In-Situ Studies of the Growth of Nanostructured Covalent Semiconductors by Electrochemical Liquid-Liquid-Solid Processes

通过电化学液-液-固过程生长纳米结构共价半导体的原位研究

基本信息

批准号：
1807755
负责人：
Stephen Maldonado
金额：
$ 46万
依托单位：
Regents of the University of Michigan - Ann Arbor
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2021-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1807755&HistoricalAwards=false
关键词：
Situ Studies Growth Nanostructured Covalent

项目摘要

This project seeks a simple, green method for preparing fully refined, pure, and crystalline nanostructured semiconductors. This would have tremendous impact on future optoelectronic, energy, and sensing technologies. Prof. Maldonado of the University of Michigan has developed a method to synthesize crystalline semiconductor nanomaterials without high temperatures or caustic reagents. This singular approach is called the electrochemical liquid-liquid-solid (ec-LLS) strategy and it works by blending two normally distinct strategies, electrochemistry and melt crystal growth. Among many salient features, the ec-LLS strategy can be performed at or near room temperature in water and the ambient atmosphere. This work aims to further develop the ec-LLS concept into a transformative methodology for environmentally-friendly and low cost semiconductor manufacture. Experiments are designed to identify the controlling features in ec-LLS that dictate crystal shape, size, and purity. The basic science proposed here accordingly spans electrochemistry, materials science, advanced electron microscopy, and X-ray spectroscopic methods, offering extensive training in these areas for participating undergraduate and graduate students. Through this project, Prof. Maldonado also expands pedagogical tools for teaching basic chemistry and electrochemistry to beginning students. Specifically, electrodeposited thin films are introduced as platforms for preparing solar cells for the education of high school students.The funding support provided by the Macromolecular, Supramolecular & Nanochemistry Program of the Chemistry Division is advancing knowledge and control over the electrochemical synthesis of semiconductor nanomaterials with liquid metals. Specifically, the electrochemical liquid-liquid-solid (ec-LLS) concept for the syntheses of crystalline covalent semiconductors offers a unique way to form technologically relevant semiconductor nanomaterials under unusually benign reaction conditions. A liquid metal is both a working electrode that facilitates heterogeneous reduction reactions and a solvent that directs semiconductor crystal growth. The purpose of this project is to gain predictive influence over the structure, physicochemical, and electrical properties of the resultant materials. The underlying research focus uses two orthogonal methods, in-situ transmission electron microscopy (TEM) and in-situ X-ray spectroscopy, to study systematically the operational features of crystal growth in ec-LLS. The chief overarching hypotheses to be tested are: (1) the extent of supersaturation in ec-LLS, rather than the specific liquid metal, most strongly dictates the form of the crystal growth and (2) the structure of the liquid metal at the electrode/electrolyte interface impacts how ec-LLS initiates. The first hypothesis is being investigated by visualizing ec-LLS syntheses of semiconductor nanowires under a variety of conditions by in-situ TEM with a liquid holder. The second hypothesis is being explored through shallow angle X-ray reflection and diffraction studies of liquid metal/liquid electrolyte interfaces during the initial stages of ec-LLS. Through the combination of these different methods, more refined ec-LLS methods are being developed to synthesize more advanced nanomaterials. Prof. Maldonado's undergraduate laboratory curriculum on perovskite solar cells is being adapted for high school students. The intent is to simplify electrodeposition platforms sufficiently so that even very beginning students can contribute meaningfully to original materials chemistry research on photovoltaics.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.

该项目寻求一种简单的绿色方法，用于准备完全精致，纯净和结晶的纳米结构半导体。这将对未来的光电，能量和传感技术产生巨大影响。密歇根大学的马尔多纳多教授开发了一种合成晶体半导体纳米材料而没有高温或苛性剂试剂的方法。这种奇异的方法称为电化学液液 - 固体（EC-LLLS）策略，它通过融合了两种正常不同的策略，电化学和熔体晶体生长。在许多显着特征中，EC-LLS策略可以在水和环境气氛中在室温或接近室温下执行。这项工作旨在将EC-LLS概念进一步发展为一种变革性的方法，用于环保和低成本的半导体制造。实验旨在识别EC-LLS中控制晶体形状，大小和纯度的控制功能。因此，这里提出的基础科学涵盖了电化学，材料科学，高级电子显微镜和X射线光谱方法，并在这些领域为参与的本科生和研究生提供了广泛的培训。通过这个项目，马尔多纳多教授还扩展了教学工具，用于教授基本的化学和电化学。具体而言，引入了电沉积薄膜作为准备太阳能电池的平台，以供高中生教育。化学部的大分子，超分子和纳米化学计划提供的资金支持正在推进知识和控制对液体液体剂量的纳米材料的电化学综合的知识和控制。具体而言，用于晶体共价半导体合成的电化学液液 - 固酸（EC-LLS）概念为在异常良性反应条件下形成技术相关的半导体纳米材料提供了一种独特的方法。液态金属既是促进异质还原反应的工作电极，又是指导半导体晶体生长的溶剂。该项目的目的是对所得材料的结构，物理化学和电性能获得预测影响。潜在的研究重点使用两种正交方法，即原位传输电子显微镜（TEM）和原位X射线光谱，用于系统地研究EC-LLS晶体生长的操作特征。要测试的主要总体假设是：（1）EC-LLS中的过饱和程度，而不是特定的液态金属，最强烈地决定了晶体生长的形式，（2）电极/电解质界面处液态金属的结构影响EC-LLS的启动方式。通过与液体持有人的原位TEM可视化半导体纳米线的EC-LLS合成，从而研究了第一个假设。在EC-LLS的初始阶段，正在通过浅角X射线反射和液体金属/液体电解质界面进行第二个假设。通过这些不同方法的组合，正在开发更精致的EC-LLS方法来合成更先进的纳米材料。 Maldonado教授在钙钛矿太阳能电池上的本科实验室课程正在为高中生改编。目的是充分简化了电沉积平台，以便甚至很小的一开始，学生也可以对Photovoltaics的原始材料化学研究做出有意义的贡献。该奖项反映了NSF的法定任务，并且被认为值得通过基金会的知识分子优点和更广泛的影响审查标准通过评估来获得支持。

项目成果

期刊论文数量（5）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Evidence for Facilitated Surface Transport during Ge Crystal Growth by Indium in Liquid Hg–In Alloys at Room Temperature

DOI：
10.1021/acs.cgd.0c01485
发表时间：
2021-02
期刊：
Crystal Growth & Design
影响因子：
3.8
作者：
Dhruba K. Pattadar;Quintin B. Cheek;A. Sartori;Yifan Zhao;R. Giri;B. Murphy;O. Magnussen;S. Maldonado
通讯作者：
Dhruba K. Pattadar;Quintin B. Cheek;A. Sartori;Yifan Zhao;R. Giri;B. Murphy;O. Magnussen;S. Maldonado

Metastable Group IV Allotropes and Solid Solutions: Nanoparticles and Nanowires