UNS: Role of dopant concentration and distribution in the environmental behavior of indium tin oxide nanoparticles

#1511826 Saleh，Navid纳米级金属氧化物是制备和使用最多的工程纳米材料之一，应用于电子，光学设备和医疗过程和设备。纳米级氧化铟锡（nITO）是一种这样的掺杂金属氧化物颗粒，其大量用于电子显示模块，例如触摸屏、电子墨水和有机发光二极管。 这些产品的制造过程和报废处置事件可能是nITO暴露于人类和自然环境的途径，因此引起了对生态和纳米毒性的担忧。该项目系统地评估了nITO的晶体特性（原子尺度）对环境健康和安全的影响。该项目的目的是确定nITO的关键物理化学性质和带隙能量作为锡掺杂的浓度和分布的函数，并阐明这些纳米级双金属化合物的命运，运输，转化和毒性的机制。本研究的主要目的是：（1）通过控制掺杂剂浓度和分布，合成具有可调能带结构的nITO：（2）对不同掺锡量的nITO进行样品制备和表征，以获得对nITO晶体结构、形貌和胶体性质的详细了解;（3）检验聚集动力学、分形维数和多孔介质传输作为离子强度和有机物组成的函数;（4）使用带隙能量学和ROS测量来评估微生物毒性（对浮游和生物膜细胞）和毒性机制;（5）评估nITO的化学转化和评估转化材料的命运和毒性。 这项研究将是第一个同类的，使用的基本电子和物理化学性质的nITO所造成的锡掺杂分布和浓度在原子水平上的控制变化的变化，以阐明在水生环境中的命运，运输和毒性的机制。拟议的工作将产生关键和基础知识，以更好地了解高度关注和商业上重要的下一代纳米材料nITO的环境影响。 nITO在触摸屏设备中用作透明催化剂，具有较高的回收率和相对较短的寿命，因此有必要了解其环境安全性。 从该项目中获得的结果将通过提供对nTO环境健康和安全的更好理解而产生直接的社会效益。 在推广和教育方面，公共教育机构将继续保持其从代表性不足的群体中招收学生的良好记录。 至少有一个来自代表性不足的群体的研究生将通过德克萨斯大学奥斯汀分校被吸引？的多样性指导奖学金，而本科妇女和少数民族学生将被带入这一前沿的纳米材料和微生物学研究利用大学的毕业生与工程本科生（GLUE）和得克萨斯州的研究经验（TREX）计划。 圣胡安迭戈高中（85%的西班牙裔学生）多管齐下的外联活动将通过研讨会和实践实验对高中生产生深远的教育影响。

#1511826Saleh, Navid Nano-scale metal oxides are one of the most prepared and used engineered nanomaterials with applications in electronics, optical devices, and medical processes and devices. Nano-scale indium tin oxide (nITO) is one such doped metal oxide particle that is used heavily in electronic display modules such as touch screens, electronic inks, and organic light-emitting diodes. Manufacturing processes and end-of-life disposal events for these products might serve as exposure pathways of nITO to humans and the natural environment and thus raise concerns for eco- and nano-toxicity. This project systematically assesses the influence of crystal properties (at the atomic scale) on the environmental health and safety of nITO. The purpose of this project is to determine key physicochemical properties and band gap energetics of nITO as a function of the concentration and distribution of tin doping and to elucidate mechanisms for fate, transport, transformation, and toxicity of these nano-scale bimetallics. This study will address the following aims: (1) synthesize nITO with tunable band structure via control over dopant concentration and distribution; (2) sample preparation and characterization of nITO for a range of tin doping to gain detailed understanding of crystal structure, bimetallic morphology, and colloidal properties; (3) examination of aggregation kinetics, fractal dimension, and porous media transport as a function of ionic strength and organic matter composition; (4) evaluation of microbial toxicity (to planktonic and biofilm cells) and toxicity mechanisms using band gap energetics and ROS measurements; (5) assessment of chemical transformation of nITO and evaluation of fate and toxicity of the transformed materials. This study will be the first of its kind, using changes in fundamental electronic and physicochemical properties of nITO caused by controlled variations in tin doping distribution and concentration at the atomistic level to elucidate mechanisms of fate, transport, and toxicity in aquatic environments. The proposed work will generate critical and fundamental knowledge to better understand the environmental implications of a highly concerning and commercially important next- generation nanomaterial, nITO. nITO, that are utilized as transparent catalysts in touch-screen devices with higher recycling rate and relatively short lifetime, necessitate understanding their environmental safety. The results obtained from this project will result in direct societal benefit by providing better understanding of nTO environmental health and safety. In outreach and education aspects, the PIs will continue their strong track records of recruiting students from underrepresented groups. At least one graduate student from an underrepresented group will be attracted via the University of Texas at Austin?s Diversity Mentoring Fellowship, while undergraduate women and minority students will be brought into this cutting-edge nanomaterial and microbiology research utilizing the University's Graduates Linked with Undergraduates in Engineering (GLUE) and the Texas Research Experience (TREX) programs. Multi-pronged outreach activities at San Juan Diego High School (which has 85% Hispanic students) will have profound educational impact on the high school students through seminars and hands-on experiments.