Light-Driven Fuel Production at Passivated Silicon Photoelectrodes

• Prof. Jillian Dempsey, University of North Carolina, Chapel Hill
• Sponsored by Stanford Department of Chemistry
• May 18, 3:00-4:00 pm, In-person, Sapp Center Auditorium (STLC 111), Learn more

Coatings and termination strategies for silicon photoelectrodes are crucial to protect the semiconductor from detrimental and uncontrolled oxidation during photoelectrochemical reactions that produce chemicals and fuels. However, these modifications must not inhibit interfacial charge transfer to catalysts and mediators. Terminating the silicon lattice with organic moieties affords stable photoelectrodes that exhibit large photovoltages. Methyl-terminated silicon can be employed to drive the selective reduction of CO2 by molecular catalysts without the competitive hydrogen evolution observed for H-terminated electrodes. Direct attachment of the catalyst is also possible, but the passivation is below unity, and defects at the surface lower photovoltage and selectivity. Collectively, these studies provide key foundations for hybrid photoelectrodes that drive fuel production with sunlight.

About the Speaker

Jillian L. Dempsey is a professor at the University of North Carolina at Chapel Hill. She is currently the Director of the Center for Hybrid Approaches in Solar Energy to Liquid Fuels (CHASE) and an Associate Editor for ACS Electrochemistry.

Jillian received her S.B. from the Massachusetts Institute of Technology in 2005 where she worked in the laboratory of Prof. Daniel G. Nocera. As an NSF Graduate Research Fellow, she carried out research with Prof. Harry B. Gray and Dr. Jay R. Winkler at the California Institute of Technology, receiving her PhD in 2011. From 2011–2012 she was an NSF ACC Postdoctoral Fellow with Daniel R. Gamelin at the University of Washington.

In 2012, Jillian joined the faculty at the University of North Carolina at Chapel Hill. Her research group explores charge transfer processes associated with energy capture and conversion, including proton-coupled electron transfer reactions and electron transfer across interfaces. Her research bridges molecular and materials chemistry and relies heavily on methods of physical inorganic chemistry, including transient absorption spectroscopy and electrochemistry.

She has received numerous awards including the Harry B. Gray Award for Creative Work in Inorganic Chemistry by a Young Investigator (2019), the J. Carlyle Sitterson Award for Teaching First-Year Students (2017), a Sloan Research Fellowship (2016), a Packard Fellowship for Science and Engineering (2015), the Agnes Fay Morgan Research Award (2020), and the University Award for Advancement of Women (2021).