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Papers by Simplice KOUDJINA
Computational and theoretical chemistry, Aug 1, 2024
Physica scripta, Feb 26, 2024
Research Square (Research Square), Feb 15, 2024
International Journal of Pharmacy and Chemistry, Oct 7, 2023
Diamond and Related Materials, Jan 31, 2024
Journal of materials physics and chemistry, May 17, 2024
Journal of Photochemistry and Photobiology A: Chemistry
Journal of Sulfur Chemistry, Feb 2, 2023
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
International Journal of Computational and Theoretical Chemistry
Organic photovoltaic performance has been investigated about the fluorination effects as one part... more Organic photovoltaic performance has been investigated about the fluorination effects as one part on the optoelectronic properties. The quantum chemical accuracy of the optoelectronic and structural properties based on D-A (Donor-Acceptor) conjugated copolymers as PDTPQX-type (Poly-dithieno-pyrrol-Quinoxaline) has been tediously exposed. The Donor-Acceptor in the copolymers was in our case constitutes to the Donor part in the photovoltaic device, while the Acceptor starting is the PC60BM in the same device, which composed the photovoltaic solar cells. The choice of the Donor part in the copolymers was obtained by their HOMO-LUMO bandgap and UV-visible absorption. The bandgap of the Donor part must be higher than that of the Acceptor part for an untroubled charges transfer from the Donor to the Acceptor according to the photovoltaic principle. The substitution of fluorine atoms (0F, 1F, 2F) on the quinoxaline constituents is an effective way to low the HOMO and LUMO energy levels of the alternating copolymers. This fluorine effect has been explored on the optoelectronic properties such as the HOMO-LUMO band gap Egap energy, the fill factor FF, the open circuit voltage Voc, the electron transfer energy ΔEet, the excitation energy ΔEex, the absorption wave length λ and the oscillator strength OS. The equilibrium geometry at the ground state, the electronic structures as the frontier orbital isosurface have been obtained under the caster of the density functional theory (DFT) assist by the time-dependent density functional theory (TD-DFT) with M05 as exchange-correlation functional to come with 6-311G(d,p) basis set. Calculations were performed both in vaccuum and Chlorobenzene (CB) solvent with IEFPCM quantum model. All this has been done with the aim to enhance the energy gap, the Voc values and the fill factor FF, which exposed the nanomorphology as the topology of the solar cells photoactive layers. The results of this study show that these promote compounds systems as in the fluorination order are excellent candidates to build photovoltaic device in aim to enhance the open-circuit voltage for donor-acceptor heterojunctions used in organic solar cells.
Journal of Molecular Graphics and Modelling
Journal of Computational Methods in Molecular Design, 2015
The theoretical investigation of hydrotreatment of pyrrolidine without catalyst and with three ca... more The theoretical investigation of hydrotreatment of pyrrolidine without catalyst and with three catalysts of hydrotreating such as the tungsten disulfide, the zinc chloride and the aluminum chloride, was performed. The calculations were carried out by ab initio methods MP2 and DFT/B3LYP in 6-31G* and Lanl2DZ basis sets. The experimental conditions taken into account by the calculations were 40 bars and 523 K. The elimination of the heteroatom source under NH3 form was modeled in two successive hydrogenolysis stages, which produced butan-1- amine and butane respectively. The lowest activation energy of the reaction was obtained with zinc chloride. The Infrared spectra calculated by TDHF/aug-cc-pVDZ method, for the various chemical systems, before and after their transformations, made it possible to propose a mechanism of reaction.
Journal of Molecular Modeling, 2019
One of the possibilities of limiting carbon dioxide emissions is to use pyrolysis oils from bioma... more One of the possibilities of limiting carbon dioxide emissions is to use pyrolysis oils from biomass. However, their very high oxygen content confers to these oils a chemical instability and a high viscosity. Among the oxygen-containing compounds present in bio-oils, furanic compounds derived from the decomposition of cellulosic and hemi-cellulosic biomass are the most refractory to deoxygenation. The major products of their hydrodeoxygenation are alkanes and secondly alkenes, but the intermediates are still subject to controversy. In this work, we performed a DFT simulation of the hydrodeoxygenation of furan (C4H4O) and 2-methylfuran in the presence of molybdenum and tungsten sulphide Mo(W)S2. The aim of this work is to elucidate the reaction intermediates and to compare the activities of the two catalytic sites used in our reaction conditions. Our calculations show that the partial hydrogenation of the two molecules occurs preferentially in position (2,5). The hydrogenolysis reactions of the C-O bonds occur in two steps. The molybdenum sulphide exhibits higher catalytic activity.
