High efficiency of photon-to-heat conversion with a 6-layered metal/dielectric film structure in the 250-1200 nm wavelength region

The optical properties and thermal stability of a 6-layered metal/dielectric film structure are investigated in this work. A high optical absorption average of > 98% is achieved in the broad spectral range of 250- 1200 nm with experiment results, in good agreement with our simulated results. The samples have a typical layered structure of: SiO₂(57.3 nm)/Ti(5.7 nm)/SiO₂(67.1 nm)/Ti(11.6 nm)/SiO₂(51.4 nm)/Cu(>100 nm), deposited on optically polished Si or K9-glass substrates by magnetron sputtering. The sample of the 6-layered metal/dielectric film structure has an AM1.5G solar absorptance of 95.5% with the features of low thermal emittance of 0.136 at 700K and good thermal stability, and will be potentially suitable for practical application in high-efficiency solar absorber devices in many fields.