Sb2MoO6, Bi2MoO6, Sb2WO6, and Bi2WO6 flake-like crystals: Generalized hydrothermal synthesis and the applications of Bi2WO6 and Bi2MoO6 as red phosphors doped with Eu3+ ions

Under hydrothermal conditions, a series of flake-like Sb2MoO6, Bi2MoO6, Sb2WO6, Bi2WO6 with the Aurivillius structure have been prepared controllably. It reveals that the initial molar ratios of SbCl3-to-NaOH (or BiCl3-to-NaOH) in the reaction system (SbCl3-Na2MoO4, BiCl3-Na2MoO4, SbCl3-Na2WO4, and BiCl3-Na2WO4) play important roles in the determination of product phases. Besides, properly changing the content of NaOH involved can produce some unexpected phases such as orthorhombic Sb2O3 and tetragonal Bi12O17Cl2. Moreover, substituting Bi3+ with Eu3+ at the A site is readily carried out because of their same valence states together with the similar ion radii. Consequently, the as-prepared Bi2WO6 and Bi2MoO6 samples have been doped with Eu3+ ions also under hydrothermal conditions to prepare the phosphors, which possess excellent red characteristics in terms of excitation and emission measurement. The present synthesis protocol has opened up an intriguing but effective avenue for producing antimony/bismuth-based materials, also exhibiting the potential application of red phosphors.