Synthesis, structural and optical properties of nanocrystalline Ba2NaNb5O15

Kundu, Swarup and Varma, KBR (2013) Synthesis, structural and optical properties of nanocrystalline Ba2NaNb5O15. In: CRYSTENGCOMM, 15 (44). pp. 8887-8893.

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Abstract

Fine powders comprising nanocrystallites of barium sodium niobate, Ba2NaNb5O15 (BNN) were obtained via a citrate assisted sol-gel route at a much lower temperature than that of the conventional solid-state reaction route. The phase evolution of BNN as a function of temperature was investigated by thermogravimetric analysis (TGA), differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). DTA data followed by XRD studies confirmed the BNN formation temperature to be around 923 K. The as-synthesized powders heat-treated at 923 K/10 h attained an orthorhombic structure akin to that of the parent BNN phase. Transmission electron microscopy revealed that the nanocrystallites are associated with dislocations. The optical band gap was calculated using the Kubelka-Munk function. These nanocrystallites exhibited strong visible photoluminescence (PL) at room temperature. The PL mechanism was explained by invoking the dielectric confinement effect, defect states and generation of self-trapped excitons.

Item Type:	Journal Article
Publication:	CRYSTENGCOMM
Publisher:	ROYAL SOC CHEMISTRY
Additional Information:	Copyright for their article belongs to ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	16 Dec 2013 07:05
Last Modified:	16 Dec 2013 07:05
URI:	http://eprints.iisc.ac.in/id/eprint/47907

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