Analysis of an ultra-broadband TiN-based metasurface absorber for solar thermophotovoltaic cell in the visible to near infrared region

Solar thermophotovoltaic (STPV) represents next-generation technology for solar cells, enabling higher efficiency and better performance through advanced photothermal processes. They can surpass the Shockley- Queisser limit due to their superior photothermal conversion efficiency. The absorber is a crucial component on which the efficiency of the entire system depends. In this article, we have proposed a TiN-based metasurface absorber (MA) which is capable of operating at high temperatures with superior efficiency. We have numerically investigated the structure using the Finite Difference Time Domain (FDTD) method. Our analysis suggests that the MA can absorb more than 90% radiation in the 200-1733.5 nm range and achieves near-perfect absorbance (more than 99.5%) in the 719.7- 1371 nm range which is suitable for solar cell applications. Moreover, the MA also emits selective radiation and works as a metasurface emitter (ME). It achieves a maximum photothermal efficiency of 80% at 1900 K temperature. The findings of this study opens a new avenue for the development of cost effective, reliable and stable, highly efficient solar thermophotovoltaic cells in the visible to near infrared region.