Thermal switching performance of surface plasmon polaritons in Ag2Se quantum-Dot/Polymer composite film

Abstract

To stabilize the working temperature of an equipment, a solid-state thermal switch is usually a requisite. In this work, the thermal switching performance of surface plasmon polaritons (SPPs) in Ag₂Se quantum-dot (QD)/polymer film was probed. Firstly, a theoretical model of thermal conductivity of SPPs was derived to reveal the dependence of the thermal conductivity on both the temperature and film structure. Then, the thermal conductivity and the thermal switching performances of SPPs were analyzed. It shows that the thermal conductivity of SPPs is ∼t^-3exp(ζ/Td) under the thin film limit, here t, d and T are film thickness, diameter of QDs and temperature, respectively. A high thermal conductivity of SPPs could be only realized at a device with a size lager than millimeter scale, due to the need of avoiding boundary scatterings of SPPs. At the millimeter scale, the heat conduction of SPPs will be on the 100 nW·K^-1 level, on the same magnitude scale as the phonon and also phonon-polariton heat conductions. At this size scale, the thermal conductivity of SPPs could be reduced by 100 times by increasing temperature from 300 to 400 K, suggesting a thermal switching ratio of 100, which is one of the highest in these of all thermal switches. This study brings a new thermal switch which has a potential application in thermal management system.