Nanoimprint lithography for thin-film solar photovoltaics

Crystalline silicon is in many respects an ideal absorber material for photovoltaics, but wafer fabrication is both expensive and energy-intensive. Film crystal-silicon solar cells employ significantly less silicon, but so-called “light trapping” must be used to sufficiently absorb red and infrared photons in order to achieve the U.S. Department of Energy's 13-16% module-efficiency goal for 2020. Diffractive light trapping – employing reflective photonic structures on the absorber film’s backside – has been suggested as a means for coupling poorly absorbed wavelengths into waveguide modes in the silicon film. In this colloquium, Dr. Weiss will discuss the feasibility of nanoimprint lithography – a simple yet powerful technique that allows for rapid and low-cost nanopatterning of large-area substrates – to create diffractive structures using ceramic resist materials developed by Professor Douglas Keszler’s group in the Department of Chemistry at OSU.