Lance WheelerNational Renewable Energy Laboratory
The landscape of photovoltaics (PV) research has changed dramatically in the last ten years. The cost of traditional monocrystalline silicon module installations has plummeted to rival the cost of US energy generation from non-renewable sources. This economic climate places greater demands on performance for next-generation PV technology and motivates new strategies for deployment beyond residential rooftops. This talk will cover two topics that address these challenges: 1) PV devices leveraging multiple exciton generation (MEG) show promise to bypass the conventional Shockley-Queisser PV efficiency limit. To date, isolated colloidal group IV quantum dots have demonstrated the most efficient MEG but are yet to be integrated into PV devices due to difficulties in synthesis and processing. This talk will discuss the development of group IV quantum dot surface chemistry to facilitate PV absorber integration. 2) PV technology employing metal halide perovskite absorber layers have reached power conversion efficiencies as high as 22.1% in just six years of research—a feat that took monocrystalline silicon technology more than thirty years to achieve. This talk will describe research on dynamically “switching” perovskite absorber layers from transparent to tinted using solar illumination to demonstrate the first example of dynamic PV glass. The technology is a glimpse into the future of PV deployment in smart buildings that dynamically adapt to weather conditions, transforming buildings from the largest sink of US energy into sources of clean renewable energy.
Lance Wheeler received a Bachelor of Arts degree in Physics from St. John’s University in Collegeville, Minnesota in 2009. As a departmental fellow, his graduate work was performed at the University of Minnesota under the advisement of Professor Uwe Kortshagen, where Wheeler received a Ph.D. in 2014. Within the Center for Advanced Solar Photophysics, a U.S. Department of Energy Frontier Research Center, his research was dedicated to the development of novel surface chemistries to enable the integration of group IV semiconductor quantum dots into photovoltaic devices. Lance joined NREL’s solar photochemistry program in June 2014 and has expanded his research to include photovoltaic energy generation in dynamic glazing and solar thermochemical fuel production using nanomaterials.
Host: Dr. Kenneth Brezinsky