Room-temperature aqueous synthesis of highly luminescent BaWO ₄-polymer nanohybrids and their spontaneous conversion to hexagonal WO₃ nanosheets

The synthesis of a highly luminescent barium tungstate polyacrylic acid (BaWO₄-PAA) nanohybrid in aqueous solution at room temperature was performed. Hexagonal WO₃ nanosheets spontaneously formed in the colloidal suspension of the resultant BaWO₄-PAA. It was observed that the incorporation of carboxy groups in PAA molecules resulted in a coordination change from a WO₄ tetrahedral structure to a WO₆ octahedral. This structural modification induced enhanced green luminescence and the spontaneous conversion into metastable h-WO₃ nanosheets. The results show that the coordination of electrolytes to the inorganic species can lead to the morphological evolution of crystals and can control the modification of the chemical structure relevant to the various optical and magnetic properties.