Collaborative Research: Thermochemistry and Chemical Kinetics of Halide-driven Crystal Structure Control of Manganese and Lanthanide Chalcogenide Nanocrystals

合作研究：卤化物驱动的锰和镧系硫族化物纳米晶体晶体结构控制的热化学和化学动力学

• 批准号: 2305153
• 负责人: Emil Hernández-Pagán
• 金额: $ 41.47万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2305153&HistoricalAwards=false
• 关键词: Collaborative; Research; Thermochemistry; Chemical; Kinetics

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Drs. Emil Hernández-Pagán of the University of Delaware, Kristina Lilova of Arizona State University, and Robert Wexler of Washington University in St. Louis will investigate how the presence of halides (chloride, bromide, and iodide) influences the final arrangements of atoms (crystal structure) in the synthesis of certain classes of nanoparticles. The team will employ experimental techniques, including ones that provide information as the reaction occurs, and computational methods to gain in depth insight into this process. The particular crystal polymorph often dictates key properties of nanocrystalline materials and, consequently, the applications for which these can be used, for example, in photovoltaics, catalysis, and energy storage. Therefore, having the knowledge and ability to control the crystal structure is important. The broader impacts of this work are centered around (a) providing experimental and computational training to the students working on this project and (b) summer research experiences for undergraduate students from Puerto Rico that aim to complement the training they receive at their home institutions to better prepare them for the workforce and/or pursuing a graduate degree. The ability to rationally synthesize a given polymorph or phase of a nanoparticles is desirable as these dictate their mechanical, optical, and electronic properties. The proposed work synergistically combines experimental and computational methods to provide a holistic framework for a model system where halides drive the control of crystal structure/phase in the synthesis of manganese chalcogenide nanocrystals. This framework will encompass identifying pre-nucleation molecular species, performing thermochemical measurement of reaction and surface-ligand interactions, and monitoring the kinetics of nucleation and growth. A suite of in situ techniques will be employed to enable such measurements under the reaction conditions. Quantum-mechanics-based calculations will be used to identify atomic-scale interactions and the mechanisms that lead to the observed crystal structures/phases. These calculations will provide input for kinetic and thermodynamic models of nanocrystal nucleation and growth and, therefore, will produce multi-scale-based computational guidance for the controlled synthesis of metal chalcogenide nanocrystals. The studies will be extended to lanthanide chalcogenide nanocrystals, which have remained largely unexplored despite unique optical and magnetic properties. This work is anticipated to further increase the level of chemical understanding of the synthesis of Mn and Ln chalcogenide nanocrystals, and such insights have the potential to provide guidance to the scientific community for the synthesis of other classes of materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系高分子、超分子和纳米化学项目的支持下，特拉华大学的 Emil Hernández-Pagán 博士、亚利桑那州立大学的 Kristina Lilova 和圣路易斯华盛顿大学的 Robert Wexler 将研究如何卤化物（氯化物、溴化物和碘化物）的存在会影响某些类别纳米粒子合成中原子的最终排列（晶体结构）。该团队将采用实验技术，包括在反应发生时提供信息的技术，以及计算方法来深入了解该过程，特定的晶体多晶型通常决定了纳米晶体材料的关键特性，从而决定了这些材料的应用。因此，拥有控制晶体结构的知识和能力非常重要，这项工作的更广泛影响集中在（a）为学生提供实验和计算培训。从事该项目并且(b) 波多黎各本科生的暑期研究经历，旨在补充他们在本国机构接受的培训，以更好地为他们进入劳动力市场和/或攻读研究生学位做好合理合成给定多晶型物或相的能力。纳米颗粒是理想的，因为它们决定了它们的机械、光学和电子特性，所提出的工作协同结合了实验和计算方法，为卤化物驱动锰硫族化物合成中晶体结构/相的控制提供了一个模型系统的整体框架。该框架将包括识别成核前分子种类、进行反应和表面配体相互作用的热化学测量，以及监测成核和生长的动力学，以在反应条件下进行此类测量。基于量子力学的计算将用于识别原子尺度的相互作用以及导致观察到的晶体结构/相的机制，这些计算将为动力学和热力学模型提供输入。纳米晶体成核和生长，因此将为金属硫族化物纳米晶体的受控合成提供基于多尺度的计算指导，该研究将扩展到镧系元素硫族化物纳米晶体，尽管这项工作具有独特的光学和磁性，但在很大程度上仍未得到探索。预计将进一步提高对Mn和Ln硫族化物纳米晶体合成的化学理解水平，这些见解有可能提供指导该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。