Discovering Novel Properties in Few-Layer MXenes Using Analytical, In-Situ Scanning Transmission Electron Microscopy

使用分析原位扫描透射电子显微镜发现少层 MXene 的新特性

• 批准号: 2309396
• 负责人: Robert Klie
• 金额: $ 54.97万
• 依托单位: University of Illinois at Chicago
• 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: 2023-06-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2309396&HistoricalAwards=false
• 关键词: Discovering; Novel; Properties; Few; Layer

NON-TECHNICAL DESCRIPTION: Materials known as MXenes are part of a growing family of two-dimensional structures that have attracted significant research interests due to their wide range of properties. These layered transition metal carbides and nitrides have the chemical formula of Mn+1XnTx (n=1-3), where M is a transition metal, X is either carbon or nitrogen, and Tx is either O, OH, F, Cl, or other surface groups that are bonded to the transition metal of the two-dimensional MXene layer. This project focuses on developing an atomic-scale understanding of the optical properties of MXenes, including their tunable plasmon resonances in the visible and near-infrared regime, which can be used for applications in nano-photonics or plasmonics. It is the PI’s hypothesis that different functional groups, Tx, control not only the layer-to-layer spacings of the two-dimensional MXene layers, but also provide the ability to tune the interactions between MXene layers as well as the density of free charges in each layer. Ti3C2 and Ti2C-based MXenes with a single type of surface termination will be used to study the atomic, electronic and plasmonic structures high-resolution electron microscopy and spectroscopy. Access to unique instrumentation at University of Illinois - Chicago (UIC) will be leveraged to study these materials over a wide range of temperatures and with unprecedented spatial and energy resolution. The project’s research activities center around hands-on research and learning experiences for science and engineering undergraduate and graduate students at the UIC, a Research-1 Hispanic-serving institution. Recruitment and training focuses on the next generation of researchers, in particular involving students from underrepresented groups and minorities through a student exchange program with Tecnologico de Monterrey, Latin@s Gaining Access to Networks for Advancement in Science and the DuSable Scholars programs. The participation of undergraduate students in active research projects is fostered through the PI’s Journal of Undergraduate Research at the University of Illinois - Chicago. Graduates of this program will contribute to academia, National Laboratories or industry, including semiconductor companies.TECHNICAL DESCRIPTION: The objectives of this research project are to develop an atomic-scale understanding of the nano-photonic and plasmonic properties of Ti3C2Tx and Ti2CTx MXenes, functionalized with a single, well-controlled species, using atomic-resolution scanning transmission electron microscopy (STEM) imaging, conventional and monochromated electron energy loss spectroscopy (EELS) combined with in-situ cooling to liquid nitrogen temperatures. Twisted bi-layer MXenes exhibiting Moiré lattice effects will be studied for the emergence of hybridized plasmons or excitons, as well as other emerging, potentially strongly correlated phenomena. Using autonomous anomaly detection in multi-dimensional data cubes via machine learning (ML), the correlation between structural defects and their impact on the plasmonic and photonic properties will be studied. This research project will consist of two tasks, i) atomic-resolution analysis of MXenes and ii) development of convolutional neural networks to identify crystal defects in atomic-resolution STEM images and identify the correlated changes in the low-loss or valence EELS. The insights from both tasks will be combined, yielding the ability to measure and control the optical or electronic, and possibly even magnetic properties of single-functionalized MXenes. The integration of research and education through the training of undergraduate and graduate students in state-of-the-art in-situ scanning transmission electron microscopy and state-of-the-art ML approaches is an integral feature of this project.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.

非技术描述：称为MXENES的材料是不断增长的二维结构家族的一部分，由于其广泛的特性，它们引起了重大的研究兴趣。这些分层的过渡金属碳和硝酸盐具有Mn+1xNTX（n = 1-3）的化学式，其中M是过渡金属，X是碳或氮，TX是O，OH，F，F，Cl，或其他表面基团，或其他与二维MXENE层的过渡金属键合的表面基团。该项目着重于对MXENES的光学特性进行原子级的了解，包括它们在可见的和近红外状态中的可调等离子体共振，可用于纳米 - 光子学或等离子体体管中的应用。 PI的假设是，不同的官能团TX不仅控制二维MXENE层的层到层间距，而且还提供了调整MXENE层之间相互作用以及每层自由电荷密度之间的相互作用的能力。具有单一类型的表面终止的基于TI3C2和TI2C的MXENE将用于研究原子，电子和等离子结构高分辨率电子显微镜和光谱。在伊利诺伊大学 - 芝加哥大学（UIC）获得独特的仪器，将利用在广泛的温度和前所未有的空间和能量分辨率的情况下研究这些材料。该项目的研究活动围绕动手研究和学习经验，为科学和工程本科生和研究生，UIC是一个研究-1西班牙裔服务机构。招聘和培训的重点是下一代研究人员，尤其是通过与Tecnologic de Monterrey的学生交流计划涉及来自代表性不足的团体和少数民族的学生，拉丁语@s可以访问科学和可疑学者计划的网络。本科生参与活跃研究项目的参与是通过伊利诺伊大学 - 芝加哥大学的本科生研究杂志来培养的。该计划的毕业生将有助于学术界，国家实验室或行业，包括半导体公司。技术描述：该研究项目的目标是对TI3C2TX和TI2CTX MXENES的TI3C2TX和TI2CTX MXENES的纳米光量和浆液性属性进行原子级了解，并在单一的传播中效果，使用了单个传播的物种。显微镜（Stem）成像，常规和单色电子损耗光谱（EEL）以及原位冷却至液氮温度。将研究扭曲的双层MXENES实验Moiré晶格效应，以出现杂交等离子体或激子的出现，以及其他出现的，潜在的，潜在的，潜在的强烈相关现象。通过机器学习（ML），使用自主异常检测，将研究结构缺陷及其对等离激子和光子性能的影响之间的相关性。该研究项目将由两个任务组成：i）MXENES的原子分辨率分析和ii）卷积神经网络的发展，以鉴定原子分辨率茎图像中的晶体缺陷并确定低损坏或价鳗鱼的相应变化。将从两个任务中的见解结合在一起，从而产生测量和控制光学或电子的能力，甚至可能的磁性特性。通过培训本科和研究生在最先进的现场扫描传输电子显微镜和最先进的ML方法的培训是该项目不可或缺的特征。该奖项反映了NSF的法定任务，并通过基金会的知识绩效和广泛的影响，这是该项目的一部分。