Synthesis and characterization of Al3+ doped LaFeO3 compounds: A novel inorganic pigments with high near-infrared reflectance

Abstract

Novel, brown and yellow inorganic pigments LaFe1−xAlxO3 (x=0, 0.1, 0.3, 0.5, 0.7) with high near-infrared (NIR) reflectance have been prepared by a Sol–Gel method. Replacing Al3+ for Fe3+ in LaFeO3 changed the color from brown to yellow and the band gap increased from 2.46ev to 2.77eV due to the quantum confinement effect arising from the small size regime. Moreover, the synthesized pigments and the coatings colored with them possess high NIR solar reflectance in the range of 700–2500nm. The temperature difference between the pigments we prepared and standard pigments was evaluated in simulating their usage as building roof materials. The thermal and chemical stability of the pigments were also studied.