6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
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Comprehensive Ab-Initio Study of Optoelectronic Properties of CsGeBr3 using Quantum Espresso and WanTiBEXOS.

8 Jul 2026, 16:20
1h 20m
Great Hall ( University of the Western Cape)

Great Hall

University of the Western Cape

Poster Presentation Track G - Theoretical and Computational Physics Poster Session 2

Speaker

Mr Kamogelo Sebolai (University of Johannesburg)

Description

Abstract
Perovskites exhibit a remarkable array of optoelectronic properties that are vital for advancing photovoltaic designs. In-depth investigations into the electronic and optical characteristics of all-inorganic CsGeBr3 have been conducted using density functional theory with the PBE exchange-correlation functional. To obtain precise and realistic bandgap values, the HSE06 hybrid functional was used, providing a comprehensive understanding of these promising materials. Various studies in the literature have done this. The electronic calculations convincingly demonstrate that CsGeBr3 is p-type semiconducting, revealing bandgap energies of 0.66 eV and 1.856 eV when using the PBE and HSE06 XC functionals, respectively. However, the optical properties of these materials have never been studied using a more accurate many-body Bethe–Salpeter equation (BSE), which accounts for excitonic effects, thereby providing in-depth optical analysis [1]. The optical properties of these materials are crucial for various applications, such as photovoltaic technology. In this study, we provide a comprehensive analysis of the optical and electronic properties of CsGeBr3 obtained using HSE06 functional coupled with BSE and Wannier interpolations [2], as implemented in Quantum-Espresso and WanTiBEXOS [3] simulation tools.
References
1. Yan, J., Jacobsen, K.W., and Thygesen, K.S., 2012. Optical properties of bulk semiconductors and graphene/boron nitride: The Bethe-Salpeter equation with derivative discontinuity-corrected density functional energies. Physical Review B—Condensed Matter and Materials Physics, 86(4), p.045208. https://journals.aps.org/prb/abstract/10.1103/PhysRevB.86.045208
2. Pela, R.R., Hsiao, C.L., Hultman, L., Birch, J., and Gueorguiev, G.K., 2024. Electronic and optical properties of core–shell InAlN nanorods: a comparative study via LDA, LDA-1/2, mBJ, HSE06, G 0 W 0 and BSE methods. Physical Chemistry Chemical Physics, 26(9), pp.7504-7514. https://pubs.rsc.org/en/content/articlehtml/2024/cp/d3cp05295h
3. Dias, A.C., Silveira, J.F., and Qu, F., 2023. WanTiBEXOS: A Wannier-based Tight Binding code for electronic band structure, excitonic, and optoelectronic properties of solids. Computer Physics Communications, 285, p.108636. https://www.sciencedirect.com/science/article/pii/S0010465522003551

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Author

Mr Kamogelo Sebolai (University of Johannesburg)

Co-author

Mr Bonginkosi Kheswa (University of Johannesburg)

Presentation materials

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