Sr2Si5N8：Eu2＋荧光粉的制备及其发光性能研究

Syntheses and Photoluminescence Properties of Sr_2Si_5N_8:Eu^(2+) Phosphors

以Sr2CO3、Si3N4和Eu2O3为原料,以C为主要还原剂,采用碳热还原氮化工艺合成Sr2Si5N8:Eu2+荧光粉,着重研究了C、Sr2CO3添加量及Eu2+浓度对产物物相及发光性能的影响。研究结果表明:当C与Si3N4的摩尔比nc/3 4Si Nn=9/5时,合成出Sr2Si5N8:Eu2+单相荧光粉,添加适当过量的Sr2CO3可提高合成产物的N含量,且荧光粉的发光强度与其N含量呈现正相关关系。在450 nm蓝光激发下,受Eu2+的4f65d1→4f7跃迁作用,Sr2Si5N8:Eu2+荧光粉在550~700 nm波段范围产生非对称宽带发射。随着Eu2+掺杂浓度由1.5mol%增加到20mol%,荧光粉的发光强度先增强后减弱,达到2mol%时发生浓度淬灭现象;发射主峰由608 nm逐步红移至641 nm;CIE色坐标从(0.606,0.393)位移至(0.656,0.343),是一种可用于白光LED的优质红色荧光粉。

Sr2Si5N8：Eu2＋ phosphors were prepared by carbothermal reduction and nitridation method using Sr2CO3, Si3N4 and EuaO3 as raw materials, and C as main reduction agent. The influence of C, Sr2CO3 and Eu2＋ contents on phase composition and photoluminescence properties of as-prepared phosphors were investigated. The experimental results indicate that single-phase Sr2Si5N8：Eu2＋ is produced with molar ratio nc/nSi3N4=9/5. Excessive Sr2CO3 addi- tion contributes to the N contents of the as-prepared phosphors, which enhances emission intensity. There is an asymmetric wide emission peaks between 550 nm and 700 nm due to the electron transfer of Eu2＋ from 4f^6 5d^1 to 4f^7 excited by 450 nm. Increasing Eu2＋ concentration from 1.5mol% to 20mo1%, the luminescence intensity hits the maximum value at Eu2＋ concentration of 2mol% followed by continuous decline. Meanwhile the emission peak position is red-shifted from 608 nm to 641 nm, and the CIE chromaticity coordinates varies from （0.606, 0.393） to （0.656, 0.343）, which indicates that Sr2Si5N8：Eu2＋ is a promising phosphor for white LEDs.