Wafer-Scale Manufacturing of Ultrathin Nanoporous Transition Metal Dichalcogenide Membranes Using Chemical Etching for Water Purification and Other Applications

这项先进的制造业资助支持研究新的生物膜，用于有效的水净化。本工作主要致力于大面积制备超薄过渡金属二硫属化物膜，以提高水过滤和处理的精度。该项目通过了解这些改进膜中原子尺度的水分子和离子运动机制，创造了新的基础知识。减小膜厚度的一个重要动机是它导致水通量增加。 这种膜是通过在箔上化学气相沉积过渡金属二硫属化物，然后在酸中进行化学蚀刻使其成为纳米多孔的。除了水净化，这项工作预计将影响使用膜的其他应用，如气体和生物分子过滤。该项目利用研究成果进行教育和推广。与广泛的纳米材料界和膜行业的外联涉及共享制造加工数据。教育部分为处于固态物理，材料科学和高分辨率显微镜交叉路口的各级学生提供创新的多学科学习机会。学生外联活动包括向高中生做演讲和参加STEM活动。该资助支持二维（2D）纳米材料的先进制造，以创建新型厘米级膜，其中单层膜由坚固的几层膜支撑。二维纳米材料，如过渡金属二硫属化物，已被证明具有许多应用潜力，从用于电子的无缺陷材料到用于膜分离技术如水脱盐和气体分离的缺陷工程材料。目前2D纳米多孔膜的制造通常在控制方面受到限制，或者依赖于使用离子和电子束照射，这是缓慢且昂贵的。这项工作使用简单的化学蚀刻，使孔膜使用工业湿法蚀刻剂，导致可控的膜孔隙率和经济的制造。这项研究回答了关于离子流的基本性质的关键科学问题，作为膜性能，厚度，孔径和密度的函数，与最先进的聚合物膜相比，实现有效的水脱盐。研究方法包括化学气相沉积生长单原子和几个原子厚的2D纳米材料，最大可达4英寸晶圆级，优化2D纳米材料转移到孔径上以制造2D纳米材料膜，然后进行湿法蚀刻和运输研究以了解基本的孔形成和离子传输机制。 该研究涉及优化膜的制造和最大限度地提高水流量，同时保持膜的完整性。这项工作进一步开发了通过纳米多孔膜的卷对卷纳米制造实现规模化的仪器。该奖项反映了NSF的法定使命，并且通过使用基金会的知识价值和更广泛的影响进行评估，被认为值得支持审查标准。

This advanced manufacturing grant supports research in novel ultrathin membranes for efficient water purification. This work focuses on large-area manufacturing of ultra-thin transition metal dichalcogenide membranes to improve the precision of water filtration and treatment. This project creates new fundamental knowledge through the understanding of the mechanisms of water molecule and ion motion at atomic scales in these improved membranes. An important motivation for decreasing the membrane thickness is that it leads to increased water fluxes. The membranes are made by chemical vapor deposition of transition metal dichalcogenides on foils, followed by chemical etching in acids to make them nanoporous. Besides water purification, this work is anticipated to impact other applications where membranes are used such as gas and biomolecule filtration. This project leverages research outcomes for education and outreach. Outreach to the broad nanomaterials community and to membrane industry involves sharing of manufacturing processing data. The educational component provides innovative multidisciplinary learning opportunities for students at all levels at the crossroads of solid-state physics, materials science and high-resolution microscopy. Student outreach includes presentations to high school students and participation in STEM activities.This grant supports advanced manufacturing of two-dimensional (2D) nanomaterials towards creating novel cm-scale membranes, in which monolayers are supported by robust few-layer membranes. Two-dimensional nanomaterials, such as, transition metal dichalcogenides, have demonstrated potential for many applications from defect-free materials for electronics to defect-engineered materials for membrane separation technologies like water desalination and gas separation. Current fabrication of 2D nanoporous membranes is often limited in terms of control or rely on the use of ion and electron beam irradiation, which is slow and costly. This work uses simple chemical etching to make holes in membranes using an industrial wet etchant, leading to controllable membrane porosity and economic manufacturing. This research answers key scientific questions about fundamental properties of ion flow as a function of membrane properties, thickness, pore size and density towards efficient water desalination in comparison with state-of-the-art polymer membranes. The research approach encompasses chemical vapor deposition growth of single- and few-atom thick 2D nanomaterials up to 4-inch wafer-scales, the optimization of 2D nanomaterials transfer on to apertures to make 2D nanomaterial membranes, followed by wet etching and transport studies to understand fundamental pore-forming and ion transport mechanisms. The research involves optimizing the manufacture of ultrathin membranes and maximizing water flow while retaining membrane integrity. This work further develops the instrumentation towards scale-up via roll-to-roll nanomanufacturing of the nanoporous membranes.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.