Thermo-optical analysis of a nanocone based solar absorber for thermophotovoltaic applications

Abstract We investigate the optical and thermal response of a 2D photonic crystal absorber composed of tungsten nanocones, with complete and truncated shapes used in a solar thermophotovoltaic (STPV) system. We explain how the absorption and temperature of the structure are affected by the presence of a protection layer, lens and an emitter. The total efficiency and contribution of thermal emittance of complete nanocone arrays are compared with truncated absorbers. Based on our results, the efficiency of a non-protected nanocone hits 67% at 400 sunlight and the temperature reaches 1350 K. By adding a silica layer on the absorber, the efficiency slightly reduces to 61%. In addition, we observed a reduction in the efficiency of all studied absorbers at higher sunlight concentration factors. Our results also indicate that the thickness of a silica layer on the tungsten substrate does not have a noticeable change in the efficiency. Finally, the deformation of the structure due to surface diffusion is studied. This study paves the way toward a multi-physical analysis of photonic crystal absorbers in STPV systems.