Ashokkumar Anumol Erumpukuthickal, Enyashin Andrey N, Deepak Francis Leonard
Nanostructured Materials Group, Department of Advanced Electron Microscopy, Imaging and Spectroscopy, International Iberian Nanotechnology Laboratory (INL), Avenida Mestre Jose Veiga, Braga, 4715-330, Portugal.
Institute of Natural Sciences and Mathematics, Ural Federal University, Turgeneva Str., 4, 620083, Ekaterinburg, Russian Federation.
Sci Rep. 2018 Jul 4;8(1):10133. doi: 10.1038/s41598-018-28446-2.
Inorganic nanotubes are morphological counterparts of carbon nanotubes (CNTs). Yet, only graphene-like BN layer has been readily organized into single walled nanotubes so far. In this study, we present a simple route to obtain inorganic single walled nanotubes - a novel ultrathin morphology for bismuth iodide (BiI), embedded within CNTs. The synthesis involves the capillary filling of BiI into CNT, which acts as a nanotemplate, by annealing the BiI-CNT mixture above the melting point of BiI. Aberration corrected scanning/transmission electron microscopy is used in characterizing the novel morphology of BiI. A critical diameter which enables the formation of BiI nanotubes, against BiI nanorods is identified. The relative stability of these phases is investigated with the density functional theory calculations. Remarkably, the calculations reveal that the single walled BiI nanotubes are semiconductors with a direct band gap, which remain stable even without the host CNTs.
无机纳米管是碳纳米管（CNTs）的形态对应物。然而，到目前为止，只有类石墨烯的氮化硼层能够容易地组装成单壁纳米管。在本研究中，我们提出了一种获得无机单壁纳米管的简单方法——一种嵌入碳纳米管内的新型超薄形态的碘化铋（BiI）。该合成过程包括通过在碘化铋熔点以上对BiI-CNT混合物进行退火，将BiI通过毛细管填充到作为纳米模板的碳纳米管中。使用像差校正扫描/透射电子显微镜来表征BiI的新形态。确定了能够形成BiI纳米管而非BiI纳米棒的临界直径。利用密度泛函理论计算研究了这些相的相对稳定性。值得注意的是，计算结果表明，单壁BiI纳米管是具有直接带隙的半导体，即使没有主体碳纳米管也能保持稳定。
