Development of novel inorganic yellowish-tacao color pigments, RbBi1-xCex(MoO4)(2) (0 <= x <= 0.30): revealing crystal structure and color properties

Inorganic yellowish-tacao color RbBi1-xCex(MoO4)(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. RbBi1-xCex(MoO4)(2) (0 <= x <= 0.30) pigments prepared in this study exhibited a single phase of monoclinic system with a space group P2(1)/c (14). They had fine angular grains with an average particle size of 10-15 mu m. 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 Ce3+ ion, leading to a yellowish-tacao color. Among the obtained RbBi1-xCex(MoO4)(2) (0 <= x <= 0.30) pigments, the RbBi0.90Ce0.10(MoO4)(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.