研究目的
To study different defects in anatase TiO2 to improve its utilization for photoelectrochemical applications, specifically through ab initio calculations on Yb and N doping to elucidate defect interactions, band gap reduction, and synergistic effects.
研究成果
Yb doping narrows the band gap of TiO2 and shifts absorption to visible light, with 2.08% Yb concentration optimal. Yb and N codoping further reduces band gap and enhances visible-light absorption, with charge compensation stabilizing the system and avoiding isolated states. The Ti16?xYbxNyO31?y, x=2, y=1 model is identified as most suitable for photoelectrochemical applications, explaining experimental synergistic effects.
研究不足
GGA-based calculations underestimate band gaps due to DFT limitations; scissor approximation used but may not fully correct. Study is computational and theoretical, lacking experimental validation; focuses on specific dopants and concentrations.
1：Experimental Design and Method Selection:
Density functional theory (DFT) based calculations using the CASTEP code with Perdew–Burke–Ernzerhof (PBE) generalized gradient approximation (GGA) for exchange-correlation potential. Scissor approximation used to update optical response. BFGS algorithm for system relaxation.
2：Sample Selection and Data Sources:
Anatase TiO2 supercell models (2x2x1 repetition with 16 Ti and 32 O atoms) with induced defects including Yb and N doping at various concentrations and oxygen vacancies, as detailed in Table
3：List of Experimental Equipment and Materials:
Computational software (CASTEP code), no physical equipment specified.
4：Experimental Procedures and Operational Workflow:
Models optimized with maximum displacement of 0.001 ?, maximum force of 0.01 eV/?, and maximum stress of 0.1 GPa. Band structures, partial density of states, and optical properties calculated.
5：001 ?, maximum force of 01 eV/?, and maximum stress of 1 GPa. Band structures, partial density of states, and optical properties calculated.
Data Analysis Methods:
5. Data Analysis Methods: Analysis of band structures, density of states, and absorption spectra to evaluate electronic and optical properties.
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