Multiferroic based reddish brown pigments: Bi1−xMxFeO3 (M=Y and La) for coloring applications

Multiferroic based reddish brown pigments: Bi1−xMxFeO3 (M=Y and La) 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. UV–vis NIR Spectrophotometer was employed to investigate the optical properties. The results indicated that the incorporation of Y3+ and La3+ offered a fine bandgap tuning contrastingly in the range from 1.95 to 2.23 eV. The color characteristics were evaluated and the typical pigment Bi0.9Y0.1FeO3 (L⁎=37.07, a⁎=13.83, b⁎=9.65) is comparable with the commercially available brown pigment (BR 300), (L⁎=34.91, a⁎=11.38, b⁎=9.86) of Kawamura Chemicals Co. Ltd., Japan. A systematic enhancement of lightness (L⁎), redness (a⁎) and yellowness (b⁎) is seen with La doping, exhibiting a bright reddish brown hue. The coloring performance of the synthesized pigments was investigated in polymer matrix for plastic coloring applications. The influence of low toxic rare earth elements as dopants on the optical properties and color performance of multiferroic BiFeO3 positions them in the class of lead free inorganic red pigments for coloring applications.