Polarized X-ray scattering reveals non-crystalline orientational ordering in organic films
Polarized X-ray scattering reveals non-crystalline orientational ordering in organic films
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DOI：
10.1038/nmat3310
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发表时间：
2012-06-01
期刊：
影响因子：
41.2
通讯作者：
Ade, H.
中科院分区：
文献类型：
--
作者：
Collins, B. A.;Cochran, J. E.;Ade, H.
分子取向对有机材料的力学、化学、光学和电学性质有着重要的影响。到目前为止，只有当样品表现出足够的结晶度时，软物质中的分子尺度有序性才能用X射线或电子显微镜技术来表征。在这里，我们展示了偏振软X射线(P-SOX)对分子轨道的共振散射不受结晶度的限制，它可以用来探测分子取向，尺寸小到10 nm。我们首先将这项技术应用于高结晶小分子薄膜，然后利用其高灵敏度来探测液晶有序对聚合物晶体管中电荷迁移率的影响。P-SOXS还揭示了全聚合物有机太阳能电池无定形区的散射各向异性，其中界面相互作用在基质相中形成取向排列，这可能在光物理中起着重要作用。散射各向异性的能量和Q依赖性使得可以识别磁区中的成分和取向有序度。
Molecular orientation critically influences the mechanical, chemical, optical and electronic properties of organic materials. So far, molecular-scale ordering in soft matter could be characterized with X-ray or electron microscopy techniques only if the sample exhibited sufficient crystallinity. Here, we show that the resonant scattering of polarized soft X-rays (P-SoXS) by molecular orbitals is not limited by crystallinity and that it can be used to probe molecular orientation down to size scales of 10 nm. We first apply the technique on highly crystalline small-molecule thin films and subsequently use its high sensitivity to probe the impact of liquid-crystalline ordering on charge mobility in polymeric transistors. P-SoXS also reveals scattering anisotropy in amorphous domains of all-polymer organic solar cells where interfacial interactions pattern orientational alignment in the matrix phase, which probably plays an important role in the photophysics. The energy and q-dependence of the scattering anisotropy allows the identification of the composition and the degree of orientational order in the domains.