Rational Design, Synthesis, and Optical Properties of Film-Forming, Near-Infrared Absorbing, and Fluorescent Chiromophores with Multidonors and Large Heterocyclic Acceptors
Rational Design, Synthesis, and Optical Properties of Film-Forming, Near-Infrared Absorbing, and Fluorescent Chiromophores with Multidonors and Large Heterocyclic Acceptors
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具有多供体和大杂环受体的成膜、近红外吸收和荧光手色团的合理设计、合成和光学性质
DOI：
10.1002/chem.200900891
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发表时间：
2009-01-01
影响因子：
4.3
通讯作者：
Wang, Zhi Yuan
中科院分区：
文献类型：
--
作者：
Luo, Min;Shadnia, Hooman;Wang, Zhi Yuan
借助于计算研究，合理设计了一系列新的成膜、低带隙发色团（1a，B和2a，B）。然后进行合成和表征。为了实现在1000 nm波长以上的吸收和发射，分子设计集中于通过将常见的杂环单元融合成充当电子受体的大的共辄核来降低LUMO能级，并通过在受体核的适当位置处连接多个供电子基团来增加电荷转移。发色团具有1.27 - 0.71 eV的带隙水平，因此在溶液中在746 - 1003 nm处吸收并在1035 - 1290 nm处发射。通过设计，相对高的分子量（高达2400 g mol（-1））和非共面结构允许这些近红外（NIR）发色团容易地旋涂成均匀的薄膜并掺杂有其他有机半导体用于潜在的器件应用。对于Ia和2a，用[6，6]-苯基-C-61丁酸甲酯掺杂导致在[1]上的吸收的红移。一个有趣的近红外电致变色被发现为2a，与吸收被打开时，在1034 nm的电化学切换（在1000 mV）从其中性状态到一个自由基阳离子状态。此外，大的斯托克斯位移（256 - 318 nm）对于这种多供体-受体类型的发色团也是独特的。表明基态和激发态之间存在显著的结构差异。在可变温度下进一步探测2a的膜的光致发光，并且结果强烈地表明，键旋转的限制肯定有助于减少非辐射衰减，从而增强这些大发色团的发光。
A new series of film-forming, low-bandgap chromophores (1a,b and 2a,b) were rationally designed with aid of a computational study., and then synthesized and characterized. To realize absorption and emission above the 1000 nm wavelength, the molecular design focuses on lowering the LUMO level by fusing common heterocyclic units into a large conjugated core that acts an electron acceptor and increasing the charge transfer by attaching the multiple electron-donating groups at the appropriate positions of the acceptor core. The chromophores have bandgap levels of 1.27-0.71 eV, and accordingly absorb at 746-1003 nm and emit at 1035-1290 nm in solution. By design, the relatively high molecular weight (up to 2400 g mol(-1)) and non-coplanar structure allow these near-infrared (NIR) chromophores to be readily spin-coated as uniform thin films and doped with other organic semiconductors for potential device applications. Doping with [6,6]-phenyl-C-61 butyric acid methyl ester leads to a red shift in the absorption on]), for la and 2a. An interesting NIR electrochromism was found for 2a, with absorption being turned on at 1034 nm when electrochemically switched (at 1000 mV) from its neutral state to a radical cation state. Furthermore, a large Stokes shift (256-318 nm) is also unique for this multidonor-acceptor type of chromophore. indicating a significant structural difference between the ground state and the excited state. Photoluminescence of the film of 2a was further probed at variable temperatures and the results strongly suggest that the restriction of bond rotations certainly helps to diminish non-radiative decay and thus enhance the luminescence of these large chromophores.