摘要
由高温固相反应制得Sr0.955Al2Si2-xTixO8∶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230~400nm,由267nm、305nm、350nm和375nm4个峰拟合成,表观峰值位于351nm;随着Ti4+置换量的增加,半高宽(FWHM)从105nm减小到93nm。发射光谱位于380~600nm,表观峰值位于407nm,可由406nm和441nm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407nm红移至417nm;利用试样荧光光谱和VanUitert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。
A series of phosphors Sr0.955Al2Si2-xTixO8∶Eu^2＋（x =0 ~1.0） were prepared via solid-state reaction. The lattice positions and the luminescent mechanism of Eu^2＋in the host were discussed; the effects of Ti^4＋-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 Sr Al2Si2O8 lattice and substitutes for Si4 ＋. The lattice parameters（a, b, c, β） and unit cell volume of phosphors Sr0.955Al2Si2-xTixO8∶Eu^2＋（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 Eu^2＋is shown from 230~400nm 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 Sr Al2Si2O8∶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 Si^4＋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.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2014年第11期2530-2536,共7页
Chinese Journal of Inorganic Chemistry
基金
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
