A fully symmetric solar absorber for thermophotovoltaic power generation

The swift pace of industrial growth has significantly increased the demand for renewable and clean energy sources. The efficient use of solar energy, a renewable and clean resource, can significantly advance national development. Enhancing solar energy absorption and utilization efficiency is a crucial research focus due to its current low efficiency. This study introduces a broadband solar absorber utilizing a pyramid structure, with its absorption characteristics simulated via the Finite Difference Time Domain (FDTD) method. The chosen wavelength range spans from 280 nm to 3000 nm. Within the 280 nm to 2097 nm range, the absorber achieves an ultra-high average absorption rate exceeding 99.73 %. In the 280 nm - 3000 nm range, the average absorption rate is higher than 99.55 %.Furthermore, the absorber exhibits an exceptional absorption rate exceeding 99.99 % in the 300 nm - 334 nm wavelength range. Analysis of electric and magnetic fields reveals that the high absorption efficiency is mainly due to propagating surface plasma resonance at the center W pyramid, gap surface plasma resonance between each pyramid, and surface plasma resonance between the W pyramid and the dielectric layer. Additionally, when the temperature reaches up to 1000 K, the absorber demonstrates a thermal radiation efficiency of 95.90 %. Under AM1.5 illumination conditions, absorption within the 280 nm to 3000 nm band surpasses 99.56 %. The absorber maintains high absorption levels across incident angles from 0 degrees to 30 degrees and is insensitive to polarization. The proposed structure offers novel perspectives for the advancement of metamaterial - based solar energy conversion devices.