Mie-Metamaterials-Based Thermal Emitter for Near-Field Thermophotovoltaic Systems

Abstract

In this work, we theoretically analyze the performance characteristics of a near-field thermophotovoltaic system consisting a Mie-metamaterial emitter and GaSb-based photovoltaic cell at separations less than the thermal wavelength. The emitter consists of a tungsten nanoparticle-embedded thin film of SiO2 deposited on bulk tungsten. Numerical results presented here are obtained using formulae derived from dyadic Green’s function formalism and Maxwell-Garnett-Mie theory. We show that via the inclusion of tungsten nanoparticles, the thin layer of SiO2 acts like an effective medium that enhances selective radiative heat transfer for the photons above the band gap of GaSb. We analyze thermophotovoltaic (TPV) performance for various volume fractions of tungsten nanoparticles and thicknesses of SiO2.

A Review of Tunable Wavelength Selectivity of Metamaterials in Near-Field and Far-Field Radiative Thermal Transport

“…Ghanekar et al proposed a near-field thermophotovoltaic system consisting of a Mie-metamaterial emitter and a GaSb-based photovoltaic (PV) cell and analyzed the performance properties of this system when the separations of emitter and PV cell was less than the thermal wavelength, as shown in Figure 11 d. The emitter had a SiO thin film embedded with tungsten nanoparticles with a bulk tungsten substrate. They analyzed the performance of the TPV systems at different volume fractions of tungsten nanoparticles and thickness of SiO thin film [ 61 ].…”

“…( c ) Schematic of near-field thermophotovoltaic system consisting of the proposed thermal emitter and GaSb-based PV cell at separation less than the thermal wavelength [ 60 ]. ( d ) Schematic of near-field thermophotovoltaic system consisting of the proposed thermal emitter and GaSb-based PV cell at separation less than the thermal wavelength [ 61 ].…”

Near-infrared optics of nanoparticles embedded silica thin films

“…The artificial thermal metamaterials which have selective high emissivity at narrowband or broadband wavelength range show promising potentials in the advanced engineering applications, such as thermophotovoltaics (TPVs), infrared thermal sensing [1][2][3][4][5][6][7][8], thermal diodes [9][10][11][12], radiation cooling [13][14][15][16], thermal rectification [17][18][19]43], biosensors, and chemical sensors [20,21]. Some materials, such as rare earth doped ceramics, possess selective high emissivity, but they do not show sufficient wavelength selectivity that are suitable for the emerging engineering applications [22].…”

“…Mie-metamaterials are one type of artificial materials which utilize Mie resonances of inclusions to shift or control the shape of emission spectra. Based on sub-wavelength-thick thin films embedded with nanoparticles, Mie-metamaterials enjoy the benefit of easy fabrication and the prospect of applications in wavelength selective thermal emitter/absorber [8,26,27]. In an earlier report [27], Theoretical studies on optical and emissive properties of Mie-metamaterials by employing the Clausius-Mossotti equation have been performed.…”

“…There are several studies pertaining to investigations of the optical properties of polymers. Since ceramics and some metals are chemically stable at high temperatures and have low thermal coefficients of refractive indices, [35], the ceramic thin films embedded with metallic nanoparticles are suitable for high temperature applications, such as Solar Thermoelectric Generators (STEG) and TPVs [8,36]. SiO 2 and W have high melting points and, recently, they have been used as thermal emitters/absorbers [37][38][39][40][41].…”