Calzaferri Gion, Li Huanrong, Brühwiler Dominik
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern, Switzerland.
Chemistry. 2008;14(25):7442-9. doi: 10.1002/chem.200800811.
Artificial photonic antenna systems have been realised by incorporating organic dyes into zeolite L. The size and aspect ratio of the cylindrically shaped zeolite crystals can be tuned over a wide range, adding to the versatility of this host material. A 600 nm sized crystal, for example, consists of about 96 000 one-dimensional channels oriented parallel to the cylinder axis. Geometrical constraints imposed by the host structure lead to supramolecular organisation of the guests, allowing high concentrations of non- or only very weakly interacting dye molecules. A special twist is added to these systems by plugging the channel openings with a second type of fluorescent dye, a so-called stopcock molecule. The two types of molecules are precisely tuned to each other; the stopcocks are able to accept excitation energy from the dyes in the channels, but cannot pass it back. The supramolecular organisation of dyes in the zeolite channels corresponds to a first stage of organisation, allowing light-harvesting within the volume of a cylindrical crystal and radiationless energy transport to either the cylinder ends or centre. The second stage of organisation represents the coupling to an external acceptor or donor stopcock fluorophore at the channel entrances, which can then trap or inject electronic excitation energy. The third stage of organisation is realised by interfacing the material to an external device through a stopcock intermediate. We observed that electronic-excitation-energy transfer in dye-zeolite L materials occurs mainly along the channel axis and we have shown that macroscopically organised materials can be prepared. The new materials offer unique possibilities as building blocks for optical, electro-optical and sensing devices.
通过将有机染料掺入L型沸石中，已实现了人工光子天线系统。圆柱形沸石晶体的尺寸和纵横比可在很宽的范围内调节，这增加了这种主体材料的多功能性。例如，一个600纳米大小的晶体由大约96000个平行于圆柱轴取向的一维通道组成。主体结构施加的几何限制导致客体的超分子组织，允许高浓度的非相互作用或仅非常弱相互作用的染料分子存在。通过用第二种荧光染料（即所谓的旋塞分子）堵塞通道开口，为这些系统增添了一个特殊的转折。这两种分子相互精确匹配；旋塞能够接受来自通道中染料的激发能量，但不能将其传回。沸石通道中染料的超分子组织对应于组织的第一阶段，允许在圆柱形晶体的体积内进行光捕获，并将无辐射能量传输到圆柱两端或中心。组织的第二阶段是在通道入口处与外部受体或供体旋塞荧光团耦合，然后该荧光团可以捕获或注入电子激发能量。组织的第三阶段是通过旋塞中间体将材料与外部设备连接来实现的。我们观察到染料-L型沸石材料中的电子激发能量转移主要沿通道轴发生，并且我们已经表明可以制备宏观组织的材料。这些新材料作为光学、电光和传感设备的构建块提供了独特的可能性。
