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Synthesis and Property Study of Phosphate and Indate Phosphor Used for White LED

Author: LiuHaiYan
Tutor: YangZhiPing
School: Hebei University
Course: Optical Engineering
Keywords: LED phosphor luminescent properties
CLC: O482.31
Type: Master's thesis
Year: 2008
Downloads: 121
Quote: 1
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Abstract


In this paper, several kinds of phosphor used for ultraviolet LED were fabricated. The optimal synthesis temperature and the concentration of impurity were confirmed. The crystal structures were analyzed. The luminescence properties of samples were researched. The chief contents are given below.(1) The phosphor SrZnP2O7:Tb3+ was synthesized by the general high temperature solid-state reaction and its luminescence properties are investigated. It shows six major emission peaks locating at 420nm,442nm,492nm,545nm,584nm and 620nm, which correspond to the 5D3→7F5,5D3→7F4,5D4→7F6,5D4→7F5,5D4→7F4 and 5D4→7F3 typical transition of Tb3+, respectively. The excitation spectra contain a broad band extending from 350 to 400 nm, which is coupled well with the emission of ultraviolet light-emitting diode(UVLED). The effects of doped-Tb3+ concentration and charge compensations of Li+, Na+ and K+ on the emission intensity are also investigated. It shows that the optimum doped-Tb3+ concentration is 10% and Li+ gives the best improvement to enhance the emission intensity. The SrZnP2O7:Tb3+ is a potential green-emitting phosphor for white light emitting diode.(2) The red phosphor SrZnP2O7:Eu3+ was synthesized by high temperature solid state reaction and its luminescence properties are investigated. The strongest excitation peak of the sample is located at 400nm, which coupled well with the emission of UVLED. The emission bands peaking at 591nm and597nm (5D0→7F1),616nm、624nm and 629nm (5D0→7F2) 656nm (5D0→7F3) and 688nm (5D0→7F4), which are corresponded to the typical transition of Eu3+. The influence of the concentration of Eu+ to the emission intensity was investigated and when the concentration of Eu3+ increases, the concentration quench was not happened but the quench trend appears. It was also found that the Bi3+ in the system can increase the emission intensity of SrZnP2O7:Eu3+. The energy transfer from Bi3+ to Eu3+ in the phosphor was also discussed.(3) The red phosphor SrIn2O4:Sm3+ was synthesized by combustion and its luminescence properties were studied. The emission spectrum consists of three major orange-red emission bands. The emission peaks are located at 570 nm, 606nm and 653 nm corresponding to the 4G5/2→6H5/2、4G5/2→6H7/2、and 4G5/2→6H9/2 typical transition of Sm3+ respectively and the strongest one appears at 606 nm. Its excitation peaks appear at 323,413, 476nm which indicates that this phosphor can be excited effectively by UV and blue LED. The influences of the concentration of Sm3+ on the emission intensity were also investigated. When the concentration of Sm3+ is 6%, the strongest emission is obtained.

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CLC: > Mathematical sciences and chemical > Physics > Solid State Physics > Solid nature of the > Optical Properties > Luminescence
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