Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (02): 299-303.doi: 10.3866/PKU.WHXB20090217

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Improved Luminous Properties of Red Emitting Phosphors for LED Application by Charge Compensation

CAO Fa-Bin; TIAN Yan-Wen; CHEN Yong-Jie; XIAO Lin-Jiu; LIU Yun-Yi   

  1. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, P. R. China; Shenyang Institute of Chemical Technology, Shenyang 110142, P. R. China
  • Received:2008-07-16 Revised:2008-10-10 Published:2009-01-16

Abstract: Froma dynamic ball-grinding solid-state reaction, a series of red-emitting phosphors Ca0.54Sr0.16-δEu0.08Gd0.12 (MoO4)0.2(WO4)0.8 (δ=0-0.16) were synthesized by charge compensation. Three approaches to charge compensation were used and are (a) 3Ca2+/Sr2+→2Eu3+/Gd3++vacancy; (b) 2 Ca2+/Sr2+→2Eu3+/Gd3++M+, where M+ is a monovalent cation like Li+, Na+, or K+ employed as a charge compensator; (c) Ca2+/Sr2+→2Eu3+/Gd3++N-, where N- is a monovalent anion like F-, Cl-, Br- or I- employed as a charge compensator. The results showed that model (b) was better at charge compensation. One red light-emitting diode (LED) was made by combining a phosphor with a 390-405 nm emitting LED chip under a 20 mA forward-bias current. The chromaticity coordinates (CIE), color purity, light intensity, and luminous efficiency were x=0.65, y=0.33, 100%, 6200 cd·m2, and 95 lm·W-1, respectively. Furthermore, the CIE and color purity of the apparatus changed little and the color was stable. This red-emitting phosphor in the field of new generation white-light LEDs has broad application prospects.

Key words: Charge compensators, Ca0.54Sr0.16-xEu0.08Gd0.12(MoO4)0.2(WO4)0.8, Red-emitting phosphors, LED

MSC2000: 

  • O645