Colour control and selectivity in TiAlN solar-thermal absorbers

ABSTRACT Optical constants for simulations were obtained by R-and T-measurements on TiAlN thin films deposited on Corning 7059 glass. The model parameterized free carrier effects and an inter-band excitation. The calculations demonstrated that the colour effects are due to interference and inter-band absorption around 500 nm in a single layer coating. The peak shifts with the thickness of the thin film which gives a simple way to obtain different colours. Solar absorptance of 86 % can be reached already for a single TiAlN-film on an Al substrate