A Structural Model for a Self-Assembled Nanotube Provides Insight into Its Exciton Dynamics

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• 作者：Min Gao ; Subhradip Paul ; Charles D. Schwieters ; Zhi-Qiang You ; Hui Shao ; John M. Herbert ; Jon R. Parquette ; Christopher P. Jaroniec
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：June 18, 2015
• 年：2015
• 卷：119
• 期：24
• 页码：13948-13956
• 全文大小：499K
• ISSN：1932-7455

文摘

The design and synthesis of functional self-assembled nanostructures is frequently an empirical process fraught with critical knowledge gaps about atomic-level structure in these noncovalent systems. Here, we report a structural model for a semiconductor nanotube formed via the self-assembly of naphthalenediimide-lysine (NDI-Lys) building blocks determined using experimental ¹³C鈥?sup>13C and ¹³C鈥?sup>15N distance restraints from solid-state nuclear magnetic resonance supplemented by electron microscopy and X-ray powder diffraction data. The structural model reveals a two-dimensional-crystal-like architecture of stacked monolayer rings each containing 鈭?0 NDI-Lys molecules, with significant 蟺-stacking interactions occurring both within the confines of the ring and along the long axis of the tube. Excited-state delocalization and energy transfer are simulated for the nanotube based on time-dependent density functional theory and an incoherent hopping model. Remarkably, these calculations reveal efficient energy migration from the excitonic bright state, which is in agreement with the rapid energy transfer within NDI-Lys nanotubes observed previously using fluorescence spectroscopy.