(Sr_(1-x)Me_(x))_(1.95)SiO_(4)0.05Eu荧光粉光谱调控机制  

Luminescent Spectra Regulation Mechanism of(Sr_(1-x)Me_(x))_(1.95)SiO_(4)0.05Eu Phosphor Powders

作　　者：汪雨 罗岚[1] 郭锐[1] 张澎鹏 高明远 Wang Yu;Luo Lan;Guo Rui;Zhang Pengpeng;Gao Mingyuan(Key Laboratory of Lightweight and High Strength Structural Materials of Jiangxi Province,School of Materials Science and Engineering,Nanchang University,Nanchang 330001,China)

机构地区：[1]南昌大学材料科学与工程学院江西省轻质高强结构材料重点实验室,江西南昌330001

出　　处：《稀有金属材料与工程》2021年第1期153-159,共7页Rare Metal Materials and Engineering

基　　金：国家重点研发计划(2016YFB0701203,2016YFB0701201,2017YFB1103701);国家自然科学基金(11564025,51671101);江西省教育厅重点计划(GJJ150010);南昌大学双创及科研训练项目基金(CX2019052,20190402352)。

摘　　要：采用高温固相法制备(Sr_(1-x)Me_(x))_(1.95)SiO_(4)0.05Eu系列荧光粉,研究不同大(Ba^(2+))、小(Mg^(2+))半径离子基体固溶对其物相、发光中心配位结构、Eu离子价态的影响,探究其光谱精细调控机制。结果表明,Sr_(2)SiO_(4)粉末中随着温度升高α-Sr_(2)SiO_(4)相增加、β-Sr_(2)SiO_(4)相减少;Mg^(2+)(小半径离子)掺杂可以提高α-Sr_(2)SiO_(4)相稳定性,但容易出现Mg2SiO4,粉末中始终为混合物;Ba^(2+)(大半径离子)掺杂可以提高α-Sr_(2)SiO_(4)相稳定性,粉体发生β-Sr_(2)SiO_(4)+α-Sr_(2)SiO_(4)→α-Sr_(2)SiO_(4)→α-Sr_(2)SiO_(4)+Ba_(2)SiO_(4)→Ba_(2)SiO_(4)转变,且随β-Sr_(2)SiO_(4)、α-Sr_(2)SiO_(4)、Ba_(2)SiO_(4)的顺序其Si-O-Me(Ⅰ)-O-Me(Ⅱ)链逐渐由锯齿状变为平直状、Me-O键长拉长。Eu离子激活的β-Sr_(2)SiO_(4)、α-Sr_(2)SiO_(4)、Ba_(2)SiO_(4)粉体在254 nm(365 nm)激发下有明亮的绿色荧光发射(且依序强度增强、光谱整体略微蓝移)和微弱的红光发射;当光学基体发生β-Sr_(2)SiO_(4)→α-Sr_(2)SiO_(4)转变时,发射光谱中Eu^(2+)(Ⅰ)蓝移Eu^(2+)(Ⅱ)红移(Si-O-Sr(Ⅰ)-O-Sr(Ⅱ)由锯齿形链成为平链,且Sr-O键拉长),发生α-Sr_(2)SiO_(4)→Ba_(2)SiO_(4)转变则Eu^(2+)(Ⅰ)、Eu^(2+)(Ⅱ)均发生蓝移(仅发生Me-O键拉长);3种粉体热释光谱中均存在Eu^(2+)和Eu^(3+)缺陷能级,且Eu^(2+)缺陷浓度更高。Eu 3d的精细X射线光电子谱表明随着β-Sr_(2)SiO_(4)→α-Sr_(2)SiO_(4)→Ba_(2)SiO_(4)转变其Eu离子以Eu^(2+)存在的可能性增大,对应的电子顺磁共振也证实这一结果。由此可见,采用Ba^(2+)离子固溶掺杂Sr_(2)SiO_(4),可在一定浓度范围得到单相粉末,实现光学基体的β-Sr_(2)SiO_(4)→α-Sr_(2)SiO_(4)→Ba_(2)SiO_(4)相变,调控Si-O-Me(Ⅰ)-O-Me(Ⅱ)链型及Me-O键长,调节Eu离子价态和配位场,进而实现其绿色荧光粉荧光强度、发射波段精确调控。The(Sr_(1-x)Me_(x))_(1.95)SiO_(4)0.05Eu phosphor powders were synthesized by high temperature solid-state reaction.The effects of solid solution of large(Ba^(2+))and small(Mg^(2+))ions on the phase,the coordination crystal structure and the valence state of Eu ions were investigated firstly,and then regulation mechanism in the photoluminescence spectra was discussed.Results show that with increasing the temperature,α-Sr_(2)SiO_(4)increases andβ-Sr_(2)SiO_(4)phase decreases in Sr_(2)SiO_(4)powder.Mg^(2+)ion dopant can increase the stability ofα-Sr_(2)SiO_(4)phase.Ba^(2+)ion dopant can lead the phase transformation ofβ-Sr_(2)SiO_(4)+α-Sr_(2)SiO_(4)→α-Sr_(2)SiO_(4)→α-Sr_(2)SiO_(4)+Ba_(2)SiO_(4)→Ba_(2)SiO_(4),in the sequence asβ-Sr_(2)SiO_(4),α-Sr_(2)SiO_(4),Ba_(2)SiO_(4),the Si–O–Me(Ⅰ)–O–Me(Ⅱ)chain changes from zigzag to straight chain,and the Me-O length increases.Under the excitation of 254 nm(365 nm),Eu-activatedβ-Sr_(2)SiO_(4),α-Sr_(2)SiO_(4),and Ba_(2)SiO_(4)powders have bright green fluorescence emission(in the same sequence,the intensity increases and the overall spectrum is slightly blue shifted)and weak red light emission.Forβ-Sr_(2)SiO_(4)→α-Sr_(2)SiO_(4),Eu(Ⅰ)emission peak is blue-shifted while Eu(Ⅱ)is red-shifted(Si–O–Me(Ⅰ)–O–Me(Ⅱ)chain changes from zigzag to straight,Me-O bond length increases).Forα-Sr_(2)SiO_(4)→Ba_(2)SiO_(4),both emission peaks of Eu(Ⅰ)and Eu(Ⅱ)are blue-shifted(Me-O bond length increases).In the thermoluminescence spectra,Eu^(2+)and Eu^(3+)defect energy levels exit in all these phosphors,and Eu^(2+)concentration looks larger.The high resolution XPS spectrum of Eu3d indicates that there are higher possibilities for Eu^(2+)in the sequence asβ-Sr_(2)SiO_(4)→α-Sr_(2)SiO_(4)→Ba_(2)SiO_(4),which is confirmed by Eu ion ESR spectra.By Ba^(2+)ions solid solution into Sr_(2)SiO_(4)crystal,phase transformation as ofβ-Sr_(2)SiO_(4)→α-Sr_(2)SiO_(4)→Ba_(2)SiO_(4)occurs,achieving the adjustments in Si–O–Me(Ⅰ)–O–Me(Ⅱ)chai

关 键 词：晶体结构 荧光光谱 X射线光电子谱 电子顺磁共振 

分 类 号：TQ422.2[化学工程]