Semiempirical SCF/CI Modeling of Ce + 3 4f and 5d Energy Levels in Oxygen–Doped SrS:Ce
Semiempirical SCF/CI Modeling of Ce + 3 4f and 5d Energy Levels in Oxygen–Doped SrS:Ce
复制标题
氧掺杂 SrS:Ce 中 Ce + 3 4f 和 5d 能级的半经验 SCF/CI 建模
DOI：
10.1149/1.1393273
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发表时间：
2000
影响因子：
3.9
通讯作者：
P. Holloway
中科院分区：
文献类型：
--
作者：
Ted A. O’Brien;M. Zerner;P. Rack;P. Holloway
在Ca0.5Sr0.5Ga2 S 4：Ce荧光粉中加入氧气可以使发光效率提高近一倍，并使Ce+34f-5d发射光谱向深蓝方向移动。为了了解氧对Ce+34f-5d发射光谱的影响，我们用自洽场组态相互作用(SCF/CI)模型计算了氧掺杂的SRS：Ce的电子光谱。通过用氧取代适当数量的硫配体，SCF/CI模型预测了两个不同的Ce-氧键距离的蓝移，这与观察到的Ca0.5Sr0.5Ga2 S 4：Ce的730 cm-1蓝移非常一致。对原子轨道电子布居的分析表明，掺入较小的O-2离子后，Ce-5d轨道的共价性发生了变化，导致了观察到的蓝移。计算的振子强度表明，观察到的由氧的添加引起的电致发光效率的增加并不是跃迁强度变化的结果。
Addition of oxygen in the Ca 0.5 Sr 0.5 Ga 2 S 4 :Ce phosphor has been found to nearly double the efficiency and shift the Ce +3 4f-5d emission spectrum to a deeper blue. To understand the effects that oxygen has on the Ce +3 4f-5d emission spectrum, we used a self-consistent-field configuration interaction (SCF/CI) model to calculate the electronic spectrum of oxygen-doped SrS:Ce. By replacing the appropriate number of sulfur ligands with oxygen ligands, the SCF/CI model predicted a blue shift for two different cerium-oxygen bond distances that is in very good agreement with the 730 cm -1 blue shift observed for Ca 0.5 Sr 0.5 Ga 2 S 4 :Ce. An analysis of atomic orbital electron populations indicates that changes in covalency of the Ce 5d orbitals upon incorporation of smaller O -2 ions causes the observed blue shift. Calculated oscillator strengths indicate that the observed increase in electroluminescent efficiency caused by addition of oxygen is not a result of changes in transition intensities.