Red emitting phosphors of Eu3+ doped Na2Ln2Ti3O10 (Ln = Gd, Y) for white light emitting diodes

A series of Eu3+ doped Na(2)Ln(2)Ti(3)O(10) (Ln = Gd, Y) red-emitting phosphors for application in ultraviolet based light emitting diodes (LEDs) were successfully synthesized by a modified sol-gel method. Their structure and luminescent properties were characterized by powder X-ray diffraction (XRD), photoluminescence excitation (PLE) and emission (PL) spectra and absorption spectra, according to these results the optimal compositions and synthesis parameters were determined. In addition, the thermal stabilities of the phosphors were investigated according to the temperature-dependent PL spectra. The red and white-LEDs (W-LEDs) comprising the Na(2)Ln(2)Ti(3)O(10):Eu3+ (Ln = Gd, Y) red emitting phosphors were fabricated with a near-ultraviolet (n-UV) chip. In comparison with Na2Y1.4Eu0.6Ti3O10, the Na2Gd0.6Eu1.4Ti3O10 phosphor offers higher brightness, quantum efficiency, and excellent thermal stability. W-LEDs comprising Na2Gd0.6Eu1.4Ti3O10 showed bright white emission with a color rendering index (Ra) of 82, a color temperature of 2151 K, and Commission Internationale de I'Eclairage (CIE) color coordinates of (0.34, 0.37). The phosphor Na2Gd0.6Eu1.4Ti3O10 is more suitable candidate for application in LEDs. (C) 2015 Elsevier B.V. All rights reserved.