Preparation and characterization of Fe3+ doped Y2Ce2O7 pigments with high near-infrared reflectance

• We have prepared a novel yellow pigments Y2Ce2−xFexO7+δ (x ranges from 0.00 to 0.15) with a Sol–Gel method.
• The doping of Fe3+ changes band gaps of pigments from 3.28 eV to 3.15 eV.
• The pigments possess very high NIR reflectance (above 80%).
• The NIR reflectance of the pigment coatings reach 73.8%, and the temperature difference of coating and general pigment coating reaches to 3.3 °C.
• These Y2Ce2−xFexO7 + δ pigments could be well serve as cool colorants.

In this work, we have synthesized a new kind of inorganic yellow pigments Y2Ce2−xFexO7 + δ (x = 0.00, 0.05, 0.10, 0.15) with high near-infrared (NIR) reflectance, using the Sol–Gel method. The substitution of Fe3+ for Ce4+ in Y2Ce2O7 decreased the band gap of pigments from 3.28 eV to 3.15 eV attributed to O2p to Fe3d 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.

The doping of Fe3+ for Ce4+ in Y2Ce2O7 samples decreases the value of the NIR reflectance, but all of the pigment coatings still possess very high NIR reflectance (>63%) calculated with ASTM G159-98.Figure optionsDownload as PowerPoint slide