Polymorph and anisotropic Raman spectroscopy of Phz-Hca cocrystals  

Phz-H2ca铁电共晶的形貌控制及其各向异性拉曼光谱

作　　者：Weigang Zhu Yunli Wang Chengcheng Huang Lingyun Zhu Yonggang Zhen Huanli Dong Zhixiang Wei Dong Guo Wenping Hu 朱伟钢;王云丽;黄程程;朱凌云;甄永刚;董焕丽;魏志祥;郭栋;胡文平(Laboratory of Organic Solids,Institute of Chemistry,Chinese Academy of Sciences,Beijing,100190,China;University of Chinese Academy of Sciences,Beijing,100049,China;Institute of Acoustics,Chinese Academy of Sciences,Beijing,100190,China;School of Materials Science and Engineering,Beihang University,Beijing,100191,China;National Center for Nanoscience and Technology,Beijing,100190,China;Tianjin Key Laboratory of Molecular Optoelectronic Sciences,Department of Chemistry,School of Science,Tianjin University&Collaborative Innovation Center of Chemical Science and Engineering(Tianjin),Tianjin,300072,China)

机构地区：[1]Laboratory of Organic Solids,Institute of Chemistry,Chinese Academy of Sciences,Beijing,100190,China [2]University of Chinese Academy of Sciences,Beijing,100049,China [3]Institute of Acoustics,Chinese Academy of Sciences,Beijing,100190,China [4]School of Materials Science and Engineering,Beihang University,Beijing,100191,China [5]National Center for Nanoscience and Technology,Beijing,100190,China [6]Tianjin Key Laboratory of Molecular Optoelectronic Sciences,Department of Chemistry,School of Science,Tianjin University&Collaborative Innovation Center of Chemical Science and Engineering(Tianjin),Tianjin,300072,China

出　　处：《Science China Materials》2021年第1期169-178,共10页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China (51303185, 21021091, 51033006, 51222306, 51003107, 61201105, 3591027043, 91222203, 91233205, 21473222 and 21773040);the Ministry of Science and Technology of China (2011CB808400, 2011CB932300, 2013CB933403, 2013CB933500 and 2014CB643600);the Chinese Academy of Sciences (Y42D0A12D1 and Y42D0412D1)。

摘　　要：The nucleation and growth mechanism and polymorph-property correlations in the molecular cocrystal field are widely sought but currently remain unclear. Herein, a new wire-like morphology of phenazine(Phz)-chloranilic acid(H2ca) cocrystal(PHC) is demonstrated for the first time, and the self-assembly of Phz and H2ca is controlled to selectively prepare kinetically stable wires and thermodynamically stable plates. Specifically, low precursor concentration is beneficial for one-dimensional(1D) self-assembly along the [010] crystallographic direction, while only supersaturation can trigger 2D self-assembly along the [100] and [010] directions, respectively. This is understandable in terms of the(020) face showing the largest attachment energy(Eatt) and the(002) face possessing the smallest surface energy(Esurf). Moreover, anisotropic Raman spectra related to the mode symmetry and atomic displacements in two types of PHCs are revealed, and the same Raman-active vibrational bands of PHC wire and plate show different polarization responses, which is intrinsically ascribed to their different molecular orientations.Overall, this is the first case that morphologies of cocrystal are precisely tuned with comprehensive investigations of their anisotropic vibrational characteristics.本文首次报道了Phz-H2ca铁电共晶的一种线状形貌,并通过原子力显微镜、透射电子显微镜、X射线衍射、紫外可见吸收光谱、差示扫描量热法和固体核磁等实验手段证实.共晶成核生长实验和Materials Studio软件模拟研究发现,(020)面具有最大的结合能,在较低前驱体浓度下晶核沿[010]方向组装形成动力学稳定的线状形貌,(002)面具有最小的表面能和最大生长势垒,即使在超饱和前驱体浓度下也只有(200)和(020)等晶面的生长势垒被突破,使晶核沿[100]和[010]两个方向生长为热力学稳定的六边形片状形貌.微区拉曼光谱实验研究表明,两种Phz-H2ca共晶的拉曼峰具有截然不同的各向异性响应性,归因于其不同的分子排布取向.该研究工作实现了对分子共晶的控制制备,阐明了其中的结构功能关系,为共晶功能材料的进一步大规模应用提供了有力借鉴.

关 键 词：molecular cocrystal POLYMORPH SELF-ASSEMBLY Raman spectroscopy anisotropy 

分 类 号：TB34[一般工业技术—材料科学与工程] O657.37[理学—分析化学]