This project, supported by the Solid State and Materials Chemistry program, will take advantage of ligand exchange processes in quantum dot materials to induce intriguing new physics in these systems: namely magnetism without the use of a chemical dopant. Focus will be placed on targeting strong-field ligands which can lead to unpaired electrons on the quantum dot surface. In addition, how the shape of the particle can affect the induced magnetism due to changes in magnetocrystalline anisotropy will be investigated. Using a host of materials characterization including synchrotron radiation techniques (x-ray absorption, photoemission, and circular dichroism), magnetometry, electron spin resonance, photoluminescence, electron microscopy, UV-Vis spectroscopy, and x-ray diffraction, correlations between ligand field strength and induced magnetism will be observed. A comprehensive understanding of ligand exchange chemistry on quantum dots, including surface coverage and effects of ligand type on exchange processes, will be obtained. The general mechanisms related to surface induced magnetism in quantum dots will lead to new quantum dot based magnetic materials which can lead to new magneto-optical devices based on UV lasers.
NON-TECHNICAL SUMMARY:
Nanomagnetism represents a new potential marketable use for nanotechnology, a field of research and technology heavily discussed by the popular media. Breakthroughs in this research venture could lead to smaller, more efficient magneto-optical materials. This project, supported by the Solid State and Materials Chemistry program, will greatly increase our understanding of how the manipulation of surface chemistry can lead to unexpected and unique magnetic properties in quantum dots. This project will find ready applications in technology sectors including magneto-optic devices. This research will take place within the Laboratory for Surface Science and Technology (LASST), an interdisciplinary center that brings together researchers from Physics, Chemistry, Electrical & Computer Engineering, and Chemical & Biological Engineering. This research program provides advanced graduate training in the fields of physics, chemistry, and materials science, and specifically in both UHV surface science and magnetometry. This project will leverage the NSF funded Maine Physical Sciences Partnership for outreach to both middle and high school students. An upper division undergraduate laboratory on advanced instrumentation is planned that will prepare the next generation of physicists, chemists, materials scientists, and engineers for both industrial and academic settings. In addition, the research laboratory, which will be housed in LASST, will be on display via tours and will introduce many underprivileged students, including a substantial Native American population, to cutting edge instrumental tools. Information collected from the instrumentation will be disseminated via many outlets, including academic publications and presentations, descriptions on UMaine websites, and public tours of LASST and the Physics Department (attended by many middle school students and teachers).
