Jifeng Liu, Thayer School of Engineering

Topic: "Nanophotonics for Sustainable Energy"  (Video)

Abstract: Sustainable energy has become a critical challenge for modern society due to its profound social and environmental impact. Energy efficiency and renewable energy are "two pillars" of sustainability. In this talk we will present applications of nanophotonics in both aspects. In our Information Age, energy consumption of Information and Communication Technologies (ICT) has become an increasingly prominent concern as the internet traffic doubles every 2 years. It has been estimated that ICT already consumes ~ 5% of the total electricity production in the U.S., and it will increase to >10% by 2018 in developed countries. Electronic-photonic synergy based on silicon nanophotonics offers a promising solution to Green ICT by combining the merits of photons in ultralow energy, high bandwidth data transmission with those of electrons in high capacity data processing on a single silicon microchip. In particular, we will present ultralow energy GeSi photonic modulators, waveguide-coupled photovoltaic photodetectors , and monolithic Ge lasers on silicon chips for large scale, energy-efficient integrated photonic data links. We will also briefly discuss nanophotonics for high efficiency solid state lighting. In terms of renewable energy technologies, we will present self-assembled nanophotonic structures for light-trapping in thin-film solar cells to enhance its performance/cost ratio. We will also discuss optoelectronics engineering for more cost-effective thermophotovoltaic (TPV) cells that convert wasted heat directly into electricity. With significant impact on energy technologies such as Green ICT, solid state lighting and photovoltaics, nanophotonics will help to "light up" the future of energy sustainability.