(257g) Plasmon-Enhanced Greenhouse Effect

The greenhouse effect occurs when a material transmits sunlight and restricts thermal radiative losses by forcing thermal photons to be absorbed and re-emitted many times before escaping. This mechanism explains why increasing concentrations of gases such as methane and carbon dioxide in the atmosphere lead to global warming. Concentrated solar thermal (CST) technologies can utilize the greenhouse effect for carbon-neutral electricity and heat generation, but its effect is too weak for efficient use. Here, we report a significant improvement in the greenhouse effect by leveraging local surface plasmon resonances within hollow three-dimensional structures. Specifically, we incorporate nanoparticles of a transparent conducting oxide into a silica aerogel matrix and characterize their impact on solar and thermal transport. We also develop a new definition for greenhouse selectivity – a quantitative measure of the greenhouse effect – and relate it to the performance of solar receivers for CST. The plasmon-enhanced greenhouse selectivity (PEGS), demonstrated here, translates into a nearly two-fold reduction in measured heat losses at high temperatures (>600 deg. C) and enables higher operating temperatures for future CST applications.