Journal of Structural Chemistry, 2018
A theoretical study of hydrotreatment of the oxolane molecule without a catalyst and in the prese... more A theoretical study of hydrotreatment of the oxolane molecule without a catalyst and in the presence of a catalyst is performed by numerical DFT/B3LYP methods with 6-31G(d) and LanL2DZ basis sets. The catalyst used in this study is tungsten disulfide (WS 2) which is modeled by a three anionic vacancy site 3 3 WS H +. Hydrogenolysis of the oxolane molecule under hydrogen pressure is simulated through two sequential stages. The temperature and pressure experimental conditions taken in account in the study were 523 K, 573 K, and 623 K under 40 bar. The analysis of variations of diverse system parameters during the process reveals that oxolane undergoes a CO bonds cleavage at a ring opening at the end of both hydrogenolysis processes. The first hydrogenolysis process leads to the formation of a butan-1-ol molecule, which then undergoes second hydrogenolysis under the same pressure and temperature conditions. Finally, second hydrogenolysis produces water and butane molecules.
![Research paper thumbnail of Fluorination as an effective tool to increase the open-circuit voltage and charge carrier mobility of organic solar cells based on poly(cyclopenta[2,1-b:3,4-b′]dithiophene-alt-quinoxaline) copolymers](https://attachments.academia-assets.com/101315698/thumbnails/1.jpg)
](Journal of Materials Chemistry A, 2015
Quinoxaline fluorination leads to enhanced properties and efficiencies in PCPDTQx-based polymer s... more Quinoxaline fluorination leads to enhanced properties and efficiencies in PCPDTQx-based polymer solar cells.
Mediterranean Journal of Chemistry, 2020
Optoelectronics properties as helical molecular fingerprints have been investigated on a set of H... more Optoelectronics properties as helical molecular fingerprints have been investigated on a set of Helicenes molecules, which form a particular class of compounds and exhibit both π-electron delocalization and chiral properties. In this paper, we investigate the IR and Raman signatures of four representative Helicenes: Hexahilicene (Hexa-Helicene), tetrathia-[7]-helicene (Helicene-4S), and its pyrrole (Helicene-4N) and furan analogs (Helicene-4O), under the visible wavelength of 532 nm. Correctly, the impact of the method of calculation on these signatures has been pointed out. The simulation of the IR and Raman signatures involves two different steps: the evaluation of the vibrational frequencies and normal modes and the calculation of the Cartesian derivatives of electric properties. While most of the time, all the quantities are evaluated with a single method, we believe that this should not be the case since both steps have not the same requirements in terms of computational method...
Topics in Catalysis, 2020
Using DFT calculations, we have investigated the cycloaddition of thiophene with ethylene, follow... more Using DFT calculations, we have investigated the cycloaddition of thiophene with ethylene, followed by desulfurization of the produced heterobicyclic molecules at 373 K. The whole reaction process has been modeled in three steps: (i) the molecule adsorption on tungsten sulfide acting as a catalyst, (ii) the cycloaddition of the adsorbed molecule with ethylene, (iii) the elimination of the sulfur atom by hydrogenation of the cycloaddition products. Cycloaddition, in the presence or in the absence of catalyst, produced a bicyclic compound including a C-S bond. Its reaction with hydrogen led to the hydrogenolysis of C-S bonds. Without catalyst, the reaction of bicyclic compounds with hydrogen led to a double hydrogenolysis producing cyclohexa-1,2-diene and hydrogen sulfur. In the presence of catalyst, the reaction took place in two steps, leading to cyclohexene. With increasing the molecular weight of compounds, cycloaddition can allow the separation between light hydrocarbons from alkyl-thiophenic molecules with distillation, knowing that boiling temperature increases with the molecular weight. Although consuming more hydrogen, the reaction with catalysts led to an unsaturated cyclic product which can improve the octane number of fuels containing them.
