Near infrared thermal emitter based on nano scale grating metamaterial for thermo photovoltaic power generation

Abstract Nonrenewable fossil fuels constitute the main source of energy for energy consumption worldwide. Therefore, new technologies are needed to capture energy from alternate sources before fossil fuel runs out. In this work, we designed a nanostructured grating for selective emitters made of tungsten/molybdenum ground film with a hafnium dioxide spacer that is used for thermophotovoltaic energy conversion. To achieve high spectral efficiency, several geometric parameters, including the grating height, dielectric thickness, and incident angle, were optimized, while all the remaining parameters remained fixed. The numerical simulation demonstrated that the mean emittance of the emitter reached 94% for the W-AlN-W structure in the wavelength range of 0.3−2.2 μm at normal incidence and 93% for the Mo-AlN-Mo structure in the wavelength range of 0.3−2.0 μm at normal incidence. Moreover, the nanostructured grating emitters with InGaAs band gaps of 0.55 eV and 0.62 eV at 1600 K attained 87% and 87.5% spectral efficiency, respectively. Furthermore, the designed metamaterial emitter was polarization independent and exhibited good emissivity over a wide range of incidence angles, from 0° to 75°. Surface plasmon polaritons, magnetic polaritons, and intrinsic metals show significant absorption at the cutoff wavelength. High mean emittance, polarization independence, easy fabrication, cost effectiveness, high spectral efficiency, and thermal stability are considered the most desirable elements of this work.