Composition dependence of luminescence of Eu and Eu/Tb doped silicate glasses for LED applications

• Published in: Journal of alloys and compounds 2013-04, Vol.555, p.232-236
• Main Authors: Zhu, Chaofeng, Chaussedent, Stéphane, Liu, Shujiang, Zhang, Yanfei, Monteil, André, Gaumer, Nathalie, Yue, Yuanzheng
• Format: Article
• Language: English
• Subjects: Asymmetry; Chromaticity; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Energy transfer; Exact sciences and technology; Fluorescence; Glass; Glasses; LED; Light-emitting diodes; Luminescence; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photoluminescence; Physics; Silicates; Wavelengths
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2012.12.052

► Eu and Eu/Tb doped silicate glasses for LED applications are studied. ► Effect of B2O3, Al2O3 and CaF2 on the local structure around Eu is investigated. ► White fluorescence is achieved for Eu/Tb co-doped glasses. ► Excitation wavelength variation can tune color coordinates of Eu/Tb doped glasses. The Eu and Eu/Tb doped silicate glasses are good candidates for light emitting diode (LED) applications. But the optical performance of these glasses is sensitive to variations in chemical composition. In this paper we report our recent findings about the effect of addition of minor components such as B2O3, Al2O3 and CaF2 on the luminescent properties of the above-mentioned glasses. We explore the role of Eu3+ ions as a structural probe of the glasses by determining the asymmetry factor, i.e., the ratio of the emission intensity of the 5D0→7F2 transition to that of the 5D0→7F1 transition. The results show that the asymmetry factor and luminescence lifetimes of as-prepared materials are dependent on composition. White fluorescence is achieved in Eu/Tb co-doped glasses, which can be attributed to the simultaneous generation of red, green and blue wavelengths from Eu3+ and Tb3+ ions. The variation of the excitation wavelength can tune the emission spectra as well as Commission Internationale de L’Eclairage (CIE) chromaticity coordinates of Eu/Tb co-doped glasses for specific applications. The energy transfer from Tb3+ to Eu3+ ions is investigated by analyzing fluorescence spectra and decay curves.