无机化学学报

白光LED用Sr_0.955Al₂Si_2-xTi_xO₈:Eu²⁺荧光粉的晶体结构和光谱特性

Crystal Structure and Luminescent Property of Sr_0.955Al₂Si_2-xTi_xO₈:Eu²⁺ Phosphors for White LED

作者	单位	E-mail
王飞	安徽三联学院实验中心, 合肥 230601
田一光	温州大学化学与材料工程学院, 温州 325035	gytian@wzu.edu.cn
张乔	温州大学化学与材料工程学院, 温州 325035

摘要: 由高温固相反应制得Sr_0.955Al₂Si_2-xTi_xO₈:Eu²⁺(x=0~1.0)系列试样,研究了Ti⁴⁺置换Si⁴⁺对其晶体结构和光谱特性的影响。Ti⁴⁺以类质同相替代Si⁴⁺进入基质晶格中,形成了连续固溶体,其晶胞参数a,b,c,β和晶胞体积V随Ti⁴⁺置换量呈线性递增。Ti⁴⁺置换Si⁴⁺对晶胞参数c的影响显著,b其次,a最小。荧光激发谱为宽带,位于230~400 nm,由267 nm、305 nm、350 nm和375 nm 4个峰拟合成,表观峰值位于351 nm;随着Ti⁴⁺置换量的增加,半高宽(FWHM)从105 nm减小到93 nm。发射光谱位于380~600 nm,表观峰值位于407 nm,可由406 nm和441 nm两峰拟合而成并且随Ti⁴⁺置换量增加线性红移,Ti⁴⁺进入晶格对长波长发射中心影响较少;Ti⁴⁺置换量为1.0时,表观发射峰位从407 nm红移至417 nm;利用试样荧光光谱和Van Uitert经验公式,得出SrAl₂Si₂O₈:Eu²⁺中Sr²⁺的配位数为9。随着Ti⁴⁺置换量Si⁴⁺进入基质晶格,造成Eu-O距离变小,使得Eu²⁺所处的晶体场强度增强,发光中心Eu²⁺的5d能级分裂增大,造成Eu²⁺最低发射能级重心下移,两拟合谱峰峰位均呈线性红移。

关键词: 荧光粉钛置换晶体结构光谱特性 SrAl₂Si₂O₈:Eu²⁺

基金项目: 国家自然科学基金(No.20771086),安徽三联学院科研项目(No.2013Z001)资助项目。

Abstract: A series of phosphors Sr_0.955Al₂Si_2-xTi_xO₈:Eu²⁺ (x=0~1.0) were prepared via solid-state reaction. The lattice positions and the luminescent mechanism of Eu²⁺ in the host were discussed; the effects of Ti⁴⁺-substitution on the host lattice and spectral property were also investigated. The results show that continuous solid solutions are formed in the whole range for x=0~1.0 while Ti⁴⁺ enterers SrAl₂Si₂O₈ lattice and substitutes for Si⁴⁺. The lattice parameters (a, b, c, β) and unit cell volume of phosphors Sr_0.955Al₂Si_2-xTi_xO₈:Eu²⁺ (x=0~1.0) increase linearly as Ti⁴⁺ content increases in the phosphors. When Ti⁴⁺ substitutes for Si⁴⁺ the most obvious change is in cell parameter c, the second is b, and the minimum is a. A broad excitation spectrum of Eu²⁺ is shown from 230~400 nm and the apparent peak is at 351 nm, which can be deconvoluted to 267, 305, 350 and 375 nm excitation bands. The full width at half maximum (FWHM) for the apparent excitation peak narrows from 105 nm to 93 nm. The broad and asymmetric emission spectrum are among 380 nm and 600 nm and apparent peak is at 407 nm, which can be deconvoluted to two peaks of 406 nm and 441 nm. The two peaks are red shifted with the increase of the amount of Ti⁴⁺ substitution. The apparent emission peak is red shifted from 407 to 417 nm. The coordination number of Sr²⁺ is 9 in SrAl₂Si₂O₈:Eu²⁺, which has been confirmed by the experimental results and empirical formula of Van Uitert. The distance of Eu and O becomes shortened due to the replacement of Si⁴⁺ by Ti⁴⁺. The crystal field of the emitting center Eu²⁺ location is enhanced, the splitting of 5d orbital levels is increased and the lowest emission level is shifted to lower position, two fitted peaks are red shifted.

Keywords: phosphor Ti⁴⁺-substitution crystal structure luminescent propertys SrAl₂Si₂O₈:Eu²⁺

投稿时间：2014-04-23 修订日期：2014-06-23

摘要点击次数: 1684

全文下载次数: 2378

王飞,田一光,张乔.白光LED用Sr_0.955Al₂Si_2-xTi_xO₈:Eu²⁺荧光粉的晶体结构和光谱特性[J].无机化学学报,2014,30(11):2530-2536.

查看全文查看/发表评论下载PDF阅读器

Support information: