Heat Conduction and Thermal Switching Performance of Surface Plasmon Polaritons in Ag2Se Quantum Dot Composite Polymer Film

TL;DR

This paper theoretically analyzes the thermal conductivity and switching performance of surface plasmon polaritons in Ag2Se quantum dot polymer films, revealing how structure and temperature influence heat conduction and enabling design of high-performance thermal resistors.

Contribution

It introduces a theoretical model linking thermal conductivity to film structure and temperature, providing new insights for designing thermal resistors using surface plasmon polaritons.

Findings

Thermal conductivity decreases with film thickness and temperature following a specific exponential rule.

High thermal conductivity requires device sizes larger than millimeters to avoid boundary scattering.

Thermal switching ratio can reach nearly 100 times by increasing temperature from 300K to 400K.

Abstract

To stabilize the working temperature of an equipment, a solid-state thermal resistor is usually a requisite, which could adjust its heat conductance continuously according to the temperature. In this work, the thermal conductivity and the thermal switching performances of surface plasmon polaritons in the polymer films filled with Ag2Se quantum dots (QDs) were theoretically analyzed, and a theoretical model was also derived to reveal the dependence of the thermal conductivity on the temperature and the structure of a composite film, which is verified to be effective by numerical calculations. It shows that the thermal conductivity will decrease following ~t-3exp({\zeta}/Td) rule under the thin film limit, here t, d and T are film thickness, diameter of QDs and temperature, respectively, and {\zeta} is a constant. A high thermal conductivity could be only realized at a device with a size lager than millimeter scale, due to the need of avoiding boundary scatterings of surface plasmon polaritons (SPPs). At the millimeter scale, the thermal conductivity could be reduced by 100 times by increasing temperature from 300 to 400 K, which suggests a very high thermal switching ratio almost in all kinds of solid-state thermal resistor. This study brings new insights in designing thermal resistor and understanding heat conduction in films by adjusting its structures.