The Planar Thermophotovoltaic Selective Nearly-Perfect Absorbers/Emitters

The spectral response of thermophotovoltaic (TPV) absorber is a key factor for TPV system efficiency. We have shown that the planar TPV emitters can be realized by using thin-metal-dielectric stacking (IEEE Photonics J. 8, 1300109, 2016). In this paper, we provide a new structure composed of alternating dielectric and deep-sub-skin-depth (DSSD) metal layers for TPV selective absorbers. The RCWA calculation and the Fourier transform infrared (FTIR) measurement of tantalum (Ta) based planar absorber shows a high absorbance below the cut-off wavelength (λ<;λc) and a suppressed absorbance beyond the cut-off wavelength (λ>λc).