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International Journal of Optics
Volume 2012, Article ID 537949, 5 pages
http://dx.doi.org/10.1155/2012/537949
Research Article

Fluorescence Properties and Synthesis of Green-Emitting Tb3+-Activated Amorphous Calcium Silicate Phosphor by Ultraviolet Irradiation of 378 nm

Department of Materials and Applied Chemistry, Faculty of Science and Technology, Nihon University, 1-8, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308, Japan

Received 27 September 2011; Accepted 31 October 2011

Academic Editor: Gong Ru Lin

Copyright © 2012 Yoshiyuki Kojima et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The excitation wavelength of conventional Tb3+-activated phosphor is near 270 nm. This study describes novel green-emitting Tb3+-activated amorphous calcium silicate by ultraviolet excitation at 378 nm. The Tb3+-activated amorphous calcium silicate was prepared by heating a sample of Tb3+-activated calcium silicate hydrate (CSH) at 900°C for 30 minutes. The emission wavelength of the resulting phosphor was 544 nm. The optimum excitation wavelength within the range 300–400 nm was 378 nm. The Tb3+-activated amorphous calcium silicate emitted green by ultraviolet irradiation. The optimum initial Tb/Ca atomic ratio of this phosphor was about 0.5. A mechanism for the action of the phosphor is proposed, in which Tb3+ ions existing in the layer of the CSH lead to loss of water molecules and OH groups.