Electronic and Optical Performance of Heavy Metal Atom-Doped Glass–Ceramics: First-Principles Insights

When using industrial nickel slag to add fly ash and other raw materials to prepare glass–ceramics, due to the lack of smelting process, there are many kinds of metal components in its composition, which often contain heavy metal atoms such as Fe, Ni, Cu, Cr, Pb, and Co, which have a significant impact on the preparation and performance regulation of glass–ceramics. In this contribution, the effects of single heavy metal atom doping on the structural and optical characteristics of glass–ceramics main phase diopside (CaMgSi₂O₆) and auxiliary crystal phase calcium feldspar (CaAl₂Si₂O₈) are systematically investigated based on density functional theory (DFT). The binding energies demonstrate that all individual heavy metal atom doping is stabilized in both crystalline phases, and that the Fe atoms are most stabilized at the W1 position and the G1 position. Additionally, the introduction of atoms other than copper can improve the static dielectric constant and polarizability, and effectively enhance the absorption characteristics of the two phases in the energy range of 5-30 and 1.59-3.18 eV. The binding energies demonstrate that all individual heavy metal atom doping is stabilized in both phases, and that the Fe atoms are most stabilized at the W1 position and the G1 position. Additionally, the introduction of atoms other than Cu can improve the static dielectric constant and polarizability, and effectively enhance the absorption characteristics of the both phases in the visible light region. Combined with the variation of lattice constants and bond angles, as well as the binding energies, the Fe-Ni co-doped system is revealed to be stable. From the viewpoint of bond population, Fe-O₂₁ and Ni-O₁₇ interact with each other with covalent bonds in the diopside phase introduced by Fe and Ni atoms, while the co-doped calcium feldspar phase, in which both Fe-O₁₈ and Ni-O₅₀ bonds are inter-bonded with covalent bonds with lower covalent compositions. The optical properties of the two-phase co-doping also show that compared with the intrinsic system, the reflectivity of the two phases has different degrees of enhancement of 0.17 and 0.07 at the energy of 0 eV, respectively, while the Fe-Ni co-doping in the low-energy range improves the refractive index and extinction coefficient of the two phases, and improves the utilization of light by the material. For the 48-50 eV energy range and the visible light region, the energy loss of all systems is almost close to zero, indicating that the doping has little or no effect on the energy loss of the material in the two-energy range. These results imply significant guidance for the experimental preparation of glass–ceramics with exceptional optical properties.