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<p>This study employed computational and experimental methods to investigate the structural and electronic modifications of pure and Zn-doped cubic NiO. Density Functional Theory (DFT) simulations were conducted using the Quantum Espresso package with the Perdew–Burke–Ernzerhof (PBE) functional, incorporating a Hubbard U correction (DFT + U), U = 6&#xa0;eV) to describe the localised 3d orbitals of Ni accurately. A 2 × 2 × 2 supercell of NiO was constructed, and Zn dopants were introduced by substituting Ni atoms at 2%, 4%, and 6% concentrations. Convergence tests confirmed the suitability of the parameters: cutoff energy (50 Ry), k-point mesh (7 × 7 × 7), and equilibrium lattice constant (4.22&#xa0;Å). The band structures, density of states, and total energies were analysed using XCrySDen and VESTA visualisation tools. Experimentally, NiO nanoparticles were synthesised via precipitation followed by calcination at 350&#xa0;°C. The agreement between theoretical and experimental findings is clear. This reinforces the conclusion that the structural framework of NiO remains stable. X-ray photoelectron spectroscopy confirmed Ni<sup>2</sup>⁺ and O<sup>2</sup>⁻ states with surface hydroxyl groups aiding photocatalysis. DFT revealed bandgap narrowing from 2.89 to 2.74&#xa0;eV with Zn doping, linked to Fermi level shifts. Zn doping enhances NiO’s crystallinity, electronic structure, and optical properties, making it promising for photocatalytic and photovoltaic applications.</p>

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Band structure and optical characteristics of p-type NiO nanoparticles: insights from experiment and density functional theory (DFT)

  • 期刊论文

  • 发表日期：

    2025年10月29日

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  • Habtamu F. Etefa,
  • Fikadu T. Geldasa,
  • Francis B. Dejene

摘要

This study employed computational and experimental methods to investigate the structural and electronic modifications of pure and Zn-doped cubic NiO. Density Functional Theory (DFT) simulations were conducted using the Quantum Espresso package with the Perdew–Burke–Ernzerhof (PBE) functional, incorporating a Hubbard U correction (DFT + U), U = 6 eV) to describe the localised 3d orbitals of Ni accurately. A 2 × 2 × 2 supercell of NiO was constructed, and Zn dopants were introduced by substituting Ni atoms at 2%, 4%, and 6% concentrations. Convergence tests confirmed the suitability of the parameters: cutoff energy (50 Ry), k-point mesh (7 × 7 × 7), and equilibrium lattice constant (4.22 Å). The band structures, density of states, and total energies were analysed using XCrySDen and VESTA visualisation tools. Experimentally, NiO nanoparticles were synthesised via precipitation followed by calcination at 350 °C. The agreement between theoretical and experimental findings is clear. This reinforces the conclusion that the structural framework of NiO remains stable. X-ray photoelectron spectroscopy confirmed Ni2⁺ and O2⁻ states with surface hydroxyl groups aiding photocatalysis. DFT revealed bandgap narrowing from 2.89 to 2.74 eV with Zn doping, linked to Fermi level shifts. Zn doping enhances NiO’s crystallinity, electronic structure, and optical properties, making it promising for photocatalytic and photovoltaic applications.