Synthesis of Novel Nontoxic Yellow Pigments: Sr2Ce1−xTbxO4

Abstract

Abstract Novel yellow inorganic pigments Sr2Ce1−xTbxO4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) were synthesized by the conventional solid-state route. The structure and morphology of the developed pigments were characterized using powder X-ray diffractometer (XRD) and scanning electron microscope (SEM), respectively. A UV–vis–NIR spectrophotometer was employed to investigate the optical properties, and the color characteristics were evaluated by CIE 1976 L*a*b* color scales. The Tb substitution extends the absorption edge to longer wavelengths by introducing an additional electronic level between the valence and conduction bands. Consequently, the prepared pigments exhibit various yellow colors by fine tuning of the band gap from 3.03 (white) to 2.52 eV (reddish-greenish yellow). Doping of Tb into Sr2CeO4 enhances the NIR reflectance at 1100 nm from 87% to 91%. The coloring performance of the synthesized pigments was investigated in the polymer matrix for plastic coloring applications. The exhibition of high NIR reflectance with comparable color properties of these pigments makes them potential candidates as cool colorants to reduce the heat build-up.