Seminar by Andrej Lenert

Tuning Energy Transport in Solar Thermal Systems Using Nanostructured Materials

Andrej Lenert
Massachusetts Institute of Technology


To propel widespread adoption, next-generation solar technologies need to be more in-tune with societal demands, in addition to being affordable and efficient. Nanoscale technologies enable us to leverage the spectral and directional characteristics of the sun to address these issues. However, the macroscale nature of our energy systems requires a multiscale engineering approach to bridge these realms.

In this talk, I elaborate on how I used a multiscale approach to elucidate our understanding and enhance the performance of solar thermophotovoltaics (STPVs). I will describe the design and development of a nanophotonic STPV that harnesses the full spectrum of the sun, in a solid-state and scalable way. Through device optimization and unprecedented control over spectral properties at these high temperatures (~1300 K), we demonstrated a device that is 3 times more efficient than previous STPVs.

To achieve this result, we developed a framework to identify which parts of the spectrum are most critical to the success of STPVs. We then tuned the spectral properties of the absorber-emitter using carbon nanotubes and a silicon/silicon dioxide photonic crystal to target these properties.

Finally, I will show how a scaled-up version of our device can achieve 20% efficiencies in the near term. With potential integration of thermal-based storage, such a technology can supply power efficiently and on-demand, which will have significant implications for the way solar power is adopted within our society.

Andrej Lenert is a Ph.D. Candidate in the Department of Mechanical Engineering at the Massachusetts Institute of Technology (MIT), advised by Prof. Evelyn N. Wang. He holds an S.M. degree from MIT, and a B.S.Eng. degree from the University of Iowa. His interests lie at the intersection of heat and mass transfer, nanophotonics, and light-matter interactions. Andrej is a fellow of the National Science Foundation, the MIT Energy Initiative, and the Martin Family Society of Fellows for Sustainability.

Seminar Date