| Abstrakt: |
Semiconductors, with their exceptional properties, have diverse applications across fields such as photovoltaics, sensing, and catalysis. In the present study, nickel pyro-vanadate compounds of high purity and homogeneity, with the chemical formula A2NiV2O7 (where A = Na, Ag), were synthesized under precisely controlled stoichiometric conditions. The primary focus is to investigate the optical and electronic properties of these compounds using a combination of experimental techniques and theoretical modeling. Initially, insights into the chemical structure and morphology of the synthesized semiconductor were obtained through powder x-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). A2NiV2O7 were found to be homogeneous, crystalline in nature, and isotypic with Κ2CoV2O7, exhibiting alternating layers of NiV2O7 and Ag/Na. Moreover, absorption spectra obtained from UV–Vis diffuse reflectance spectroscopy (DRS) showed direct optical bandgaps of 1.83 eV for Na2NiV2O7 and 1.92 eV for Ag2NiV2O7, affirming their semiconductor properties. Further characterization was performed using density functional theory (DFT) and hybrid-DFT methods. These advanced techniques provide detailed understanding of the electronic structure and properties across different sodium–silver ratios. The computed electronic structures demonstrate the separation of the conduction band (CB) and valence band (VB) around the Fermi level, with bandgaps of 0.44 eV and 1.76 eV for Na2NiV2O7, and 0.56 eV and 1.60 eV for Ag2NiV2O7, as determined using the Perdew–Burke–Ernzerhof (PBE) and DFT+U methods, respectively. This comprehensive investigation offers valuable insights into the optical and electronic dynamics of nickel pyro-vanadate compounds, establishing a foundation for their potential applications in various fields, including optoelectronics, photocatalysis, and energy storage. [ABSTRACT FROM AUTHOR] |
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