Two-Dimensional Layered Materials: Thermodynamic and Electrical Studies

点击翻译按钮获取中文摘要

Non-Technical AbstractWith support from the Solid State and Materials Chemistry Program in the Division of Materials Research, this project focuses on the basic scientific research of the properties of small crystals, the education of graduate and undergraduate students, and the further development of specialized scientific instruments such as nanocalorimetry. Using a newly discovered method, small, two-dimensional crystals of important materials will be grown and the melting temperature and conductive electronic properties will be investigated. The comprehensive study of these crystals will help develop breakthrough technologies in electronic materials and will provide a new understanding in biological membrane science. Further development of fast-scanning nanocalorimetry will also enhance the national infrastructure of scientific instrumentation. One of the important broader impact goals will be to increase participation in scientific and technical education through the building of devices (e. g. voltmeter and student nanocalorimeter measuring solar and battery heat) within the Native American community. Blackfeet Community College (BFCC) is located in Browning, Montana, which is the center for the Blackfeet Nation. The activities include a Science Summer Camp at the BFCC for the local students from the middle school, high school and the community college. The research team includes faculty and students from BFCC and the University of Illinois. Technical AbstractThe research team will prepare and characterize extremely thin crystals of two-dimensional layered materials (e.g. graphene and chalcogenides). One key attribute of all two-dimensional layered materials is the very weak van der Waal bonding between layers which allows the stacking of just a few layers. Special thermodynamic and electronic properties of these materials are only revealed if the crystals are extremely thin - as thin as a single layer of atoms or molecules. The focus of this project is to synthesize and characterize variations of silver alkanethiolates (AgSCn) and chalcogenides using a newly developed vapor deposition technique developed in the principal investigator's laboratory. The rigid central (Ag-S) plane of the AgSCn crystal controls crystal structure and is the key to its unique electronic properties. The synthesis activity focuses on incrementally decreasing the number layers of AgSCn (and chalcogenides) down to a single layer and decreasing the chain-length (n) of the alkane side chains down to one-carbon (AgSC1) thiloate. Using nanocalorimetry, which has the capability of measuring the melting of a single layer of atoms, the principal investigator will measure the melting characteristics of AgSCn crystals. The research team will also study the vertical and lateral conductive properties of the AgSCn and chalcogenides crystals using conductive probe atomic force microscopy. This dual synthesis and characterization approach will uncover the ultimate structural and electronic properties of these two material systems. New understanding of these systems is applicable to biological lipid membranes which are another example of single-layer materials, consisting of a single bilayer of organic molecules.