The synthesis, characterization and optical properties of silicon and praseodymium doped Y6MoO12 compounds: Environmentally benign inorganic pigments with high NIR reflectance

Novel, yellow. blown and brick-red colored, near-infrared reflective pigments based on yttrium molybdate doped with metal ions such as Si4+ or Pr4+ are described Replacing Si4+ for Y3+ in Y(6)M0O(12) changed the color from light-yellow to dark-yellow and the band gap decreased from 2 60 to 2 45 eV due to O(2)p-Mo-4d charge transfei transitions In contrast, replacing Pr4+ for Y3+ changed the color from light-yellow to dark brown and the band gap shifted from 2 60 to 1 90 eV. The coloring mechanism is based on the introduction of an additional 4(f1) electron energy level of Pi(4+) between the valence and conduction bands. The NIR reflectance of the pigments on asbestos cement sheet was measured (C) 2010 Elsevier Ltd All rights reserved