Characterization of hollow BaTiO3 nanofibers and intense visible photoluminescence

BaTiO3 hollow nanofibers were fabricated by electrospinning and then subsequent calcination of as-spun nanofibers with a heating rate of 2.5 degrees C/min. Scanning electron microscope and transmission electron microscope (TEM) results indicated that the heating rate had a significant effect on the morphology of the BaTiO3 hollow nanofibers. The X-ray diffraction, Raman spectroscopy, and TEM results indicate the prepared BaTiO3 hollow nanofibers have tetragonal phases. From the results of the X-ray photoelectron spectroscopy analysis, in the amorphous BaTiO3 nanofiber, peaks at 457.2 eV for Ti 2p(3/2) were also found, which corresponded to the Ti3+ ions. However, in the crystalline BaTiO3 nanofibers, peaks of Ti 2p(3/2) showed the Ti4+ ions. Intense visible photoluminescence was observed in the amorphous BaTiO3 nanofiber, which is calcined below a temperature of 500 degrees C. The observed intense photoluminescence was ascribed to a multiphonon process with localized states within the band gap of the highly disordered states. In the crystalline BaTiO3 hollow fiber, low intensity of photoluminescence showed at the visible region, which is originated from an intrinsic Ba defect. (C) 2013 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.