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、绿色的方法来制备完全精炼、纯净的晶体纳米结构半导体。这将对未来的光电、能源和传感技术产生巨大影响。密歇根大学马尔多纳多教授开发了一种无需高温或腐蚀性试剂即可合成晶体半导体纳米材料的方法。这种独特的方法称为电化学液-液-固（ec-LLS）策略，它的工作原理是混合两种通常不同的策略：电化学和熔融晶体生长。在许多显着特征中，ec-LLS 策略可以在室温或接近室温的水和环境大气中执行。这项工作旨在将 ec-LLS 概念进一步发展为环保和低成本半导体制造的变革性方法。实验旨在确定 ec-LLS 中决定晶体形状、尺寸和纯度的控制特征。这里提出的基础科学相应地涵盖了电化学、材料科学、先进电子显微镜和X射线光谱方法，为参与的本科生和研究生提供了这些领域的广泛培训。通过这个项目，马尔多纳多教授还扩展了向初学者教授基础化学和电化学的教学工具。具体来说，电沉积薄膜被引入作为高中生教育中制备太阳能电池的平台。化学系的高分子、超分子和纳米化学项目提供的资金支持正在推进对半导体纳米材料电化学合成的知识和控制，液态金属。具体来说，用于合成晶体共价半导体的电化学液-液-固（ec-LLS）概念提供了一种独特的方法，可以在异常良性的反应条件下形成技术相关的半导体纳米材料。液态金属既是促进非均相还原反应的工作电极，又是指导半导体晶体生长的溶剂。该项目的目的是获得对所得材料的结构、物理化学和电性能的预测影响。基础研究重点使用原位透射电子显微镜 (TEM) 和原位 X 射线光谱这两种正交方法来系统地研究 ec-LLS 中晶体生长的操作特征。要测试的主要假设是：(1) ec-LLS 中的过饱和程度，而不是特定的液态金属，最有力地决定了晶体生长的形式；(2) 电极处液态金属的结构/电解质界面影响 ec-LLS 的启动方式。第一个假设正在通过使用液体支架的原位 TEM 可视化各种条件下半导体纳米线的 ec-LLS 合成来进行研究。第二个假设正在通过 ec-LLS 初始阶段液态金属/液态电解质界面的浅角 X 射线反射和衍射研究来探索。通过这些不同方法的结合，正在开发更精细的 ec-LLS 方法来合成更先进的纳米材料。马尔多纳多教授的钙钛矿太阳能电池本科实验室课程正在针对高中生进行调整。其目的是充分简化电沉积平台，以便即使是刚入门的学生也可以为光伏发电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。

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