Potential NIR reflecting yellow pigments in (BiV)(1-x)(YNb)(x)O-4 solid solutions

Abstract

New yellow inorganic pigments, (BiV)(1-x)(YNb)(x)O-4 with high NlR reflectance were synthesized by a conventional solid-state reaction method. The effect of isovalent dopants, namely, Y3+ and Nb5+ on BiVO4 samples was characterized using powder X-ray diffractometer, scanning electron microscope, UV-vis-NIR diffuse reflectance spectrometer, and CIE 1976 L*a*b* color scales. The prepared pigments exhibit brilliant yellow colors with significant enhancement of NIR reflectance to 90.8% when compared to undoped BiVO4 at the 1100nm range. Further, the solid solutions allow fine tuning of the band gap displaying various yellow colors. The lattice distortion and reduction in particle size are responsible for the enhancement of the pigment characteristics. The above results indicate that these yellow pigments have potential to be used as cool colorants for roofs and automotives as energy-saving coatings.