Geldasa Fikadu Takele, Dejene Francis Birhanu
Department of Chemical and Physical Sciences, Walter Sisulu University, Private Bag X1, Mthatha 5117, South Africa.
Nanomaterials (Basel). 2025 May 5;15(9):694. doi: 10.3390/nano15090694.
In this work, a density functional theory (DFT) with Hubbard correction (U) approaches implemented through the Quantum ESPRESSO code is utilized to investigate the effects of fluorine (F) doping on the structural, electronic, and optical properties of rutile TiO. Rutile TiO is a promising material for renewable energy production and environmental remediation, but its wide bandgap limits its application to the UV spectrum, which is narrow and expensive. To extend the absorption edge of TiO into the visible light range, different concentrations of F were substituted at oxygen atom sites. The structural analysis reveals that the lattice constants and bond lengths of TiO increased with F concentrations. Ab initio molecular dynamics simulations (AIMD) at 1000 K confirm that both pristine and F-doped rutile TiO maintains structural integrity, indicating excellent thermal stability essential for high-temperature photocatalytic applications. Band structure calculations show that pure rutile TiO has a bandgap of 3.0 eV, which increases as the F concentration rises, with the 0.25 F-doped structures exhibiting an even larger bandgap, preventing it from responding to visible light. The absorption edge of doped TiO shifts towards the visible region, as shown by the imaginary part of the dielectric function. This research provides valuable insights for experimentalists, helping them understand how varying F concentrations influence the properties of rutile TiO for photocatalytic applications.
在这项工作中，利用通过量子 espresso 代码实现的带有哈伯德修正（U）的密度泛函理论（DFT）来研究氟（F）掺杂对金红石型 TiO₂ 的结构、电子和光学性质的影响。金红石型 TiO₂ 是一种用于可再生能源生产和环境修复的有前景的材料，但其宽带隙限制了其在紫外光谱范围内的应用，而紫外光谱范围窄且成本高。为了将 TiO₂ 的吸收边扩展到可见光范围，在氧原子位置取代了不同浓度的 F。结构分析表明，TiO₂ 的晶格常数和键长随 F 浓度增加。在 1000 K 下的从头算分子动力学模拟（AIMD）证实，原始的和 F 掺杂的金红石型 TiO₂ 都保持结构完整性，表明对于高温光催化应用至关重要的优异热稳定性。能带结构计算表明，纯金红石型 TiO₂ 的带隙为 3.0 eV，随着 F 浓度的增加而增大，0.25 F 掺杂的结构表现出更大的带隙，使其无法响应可见光。如介电函数的虚部所示，掺杂 TiO₂ 的吸收边向可见光区域移动。这项研究为实验人员提供了有价值的见解，帮助他们了解不同 F 浓度如何影响金红石型 TiO₂ 在光催化应用中的性质。
