(1. 廣州有色金屬研究院 稀有金屬科技有限公司，廣州 510650；
2. 廣州有色金屬研究院 稀有金屬研究所，廣州 510650)
摘 要: 利用基于密度泛函理論框架下的平面波贗勢法和廣義梯度近似，計算分析Ca0.97Sr1.97AlO4F晶體結(jié)構(gòu)的能帶結(jié)構(gòu)、態(tài)密度及電子密度差；采用價鍵理論研究Ca0.97Sr1.97AlO4F的共價性，并探討Ce3+在Ca0.97Sr1.97 AlO4F體系中的激發(fā)、發(fā)射光譜及熒光壽命。結(jié)果表明，價帶主要由O、F原子的2p軌道構(gòu)成，導(dǎo)帶則主要由Al原子的2p軌道和Sr(1)和Sr(2)原子的4d軌道構(gòu)成，能帶間隙為6.235 eV；在Sr3AlO4F摻入Ca2+離子后，Ca/Sr(2)—O 和Ca/Sr(2)—F共價性明顯增強(qiáng)；Ce3+離子在十配位的Sr(1)O8F2和八配位的Sr(2)O6F2格位中的發(fā)射主峰分別約為472和550 nm，熒光壽命(τ1/e)分別為38.35和49.45 ns。
關(guān)鍵字: 熒光材料；稀土；電子結(jié)構(gòu)；發(fā)光性能；第一性原理
（1. Science and Technology Company of Rare Metals, Guangzhou Research Institute of Non-ferrous Metals,
Guangzhou 510650, China;
2. Institute of Rare Metals, Guangzhou Research Institute of Non-ferrous Metals, Guangzhou 510650, China）
Abstract:The energy band structure, density of states and electronic density difference of Ca0.97Sr1.97AlO4F were calculated using the planewave pseudopotential method based on density function theory and generalized gradient approximation. The covalence of Ca0.97Sr1.97AlO4F was studied with valence bond theory. The excitation and emission spectra and fluorescent lifetimes of Ca0.97Sr1.97AlO4F doped with Ce3+ were investigated. The results show that the valence band is mostly composed of O and F 2p orbital, while the conduction band is mainly constructed from the Sr(1), Sr(2) atoms 4d and Al atoms 2p orbits, the energy gap is 6.235 eV. The bond covalence of Ca/Sr(2)—O and Ca/Sr(2)—F is strengthened with increasing the concentration of Ca2+ in Sr3AlO4F host. The emission peaks and fluorescence lifetime (τ1/e) of Ce3+ in both two sites of 10-fold oxy-fluoride coordination (Sr(1)O8F2) and 8-fold coordination (SrO6F2) are about 472 nm, 38.35 ns and 550 nm, 49.45 ns, respectively.
Key words: fluorescence material; electronic structure; rare earth; luminescence; first principles
