Hierarchical structured nanohelices of ZnS
Hierarchical structured nanohelices of ZnS
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DOI：
10.1002/anie.200600429
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发表时间：
2006-01-01
影响因子：
16.6
通讯作者：
Wang, Zhong Lin
中科院分区：
文献类型：
--
作者：
Moore, Daniel;Ding, Yong;Wang, Zhong Lin
侧分支排列良好，并沿着纳米螺旋的整个长度形成有序结构。图1c显示了一个长而适度分支的螺旋，这是迄今为止最常见的ZnS纳米螺旋，尽管其他纳米螺旋也很常见。图1d显示了一个螺旋，它卷曲成一个环状结构。纳米螺旋由两部分组成：第一部分是螺旋状的脊柱；第二种是y形的分支，它们在每个纳米螺旋中都长到相同的大小和脊柱的同一侧。y分支结构总是向螺旋的内部生长（图2a），并且它们旋转并遵循纳米螺旋的卷曲形状。Ybranches密集排列，形成一个排列有序的阵列，遵循螺旋的卷曲几何形状（图2b）。统计数据记录了螺旋的各个方面。对近100个分离螺旋的分析记录了螺旋的螺距、半径和旋向性。没有发现螺距和半径之间的直接关系，也没有注意到对惯用手的偏好（在可以测量的螺旋中，大约60%是右撇子，大约40%是左撇子）。利用透射电子显微镜（TEM）分析了分层纳米螺旋的结构，以了解其形成过程。图3a显示了纳米螺旋片段的低放大TEM图像：Y结构有两个v形分支，形状相当光滑，但与脊柱相连的底部分支相当粗糙，因此可能表明侧表面有一些后续生长（图3b）。图3c和图e分别为透射电镜
side branches align well and form an ordered structure along the entire length of the nanohelix. Figure 1c shows a helix that is long and moderately branched, which is by far the most commonly observed ZnS nanohelix, though the others are common as well. Figure 1d shows a helix that has curled up into itself to form a ringlike structure. The nanohelices are made up of two parts: The first is the spine, which coils into a helical shape; the second has Y-shaped branches that all grow to the same size and at the same side of the spine in each nanohelix. The Y-branched structures always grow toward the inside of the helix (Figure 2a), and they rotate and follow the curled shape of the nanohelix. The Ybranches are densely packed to form an aligned and ordered array that follows the coiling geometry of the helix (Figure 2 b).Statistical data were recorded a wide range of aspects of the helices. The analysis of nearly one hundred separated helices recorded the pitch, radius, and handedness of the helix. No direct relationship was found between pitch and radius, and no preferences towards handedness was noticed (of the helices that could be measured, about 60% were righthanded and about 40% left-handed). The structure of the hierarchical nanohelix was analyzed by transmission electron microscopy (TEM) to understand the formation process. Figure 3a shows a low-magnification TEM image of a segment of the nanohelix: The Y structure has two V-shaped branches that are rather smooth in shape, but the bottom branch connected to the spine is rather rough, thus possibly indicating some subsequent growth at the side surface (Figure 3b). Figure 3c and e are, respectively, a TEM