Abstract
One-dimensional nanostructures of BaO-xTiO 2 binary oxides with a high oxygen deficiency and a good dielectric performance are of great interest but seldom studied. In the present study, single-crystalline BaTi 4 O 9 (stoichiometric BaO-4TiO 2 ) nanowires were synthesized using a simple, one-step molten-salt method by co-heating the powder mixtures of NaCl, TiO 2 and BaCl 2 nanoparticles at 750°C. A series of spontaneous processes in the molten NaCl/BaCl 2 salt mixture with the dispersed TiO 2 nanoparticles, including ion diffusion, chemical reaction, particle agglomeration and ion exchange, yielded the BaTi 4 O 9 nanowires. Photoelectron spectroscopic and dielectric analyses indicated that a high fraction of oxygen deficiency for 10.4% provided the as-synthesized BaTi 4 O 9 nanowires with a high capacitance density of 13 F/m 2 . Thermal annealing lowered the oxygen deficiency to 6.6% and the capacitance density to 9 F/m 2 . The increase in wire length increased the oxygen deficiency and dielectric constant of the nanowires. © 2013 The Royal Society of Chemistry.