电子给体-受体型热活化延迟荧光蓝光材料研究进展

热活化延迟荧光材料由于其最低激发单重态和最低激发三重态之间的能级差较小,三重态激子可以通过反向系间窜越过程上转换到单重态,实现无贵金属添加的三重态激子参与的荧光发射,大大提高了发光效率,解决了传统荧光有机发光二极管(OLED)内/外量子效率(≤25%/≤5%)低下的问题;与磷光OLED相比,避免了使用贵金属,在造价方面具有更大优势.在类型众多的热活化延迟荧光(TADF)材料中,由于电子给体-受体型分子合成简单,性能出众而成为近年来的研究热点.另一方面,高效蓝光材料的稳定性及色纯度问题一直是该领域研究亟待解决的难题.本文将依据不同电子给受体单元,对电子给体-受体型热活化延迟荧光蓝光材料及其OLED器件的最新进展、发光原理和设计原则进行了简要综述,并对其发展作出展望.     

基于给-受体结构的热活化延迟荧光材料

热活化延迟荧光（TADF）材料由于第一单线态（S₁）与三线态激发态（T₁）之间的能级差较小,使得三线态激子能够有效地系间窜越至单线态发光,实现100%的激子利用率,在有机发光二极管（OLED）等领域得到广泛应用,是目前有机电子学研究的热点之一。基于给-受体（D-A）结构构建TADF材料具有分子设计简便、易于制备、性能优异等特点,引起了人们的普遍关注。本文综述了基于D-A结构设计TADF材料的基本原则,依据给受体构筑单元的不同,概括了各类TADF材料的结构和性能特点以及在器件应用等方面的最新研究进展,最后总结了D-A结构型TADF材料尚存在的问题,并对其未来的关键研究方向进行了分析和展望。     

基于苊并[1,2-b]喹喔嗪为受体单元设计合成新型红光热活化延迟荧光分子

采用苊并[1,2-b]喹喔嗪(AQ)作为一种新的热活化延迟荧光(TADF)电子受体(A)基团,通过与强电子给体(D)基团吩噁嗪连接成D-A结构,合成出一种新型TADF分子10,10',10'-(苊并[1,2-b]喹喔嗪-3,9,10-三基)-三(10H-吩噁嗪)(AQ-TPXZ),该分子材料发射红色荧光.理论计算表明,该分子的轨道电子云重叠度很小.通过荧光和磷光光谱计算得出,其单线态-三线态能隙差为0.02eV.瞬态衰减测试显示AQ-TPXZ具有瞬时寿命和延迟寿命两种组分.以AQ-TPXZ为发光材料的有机电致发光器件(OLED)实现了红光发射,峰值位于624nm处.该器件的最大外量子效率为7.4%,高于传统的OLED的理论最大外量子效率(5%),这一结果不仅表明AQ-TPXZ为红光TADF分子,同时表明AQ可作为一种新的红光TADF电子受体片段.     

聚集诱导延迟荧光材料及器件研究进展

热活化延迟荧光(TADF)材料无需贵金属参与即可实现单线态和三线态激子的全利用,成为了有机电致发光的研究热点.但是目前大部分TADF材料都表现出严重聚积诱导发光猝灭现象,这对其应用和发展不利.聚集诱导延迟荧光材料作为一种新型TADF材料,具有独特的聚集诱导荧光增强现象引起科研工作者极大兴趣.基于聚集诱导延迟荧光材料分子设计及其光物理性能和器件研究具有重要意义.将依据不同电子受体单元,对聚集诱导延迟荧光材料的发光原理、设计策略及其有机发光器件的最新进展进行简要综述,并对其发展做出展望.     

基于咔唑和三嗪单元的位点调控设计并合成高效蓝光热活化延迟荧光分子

利用咔唑作为给体基元、三嗪作为受体基元,通过有效组合和位点调控设计合成了两个发光机理-热活化延迟荧光(TADF)分子:m-CzTri和p-CzTri.这两个材料均发射明亮的蓝色荧光,且具有非常小的单线态-三线态激子分裂能.计算模拟表明,给体和受体基团分离了最高占据轨道(HOMO)和最低未占据轨道(LUMO),使它们之间交叠很小.此外,测试了它们的热学、电化学、光物理和器件性质,其中, m-CzTri作为发光分子的有机发光二极管(OLED)器件的色坐标为(0.15, 0.25),得到了高达18%的外量子效率.     

