Broadband omnidirectional infrared nanophotonic spectral controller for GaInAsSb thermophotovoltaic cell

Spectral controllers (SC) based on the square array of AlAs0.06Sb0.94 nanopillars (NP) and the aluminum back surface reflectors (BSR) are designed for the Ga0.84In0.16As0.14Sb0.86 TPV cells. The multiple optical resonance characteristics of the NP-BSR nanophotonic resonators are analyzed, which show the excellent light management performances. For the emitter temperature of 1000 degrees C, the angle-of-incidence and polarization-of-light weighted spectral efficiency of 90% is obtained by the optimized NP-BSR SC. Photovoltaic performances of the TPV cells are analyzed based on the coupled optical and electrical simulations. The results show the NP-BSRs perform substantially better than the normal quarter-wavelength anti-reflection coatings. In particular, the NP-BSRs show the strong light concentration ability and can be used to enhance the output power density of the ultra-thin film structured TPV cells. For the active layer of 0.6 mu m, the output power density of over 1W.cm ? 2 and the con-version efficiency of nearly 30% are obtained by the NP-BSR TPV cell under the emitter temperature of 1000 degrees C.