Long-range energy transport in single supramolecular nanofibres at room temperature
Long-range energy transport in single supramolecular nanofibres at room temperature
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DOI：
10.1038/nature14570
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发表时间：
2015-07-09
期刊：
影响因子：
64.8
通讯作者：
Hildner, Richard
中科院分区：
文献类型：
--
作者：
Haedler, Andreas T.;Kreger, Klaus;Hildner, Richard
激发能的长距离有效传输是光捕获系统以及分子电子学中的关键过程（1-3）。然而，在合成无序有机材料中，激子扩散长度通常仅为约10纳米（参考文献4、5），或在例外情况下约50纳米（参考文献6、7），该距离主要由非相干激子跳跃的概率定律确定。只有高度有序的有机系统才能在宏观距离上传输激发能-例如，室温下蒽单晶中的三重态激子（8），以及低温（10开尔文或-263摄氏度）下沿着嵌入其单体晶体基质中的单个聚二乙炔链（9）。对于超分子纳米结构，在室温下的单轴长程输运尚未得到证实。在这里，我们表明，单个自组装纳米纤维与分子尺度的直径有效地传输单重态激子在环境条件下超过4微米，距离仅受纤维长度的限制。我们的数据表明，这种显着的长距离传输主要是连贯的。这种相干的长程传输是通过基于羰基桥接的三芳基胺10的超分子结构单元的一维自组装成具有大量电子相互作用的明确定义的H型聚集体（其中单个单体共面排列）来实现的。这些发现将有助于有机纳米光子器件和量子信息技术的发展。
Efficient transport of excitation energy over long distances is a key process in light-harvesting systems, as well as in molecular electronics(1-3). However, in synthetic disordered organic materials, the exciton diffusion length is typically only around 10 nanometres (refs 4, 5), or about 50 nanometres in exceptional cases(6,7), a distance that is largely determined by the probability laws of incoherent exciton hopping. Only for highly ordered organic systems has the transport of excitation energy over macroscopic distances been reported-for example, for triplet excitons in anthracene single crystals at room temperature(8), as well as along single polydiacetylene chains embedded in their monomer crystalline matrix at cryogenic temperatures (at 10 kelvin, or -263 degrees Celsius)(9). For supramolecular nanostructures, uniaxial long-range transport has not been demonstrated at room temperature. Here we show that individual self-assembled nanofibres with molecular-scale diameter efficiently transport singlet excitons at ambient conditions over more than four micrometres, a distance that is limited only by the fibre length. Our data suggest that this remarkable long-range transport is predominantly coherent. Such coherent long-range transport is achieved by one-dimensional self-assembly of supramolecular building blocks, based on carbonyl-bridged triarylamines10, into well defined H-type aggregates (in which individual monomers are aligned cofacially) with substantial electronic interactions. These findings may facilitate the development of organic nanophotonic devices and quantum information technology.