基于硼氮杂稠环芳烃的多重共振热活化延迟荧光材料研究进展

近年来,多重共振热活化延迟荧光(multi-resonance thermally activated delayed fluorescence, MR-TADF)材料由于其优异的光物理性质和电致发光器件性能而受到广泛关注.这类材料通常以稠环芳烃骨架为基础,通过引入具有相反共振效应的缺电子中心(如硼原子)和富电子中心(如氮原子),诱导最高占据分子轨道(HOMO)和最低未占分子轨道(LUMO)在分子骨架中分别定域在不同原子上,从而获得小的单线态-三线态能级差(ΔEST),实现TADF的性质.与传统的给受体型TADF材料相比, MR-TADF材料具有刚性结构和局域电荷转移特征,有利于获得高色纯度的窄谱带发光和极高的量子效率,使其成为理想的发光材料并广泛应用于有机发光二极管(organiclight-emittingdiode,OLED)中.自2016年首例基于硼氮杂稠环芳烃的MR-TADF材料被报道以来,该领域取得了飞速的发展,但尚缺乏针对材料分子研究进展的系统总结.综述了基于硼氮杂稠环芳烃的MR-TADF分子的设计策略和合成方法,从分子骨架的发展、分子骨架的取代基修饰策略以及新型手性MR...     

蓝光热激活延迟荧光分子设计策略概述

热激活延迟荧光（thermally activated delayed fluorescence,TADF）分子由于三重态上的激子可以通过反向系间窜越到单重态并辐射发出荧光，因此在有机发光二极管（organic lightemitting diode, OLED）中理论上可以实现100%的激子利用率。具有TADF特性的发光材料融合了第一代荧光材料和第二代磷光材料的优点，不仅可以实现100%的内量子效率，还有助于降低器件的材料成本，被誉为第三代OLED发光材料，并成为突破高效稳定蓝光OLED瓶颈的潜在解决方案。本文从发光机理出发，系统阐述了高效稳定蓝光TADF分子的设计策略，包括高荧光量子产率、短延迟荧光寿命、窄发射光谱半峰宽、显著的水平分子取向和良好的光电稳定性等。本文旨在为高性能蓝光TADF分子的开发提供理论支持。最后，总结了当前蓝光TADF材料存在的问题，并对其未来的发展前景进行了展望。     

溶液加工型自主体热活化延迟荧光材料的研究进展

十年来,作为第三代有机发光二极管(organic light-emitting diodes, OLED)发光材料的热活化延迟荧光(thermally activated delayed fluorescence, TADF)材料备受学术界和产业界的广泛关注. TADF分子由于单重态与三重态之间的能级差较小,当受到环境热激活时,三重态激子可以通过反系间窜越转化为单重态,从理论上讲,可以实现100%的激子利用率.这一特性使得OLED器件外量子效率显著提高.溶液加工法具有成本低、方法简单、材料利用率高、可大面积生产等优势,是柔性及印刷OLED器件制备工艺的理想候选.具有良好的电荷传输能力的主体材料能有效降低激子密度和促进能量高效传递.利用自主体TADF材料制备的溶液加工型器件能有效平衡载流子传输和提升器件性能,同时在使用过程中可避免相分离,保持薄膜的均匀性和提高器件的稳定性.本综述总结了溶液加工型自主体TADF材料的研究进展.首先介绍了TADF材料的基本原理和研究意义,强调了溶液加工型自主体TADF材料在显示器件和照明器件等方面的应用潜力.然后详细讨论了溶液加工型自主体TADF材料的不同分...     

氰基取代的螺芴氧杂蒽衍生物:激基复合物发光与性质调控

热活化延迟荧光分子因具有高效发光、价格低廉等优点,在发展有机发光二极管方面显示出巨大潜力.与单分子相比,激基复合物容易实现小的单线态-三线态能隙差,在开发延迟荧光材料方面备受关注.然而,相应受体材料的种类仍较为稀少,且激基复合物延迟荧光性质与受体材料结构之间的关系还需深入探讨.本工作设计合成出两个新型的基于螺芴氧杂蒽的电子受体材料（CNSFDBX和DCNSFDBX）.结果表明,它们与给体材料TCTA掺杂后均呈现激基复合物发射,其中TCTA：DCNSFDBX掺杂体系显示更高的发光效率,其原因归结为双氰基取代使得DCNSFDBX具有更强的接收电子的能力.该工作为开发新型电子受体材料用于激基复合物延迟荧光提供了思路.     

热激活延迟荧光材料的光物理行为及性能预测

热激活延迟荧光(Thermally activated delayed fluorescence, TADF)材料由于三线态激子可通过反系间窜越(Reverse intersystem crossing, RISC)转换为单线态激子,在有机发光二极管(Organic light-emitting diodes, OLEDs)中理论上可达到100%的激子利用率而被广泛关注。但实验上开发设计高性能TADF材料较为复杂且研究周期较长,理论研究可以从本质上建立材料结构-性能的关系,预测材料的性质并提供一定的分子设计策略。本文围绕高性能TADF材料的开发,从发光原理出发,系统阐述了分子的设计策略及光物理参数如材料单-三线态能级差(Single-triplet energy gap, ΔE_ST)、系间/反系间窜越速率、吸收/发射光谱、辐射/非辐射速率等的计算原理、计算方法和研究进展。最后我们探讨了TADF材料理论研究面临的机遇和挑战,通过对TADF材料的理论研究综述和研究前景的展望,期待吸引更多的研究工作者,推动该领域的发展和突破。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.