Synthesis and luminescence properties of green phosphors Ca₆Sr₄(Si₂O₇)₃Cl₂:Eu²⁺ for white light emitting diodes

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• 作者：Zhaomei Li ; Shaokang Gao ; ^{gaosk@fzu.edu.cn} ; Xiuxia Chen ; Qun Yu
• 关键词：Luminescence ; Green phosphor ; Ca6Sr4(Si2O7)3Cl2 ; Eu2+ ; Energy transfer
• 刊名：Journal of Luminescence
• 出版年：2012
• 期刊代码：54_00222313
• 类别：ch
• 出版时间：June, 2012
• 卷：132
• 期：6
• 页码：1497-1500
• 文件大小：503 K

摘要

Divalent europium-activated chlorosilicate Ca₆Sr₄(Si₂O₇)₃Cl₂:Eu²⁺ phosphors were synthesized by a conventional solid-state reaction under reductive atmosphere. These phosphors can be efficiently excited by UV-visible light from 320 to 420 nm, which matches that of a near UV-emitting InGaN chip. Under the 360 nm excitation, Ca₆Sr_3.97(Si₂O₇)₃Cl₂:0.03Eu²⁺ phosphor shows a strong and broad emission centering at 515 nm, which is attributed to the 5d鈫?f transition of Eu²⁺ ion. The mechanism of concentration quenching was determined to be the dipole-dipole interaction and the critical energy-transfer distance of Eu²⁺ was calculated as 3.31 nm. The CIE chromaticity coordinates of Ca₆Sr_3.96(Si₂O₇)₃Cl₂:0.03Eu²⁺ phosphor are (0.127, 0.770) according to the emission spectrum. It can be expected that Ca₆Sr₄(Si₂O₇)₃Cl₂:Eu²⁺ phosphor is a promising candidate as the green component for near-ultraviolet InGaN-based white LED.