Publications Internationales

Permanent URI for this collectionhttps://dspace.univ-boumerdes.dz/handle/123456789/13

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Author: search.filters.author.Guemmour, HindHas files: No

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    Impact of π-Extended Auxiliary Acceptors on the Photovoltaic Performance of Dithienosilole-Based Sensitizers. A DFT/TDDFT Investigation
    (Springer, 2025) Kheffache, Djaffar; Goudjil, Manal; Guemmour, Hind; Rekis, Maammar
    A novel series of dithienosilole-based D-A-π-A sensitizers was designed for potential application in organic photovoltaic devices by modifying the auxiliary acceptor in the reference dye B-87. Several π-extended electron-withdrawing acceptors, such as benzobisthiadiazole (BBT), thiadiazolobenzotriazole (TBT), thiadiazoloquinoxaline (TQX), pyrazinoquinoxaline (PQX), naphthothiadiazole (NTD), and naphthotriazole (NTA), were investigated for their impact on photovoltaic performance. Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) calculations were employed to analyze optical and photophysical properties, considering key photovoltaic parameters such as light harvesting efficiency (LHE), injection driving force (), free energy of regeneration (), and open circuit voltage (VOC). Additional analyses were conducted on the geometries, electronic structures, and absorption spectra of all dyes adsorbed onto the (TiO2)9 anatase cluster. While π-extended auxiliary acceptors generally lowers the HOMO-LUMO gap and broadens absorption, it also reduces intramolecular charge transfer and increase electron trapping. Notably, BBT, TBT, TQX, PQX, and NTD negatively affect charge transfer, leading to weakened photovoltaic performance, particularly a reduced Voc. The designed dye, featuring the π-extended acceptor naphthotriazole (NTA), demonstrates strong potential for DSSC applications due to its enhanced optoelectronic properties and efficient intramolecular charge transfer
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    Theoretical investigation of the self-association of antitumor drug imexon
    (Springer, 2020) Guemmour, Hind; Kheffache, Djaffar
    The dimers resulting from self-association of oxo-imino, oxo-amino, and hydroxyl-imino tautomers of imexon, that present two hydrogen bonds, were fully optimized with the density functional methods B3LYP, M06-2X in conjunction with 6-311++G(d,p) basis set. Additionally, second-order Møller-Plesset (MP2) level in combination with 6-311++G(d,p) basis set was employed for comparison purpose. The thermodynamic stability of the self assembled structures in gaseous phase has been obtained according to the analyses of total electronic energies and hydrogen bonding interactions. The bulk water environment has been simulated using the universal solvation model based on solute electron density (SMD). Stability and structure of homochiral and heterochiral imexon dimers resulting from the three imexon tautomers have been carried out to investigate the chiral discrimination. The imexon dimer with heterochiral configuration resulting from self-assembling oxo-amino tautomer is found to be thermodynamically most stable in both gas and aqueous phases. The interaction energies for these self assembled structures were further evaluated with the basis set superposition error corrections. The so-called seven-point interaction energy which includes corrections for BSSE and deformation was calculated. The intermolecular interactions of the selected dimers have been analyzed by calculation of electron density (ρ) and Laplacian (∇2ρ) at the bond critical points (BCPs) using atoms-in-molecule (AIM) theory.
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    Sustainable starch-based bioplastics reinforced with carob filler: characterization and biodegradability assessments
    (Taylor and Francis Ltd., 2024) Guemmour, Hind; Kheffache, Djaffar; Khier, Nawal
    Starch-based thermoplastic polymer is a biopolymer that is being widely explored as a replacement for conventional polymers. Since thermoplastic starch suffers from mechanical defects, certain mechanical and thermal properties of starch-based polymers can be improved by incorporating fillers or reinforcements derived mainly from natural substances. This article reports the preparation, physicochemical, and mechanical characterization and biodegradation of starch-based bioplastics extracted from potato (Solanum tuberosum) peels using glycerol (G) as plasticizer and reinforced with carob powder, a readily growing plant in Mediterranean climates. The present study investigates the effect of incorporating different proportions (0, 2, 5, 10, and 15 wt.%) of carob powder (Cb) in the films thus prepared. These biopolymer films were fully characterized using analytical techniques including Fourier transform infrared spectroscopy with attenuated total reflection (FTIR/ATR), thermogravimetric analysis (TGA/DTG), X-ray diffraction (XRD), optical microscopy (OM), Scanning electron microscopy (SEM), mechanical evaluations, and biodegradability assessments. The biodegradability of the obtained bioplastic samples was evaluated. Scanning electron microscopy (SEM) revealed strong interfacial adhesion between the constituent filler and the polymer matrix.