美国纽约城市大学的城市学院Dorthe M. Eisele研究小组的通过可调笼型支架实现热应力超分子纳米复合材料中的弗伦克尔激子。 该研究于2020年发表于国际一流学术期刊《自然—化学》。

非定域弗伦克尔(Frenkel)激子——在发色团之间的相干共享激子——是光合生物体内超分子集光装置效率显著的原因。由于所用超分子结构的脆弱性和Frenkel激子的脆弱性，尤其是在温和变化的溶剂条件和高温下以及沉积在固体基底上时，自然设计原理在光电器件中的应用受到了限制。

在该研究中，研究人员通过合成稳定的超分子捕光纳米管来克服这些功能化障碍，这些纳米管由可调谐（~4.3–4.9nm）、均匀（±0.3nm）笼状支架实现。高分辨低温电子显微镜结合扫描电子显微镜、宽频飞秒瞬态吸收光谱和近场扫描光学显微镜，发现笼状支架内的激子即使在极端热应力下也具有很强的稳定性，而对纳米复合材料尺寸的控制是在固体基底上进行的。

研究人员开发的仿生纳米复合材料为开发由稳定超分子材料制成的下一代有机器件提供了一个总体框架。

大自然成功地将超分子组件用于高效和强大的太阳能收集；然而，由于所用超分子结构的脆弱性和Frenkel激子的脆弱性等稳定性问题，限制了模拟此类材料系统在光电器件中应用。现在，在可调笼状支架的支持下，稳定的超分子光收集纳米管已经被合成，即使在热应力下也很稳定。

附：英文原文

 Title: Frenkel excitons in heat-stressed supramolecular nanocomposites enabled by tunable cage-like scaffolding

Author: Kara Ng, Megan Webster, William P. Carbery, Nikunjkumar Visaveliya, Pooja Gaikwad, Seogjoo J. Jang, Ilona Kretzschmar, Dorthe M. Eisele

Issue&Volume: 2020-11-16

Abstract: Delocalized Frenkel excitons—coherently shared excitations among chromophores—are responsible for the remarkable efficiency of supramolecular light-harvesting assemblies within photosynthetic organisms. The translation of nature’s design principles to applications in optoelectronic devices has been limited by the fragility of the supramolecular structures used and the delicate nature of Frenkel excitons, particularly under mildly changing solvent conditions and elevated temperatures and upon deposition onto solid substrates. Here, we overcome those functionalization barriers through composition of stable supramolecular light-harvesting nanotubes enabled by tunable (~4.3–4.9nm), uniform (±0.3nm) cage-like scaffolds. High-resolution cryogenic electron microscopy, combined with scanning electron microscopy, broadband femtosecond transient absorption spectroscopy and near-field scanning optical microscopy revealed that excitons within the cage-like scaffolds are robust, even under extreme heat stress, and control over nanocomposite dimensions is maintained on solid substrates. Our bio-inspired nanocomposites provide a general framework for the development of next-generation organic devices made from stable supramolecular materials.

DOI: 10.1038/s41557-020-00563-4

Source: https://www.nature.com/articles/s41557-020-00563-4