Tungsten Complex Gratings as a Thermophotovoltaics Selective Emitter
International Journal of Energy Information and Communications
A kind of concave tungsten complex grating based on superposition of two simple binary tungsten gratings with different groove depths has been proposed for potential application as thermophotovoltaic (TPV) selective emitters. The effect of the simple grating geometric parameters on the spectral emittance is calculated numerically by using the rigorous coupled-wave analysis (RCWA). The emittance of the complex grating shows broadband-directional insensitive peak in the spectral region where the
... l region where the quantum efficiency of TPV cells is high, which is explained by the surface plasmon polariton (SPP). The results show that the complex grating has high emittance value, above 0.8, within the spectral range of 0.8 μ m 1 .7 6 μ m . At longer wavelengths, the emittance remains low and this is highly desired for thermophotovoltaic applications, to reduce the thermal leakage due to low-energy photons that do not produce any photocurrent. It is concluded that the complex grating has great potential to be used as a selective emitter for TPV applications. Copyright ⓒ 2015 SERSC 9 between 0.8 and 1.7 μm . It has three groove heights in one period. The emittance enhancement for TM waves can be explained by the excitation of surface plasmon polaritons coupled with the grating microstructures. The emittance of the complex grating numerically exhibits a wide peak in our wavelength of interest but lower than 0.2 at 2 .2 μ m . The performance of the complex grating with different polarization and incident angle is also studied for comparison between plain tungsten and simple tungsten gratings. The complex grating can be used as a selective emitter for TPV applications.