【摘要】 利用基于密度泛函理论框架下的平面波赝势法和广义梯度近似,计算分析Ca_0.97Sr_1.97AlO₄F晶体结构的Ca_0.97Sr_1.97AlO₄F能带结构、态密度及电子密度差;采用价键理论研究Ca_0.97Sr_1.97AlO₄F的共价性,并探讨Ce³⁺在Ca_0.97Sr_1.97AlO₄F体系中的激发、发射光谱及荧光寿命。结果表明,价带主要由O、F原子的2p轨道构成,导带则主要由Al原子的2p轨道和Sr（1）和Sn（2）原子的4d轨道构成,能带间隙为6.235 eV;在Sr₃A1O₄F掺入Ca²⁺离子后,Ca/Sr（2）—O和Ca/Sr（2）——F共价性明显增强;Ce³⁺离子在十配位的Sr（1）O₈F₂和八配位的Sr（2）O₆F₂格位中的发射主峰分别约为472和550 nm,荧光寿命(τ_1/e)分别为38.35和49.45 ns。更多还原

【Abstract】 The energy band structure,density of states and electronic density difference of Ca_0.97Sr_1.97AlO₄F were calculated using the planewave pseudopotential method based on density function theory and generalized gradient approximation.The covalence of Ca_0.97Sr_1.97AlO₄F was studied with valence bond theory.The excitation and emission spectra and fluorescent lifetimes of Ca_0.97Sr_1.97AlO₄F 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(τ_1/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.更多还原