Quantum-Engineered LiXO2 (X = Co, Ni) Delafossites: First-Principles Design of Structural, Optoelectronic, Thermodynamic, and Magnetic Frameworks for Next-Generation Energy Harvesting

초록

The structural, optoelectronic, and magnetic properties of LiXO2 (X = Co, Ni) delafossite compounds are evaluated using first-principles based DFT calculations to investigate their potential applications in optoelectronic and spintronic devices. Based on calculated ground state energies, LiNiO2 is a more stable compound, compared to LiCoO2. The indirect energy band gap for LiCoO2 and LiNiO2 are 4.95 and 5.02 eV, respectively, in spin (up arrow) direction. However, in spin (down arrow) direction, the values of energy band gaps are 2.05 and 1.82 eV for LiCoO2 and LiNiO2, respectively. The total magnetic moment mtot$m_{tot}$ values for LiCoO2 are higher, compared to LiNiO2. Unfilled d-orbitals (Co -3d7$-3d{<}^{>}7$ and Ni -3d8$-3d{<}^{>}8$) in transition metals are responsible for highest portion of mtot$m_{tot}$. Based on n(omega)$n(\omega )$ values of LiXO2 (X = Co, Ni) delafossite compounds, we can infer that these compounds are optically active materials, as their values are between 1.0 and 2.0. The epsilon 2(omega)${\epsilon }_2(\omega )$ spectra demonstrate that LiXO2 (X = Co, Ni) compounds are auspicious entrants for solar cell appliances working in visible and UV regions. It can be inferred from the computed results that these crystalline materials are promising candidates for prospective photovoltaic appliances.

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