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International Journal of Photoenergy
Volume 2014, Article ID 407239, 6 pages
http://dx.doi.org/10.1155/2014/407239
Research Article

Color Rendering Index Thermal Stability Improvement of Glass-Based Phosphor-Converted White Light-Emitting Diodes for Solid-State Lighting

Department of Optoelectronic Engineering, Far East University, Tainan 744, Taiwan

Received 29 January 2014; Revised 18 March 2014; Accepted 1 April 2014; Published 5 June 2014

Academic Editor: Ray-Hua Horng

Copyright © 2014 Chun-Chin Tsai. 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

High color rendering index performance has been required for phosphor-converted warm-white light-emitting diodes (PC-WWLEDs) in lighting industry. The characteristics of low-temperature fabricated phosphor (yellow: Ce3+:YAG, green: Tb3+:YAG, and red: CaAlClSiN3:Eu2+) doped glass were presented for applications to high color rendering index warm-white-light-emitting diodes. Color coordinates (x, y) = (0.36, 0.29), quantum yield (QY) = 55.6%, color rending index (CRI) = 85.3, and correlated color temperature (CCT) = 3923 K were characterized. Glass-based PC-WWLEDs was found able to maintain good thermal stability for long-time high-temperature operation. QY decay, CRI remenance, and chromaticity shift were also analyzed for glass- and silicone-based high-power PC-WLEDs by thermal aging at 150°C and 250°C for industrial test standard’s aging time 1008 hours. Better than the silicone’s, thermal stability of glass-based PC-WLEDs has been improved. The resulted high color rendering index (CRI) glass phosphor potentially can be used as a phosphor layer for high-performance and low-cost PC-WLEDs used in next-generation indoor solid-state lighting applications.