DESIGN AND ANALYSIS OF COLORED SOLAR SELECTIVE ABSORBING FILMS WITH THREE-LAYER STRUCTURE

Using glasses with 200-nm Cu films as substrates, the colored solar energy selective absorbing films with three-layer structure had been designed by optical multilayer design software. The three layers materials were Fe doped AlN and AlN. The optical constants of Fe doped AlN films with different Fe volume fractions were calculated by the effective medium theories. The color of the absorbing films includes orange yellow, purplish pink, pink, purple, and green. The solar absorptance of each colored film is between 0.89 and 0.96. The thermal emittance is lower than 0.1. The green film has the highest brightness. The purplish pink film has the highest absorptance, while the orange yellow and purple films have the lowest emittance. The color, absorptance, emittance, and brightness of the green film at different angles of light incidence had been analyzed. When the incident angle increases from 0° to 50°, the color of the green film changes from green to blue, and its absorptance and emittance decrease.