Formation of Co2+-doped nanocrystals in La2O3–MgO–Al2O3–SiO2 glass-ceramics
Formation of Co2+-doped nanocrystals in La2O3–MgO–Al2O3–SiO2 glass-ceramics
复制标题
DOI：
10.1016/j.jnoncrysol.2010.11.070
复制
发表时间：
2011-06
影响因子：
3.5
通讯作者：
Li Chen;Chunlei Yu;Dongbing He;Lili Hu;Wei Chen
中科院分区：
文献类型：
--
作者：
Li Chen;Chunlei Yu;Dongbing He;Lili Hu;Wei Chen
对组成为5La 2 O3 -13.2MgO-28.8Al2O3- 46 SiO2 -4.5TiO2-2.5ZrO2-0.15CoO（LMAS）（wt.%）的玻璃进行热处理，制备了透明微晶玻璃。由不同升温速率下的差热曲线确定了LMAS玻璃的析晶活化能和Avrami参数。初始玻璃的拉曼光谱在~ 810 cm − 1和~ 900 cm − 1处的两个最强峰分别与[SiO 4]和[TiO 4]四面体的存在有关。经700°C/10 h +820°C/8h热处理后，[TiO 4]四面体的能带强度减弱，而在~ 800 cm − 1处出现了Ti-O键的强带。其它谱带为高硅酸盐网络和x（MgTi 2 O 5）·y（Al 2 TiO 5）多晶的特征谱带。这些变化反映了初始玻璃热处理后的相分离。微晶玻璃在580 nm处的强吸收峰归属于4A 2（4F）→ 4 T1（4P）跃迁，在1100- 1700 nm处的宽吸收峰归属于四面体配位的Co ~（2+）离子的4A 2（4F）→ 4 T1（4F）跃迁。微晶玻璃的两个宽发射带分别位于660 nm和800 ~ 1050 nm，分别对应于四面体配位的Co ~（2+）离子的4 T1（4P）→ 4A 2（4F）和4 T1（4P）→ 4 T2（4F）跃迁。吸收和发射特征清楚地表明，Co2+离子被纳入纳米晶体，并位于四面体网站。
Transparent glass-ceramics were synthesized by heat-treatment of glass with a composition of 5La2O3–13.2MgO–28.8Al2O3–46SiO2–4.5TiO2–2.5ZrO2–0.15CoO (LMAS) (wt.%). The activation energy of crystallization and the Avrami parameter for the LMAS glass were determined from the DTA curves at different heating rates. The most two intense bands of Raman spectrum of initial glass at ~810cm−1and ~900cm−1were connected with the presence of [SiO4] and [TiO4] tetrahedral, respectively. After heat-treated at 700°C/10h+820°C/8h, the intensity of the band for [TiO4] tetrahedral weakened, while an intensive band at ~800cm−1for the Ti–O bond appeared. Other bands were characteristics of high-silicate network and x(MgTi2O5)·y(Al2TiO5) polycrystals. The changes reflected phase separation after heat-treatment of the initial glass. The strong absorption band of glass-ceramics centered at 580nm can be assigned to4A2(4F)→4T1(4P) and the broad absorption band at 1100–1700nm to4A2(4F)→4T1(4F) transitions of tetrahedral coordinated Co2+ion. Two broad emission bands, one was around 660nm, the other was from 800nm to 1050nm, of glass-ceramics correspond to the4T1(4P)→4A2(4F) and4T1(4P)→4T2(4F) transitions of tetrahedral coordinated Co2+ions. The absorption and emission features clearly demonstrated that Co2+ions were incorporated into nanocrystals and located in tetrahedral sites.