STRUCTURAL ORIGINS IN PHOTOSWITCHABLE ORGANIC FERROELECTRICITY USING TIME-RES

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 有机铁电材料在信息存储、分子马达和执行器等方面具有重要的应用价值。与无机铁电材料相比，有机铁电材料的优势在于其化学可调性、可加工性和自修复能力。因此，了解有机铁电材料的结构起源及其与材料性能的关系对于开发具有广泛应用的新材料是至关重要的。这项拟议的工作将研究一组由小芳香有机电子给体(D)和受体(A)自组装成交替的三维数据？在APS的14ID光束线上，采用稳态和时间分辨X射线衍射技术对阵列进行处理。这种可光开关铁电材料的结构起源是由于DA距离的改变或形成或破坏氢键的侧基的旋转而引起的结构变化。利用TR-X射线衍射仪、Collet、Techert等。在ESRF开展了类似类型材料的功率衍射开创性研究。我们为他们的成功感到鼓舞，并相信我们的材料可以用Beanline 14ID单晶上的劳厄衍射法进行研究。我们想要捕捉使铁电性成为可能的结构起源，并区分不同类型的结构变化。建议的结构研究将与我们在西北大学实验室进行的单晶超快瞬时吸收和发射光谱相结合。在APS上获得的结构信息以及光谱和理论以及化学合成将使富有成效的跨学科研究能够发现、表征和应用新材料。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Organic ferroelectric materials are important for applications of information storage, molecular motors and actuators. The advantages of organic ferroelectric materials over their inorganic counter part are their chemical tunability, processibility and self-repair capability. Therefore, understanding the structural origins in organic ferroelectric materials and their connections to the properties of the materials is crucial in developing new materials with broad applications. The proposed work will investigate the structural origins of a group of photo-switchable organic ferroelectric materials made of small aromatic organic electron donors (D) and acceptors (A) self-assembled into alternating three dimensional DADA? arrays by steady-state and time-resolved x-ray diffraction techniques at Beamline 14ID of the APS. The structural origins for such photoswitchable ferroelectric materials are structural changes either due to change of the DA distances or rotation of the side groups that form or disrupt the hydrogen bonds. Using TR-XRD, Collet, Techert, et al. carried out pioneering studies on similar type of materials with power diffraction at ESRF. We are encouraged by their success and believe that our materials can be studied by the TR-XRD with Laue diffraction on single crystals at Beanline 14ID. We would like to capture the structural origins that enable the ferroelectricity and distinguish different types of the structural changes. The proposed structural studies will be combined with single crystal ultrafast transient absorption and emission spectroscopy conducted in our labs in Northwestern University. The structural information obtained at the APS and spectroscopic and theoretical as well as chemical synthesis will enable a productive interdisciplinary research to discover, character, and applying new materials.