Spectrally Selective Thermal Emission from Graphene Decorated with Metallic Nanoparticles

TL;DR

This paper demonstrates that decorating graphene with metallic nanoparticles enables tunable, spectrally selective thermal emission in the mid-infrared, with potential applications in thermal management and smart fabrics.

Contribution

It introduces a novel method of achieving spectrally selective thermal emission using metallic nanoparticles on graphene, tunable via gate voltage, expanding on previous plasmonic approaches.

Findings

Thermally emitted spectra can be tuned between 5-8 μm and 8-12 μm regimes.

Electric gating allows switching between heat trapping and cooling modes.

Theoretical results suggest applications in graphene-based thermal management systems.

Abstract

We showed in past work that nanopatterned monolayer graphene (NPG) enables spectrally selective thermal emission in the mid-infrared (mid-IR) from 3 to 12 $\mu$m. In that case the spectral selection is realized by means of the localized surface plasmon (LSP) resonances inside graphene. Here we show that graphene decorated with metallic nanoparticles, such as Ag nanocubes or nanospheres, also realize spectrally selective thermal emission, but in this case by means of acoustic graphene plasmons (AGPs) localized between graphene and the Ag nanoparticle inside a dielectric material. Our finite-difference time domain (FDTD) calculations show that the spectrally selective thermal radiation emission can be tuned by means of a gate voltage into two different wavelength regimes, namely the atmospherically opaque regime between $\lambda=5$ $\mu$m and $\lambda=8$ $\mu$m or the atmospherically transparent regime between $\lambda=8$ $\mu$m and $\lambda=12$ $\mu$m. This allows for electric switching between radiative heat trapping mode for the fomer regime and radiative cooling mode for the latter regime. Our theoretical results can be used to develop graphene-based thermal management systems for smart fabrics.