Novel and efficient Mie-metamaterial thermal emitter for thermophotovoltaic systems

Abstract

We theoretically demonstrate a novel, efficient and cost effective thermal emitter using a Mie-resonance metamaterial for thermophotovoltaic (TPV) applications. We propose for the first time the design of a thermal emitter which is based on nanoparticle-embedded thin film. The emitter consists of a thin film of SiO₂ on the top of tungsten layer deposited on a substrate. The thin film is embedded with tungsten nanoparticles which alter the refractive index of the film. This gives rise to desired emissive properties in the wavelength range of 0.4 μm to 2 μm suitable for GaSb and InGaAs based photovoltaics. Effective dielectric properties are calculated using Maxwell-Garnett-Mie theory. Our calculations indicate this would significantly improve the efficiency of TPV cells. We introduce a new parameter to gauge the efficacy of thermal emitters and use it to compare different designs.

Design of Multilayer Ring Emitter Based on Metamaterial for Thermophotovoltaic Applications

“…To evaluate the efficiency of an optimized emitter for a TPV cell, we analyze the efficiency of the TPV system. The efficiency of a TPV system to convert radiated heat to electrical power is given by Equation 3 [3,22]:…”

“…For this reason, the selective emitter should be a perfect broadband and wide-angle emissivity above the band gap energy of the PV cell. If the TPV emitter has high emissivity within the targeted wavelength region and low emissivity above cut-off wavelength, the PV cell can effectively operate to generate electrical power with relatively low thermal loss [3][4][5].…”

“…Metamaterials contain repeating patterns at small scales and have properties that have not yet been found in nature [12,13]. Metamaterial emitters are typically designed with different symmetry structures such as disks [14,15], squares [16][17][18], crosses [19][20][21], pyramids [22][23][24][25], nanowires [26,27], cones [28], and nanoparticles [3] to increase TPV performance achieved by perfect emissivity above the energy band gap of PV cell. Similarly, the nano-sized ring has been studied for various applications because of high sensitivity and multiplexing capability [29].…”

Ultra-broadband, polarization-independent, wide-angle absorption in impedance-matched metamaterials with anti-reflective moth-eye surfaces

“…Similar absorbers in the terahertz (THz) [5], infrared (IR) [6] and visible [7] regions followed soon thereafter. The applications of these materials are widespread and include solar light harvesting [8], thermophotovoltaic cells [9], selective thermal emitters [10], optoelectronic devices [11], plasmonic sensors [12], and stealth applications [13]. The first generation of metamaterial absorbers was based on split ring resonance or electric ring resonance mechanisms, but this approach is difficult to implement in practice as the wavelength becomes shorter.…”

High Contrast Far-Field Radiative Thermal Diode

“…Customization of absorption/emission spectra is often achieved by the use of multilayer thin film structures 29 , nanoparticles 30, 31 , dielectric mixtures 32, 33 , photonic crystals 34, 35 , 1-D/2-D gratings 36 and metamaterials 37, 38 . Absorbers that utilize Fabry-Perot cavities 39, 40 , Salibury screens 41 and Jaumann absorbers 42 and ultra-thin lossy thin films bounded by transparent substrate and superstate 43–45 have been investigated for decades.…”