Collaborative Research: From Synthesis, Local and Electronic Structures, to Optical and Scintillating Properties of Lanthanoid Hafnate Nanoparticles

许多化学物质具有发射辐射的性质，称为发光，这在发光应用中很有用。镧系发光在我们的日常生活中起着至关重要的作用，因为这些离子在光的产生和放大方面具有独特的光学特性。从激光物理延伸，我们日常生活中其他熟悉的应用包括照明，显示器，光通信，夜视，防伪油墨，防伪标签，发光涂层，医疗成像，医疗诊断和机场安全检查。为了制造廉价、广泛使用、持久的发光或光子器件，无论是从技术上还是从经济上都需要新的、更有效的发光材料。德克萨斯大学格兰德谷分校的毛元兵博士和路易斯安那州立大学的詹姆斯·多尔曼博士正在开发新的制备方法，使金属氧化物纳米颗粒的发光能力增强。利用各种技术，并与橡树岭国家实验室的科学家合作，研究小组正在研究他们可靠的合成方法如何使这些纳米粒子超小，形状和尺寸均匀，比人类头发直径小1000多倍。该团队还研究了这些纳米颗粒的大小、形状、结构、组成和发光性能之间的关系。在这个项目中获得的基本理解有助于未来设计新的发光纳米材料，光子器件和纳米颗粒合成方法。毛博士和多曼斯博士的研究在很多层面上都对学生有吸引力，强调了代表性不足的学生作为研究助理的参与。研究小组推出了一个全校范围的系列研讨会和几个新的课程模块。通过这些活动，博士。毛和。Dorman直接在不同的人口群体中提高对纳米科学和光电子材料的认识和倡导，作为改善社区、国民经济和环境的一种方式。这一伙伴关系的重点是为代表性不足的学生建立一个强大的渠道，并使两所大学之间的师生交流项目取得成果。在这个研究项目中，德克萨斯大学（UTRGV）的毛媛冰博士和路易斯安那州立大学（LSU）的James Dorman博士在大分子、超分子和纳米化学（MSN）项目的支持下，开发了一种可靠的合成工艺，了解了生长机制，研究了尺寸效应，并将晶体、局部和电子结构与这些类镧半酸盐纳米荧光粉的光学和闪烁特性联系起来。采用原位和非原位技术研究了决定Ln2Hf2O7纳米颗粒尺寸和结构参数的合成参数。在此基础上，研究了这些纳米粒子的生长机理，为基于应用规范的发光纳米粒子定向设计提供了依据。接下来，通过拉曼光谱、同步加速器x射线和中子衍射、x射线吸收、发射和光电子能谱、光致发光和放射发光等互补技术，探讨这些纳米粒子的晶体结构、局部结构和电子结构与其发光性能之间的关系。此外，该研究为Ln2Hf2O7化合物的正确选择提供了一般指导，以适合各种器件的应用，如高温固体氧化物燃料电池中的固体电解质，热障涂层和核废料储存。毛博士的研究涉及高中、本科生和研究生，重点关注代表性不足的学生，并引入了全校范围的系列研讨会和新的课程模块，突出了他的团队的研究主题。他和路易斯安那州立大学（LSU）的詹姆斯·多尔曼博士（Dr. James Dorman）向各个年龄段的学生传播科学知识，直接提高不同人口群体对纳米科学和光电子材料的认识和倡导，以此作为改善社区、国民经济和环境的一种方式。这些活动还为代表性不足的学生建立了强大的渠道，并使UTRGV和路易斯安那州立大学之间的学生-教师交流项目取得了丰硕成果。

Many chemical substances have the property of emitting radiation, called luminescence, which is useful in light-emitting applications. Lanthanide luminescence plays a vital role in our daily life due to the unique optical properties of these ions with respect to light generation and amplification. Extending from laser physics, other familiar applications in our regular life include lighting, displays, optical telecommunications, night vision, security inks, counterfeiting tags, luminescent coatings, medical imaging, medical diagnostics, and airport security checks. New and more effective luminescent materials are desirable from both a technological and an economic necessity in order to make cheap, widely available, and long-lasting light emitting, or photonic, devices. Dr. Yuanbing Mao of the University of Texas Rio Grande Valley and Dr. James Dorman of Louisiana State University are making metal oxide nanoparticles with increased luminescence by developing new preparation methods. Using various techniques and in collaboration with scientists at Oak Ridge National Laboratory, the research team is figuring out how their reliable synthesis methods make these nanoparticles ultra-small and uniformly shaped and sized, at more than 1000 times smaller than the diameter of a human hair. The team also studies the relationship between the size, shape, structure, composition, and luminescence performance of these nanoparticles. The fundamental understanding gained in this project helps the future design of new luminescent nanomaterials, photonic devices, and nanoparticle synthesis methods. Dr. Mao's and Dr. Dormans's research is attractive to students at many levels, emphasizing the involvement of underrepresented students as research assistants. The research team has introduced a university-wide seminar series and several new course modules. Through these activities, Drs. Mao and. Dorman directly raise awareness and advocacy for nanoscience and optoelectronic materials among varied demographic groups as a way to improve the community, the national economy, and the environment. The partnership focuses on building a strong pipeline for underrepresented students and enabling fruitful student-faculty exchange programs between the two universities.In this research program, Dr. Yuanbing Mao of the University of Texas Rio Grande Valley (UTRGV) and Dr. James Dorman of Louisiana State University (LSU) are supported by the Macromolecular, Supramolecular and Nanochemistry (MSN) Program to develop a reliable synthetic process, understandthe growth mechanism, investigate the size effects, and correlate the crystal, local and electronic structures with the optical and scintillating properties of these lanthanoid hafnate nanophosphors. Ex situ and in situ techniques are used to elucidate the synthetic parameters which determine the particle size and structural parameters for these Ln2Hf2O7 nanoparticles. Based on the obtained results, growth mechanisms of these nanoparticles are developed for directed design of luminescent nanoparticles based on application specifications. Next, the relationship between the crystal, local, and electronic structures of these nanoparticles and their luminescent properties is probed via complementary techniques, such as Raman spectroscopy, synchrotron X-ray and neutron diffractions, X-ray absorption, emission and photoelectron spectroscopies, photoluminescence, and radioluminescence. In addition, this study provides general guidance for proper selection of Ln2Hf2O7 compounds for suitable applications in a wide variety of devices, such as solid electrolytes in high temperature solid oxide fuel cells, thermal barrier coatings, and nuclear waste storage. Dr. Mao involves high school, undergraduate, and graduate students, with an emphasis on underrepresented students, in his research, and has introduced a university-wide seminar series and new course modules which highlight the topics of his team?'research. He and Dr. James Dorman of the Louisiana State University (LSU) communicate science to students at all age levels, directly raising awareness and advocacy for nanoscience and optoelectronic materials among varied demographic groups as a way to improve the community, the national economy, and the environment. The activities also build a strong pipeline for underrepresented students and enable fruitful student-faculty exchange programs between UTRGV and LSU.