Preparation and characterization of Fe~(3+) doped Y_2Ce_2O_7 pigments with high near-infrared reflectance

摘要

In this work, we have synthesized a new kind of inorganic yellow pigments Y_2Ce_(2-x)Fe_xO_(7 + δ)(x = 0.00, 0.05, 0.10, 0.15) with high near-infrared (NIR) reflectance, using the Sol-Gel method. The substitution of Fe~(3+) for Ce~(4+) in Y_2Ce_2O_7 decreased the band gap of pigments from 3.28 eV to 3.15 eV attributed to O_(2p) to Fe_(3d) charge transfer transitions, which resulted in the color of powder pigments samples changing from ivory white to light yellow. The pigments possess high NIR reflectance (＞80.6%) in the range of 700-2500 nm, and the coatings colored with pigments also possess high values (＞65.3%) of the solar reflectance too. We have evaluated the indoor air temperature difference of pigment coatings used as building roof materials. In conclusion, these pigments could well serve as cool colorants.