MMAE Seminar - Dr. Uwe Kortshagen - Nonthermal Plasma Synthesis of Nanocrystals and Quantum Dots for Energy Applications

Armour College of Engineering's Mechanical, Materials & Aerospace Engineering Department will welcome Dr. Uwe Kortshagen, the James J. Ryan Professor and a Distinguished McKnight University Professor and Head of the Department of Mechanical Engineering at the University of Minnesota, on Wednesday, March 29th, to present his lecture, Nonthermal Plasma Synthesis of Nanocrystals and Quantum Dots for Energy Applications.

Abstract

Nonthermal plasma synthesis of nanocrystals is particularly suited for covalently bonded materials that require high temperatures to be produced with good crystallinity. Several years ago, Kortshagen's group showed that plasma produced silicon nanocrystals are capable of high-efficiency photoluminescence, different from bulk silicon material. More recently, the capability of nonthermal plasmas to produce substitutionally doped nanocrystal materials has attracted attention, as substitutional doping had presented a significant challenge both for liquid and gas phase synthesis due to effects such as self-purification.

This presentation discusses the physics of plasma synthesis process. High photoluminescense quantum yields are achieved by careful surface functionalization through grafting alkene ligands to the nanocrystal surfaces. Solar luminescent concentration is a potential application for these highly luminescent nanocrystals (Nature Photonics 2017). We also discuss the substitutional doping of silicon nanocrystals with boron and phosphorous using a nonthermal plasma technique. The ability of plasmas to produce doped nanocrystals has recently enabled new insights into the electronic transport in nanocrystal films (Nature Materials 2016).

Biography

Uwe Kortshagen is the James J. Ryan Professor and a Distinguished McKnight University Professor and Head of the Department of Mechanical Engineering at the University of Minnesota. He is also a member of the graduate faculties of Physics and Chemical Engineering and Materials Science. He earned his Diploma degree in Physics in 1988, and his Ph.D. in Physics in 1991 from the Ruhr-University Bochum, Germany, under Professor Hans Schlüter. He came to the U.S. in 1995 with a Lynen Fellowship of the Alexander von Humboldt Foundation and spent a year at the University of Wisconsin-Madison. He earned the Habilitation in Experimental Physics at the University of Bochum in 1995. In 1996, he joined the Department of Mechanical Engineering at the University of Minnesota as Assistant Professor, where he was promoted to Associate Professor in 1999, and to Full Professor in 2003. He served as President of the International Plasma Chemistry Society and is a Fellow of the American Society of Mechanical Engineers, the Institute of Physics (London, UK), and the International Plasma Chemistry Society. He was awarded the 2015 Plasma Prize of the American Vacuum Society. His work is in the areas of nonthermal plasmas at low and atmospheric pressures, kinetic theory of plasmas, and in the use of plasmas in materials science and renewable energy technology. His work has been published in more than 180 articles in peer-reviewed journal articles and more than 300 invited and contributed conference presentations.