Location, Location, Location - Strategic Positioning of 2,1,3-Benzothiadiazole Units within Trigonal Quaterfluorene-Truxene Star-Shaped Structures
Location, Location, Location - Strategic Positioning of 2,1,3-Benzothiadiazole Units within Trigonal Quaterfluorene-Truxene Star-Shaped Structures
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DOI：
10.1002/adfm.201202644
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发表时间：
2013-06-13
影响因子：
19
通讯作者：
Bradley, Donal D. C.
中科院分区：
文献类型：
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作者：
Belton, Colin R.;Kanibolotsky, Alexander L.;Bradley, Donal D. C.
稠合双环分子 2,1,3-苯并噻二唑 (BT) 已成为用于发光和能量收集应用的新型有机半导体设计的关键成分。在这里，报道了一系列三角星形化合物的合成，这些化合物包含一个 truxene 核心和三个四二烷基芴臂，每个臂中的每个可能位置（T4BT-A 至 T4BT-E）顺序插入一个 BT 单元。对所得电子特性的分析表明，由于与核的共轭耦合以及由此产生的对称性，BT 单元具有三个不同的位置，并且讨论了这些位置对光发射和其他光谱特性的影响。不同结构异构体光物理性质的系统变化有助于阐明 BT 单元添加到 9,9-二烷基芴链的影响。它还有助于建立一个设计模板，用于构建具有目标特性的供体-受体共轭材料。对于在每个臂的末端位置具有BT单元的T4BT-E，光致发光量子效率显着降低，并且在典型泵浦条件下没有观察到放大的自发发射。理论计算有助于理解 T4BT-X 化合物家族之间行为的变化，特别是与其光致发光衰减时间和以 BT 单元为中心的主要分子振动的拉曼散射强度有关。
The fused, bicyclic molecule, 2,1,3-Benzothiadiazole (BT), has become a key ingredient in the design of new organic semiconductors for light emission and energy harvesting applications. Here, the synthesis is reported of a series of trigonal, star-shaped compounds comprising a truxene core and three quater-dialkylfluorene arms into each of which a BT unit is inserted sequentially at each possible position (T4BT-A to T4BT-E). Analysis of the resulting electronic properties shows that as a consequence of conjugative coupling to the core and the resulting symmetry there are three distinct locations for the BT unit and the influence that these locations have on light emission and other spectroscopic characteristics is discussed. The systematic variation in photophysical properties for the different structural isomers helps to clarify the influence of BT unit addition to 9,9-dialkylfluorene chains. It also helps to establish a design template for the construction of donor-acceptor conjugated materials with targeted properties. For T4BT-E with a BT unit at the terminal position of each arm, the photoluminescence quantum efficiency is significantly reduced and no amplified spontaneous emission is observed under typical pumping conditions. Theoretical calculations assist in understanding the variation in behaviors among the T4BT-X family of compounds, especially in relation to their photoluminescence decay times and the Raman scattering intensities of their dominant BT-unit-centred molecular vibrations.