RUI: Post-synthetic transformations of anions in metal chalcogenide nanoparticles: Uncovering synthetic design rules and the effect on subsequent transformations

非技术总结纳米技术在太阳能捕获和储存以及可持续电子设备等问题上的应用依赖于设计具有特定性质和化学组成的纳米粒子的能力。在美国国家科学基金会材料研究部固态和材料化学项目的支持下，富兰克林和马歇尔学院的首席研究员团队试图开发新的方法来设计复杂的纳米颗粒，方法是从只有两种元素-铜和硫-的简单颗粒开始，然后用相关元素硒和碲来交换硫成分。这代表了一种制造多组分纳米颗粒的新化学方法。预计通过瞄准硫磺成分，PI的团队将能够创造出否则无法实现的纳米级图案。同行指导的本科生团队将开展实验工作，在材料和其他STEM领域接受优秀的职业培训。通过纳米机器人早期大学研究经验，一年级和二年级的学生将对这些过程进行计算建模。早期大学研究体验是一个包容性和支持性的研究队列，旨在创造一个欢迎进入STEM的机会，鼓励不同类型的学生继续进行研究和STEM课程。技术概述纳米颗粒的合成后转化可以产生复杂的多组分纳米异质结构。Cu2-XS纳米粒子是阳离子交换的常见起始材料，通过重复的部分阳离子交换形成整个纳米粒子文库的基础。尽管阳离子交换在纳米异质结构设计中取得了成功，但阴离子交换的实现却少得多。Pi的小组最近开发了Cu2-xS纳米棒的硒和碲的阴离子交换转化。该项目在美国国家科学基金会材料研究部固态和材料化学项目的支持下，将寻求更好地了解这些阴离子转变如何影响Cu2-XS纳米粒子，这些转变的适用范围有多广，以及它们如何影响等离子体性质、新成分的区域选择性和缺陷形成。此外，还将使用分子动力学模拟来从机理上深入了解合成后的转化过程。最后，阴离子转换将与二次转换相结合，以揭示指导后合成转换的设计规则的相互作用。这项基础性工作将促进人们对如何设计纳米异质结构的先验认识，为光电子应用提供新的材料途径。所研究的金属硫化物颗粒有可能用作催化剂、光伏或太阳能蒸发中的太阳能吸收剂、光热癌症治疗中的近红外吸收剂、传感器或热电材料。建议的活动是通过本科生研究加强材料化学方面的培训，与学生和教师密切互动，并在PUI和R1实验室之间建立创新的合作伙伴关系，所有这些都通过同行和接近同行的指导结构来改善学生培训和归属感。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARYApplications of nanotechnology to problems like solar energy capture and storage and sustainable electronic devices rely on the ability to design nanoparticles with specific properties and chemical make-ups. With support from the Solid State and Materials Chemistry program in NSF’s Division of Materials Research, the principal investigator’s group at Franklin and Marshal College seek to develop new ways to design complex nanoparticles by starting with simple particles that we can make reproducibly that have only two components–the elements copper and sulfur and then swapping-out the sulfur component with the related elements selenium and tellurium. This represents a new chemical approach to making many-component nanoparticles. It is expected that by targeting the sulfur component, the PI’s team will be able to create nanoscale patterns that would not be achievable otherwise. Peer-mentored undergraduate student teams will carry out experimental work, receiving excellent training for careers in materials and other STEM fields. Through the nanobots Early College Research Experience, first- and second-year students will perform computational modeling of these processes. The Early College Research Experience is an inclusive and supportive research cohort intended to create a welcoming entry to STEM that will encourage a diverse set of students to continue with research and STEM coursework. TECHNICAL SUMMARY Post-synthetic transformations of nanoparticles can create complex multi-component nanoheterostructures. Cu2-xS nanoparticles are common starting materials for cation exchanges, forming the basis for whole libraries of nanoparticles through repeated partial cation exchanges. Despite the success of cation exchange in nanoheterostructure design, anion exchange has been much less implemented. The PI’s group has recently developed selenide and telluride anion exchange transformations of Cu2-xS nanorods. This project, with support from the Solid State and Materials Chemistry program in NSF’s Division of Materials Research, will seek to better understand how these anionic transformations affect Cu2-xS nanoparticles, how broadly applicable these transformations are, and how they affect plasmonic properties, regioselectivity of new components, and defect formation. Addtionally, molecular dynamics simulations will be used to gain mechanistic insight into the post-synthetic transformation processes. Finally, anionic transformations will be coupled with secondary transformations to uncover the interplay of the design rules guiding post-synthetic transformations. This fundamental work will advance knowledge of how to design nanoparticle heterostructures a priori, affording new routes to materials for optoelectronic applications. The metal chalcogenide particles investigated have the potential to act as catalysts, solar energy absorbers in PV or solar water evaporation, NIR absorbers in photothermal cancer treatment, sensors, or thermoelectrics. Activities are proposed that strengthen training in materials chemistry through undergraduate research with close student-faculty interaction and innovative partnerships between PUI and R1 laboratories, all of which improve student training and sense of belonging through peer- and near-peer mentoring structures.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.