First-principles study of the structural, electronic, mechanical, and optical properties of Zintl-phase K2AgBi ternary compound for optoelectronic applications Open Access

Publication Type

Journal Article

Name of Author

• John Peter Kachira, Monolith Research Group, Department of Physics, Faculty of Science and Technology, University of Nairobi, Kenya
• Robinson Musembi, Monolith Research Group, Department of Physics, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
• Francis Nyongesa, Monolith Research Group, Department of Physics, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
• Mwende Mbilo, Monolith Research Group, Department of Physics, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
• Martin Nyamunga, Monolith Research Group, Department of Physics, Faculty of Science and Technology, University of Nairobi, Kenya
• Ibrahim Musanyi, Monolith Research Group, Department of Physics, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya

Publication Date (Issue Year)

2025

Journal Name

AIP Advances

Abstract

A comprehensive first-principles study was conducted to explore the structural, electronic, mechanical, thermophysical, and optical properties of a Zintl-phase K₂AgBi ternary semiconductor compound using density functional theory. The calculations employed the local density approximation (LDA), generalized gradient approximation (GGA), and meta-GGA methods. The computed negative formation energies proved the thermodynamic stability of the K₂AgBi ternary compound. The computed bandgap values were 0.6732 and 0.7848 eV for the LDA and GGA, respectively. More refined bandgap estimates were obtained using meta-GGA methods, with the Tran–Blaha modified Becke–Johnson potential yielding 0.9346 eV and the revised strongly constrained and appropriately normed functional yielding 0.9778 eV. The projected density of states study revealed that the Ag3d, Bi2p, and K1s orbitals dominate the formation of the valence band, whereas the K4p, Ag2p, and K2s orbitals contribute significantly to the formation of the conduction band. Analysis of the mechanical properties confirmed that K₂AgBi is mechanically stable and ductile. Optical analysis revealed strong absorption in the 1.0–15 eV energy range, high refractive index in the low-energy region, and distinct plasmonic response, suggesting potential applications in photovoltaics, optoelectronics, and plasmonic-based technologies.

Keywords

First-principles study, structural, electronic, mechanical, optical properties, Zintl-phase, K2AgBi ternary compound, optoelectronic

Grantee Name(s)

Robinson Musembi

Project Title

Self-cleaning solar module for enhanced electrical output

Type of Grant

Research Award

Thematic Area

Energy including Renewables

Recommended Citation

Kachira, J. P., Musembi, R., Nyongesa, F., Mbilo, M., Nyamunga, M., & Musanyi, I. (2025). First-principles study of the structural, electronic, mechanical, and optical properties of Zintl-phase K2AgBi ternary compound for optoelectronic applications Open Access. AIP Advances https://doi.org/10.1063/5.0267495