Fabrication of well-dispersed barium titanate nanoparticles by the electrospray of a colloidal solution

Abstract

The electrospray of a colloidal microemulsion (ME) solution and subsequent on-line annealing were used to produce barium titanate nanoparticles (BTO-NPs). The solvent of the ME solution (cyclohexane) was replaced with a high-conductivity solution (solute: ammonium acetate, solvent: tetrahydrofurfuryl alcohol, conductivity: 3.1 × 10−2 S/m) to generate ultrafine droplets during the electrospraying. Well-dispersed and well-crystallized BTO-NPs with a perovskite structure were successfully fabricated at an annealing temperature of 1173 K. The size distribution of the BTO-NPs was successfully measured by applying a differential mobility analyzer and condensation nucleation counter to nanoparticles in-flight. The average size of the BTO-NPs was controlled within a range of 15 to 25 nm by changing the feeding rate. The electrospray of an ME solution with lower conductivity (solvent: 1-octanol, conductivity: 7.0 × 10−4 S/m) yielded amorphous particles with larger particle sizes. Thus, the electrospray of a high-conductivity solution is required to fabricate well-crystallized and dense BTO-NPs with smaller particle sizes.