Date/Time
Date(s) - 13 Feb 2012
1:10 PM - 2:00 PM
Location
3043 ECpE Building Addition
Title: “Enhancing performance of thin film solar cells with photonic and plasmonic crystals – overcoming the Lambertian limit”
Speaker: Rana Biswas – Adjunct Professor and Scientist, Ames Laboratory
Abstract: Light trapping is essential to capture red and near-infrared photons in thin film silicon solar cells. It has been commonly believed that the limiting absorption in thin solar absorber layer is given by the “Lambertian” limit or the ergodic limit, in which incoming light is scattered uniformly in the cell, and distributed uniformly (i.e. ergodically) in the modes of the system. By rigorous simulations of thin film silicon cells with periodic plasmonic crystal back reflectors, I will describe recent solar cell designs that overcome the Lambertian limit over all wavelengths in the solar spectrum. Strong diffraction coupled with light concentration are the two critical effects for this enhancement. I will briefly describe our local advances in experimental solar cells with photonic- and plasmonic-crystals, that demonstrate very large enhancements in the absorption and photo-currents.
The experimental portion of this work was in collaboration with Vikram Dalal, and staff and students at the Microelectronics Research Center.
Speaker Biography: Rana Biswas obtained his PhD in Physics from Cornell University. This was followed by a post-doctoral fellowship at AT&T Bell Labs (Murray Hill,NJ). He was a consultant at the Xerox Palo Alto Research Centerand at Exxon Research in NJ, before moving toIowaStateUniversityand Ames Laboratory. He has co-organized 3 Materials Research Society Symposia. His research focuses on photonic crystals, plasmonics, solar cells, semiconductor physics and atomistic simulation. He has more than 120 refereed journal publications (including 2 Nature papers), and 3 patents. Rana Biswas is a Fellow of the American Physical Society, elected in 2009, for contributions to semiconductors and photonics.
