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ANDREAS LYRAS

Associate Professor

FACULTY, DEPARTMENT OF PHYSICS and ASTRONOMY

كلية العلوم
Department Of Physics & Astronomy
publication
Journal Article
2020

Computational Investigation of the Folded and Unfolded Band Structure and Optical Properties of CsPb(I1-xBx)3 Perovskites

Aldwayyan, H. G. Ghaitan, Z. A. Alhamed, A. Lyras, S. H. M. Qaid, A. S. . 2020

The structural, electronic, and optical properties of inorganic CsPb(I1−xBrx)3 compounds were investigated using the full-potential linear augmented-plane wave (FP-LAPW) scheme with a generalized gradient approximation (GGA). Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA) and modified Becke–Johnson GGA (mBJ-GGA) potentials were used to study the electronic and optical properties. The band gaps calculated using the mBJ-GGA method gave the best agreement with experimentally reported values. CsPb(I1−xBrx)3 compounds were wide and direct band gap semiconductors, with a band gap located at the M point. The spectral weight (SW) approach was used to unfold the band structure. By substituting iodide with bromide, an increase in the band gap energy (Eg) values of 0.30 and 0.55 eV, using PBE-GGA and mBJ-GGA potentials, respectively, was observed, whereas the optical property parameters, which were also investigated, demonstrated the reverse effect. The high absorption spectra in the ultraviolet−visible energy range demonstrated that CsPb(I1−xBrx)3 perovskite could be used in optical and optoelectronic devices by partly replacing iodide with bromide.

Publication Work Type
Research article
Volume Number
10
Issue Number
5
Magazine \ Newspaper
Crystals
Pages
342 to 354
more of publication
publications

We present the theoretical framework and the approximations needed to numerically simulate the response of alkali metal atoms under multi-photon excitation.

by N Merlemis, A Lyras, G Papademetriou, D Pentaris, T Efthimiopoulos
2022
Published in:
SPRINGER
publications

We report theoretical results for the transition amplitudes of two-photon transitions induced in a one-active-electron atomic system by a LG10 beam. We identify the excitation pathways for…

by A Al-Khateeb, A Lyras, V E Lembessis, O M Aldossary
2022
Published in:
ELSEVIER
publications

We investigate the quantized states of a two-level Rb atom that is trapped by the optical dipole potential when the atom interacts with a helical optical tube light field.

by Vassilis E. Lembessis, Andreas Lyras, and Omar M. Aldossary
2022
Published in:
OPTICA