LDRD seminar: Dec. 11
Two Argonne researchers will discuss their Laboratory-Directed Research and Development (LDRD) sponsored work at the LDRD Seminar Series presentation Tuesday, Dec. 11, 2018, at 12:30 p.m. in Building 212, Room A157. All are welcome to attend.
Visit the LDRD website to view upcoming seminars.
“Computational Simulation of Chemical Vapor/Atomic Layer Deposition and Phase Transition of Silicon Carbide Films,” by Materials Scientist Zhi-Gang Mei (CFC)
Silicon carbide films have attracted great interest for a variety of applications, such as electronic devices and nuclear claddings. However, chemical precursors for low temperature deposition of SiC films using chemical vapor or atomic layer deposition techniques are still lacking. In this talk, I will present our work on computational screening of novel chemical precursors for SiC using high throughput density functional theory calculations, and multiscale simulations of phase transition in SiC films and chemical vapor/atomic layer deposition process for optimized deposition conditions and film properties.
Zhi-Gang Mei is a materials scientist in the Chemical and Fuel Cycle Technology division. His research focus on atomistic and mesoscale simulations of nuclear material behavior under irradiation.
“Halide Perovskites as a Stepping Stone to Solar Energy Conversion Beyond the Single-Junction Limit,” by Chemist Alex Martinson (MSD)
Metal halide perovskites are attractive optoelectronic materials for high-performance photovoltaics, light-emitting diodes and photodetectors. The semiconducting properties of these materials are exceptionally tunable via ready alloying of monocations, metals and halogens. However, very few intentionally phase-separated mixtures (i.e. non-alloying phases) of metal halide perovskites have been identified or leveraged to understand their photophysical interactions. One technology of particular interest in which such phase-separated mixtures may be useful is intermediate band (IB) photovoltaics (PV). IBPV offer the potential to exceed the Shockley-Queisser efficiency limit for single p-n junction solar cells through a stepping-stone approach to light absorption across at least three distinct bands. In the most successful IBPV to date quantum dots of InAs are strategically grown within a larger bandgap GaAs matrix, enabling useful sub-gap absorption of infrared light by InAs which contributes to photocurrent without significant loss of device photovoltage. The exquisite photophysical properties of GaAs, especially a long excited state lifetime, enables the successful multi-level excitation. We propose and provide evidence that an analogous materials mixture might be developed that leverages the attractive photophysical properties of lead halide perovskites but offers greater ease of fabrication, facile bandgap tunability, and higher defect-tolerance.
Alex Martinson is a chemist in the Materials Science division, Interfaces for Clean Energy Theme, Surface Chemistry Group. The aim of his research is to elucidate and leverage a multitude of technologically relevant surface chemistries and optoelectronic processes that occur at the interface between materials. The research tests the limits of what is possible in digital materials synthesis and device fabrication at length scales approaching the atomic level. Present work is intended to advance the science of solar energy conversion, catalysis and water remediation through the design, modeling and fabrication of photovoltaics (PV), solar fuels platforms, single site catalytic frameworks and advanced membrane materials. These studies explore the intersection of earth-abundant materials, photoelectrochemistry, and targeted surface synthesis in order to study their synergies and reveal the shortcomings of our control over energy and matter.