In this study, both the generalized gradient approximation (GGA) and the GGA-1/2 methods were applied to examine the effect of oxygen vacancies on the electronic and optical properties of bulk monoclinic SrAl₂O₄. Since the monoclinic structure of SrAl₂O₄ has two non-equivalent sites for oxygen atoms, we can distinguish between two kinds of oxygen vacancies (V_O) in this material. These two kinds of V_O are labeled V_OI and V_OII. Our results show that although these two types of vacancies have comparable formation energies, their electronic and optical properties are significantly different. The formation energy of the V_O defect under Sr-rich, Al-rich, and O-poor conditions was less than 1 eV, which means that it could exist at high concentrations. Moreover, the results of density of states (DOS) analysis show that the oxygen vacancy had a deep donor defect featuring a fully occupied electronic level located deep in the band gap of SrAl₂O₄. This electronic level was located at $E_v+2.9\text{eV}$ in case of V_OI and at $E_v+3.3\text{eV}$ in case of V_OII. This defect induced a noticeable change in the spectrum of optical absorption of SrAl₂O₄. Our results show that the formation of oxygen vacancies can significantly enhance the UV absorption-related properties of this material.

在这项研究中，广义梯度近似 (GGA) 和 GGA-1/2 方法都被应用于检查氧空位对体单斜 SrAl ₂ O ₄的电子和光学性质的影响。由于 SrAl ₂ O ₄的单斜结构有两个氧原子的非等价位点，我们可以区分该材料中的两种氧空位 (V _O )。这两种V _O被标记为V _OI和V _OII。我们的结果表明，尽管这两种空位具有相当的形成能，但它们的电子和光学性质却有显着差异。V _O的形成能在富锶、富铝和贫氧条件下，缺陷小于 1 eV，这意味着它可以在高浓度下存在。此外，状态密度（DOS）分析的结果表明，氧空位具有深施主缺陷，其特征是完全占据的电子能级位于 SrAl ₂ O ₄的带隙深处。该电子水准仪位于${乙}_v+2.9\text{电动汽车}$在 V _OI和在的情况下${乙}_v+3.3\text{电动汽车}$在 V _{OII 的}情况下。该缺陷导致 SrAl ₂ O ₄的光吸收光谱发生显着变化。我们的结果表明，氧空位的形成可以显着增强这种材料的紫外线吸收相关性能。