The Division of Chemistry supports Jillian Dempsey of the University of Washington as an American Competitiveness in Chemistry Fellow. Dr. Dempsey will work on synthesizing and characterizing new kinds of magnetic nanoparticles with interesting, long-lived photomagnetic effects. The nanoparticles will be Mn(I)-doped CdSe quantum dots with various shapes and internal structures. The resulting work will help in the development of future spintronics and spin-photonics materials. Dr. Dempsey will collaborate with scientists at Los Alamos National Laboratory's high magnetic field laboratory to examine barriers to magnetization reversal and antiferromagnetic superexchange interactions of Mn(II)-Mn(II) dimer pairs in these materials at 120 Tesla. In addition to her research, Dr. Dempsey will develop curriculum materials in nanoscience that she will disseminate to Seattle-area students and teachers.
Research like that of Dr. Dempsey is aimed at developing new kinds of materials that have interesting or unique physical properties. The specific kinds of materials that Dempsey is working on could be useful in new generations of computers and electronics. The efforts at broadening participation being pursued by Dr. Dempsey are aimed at giving a broad population of students and the public exposure to an emerging area of the chemical sciences.
The primary goal of this project was to enhance understanding of the magneto-optical properties of diluted magnetic semiconductor nanocrystals. Diluted magnetic semiconductors are promising materials for application in spin-based electronic devices, which promise to transform information technology by increasing storage density and providing new methods for data processing. In these devices, information is stored or transmitted via electron spin orientation, enabling electronics to be smaller, more versatile and more robust than current technologies. One of the ultimate goals of the Gamelin group is to be able to read, write and manipulate electron spins with light. By exploring the magneto-optical properties of materials like manganese(II) doped zinc selenide nanocrystals during the course of this project, important details about the electronic structure of the manganese(II) ions embedded in semiconductor lattices were discovered. Additionally, key effects of magnetic dopant density on the spin relaxation processes were uncovered. By comparing semiconductor nanocrystals, which are of interest for microelectronic technologies, to bulk semiconductor materials, it was shown that the magnetic properties of manganese ions are comparable in quantum confined and un-confined materials. These findings are helping to advance the development of diluted magnetic semiconductor nanocrystals for spin-photonic applications. In addition to carrying out the research described above, the PI was very active in scientific outreach activities. She partnered with the NSF funded Seattle Hub for Industry-driven Nanotechnology Education (SHINE) for several activities. First, in both 2011 and 2012 she designed and taught a lab module as part of the North Seattle Community College Nanotechnology program (Nano 230). The educational materials developed for this lab are still being used at NSCC. Second, she helped train 25 high school and community college educators in various nanotechnology-based classroom lab activities at the 2011 SHINE "Train the Nanotrainer" teacher training workshop in Salem, OR. Lastly, she led nanotechnology workshops and demonstrations as part of six different community programs, including the Expand your Horizons Workshop. Ultimately, these efforts provided exposure to nanotechnology to 30 educators, 20 community college students, 400 K-12 students, and 200 members of the general public, approximately 40% of whom were members of underrepresented groups in the sciences. This project provided the PI with opportunities for research, teaching and mentoring in science. The training she received as an American Competitiveness in Chemistry Postdoctoral Fellow prepared her for her independent career as an assistant professor at the University of North Carolina, where she is now leading her own research program aimed at exploring charge transfer processes relevant to solar fuel production.
