Examinando por Autor "Bouachrine, Mohammed"

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    DFT study of polythiophene energy band gap and substitution effects
    (Hindawi Publishing Corporation, 2015) Bouzzine, Si. Mohamed; Salgado-Morán, Guillermo; Hamidi, Mohamed; Bouachrine, Mohammed; Pacheco, Alison Geraldo; Glossman-Mitnik, Daniel
    Polythiophene (PTh) and its derivatives are polymer-based materials with a π-conjugation framework. PTh is a useful photoelectric material and can be used in organic semiconductor devices, such as PLED, OLED, and solar cells. Their properties are based on molecular structure; the derivatives contain different substitutes in the 3 and 5 positions, such as electron-donating or electron-withdrawing groups. All molecular geometries were optimized at B3LYP/6-31G(d,p) level of theory. The energy gap (Egap) between the HOMO and LUMO levels is related to the π-conjugation in the PTh polymer backbone. In this study, the DFT calculations were performed for the nonsubstituted and 3,5-substituted variants to investigate the stability geometries and electrical properties. The theoretical calculations show that the substituted forms are stable, have low Egap, and are in good agreement with the experimental observations. © 2015 Si. Mohamed Bouzzine et al.
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    Tuning the electronic, photophysical and charge transfer properties of small D-A molecules based on Thienopyrazine-terthienyls by changing the donor fragment: A DFT study
    (Sociedad Chilena de Quimica, 2017) Aicha, Youssef Ait; Bouzzine, Si Mohamed; Zair, Touriya; Bouachrine, Mohammed; Hamidi, Mohamed; Salgado-Morán, Guillermo; Tagle, R. Ramirez; Mendoza-Huizar, Luis H.
    Four acceptor-donor organic conjugated molecules based on thieno[3,4-b]pyrazine-terthienyls were analyzed in order to explore the effect of the donor substituent on their molecular structures, electronic and optical properties. Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD/DFT) calculations were carried out employing the B3LYP hybrid functional in combination with the 6-31G(d,p) basis set. The results suggests that the addition of electron-donating substituents to the conjugated molecules can diminish their energy gap value, which is beneficial to the photon harvesting. The lowest-lying absorption spectra of compounds substituted with electron donor groups exhibited a red-shift and a high oscillation factor compared with the unsubstituted molecule. Additionally, the ionization potential (IP), electron affinity (EA), reorganization energy (λ) and open-circuit voltage (Voc) of the molecules were evaluated. According to these values, the molecules show good photovoltaic properties, and efficient charge transfer for hole and electron and balanced charges.