Structure-Property Relationships of Anion Vacancy Plasmonic Metal Oxide Nanocrystals

科学技术的蓬勃发展得益于具有独特光电性能的新材料的发现。纳米材料通常被称为纳米粒子，由于其不断扩大的应用，特别是在可持续未来的能源储存和转换方面，它们处于现代科学研究的前沿。在材料研究部固态和材料化学项目的支持下，印第安纳大学-普渡大学印第安纳波利斯分校的Rajesh Sardar教授和他的团队将扩大对通过胶体合成方法合成金属氧化物纳米颗粒的科学理解。由于这些纳米颗粒含有与无毒金属以独特方式偶联的氧，因此研究允许高度可调和环境友好的纳米颗粒组合物。这些纳米粒子的形状各向异性和表面化学的独特组合将被优化，以增强它们针对高度先进的电子设备和催化剂的光电性能。该项目旨在通过有指导的研究以及将研究成果纳入大学研究生和本科课程来培训代表性不足的少数族裔学生。通过大学和国家实验室的科学家之间的多方面合作以及指导和讲习班，将提高各级学生的科学和交流技能。技术总结具有独特光学和电学性质的新型功能材料的发现将使合理设计性能更好的光电子器件成为可能。该项目由美国国家科学基金会材料研究部的固态和材料化学计划支持，旨在合成局域表面等离子体共振(LSPR)活性金属氧化物纳米粒子，其中LSPR性能是由化学计量无机晶格中的氧空位(阴离子缺陷)产生的，这种空位导致自由(导带)电子密度与等离子体贵金属(Au和Ag)纳米粒子一样高。这些缺乏阴离子的金属氧化物纳米粒子有望产生强大的电磁场增强和热电子，这是各种光驱动应用最理想的。本项目旨在了解配体钝化纳米颗粒的结构-性质关系。具体地说，该项目(1)通过种子介导的生长方法合成具有LSPR活性的靶向各向异性形状的纳米颗粒，(2)进行光谱和微观分析，并进行理论计算，以了解控制此类纳米颗粒的形状和所需组成的机制，以及(3)利用有机钝化配体来控制和实现具有独特能力的显著增强的光电性能。作为更广泛的影响活动的一部分，研究生和本科生以及代表不足的高中生将通过导师和研讨会发展研究技能。此外，研究成果将被整合到本科和研究生课程中，并在国内和国际会议上传播，以及同行评议的出版物。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 SUMMARYScience and technology thrive on the discovery of new materials with unique optoelectronic properties. Nanosized materials commonly referred to as nanoparticles are in the forefront of modern scientific research because of their ever-expanding applications, specifically in energy storage and conversion for a sustainable future. With support from the Solid State and Materials Chemistry program in the Division of Materials Research, Prof. Rajesh Sardar and his group at Indiana University-Purdue University Indianapolis will expand the scientific understanding of metal oxide nanoparticle synthesis via colloidal synthetic methods. Because these nanoparticles contain oxygen coupled in a unique manner with non-toxic metals, the research allows for highly tunable and environmentally friendly nanoparticle compositions. The unique combination of shape anisotropy and surface chemistry of these nanoparticles will be optimized to enhance their optoelectronic properties directed towards highly advanced electronic devices and catalysts. The project aims to train underrepresented minority students through mentored research, and integration of research results into the university level graduate and undergraduate courses. The scientific and communication skills of students at every level will be enhanced through multi-faceted collaboration between scientists from universities and national laboratories, as well as mentoring and workshops. TECHNICAL SUMMARYThe discovery of new functional materials with unique optical and electronic properties will allow rational design of optoelectronic devices with better performance. This project supported by the Solid State and Materials Chemistry program in the NSF’s Division of Materials Research aims to synthesize localized surface plasmon resonance (LSPR)-active metal oxide nanoparticles where LSPR properties are generated from oxygen vacancies (anion deficiencies) in the stoichiometric inorganic lattice that leads to free (conduction band) electron density as high as in plasmonic noble metal (Au and Ag) nanoparticles. These anion deficient metal oxide nanoparticles are expected to produce strong electromagnetic field enhancement and hot electrons that are most desirable for various light-driven applications. This project seeks to understand the structure-property relationships of ligand-passivated nanoparticles. Specifically, the project (1) synthesizes LSPR-active, targeted anisotropic shaped nanoparticles via seed-mediated growth approaches, (2) performs spectroscopic and microscopic analyses, along with theoretical calculations to understand the mechanisms that control the shape and desired composition of such nanoparticles, and (3) utilizes organic passivating ligands to control and achieve substantially enhanced optoelectronic properties with unique abilities. As a part of the broader impact activities, graduate and undergraduate, along with underrepresented high school students will develop research skills through mentorship and workshops. Additionally, research outcomes will be integrated into undergraduate and graduate courses, as well as disseminated at national and international meeting, and peer-reviewed publications.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.