Investigation of heat transfer modes in plasmonic nanoparticles

There has been much recent interest in understanding heat transfer in nanoparticle packings in nanotechnology such as emerging photonics applications. In this paper, we analyze heat transfer between two plasmonic nanoparticles in finite contact and suspended in air to delineate the dominant modes of heat transfer. We have previously investigated the heat transfer analysis of laser heating in a nanoparticle packing such that interfacial thermal conductance between the nanoparticle packings in contact and the predicted average nanoparticle packing temperature matches with the observations of laser sintering temperature well when G(IC) is about 20 (MW/m(2) K). When G(IC) is less than 20 (MW/m(2) K), the primary pathway for heat transfer is that across the particle-air-particle interface. Thermal transport in these assemblies is subject to electromagnetic field enhancements due to near-field energy transfer; however, we show that radiation heat transfer between the nanoparticles is not a significant heat transport mode. Sub-continuum thermal effects are found to strongly retard overall thermal transport between the particles through the air pathway. (C) 2020 Elsevier Ltd. All rights reserved.