Woodruff School of Mechanical Engineering

Faculty Candidate Seminar


Atomic Layer Deposition for Interfacial Engineering of Solar Energy Conversion Devices


Dr. Neil Dasgupta


University of California, Berkeley


Monday, April 8, 2013 at 11:00:00 AM


MRDC Building, Room 4211


Samuel Graham


Nanoscale materials offer several benefits for energy conversion and storage devices due to their ability to modify optical, electronic, and chemical properties. In particular, for any devices in which charge transfer occurs, control of surfaces and interfaces is critical in order to reduce efficiency losses and improve the kinetics of transport phenomena across the interface. Recently, the use of nanowires has been explored for photovoltaic and photoelectrochemical energy conversion due to favorable properties including enhanced light scattering and trapping, efficient separation and extraction of charge carriers, and large surface areas to drive electrochemical reactions. However, the ability to uniformly coat the surface of high-aspect-ratio structures with precise control of material thickness and composition remains challenging using traditional material deposition techniques. This leads to inefficient use of material and poor control of the interfacial properties. In this talk, I will present results on the development of atomically precise deposition of materials on nanowire surfaces using atomic layer deposition (ALD). Due to the self-limiting surface chemistry of this process, thin-films or nanoparticles can be deposited uniformly over high-aspect-ratio structures. The ability to modify a surface with atomic precision allows for the fabrication of quantum dot-nanowire hybrid structures with tunable optical and electronic properties, as well as supported catalyst structures with ultra-low material loading for solar-to-fuel conversion. This facilitates a dramatic reduction in raw material usage without the need for high temperature or high vacuum processing, enabling a new class of devices based on abundant, low-cost materials and processing techniques.


Neil P. Dasgupta is currently a SunShot Postdoctoral Fellow working in the research group of Prof. Peidong Yang in the Department of Chemistry at the University of California, Berkeley. He completed his Ph.D. in Mechanical Engineering with a minor in Materials Science and Engineering at Stanford University in 2011 under the supervision of Prof. Fritz B. Prinz. His Ph.D. research was in atomic layer deposition (ALD) of quantum confinement structures for efficient energy conversion. His postdoctoral work at Berkeley has focused on the application of ALD on semiconductor nanowire surfaces for photovoltaic and solar-to-fuel applications. He has also served as a course instructor for graduate engineering courses in fuel cells, solar cells and batteries at Stanford and UC Berkeley. He is the recipient of a U. S. Department of Energy Postdoctoral Research Award (SunShot Fellowship) and a Stanford Graduate Fellowship for his Ph.D. Research.


Refreshments will be served.