Chemistry & Nanoscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
Materials Science Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
Nanoscale. 2019 Nov 28;11(44):21196-21206. doi: 10.1039/c9nr07821e. Epub 2019 Oct 30.
Semiconducting single-walled carbon nanotubes (s-SWCNTs) are attractive light-harvesting components for solar photoconversion schemes and architectures, and selective polymer extraction has emerged as a powerful route to obtain highly pure s-SWCNT samples for electronic applications. Here we demonstrate a novel method for producing electronically coupled thin films of near-monochiral s-SWCNTs without wrapping polymer. Detailed steady-state and transient optical studies on such samples provide new insights into the role of the wrapping polymer on controlling intra-bundle nanotube-nanotube interactions and exciton energy transfer within and between bundles. Complete removal of polymer from the networks results in rapid exciton trapping within nanotube bundles, limiting long-range exciton transport. The results suggest that intertube electronic coupling and associated exciton delocalization across multiple tubes can limit diffusive exciton transport. The complex relationship observed here between exciton delocalization, trapping, and long-range transport, helps to inform the design, preparation, and implementation of carbon nanotube networks as active elements for optical and electronic applications.
半导体单壁碳纳米管（s-SWCNTs）是太阳能光转换方案和结构中极具吸引力的光捕获组件，而选择性聚合物提取已成为获得用于电子应用的高纯度 s-SWCNT 样品的有力途径。在这里，我们展示了一种生产具有近单手性 s-SWCNT 的电子耦合薄膜的新方法，而无需包裹聚合物。对这些样品进行的详细稳态和瞬态光学研究提供了有关包裹聚合物在控制束内纳米管-纳米管相互作用以及束内和束间激子能量转移方面的新见解。从网络中完全去除聚合物会导致纳米管束内激子快速捕获，从而限制长程激子输运。结果表明，管间电子耦合和相关的激子离域化跨越多个管可以限制扩散激子输运。这里观察到的激子离域化、捕获和长程输运之间的复杂关系有助于为作为光学和电子应用的活性元件的碳纳米管网络的设计、制备和实施提供信息。
