The industrial sector accounted for ~31 Quads of the ~97.4 Quads of primary U.S. energy used in 2013. More than half of this energy 59.0 Quads) was lost as waste heat, much of it at low temperatures. There is currently no commercially viable technology for capturing low grade heat with temperatures <450F 230C), and higher grade waste heat is frequently not captured either because there is no nearby use for the heat or the economic payback time is too long using existing, expensive capture devices. This program will provide the first demonstration of a transformative thermal energy harvesting device that integrates metal-insulator-metal tunneling diodes into high efficiency surface plasmon resonant cavities for direct conversion of infrared radiation to DC electricity. The plasmonic structure concentrates infrared radiation from a heat source into a tunneling diode, which generates electricity. The proposed effort will combine nanofabrication of plasmonically coupled MIM tunneling diode test structures with finite element simulations for design optimization. An experimental demonstration of power generation will be obtained near the 5.8m emission peak of a 450F blackbody using laboratory sources. A manufacturing cost of $1/W for low grade heat and much lower for higher grade heat) will allow widespread adoption of the plasmonic energy harvesting device. Near-term opportunities exist with military applications in more efficient portable power generation, battery recharging, and transportation waste heat recovery. As the technology matures, larger markets such as automotive, manufacturing, and power generation will open up. Harvesting waste energy in manufacturing and power generation plants would also lead to large efficiency gains, with a corresponding reduction in pollution from burning fossil fuels.
