Synthesis of and New Functionality in Heteroepitaxial Gallate / Ferrite Core@Shell Nanoparticles

异质外延没食子酸盐/铁氧体核@壳纳米粒子的合成及其新功能

• 批准号: 2327667
• 负责人: Dario Arena
• 金额: $ 30万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-11-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2327667&HistoricalAwards=false
• 关键词: Synthesis; New; Functionality; Heteroepitaxial; Gallate

Non-technical summary: Epitaxy in crystalline materials is the regular growth of one material on top of another, like the growth of a layer of yellow Lego bricks on top of several layers of red bricks. Strain occurs when the length of the two bricks is slightly different, so that the yellow layer grows with a slightly larger spacing (tensile strain) or slightly smaller (compressive). In two-dimensional thin films, epitaxial strain can produce dramatic variations in physical properties, but this type of epitaxial strain has been under-exploited in spherical nanoparticles and other nanostructures. Growing nanoparticles in a core / shell structure results in the combination of different physical properties, similar to how a candy comprised of a peanut covered with chocolate and hard sugar shell has a different flavor (a physical property) than a candy that is a solid piece of chocolate covered with the sugar shell. With support from the Solid State and Materials Chemistry program in the Division of Materials Research, Prof. Dario Arena and his team at the University of South Florida will explore core and shell materials with the same type of lattice structure, but very different physical properties. The core will be a type of oxide (zinc gallate) that has optical properties which are useful for biomedical imaging. The shell will be an iron oxide called magnetite and certain magnetic signatures of this material can be used to confirm epitaxial growth of the magnetite on the zinc gallate core. Realizing this combination of epitaxial optically-active cores and magnetically-sensitive shells opens up new possibilities for high-frequency electronics, gas sensing, environmental remediation, and biomedical applications that combine diagnostic + therapeutic capabilities in a single nanoparticle. Technical summary: Many minerals and other chemical compounds adopt the spinel structure in their atomic lattice. In this project, supported by the Solid State and Materials Chemistry program in the NSF’s Division of Materials Research, core / shell nanoparticles that combine two different types of oxide spinels will be chemically synthesized. Zinc gallate (ZnGa2O4) will form the core and magnetite (Fe3O4) will be the shell material. Zinc gallate and magnetite share the same spinel crystal structure which will enable the epitaxial growth of magnetite shell on the zinc gallate core. The zinc gallate will impart a compressive strain of 0.7% on the magnetite shell, which is still relatively weak. A high degree of epitaxy in the magnetite shell will be verified with temperature dependent magnetometry by identifying the Verwey transition (an abrupt drop in the sample magnetic moment) at ~105 K. Only samples with excellent crystallinity and which have the proper iron to oxygen ratio will exhibit the Verwey transition, and the magnetometry provides an efficient method of screening promising synthesis strategies. In samples that exhibit a sharp Verwey transition, the epitaxy will be verified with advanced electron microscopy, x-ray spectroscopy and scattering, and neutron scattering techniques. These combinations of spinel ferrites and gallates have not been grown before and the combination opens up new possibilities for high-frequency electronics, gas sensing, environmental remediation, and biomedical / theranostic (diagnostic + therapeutic) applications. The project will also support the PhD study of two graduate students and will help foster collaboration with the graduate program of a one or more Minority Serving Institutions.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.

非技术总结：晶体材料中的外延生长是一种材料在另一种材料之上的规则生长，就像一层黄色乐高积木在几层红砖之上生长一样，当两块砖的长度相同时会发生应变。略有不同，使得黄色层以稍大的间距（拉伸应变）或稍小（压缩）生长。在二维薄膜中，外延应变可以产生物理性质的巨大变化，但这种类型的外延应变具有在球形纳米颗粒和其他纳米结构中，纳米颗粒的开发尚未得到充分利用，在核/壳结构中生长纳米颗粒会产生不同的物理特性，类似于由巧克力和硬糖壳包裹的花生组成的糖果具有不同的风味（a在材料研究部固态和材料化学项目的支持下，南佛罗里达大学的达里奥·阿雷纳教授和他的团队将探索具有相同类型晶格结构但物理特性截然不同的核和壳材料，核是一种氧化物（没食子酸锌），其具有可用于生物医学成像的光学特性，壳是一种称为氧化铁的材料。磁铁矿和该材料的某些磁性特征可用于确认磁铁矿在镓酸锌核上的外延生长，实现外延光学活性核和磁敏壳的这种组合为高频开辟了新的可能性。电子、气体传感、环境修复和生物医学应用，将诊断和治疗功能结合在单个纳米颗粒中。技术摘要：在该项目中，许多矿物质和其他化合物在其原子晶格中采用了尖晶石结构，并得到了固态和纳米粒子的支持。美国国家科学基金会材料研究部的材料化学项目将化学合成结合两种不同类型的氧化物尖晶石的核/壳纳米粒子（ZnGa2O4）。核和磁铁矿（Fe3O4）将是壳材料，没食子酸锌和磁铁矿具有相同的尖晶石晶体结构，这使得磁铁矿壳能够在没食子酸锌核上外延生长，而没食子酸锌将赋予0.7%的压缩应变。磁铁矿壳的高度外延仍然相对较弱，将通过识别 Verwey 转变（样品磁矩的突然下降）来通过温度相关磁力测定来验证。 ~105 K。只有具有良好结晶度和适当铁氧比的样品才会表现出 Verwey 转变，磁力合成提供了一种筛选有前景策略的有效方法，在表现出急剧 Verwey 转变的样品中，外延将是。通过先进的电子显微镜、X 射线光谱和散射以及中子散射技术进行了验证。这些尖晶石铁氧体和没食子酸盐的组合以前从未生长过，并且这种组合开辟了新的可能性。该项目还将支持两名研究生的博士研究，并有助于促进与一个或多个少数族裔服务的研究生项目的合作。机构。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。