Tailoring size of BaTiO₃ nanocrystals via ambient conditions sol process

Abstract

As the miniaturization of electronic devices continues to demand smaller and uniform particle size of the powders, size control of the powder becomes critical. Under carefully controlled experimental conditions, nanocrystalline BaTiO₃ particles have been prepared by ambient condition sol process. Soluble precursors of barium and titanium in water have been used to produce a mixed metallic gel using KOH as the mineralizer. The gel was peptized and crystallized in water under refluxing condition. The effect of various experimental parameters such as the starting Ba/Ti ratio, temperature, time, and additives on the size of the crystallites have been investigated. A higher Ba/Ti ratio in the precursor solution led to smaller crystallite sizes of BaTiO₃ particles. A higher temperature of refluxing had a positive effect of producing smaller crystallites, as well as particle sizes of the resulting powder. Using a polymeric surface modifier during BaTiO₃ synthesis led to a smaller particle size and increased re-dispersibility of the particles in water. The duration of refluxing was determined to have a minimal effect on the resulting particle size. The powders have been characterized by X-ray diffractometry for phase purity, and by dynamic light scattering for particle size. Field emission scanning electron microscopy and transmission electron microscopy have been utilized to examine the morphology of the particles.