Jacob Krich (SIMES Seminar)

Date(s) - Sep 4 2015
2:15 PM - 3:15 PM

Room 335, McCullough Building


Prof. Jacob Krich,

Department of Physics, University of Ottawa

Intermediate band solar cells and the path to high efficiency

Intermediate band (IB) materials are a novel class of materials that, like semiconductors, have a band gap but also have an extra set of allowed electronic levels entirely contained inside the semiconductor band gap. Solar cells made from such materials have the potential to radically improve photovoltaic efficiencies. Current intermediate band devices are hampered by short carrier lifetimes, limiting efficiency improvements. I will describe theoretical and experimental work to understand carrier lifetimes and their impact on device efficiencies. I will introduce a figure of merit, which predicts the potential effectiveness of candidate IB materials in advance of device fabrication. This figure of merit captures in a single parameter the inherent tradeoff between enhanced absorption and enhanced recombination within an IB material, and it suggests a path toward efficient IB materials. I will give examples of measurements of the figure of merit and theoretical predictions for new systems. I will conclude with a list of appealing and unappealing candidate material systems.