Development of novel inorganic yellowish-tacao color pigments, RbBi 1− x Ce x (MoO 4 ) 2 (0 ≤ x ≤ 0.30): revealing crystal structure and color properties

Inorganic yellowish-tacao color RbBi 1− x Ce x (MoO 4 ) 2 (0 ≤ x ≤ 0.30) pigments were synthesized by a conventional solid-state reaction method, followed by characterization of their crystal structure and optical and color properties. RbBi 1− x Ce x (MoO 4 ) 2 (0 ≤ x ≤ 0.30) pigments prepared in this study exhibited a single phase of monoclinic system with a space group P 2 1 / c (14). They had fine angular grains with an average particle size of 10–15 μm. The synthesized pigments showed strong optical absorption in the UV and blue light regions due to the ligand-metal charge transfer (LMCT) transition in the host lattice and the 4f → 5d transition of Ce 3+ ion, leading to a yellowish-tacao color. Among the obtained RbBi 1− x Ce x (MoO 4 ) 2 (0 ≤ x ≤ 0.30) pigments, the RbBi 0.90 Ce 0.10 (MoO 4 ) 2 pigment showed the strongest yellowish-tacao color hue, where the L *, a *, and b * values were 78.3, 14.7, and 38.9, respectively. These pigments showed excellent resistance to UV irradiation.