Chemistry Department Seminar

"Artificial Photosynthesis on III-Nitride Nanowire Arrays"

Presented by Zetian Mi, Department of Electrical and Computer Engineering, McGill University, Canada

Tuesday, June 21, 2016, 11:00 am — Room 300, 3rd Floor, Chemistry Bldg. 555

Abstract: High efficiency artificial photosynthesis, that can convert solar energy directly into chemical fuels, has been extensively investigated. Critical to this development is the stable and efficient generation of H2 from water under direct sunlight irradiation. To date, however, success in finding abundant visible-light active photocatalyst has been very limited. Recently, metal-nitrides have attracted considerable attention for applications in artificial photosynthesis, due to their extraordinary stability and tunable energy bandgap across nearly the entire solar spectrum. Moreover, III-nitrides are the only known material whose energy bandgap can straddle the redox potential of water under deep visible and near-infrared light irradiation. In 2011, we have demonstrated, for the first time, spontaneous overall water splitting on GaN nanowire arrays. We have discovered that the quantum efficiency for overall water splitting and hydrogen generation on the emerging nanostructured photocatalysts can be dramatically enhanced by precisely tuning the surface Fermi-level. We have further developed InGaN/GaN nanowire photoanodes and photocathodes, which are monolithically integrated on Si solar cell wafer through a polarization-enhanced tunnel junction. The devices exhibit highly stable hydrogen generation under simulated sunlight illumination. Such high efficiency photocatalysts also offer an entirely new avenue for recycling anthropogenic carbon dioxide to renewable fuels and for reducing nitrogen to ammonia.

Zetian Mi is an Associate Professor in the Department of Electrical and Computer Engineering at McGill University. He received the Ph.D. degree in Applied Physics from the University of Michigan, Ann Arbor in 2006. Prof. Mi's teaching and research interests are in the areas of III-nitride semiconductors, solid state lighting, nanophotonics, and solar fuels. He has published 7 book chapters and more than 150 refereed journal papers. He has received ma

Hosted by: Jim Muckerman

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