Sol-gel-nitridation preparation and photoluminescence properties of Dy³⁺-doped M₂Si₅N₈ (M=Ca, Sr, Ba) phosphors for white light emitting diodes

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• 作者：Wentao Zhang^a ; ^b ; ^{zhangwentao2005@163.com" class="auth_mail" title="E-mail the corresponding author} ; Yuheng Lu^a ; Haiying Du^a ; Jinhui Lin^a ; Jianping Long^a ; ^b
• 关键词：M2Si5N8 ; Sol-gel-nitridation ; Rare earth doping ; Photoluminescence ; White LEDs
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：1080-1085
• 全文大小：1159 K

文摘

M₂Si₅N₈:Dy³⁺(M=Ca, Sr, Ba) nitride phosphors with different Dy³⁺ ion concentrations were prepared via a novel sol-gel-nitridation method involving an annealing step at 1300 or 1400 °C. The X-ray diffraction patterns indicate that the structure of these phosphors is in good agreement with the standard M₂Si₅N₈ crystal structure. The photoluminescence spectra recorded for the prepared phosphors exhibited an intense white emission consisting of a blue emission peak (485 nm) and a yellow emission peak (582 nm), which are attributed to the characteristic ⁴F_9/2→⁶H_15/2 and ⁴F_9/2→⁶H_13/2 transitions of the Dy³⁺ ions, respectively. When using a different alkaline earth metal, the structure of the resulting M₂Si₅N₈ phosphors changed and the luminescence was also affected. The chromaticity coordinates of the prepared Sr₂Si₅N₈:Dy³⁺, Ca₂Si₅N₈:Dy³⁺, Ba₂Si₅N₈:Dy³⁺ phosphors with blue and yellow emission peaks were (x=0.391, y=0.397), (x=0.448, y=0.433) and, (x=0.42, y=0.414), respectively, which are all close to the standard white light coordinates (0.33, 0.33). The lifetime values of the obtained Ca₂Si₅N₈:Dy³⁺, Sr₂Si₅N₈:Dy³⁺ and Ba₂Si₅N₈:Dy³⁺ phosphors were determined to be 0.028, 0.0167 and 0.0113 ms, respectively.