Synthesis and Growth of Ce,Pr:YLuAG Crystal for LED Application

doi:10.15541/jim20150160

Abstract

Abstract:

Ce,Pr:YLuAG pure phase powder was synthesized by co-precipitation method and calcined at 1450℃, which had a garnet structure. The feed rod was prepared by press forming and solid state sintering. TEM showed that the sintered rod had good crystallinity and density. Ce,Pr:YLuAG single crystal was grown by the floating zone method. The as-grown crystal was transparent with a pale yellow color, and small cracks were observed in the shoulder. The transmittance of the crystal is 81.8%, which is close to the theoretical value 84.2%. Under 460 nm excitation, Ce,Pr:YLuAG crystal shows the emission band of Ce³⁺ at 530 nm and peak of Pr³⁺at 610 nm, which shows that Ce³⁺ can transfer the energy to Pr³⁺. However, only Pr³⁺ emission peak appears when it is excitated at 487 nm. The color coordinate is located at (0.474, 0.495) which shifts to red zone compared with commercial Ce:YAG yellow phosphor. As a result, Ce,Pr:YLuAG crystal is more suitable to fabricate white LED.

Key words: floating zone method, crystal growth, doping, YLuAG crystal

CLC Number:

O799

NIU Xue-jiao, XU Jia-Yue, ZHOU Ding,WANG Shu-Xian, ZHANG Huai-Jin. Synthesis and Growth of Ce,Pr:YLuAG Crystal for LED Application[J]. Journal of Inorganic Materials, 2015, 30(11): 1183-1188.

Figures/Tables 10

Fig. 1 XRD patterns of Ce,Pr:YLuAG feed calcined at different temperatures (the inset showing a feed rod)

Fig. 2 TEM images of sintered Ce,Pr:YLuAG feed powders

Table 1 Growth parameters for Ce,Pr:YLuAG crystal

Diameter of feed rod	4-5 mm
Length of feed rod	60-70 mm
Power of halogen lamp	3 kW
Rotation speed	15-20 r/min
Growth speed	5-7 mm/h
Atmosphere	O₂
Heating rate	200℃/h
Cooling rate	300℃/h

Fig. 3 Picture of as-grown Ce,Pr:YLuAG crystal

Fig. 4 Powder XRD pattern of Ce,Pr:YLuAG crystal

Fig. 5 X-ray rocking curve of Ce,Pr:YLuAG crystal

Fig. 6 Transmission spectrum of Ce,Pr:YLuAG crystal

Fig. 7 Excitation (a,b) and emission (c,d) spectra of Ce,Pr: YLuAG single crystal

Fig. 8 CIE coordinates of Ce,Pr:YLuAG crystal and commercial Ce:YAG phosphor

Fig. 9 Decay curves of Ce,Pr:YLuAG crystal

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