CBE Seminar: From Quantum Wells to Quantum Dots - Synthesis, Functionalization and Biological Sensing Applications of Semiconductor Nanocrystals

Abstract: Multilayer structures of thin single-crystalline films of III-V compound semiconductors (Quantum Wells) form the basis of advanced optoelectronic devices that have revolutionized numerous technologies, including optical communications, imaging and lighting, information storage, optical sensors and photovoltaics. The design of metalorganic vapor-phase epitaxy (MOVPE) reactors used for large-scale growth of such films requires fundamental understanding of the underlying transport phenomena and chemical kinetics. Fundamental models of rotating-disc MOVPE reactors have been developed and used to explore their vast dimensionless parameter space to identify operating conditions maximizing film thickness and compositional uniformity and optimize the operation of commercial reactors. More recently, II-VI compound semiconductor nanocrystals (Quantum Dots or QDs) have emerged as a new class of photonic materials that exhibit size-tunable fluorescence and other unique properties making them attractive for applications in biological imaging, solar energy conversion, quantum computing and ultra-high definition color displays. However, a key impediment to the commercial exploitation of QDs is the lack of efficient large-scale synthesis techniques that can lower their high production cost. Our group has developed novel scalable synthesis methods that employ the dispersed domains of microemulsions and liquid crystals as templates for growing QDs with precise control over their size, shape and size distribution. Kinetic Monte Carlo simulations have provided insights into QD nucleation and growth rates and Density Functional Theory calculations have elucidated doping mechanisms and the thermodynamic stability of core/shell nanostructures. Surface functionalization has enabled the development of a novel class of biosensors that provide rapid detection and quantification of biomolecular targets by measuring the amplification of fluorescence emission upon binding of a QD-labelled probe to its intended target. Potential applications include high throughput screening of biomolecules for drug discovery and multiplexed medical diagnostics.

Bio: T.J. Mountziaris earned a diploma from the Aristotle University of Thessaloniki, Greece, and a doctorate from Princeton University, both in chemical engineering. After completing postdoctoral studies at the University of Minnesota, he joined the Department of Chemical Engineering at the University at Buffalo (SUNY) in 1989 and was a member of the faculty until 2005. From 2003 to 2005, he served as rotating NSF program director for particulate and multiphase processes and contributed to the National Nanotechnology Initiative. In 2005 he was hired by the University of Massachusetts-Amherst as professor and head of chemical engineering and over the next nine years led his department into a period of unprecedented growth. He returned to NSF to serve as program director for process systems, reaction engineering and molecular thermodynamics from 2015 to 2019 and led several new funding initiatives, including the Emerging Frontiers in Research and Innovation solicitation on Distributed Chemical Manufacturing. In 2021 he joined the University of Houston as the inaugural William A. Brookshire Chair and Professor of Chemical & Biomolecular Engineering. Mountziaris is a senior member of the U.S. National Academy of Inventors, a fellow of the American Association for the Advancement of Science, and a fellow of the American Institute of Chemical Engineers. He is the recipient of the Norman Hackerman Award in Solid State Science and Technology from the Electrochemical Society, the SUNY Chancellor’s Award for Excellence in Teaching, and the Thomas Baron Award in Fluid-Particle Systems from AIChE.

Host: Assistant Professor Erdem Sasmaz