Molecular wire encapsulated into π organogels:: Efficient supramolecular light-harvesting antennae with color-tunable emission
Molecular wire encapsulated into π organogels:: Efficient supramolecular light-harvesting antennae with color-tunable emission
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DOI：
10.1002/anie.200701925
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发表时间：
2007-01-01
影响因子：
16.6
通讯作者：
George, Subi J.
中科院分区：
文献类型：
--
作者：
Ajayaghosh, Ayyappanpillai;Praveen, Vakayil K.;George, Subi J.
在自然采光(LH)组件中，吸收光的发色团以特定的几何形状组织起来，并被封装在软凝胶状的生物组织中。在将激发能转移到反应中心之前，发色团组件内的激发能量的快速定向迁移对LH过程至关重要。[1]这种系统运行的体系结构和机制的魅力一直是用人工分子组件模拟自然LH系统的驱动力。[2-5]先进材料领域的最新发展进一步推动了这一方向的研究，特别是在光电子器件的设计中，其中能量和电子传输过程在几个纳米以上是至关重要的。6]功能染料和π共轭分子的超分子化学在上述发展中发挥了重要作用。[7]有机凝胶是促进能量转移过程的极佳介质。[8-10]在基于有机凝胶的光收集组件的设计中，具有合适的光学和自组装性质的供体和受体的选择是极其重要的。Meijer和他的同事的广泛研究表明，自组装的低聚对苯乙叉S(OPV)是合适的受体的有效激发能量供体。[11]在一系列研究中，我们证明了适当的官能化OPV可以形成具有不同大小和形状的超分子结构以及不同光学性质的发光π有机凝胶体。[12]通过结合OPV的这些性质，我们早先证明了OPV凝胶可以发生能量转移到被捕获的受体。[10]在这些情况下，高效的能量转移需要大量的受体。因此，挑战是找到合适的受体，当被封装在供体凝胶支架中时，通过有效的天线效应捕获激发能量。在这里，我们表明，在有机凝胶支架OPV中包裹小于2mol%的PYPV(方案1)促进了激子的快速漏斗和高效
In natural light-harvesting (LH) assemblies, the light-absorbing chromophores are organized in a specific geometry and encapsulated within the soft gel-like biological tissues. Fast directional migration of excitation energy within the chromophore assemblies before being transferred to the reaction center is crucial to the LH process.[1] The fascination of the architecture and mechanism by which such systems operate has been the driving force to mimic natural LH systems with artificial molecular assemblies.[2–5] Research in this direction is further driven by the recent developments in the area of advanced materials, particularly in the design of optoelectronic devices, where energy-and electron-transport processes over a few nanometers are crucial.[2d, 5, 6] The supramolecular chemistry of functional dyes and π-conjugated molecules has been playing a significant role in the above developments.[7]Organogels are excellent media to facilitate energy-transfer processes.[8–10] The choice of a donor and an acceptor with suitable optical and self-assembly properties is extremely important in the design of an organogel-based light-harvesting assembly. Extensive studies by Meijer and co-workers have revealed that self-assembled oligo (p-phenylenevinylene) s (OPVs) are efficient excitation energy donors to suitable acceptors.[11] In a series of studies we have demonstrated that suitably functionalized OPVs can form luminescent π organogelators with supramolecular architectures of different sizes and shapes as well as with distinct optical properties.[12] By combining these properties of OPVs, we have shown earlier that energy transfer can occur from OPV gels to entrapped acceptors.[10] In these cases, a large number of acceptors were needed for efficient energy transfer. Therefore, the challenge is to identify a suitable acceptor that traps the excitation energy through an efficient antenna effect when encapsulated in extremely small quantities within a donor gel scaffold. Herein we show that the encapsulation of less than 2 mol% PYPV (Scheme 1) within the organogel scaffold of OPVs facilitate fast exciton funneling and efficient