Cooperative role of dual surfactants in synthesis of single crystal BaMoO4 microcrystals

Single crystalline BaMoO4 microcrystals with three-dimensional bipyramidal-like architectures were synthesised by adjusting the pH value of the catanionic reverse micelles formed by a cationic surfactant hexadecyltrimethylammonium bromide (CTAB) and an anionic surfactant sodium dodecyl sulphonate (SDS), followed by a hydrothermal process. It was found that the external conditions such as the molar ratio of the two kinds of surfactants, reaction time and temperature had no crucial influence on the crystallisation and the shape evolution of the products. The internal properties of the crystals were the real reason for the typical morphology. The coexistence of the dual surfactants and the cooperation of oriented attachment and Ostwald ripening played important roles in the formation of the crystals. The products were characterised by X-ray diffraction, transmission electron Microscopy and field emission scanning electron microscopy. Room temperature photoluminescence indicated that the as prepared BaMoO4 microcrystals had strong blue emission peaks at 417 and 435 nm.