional dendritic emitter:aggregation-induced emission enhanced, thermally activated delayed fluorescent material for solution-processed multilayered organic light-emitting diodes MATSUOKA K , ALBRECHT K , NAKAYAMA A , et al . Highly efficient thermally activated delayed fluorescence organic light-emitting diodes with fully solution-processed organic multilayered architecture:impact of terminal substitution on carbazole-benzophenone dendrimer and interfacial engineering [J]. ACS Appl. Mater. Interfaces , 2018 , 10 ( 39 ): 33343 - 33352 . Highly efficient thermally activated delayed fluorescence organic light-emitting diodes with fully solution-processed organic multilayered architecture:impact of terminal substitution on carbazole-benzophenone dendrimer and interfacial engineering SUN K Y , CHU D , CUI Y D , et al . Near-infrared thermally activated delayed fluorescent dendrimers for the efficient non-doped solution-processed organic light-emitting diodes [J]. Org. Electron. , 2017 , 48 : 389 - 396 . Near-infrared thermally activated delayed fluorescent dendrimers for the efficient non-doped solution-processed organic light-emitting diodes SUN K Y , SUN Y B , LIU D , et al . CBP derivatives dendronized self-host TADF dendrimer:achieving efficient non-doped near-infrared organic light-emitting diodes [J]. Dyes Pigm. , 2017 , 147 : 436 - 443 . CBP derivatives dendronized self-host TADF dendrimer:achieving efficient non-doped near-infrared organic light-emitting diodes BAN X X , ZHU A Y , ZHANG T L , et al . Highly efficient all-solution-processed fluorescent organic light-emitting diodes based on a novel self-host thermally activated delayed fluorescence emitter [J]. ACS Appl. Mater. Interfaces , 2017 , 9 ( 26 ): 21900 - 21908 . Highly efficient all-solution-processed fluorescent organic light-emitting diodes based on a novel self-host thermally activated delayed fluorescence emitter LIU D , TIAN W W , FENG Y L , et al . Achieving 20% external quantum efficiency for fully solution-processed organic light-emitting diodes based on thermally activated delayed fluorescence dendrimers with flexible chains [J]. ACS Appl. Mater. Interfaces , 2019 , 11 ( 18 ): 16737 - 16748 . Achieving 20% external quantum efficiency for fully solution-processed organic light-emitting diodes based on thermally activated delayed fluorescence dendrimers with flexible chains SUN K Y , SUN Y B , TIAN W W , et al . Thermally activated delayed fluorescence dendrimers with exciplex-forming dendrons for low-voltage-driving and power-efficient solution-processed OLEDs [J]. J. Mater. Chem. C , 2018 , 6 ( 1 ): 43 - 49 . Thermally activated delayed fluorescence dendrimers with exciplex-forming dendrons for low-voltage-driving and power-efficient solution-processed OLEDs WANG X D , WANG S M , LV J H , et al . Through-space charge transfer hexaarylbenzene dendrimers with thermally activated delayed fluorescence and aggregation-induced emission for efficient solution-processed OLEDs [J]. Chem. Sci. , 2019 , 10 ( 10 ): 2915 - 2923 . Through-space charge transfer hexaarylbenzene dendrimers with thermally activated delayed fluorescence and aggregation-induced emission for efficient solution-processed OLEDs SHAO S Y , HU J , WANG X D , et al . Blue thermally activated delayed fluorescence polymers with nonconjugated backbone and through-space charge transfer effect [J]. J. Am. Chem. Soc. , 2017 , 139 ( 49 ): 17739 - 17742 . Blue thermally activated delayed fluorescence polymers with nonconjugated backbone and through-space charge transfer effect CHEN F , HU J , WANG X D , et al . Synthesis and electroluminescent properties of through-space charge transfer polymers containing acridan donor and triarylboron acceptors [J]. Front. Chem. , 2019 , 7 : 854-1-10 . Synthesis and electroluminescent properties of through-space charge transfer polymers containing acridan donor and triarylboron acceptors HU J , LI Q , WANG X D , et al . Developing through-space charge transfer polymers as a general approach to realize full-color and white emission with thermally activated delayed fluorescence [J]. Angew. Chem. Int. Ed. , 2019 , 58 ( 25 ): 8405 - 8409 . Developing through-space charge transfer polymers as a general approach to realize full-color and white emission with thermally activated delayed fluorescence CHEN F , HU J , WANG X D , et al . Through-space charge transfer blue polymers containing acridan donor and oxygen-bridged triphenylboron acceptor for highly efficient solution-processed organic light-emitting diodes [J]. Sci. China Chem. , 2020 , 63 ( 8 ): 1112 - 1120 . Through-space charge transfer blue polymers containing acridan donor and oxygen-bridged triphenylboron acceptor for highly efficient solution-processed organic light-emitting diodes HU J , LI Q , SHAO S Y , et al . Single white-emitting polymers with high efficiency, low roll-off, and enhanced device stability by using through-space charge transfer polymer with blue delayed fluorescence as host for yellow phosphor [J]. Adv. Opt. Mater. , 2020 , 8 ( 11 ): 1902100-1-9 . Single white-emitting polymers with high efficiency, low roll-off, and enhanced device stability by using through-space charge transfer polymer with blue delayed fluorescence as host for yellow phosphor LI Q , HU J , LV J H , et al . Through-space charge-transfer polynorbornenes with fixed and controllable spatial alignment of donor and acceptor for high-efficiency blue thermally activated delayed fluorescence [J]. Angew. Chem. Int. Ed. , 2020 , 59 ( 45 ): 20174 - 20182 . Through-space charge-transfer polynorbornenes with fixed and controllable spatial alignment of donor and acceptor for high-efficiency blue thermally activated delayed fluorescence ZHENG X J , HUANG R J , ZHONG C , et al . Achieving 21% external quantum efficiency for nondoped solution-processed sky-blue thermally activated delayed fluorescence OLEDs by means of multi-(donor/acceptor) emitter with through-space/-bond charge transfer [J]. Adv. Sci. , 2020 , 7 ( 7 ): 1902087-1-7 . Achieving 21% external quantum efficiency for nondoped solution-processed sky-blue thermally activated delayed fluorescence OLEDs by means of multi-(donor/acceptor) emitter with through-space/-bond charge transfer 10.37188/CJL.20210099 O482.31 A 1000-7032(2021)07-0904-13 吉林省科技发展计划国际合作项目（20200801006GH）；吉林省科技发展计划学科布局项目（20200201235JC）；吉林省教育厅“十三五”科学技术项目（JJKH20200744KJ）资助 Supported by Jilin Provincial Science and Technology Development Program (20200801006GH, International Cooperation Project); Jilin Provincial Science and Technology Development Program (20200201235JC); The Education Department of Jilin Province (JJKH20200744KJ) 2021-03-19 2021-04-02 2021-07-01 2021-10-22 2021 发光学报 07 42