Absorbing film on metal for solar selective surface

Zero reflectance conditions for an absorbing thin film coated on metal subs trate are inferred based on Fresnel equations. The required film thickness as well as the complex refractive index range are deduced. Based on such co nsideration, a thermal control coating with special selective absorbing cha racteristic was prepared by reactively sputtering NiCrOx absorbing him on s tainless steel substrate. The optical constants of this NiCrOx film are mea sured and the required film thickness is calculated. The spectral reflectan ce of the tandem was measured in the wavelength range of 0.3-25 mum, which shows a near zero reflectance at 0.8 mum and a high reflectance at infrared . The solar absorbance is 0.8 while normal emittance is 0.14. (C) 2000 Else vier Science S.A. All rights reserved.