Computational and theoretical chemistry, Aug 1, 2024
Physica scripta, Feb 26, 2024
Research Square (Research Square), Feb 15, 2024
International Journal of Pharmacy and Chemistry, Oct 7, 2023
Diamond and Related Materials, Jan 31, 2024
Journal of materials physics and chemistry, May 17, 2024
Journal of Photochemistry and Photobiology A: Chemistry
Journal of Sulfur Chemistry, Feb 2, 2023
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
International Journal of Computational and Theoretical Chemistry
Organic photovoltaic performance has been investigated about the fluorination effects as one part... more Organic photovoltaic performance has been investigated about the fluorination effects as one part on the optoelectronic properties. The quantum chemical accuracy of the optoelectronic and structural properties based on D-A (Donor-Acceptor) conjugated copolymers as PDTPQX-type (Poly-dithieno-pyrrol-Quinoxaline) has been tediously exposed. The Donor-Acceptor in the copolymers was in our case constitutes to the Donor part in the photovoltaic device, while the Acceptor starting is the PC60BM in the same device, which composed the photovoltaic solar cells. The choice of the Donor part in the copolymers was obtained by their HOMO-LUMO bandgap and UV-visible absorption. The bandgap of the Donor part must be higher than that of the Acceptor part for an untroubled charges transfer from the Donor to the Acceptor according to the photovoltaic principle. The substitution of fluorine atoms (0F, 1F, 2F) on the quinoxaline constituents is an effective way to low the HOMO and LUMO energy levels of the alternating copolymers. This fluorine effect has been explored on the optoelectronic properties such as the HOMO-LUMO band gap Egap energy, the fill factor FF, the open circuit voltage Voc, the electron transfer energy ΔEet, the excitation energy ΔEex, the absorption wave length λ and the oscillator strength OS. The equilibrium geometry at the ground state, the electronic structures as the frontier orbital isosurface have been obtained under the caster of the density functional theory (DFT) assist by the time-dependent density functional theory (TD-DFT) with M05 as exchange-correlation functional to come with 6-311G(d,p) basis set. Calculations were performed both in vaccuum and Chlorobenzene (CB) solvent with IEFPCM quantum model. All this has been done with the aim to enhance the energy gap, the Voc values and the fill factor FF, which exposed the nanomorphology as the topology of the solar cells photoactive layers. The results of this study show that these promote compounds systems as in the fluorination order are excellent candidates to build photovoltaic device in aim to enhance the open-circuit voltage for donor-acceptor heterojunctions used in organic solar cells.
Journal of Molecular Graphics and Modelling
Journal of Computational Methods in Molecular Design, 2015
The theoretical investigation of hydrotreatment of pyrrolidine without catalyst and with three ca... more The theoretical investigation of hydrotreatment of pyrrolidine without catalyst and with three catalysts of hydrotreating such as the tungsten disulfide, the zinc chloride and the aluminum chloride, was performed. The calculations were carried out by ab initio methods MP2 and DFT/B3LYP in 6-31G* and Lanl2DZ basis sets. The experimental conditions taken into account by the calculations were 40 bars and 523 K. The elimination of the heteroatom source under NH3 form was modeled in two successive hydrogenolysis stages, which produced butan-1- amine and butane respectively. The lowest activation energy of the reaction was obtained with zinc chloride. The Infrared spectra calculated by TDHF/aug-cc-pVDZ method, for the various chemical systems, before and after their transformations, made it possible to propose a mechanism of reaction.
Journal of Molecular Modeling, 2019
One of the possibilities of limiting carbon dioxide emissions is to use pyrolysis oils from bioma... more One of the possibilities of limiting carbon dioxide emissions is to use pyrolysis oils from biomass. However, their very high oxygen content confers to these oils a chemical instability and a high viscosity. Among the oxygen-containing compounds present in bio-oils, furanic compounds derived from the decomposition of cellulosic and hemi-cellulosic biomass are the most refractory to deoxygenation. The major products of their hydrodeoxygenation are alkanes and secondly alkenes, but the intermediates are still subject to controversy. In this work, we performed a DFT simulation of the hydrodeoxygenation of furan (C4H4O) and 2-methylfuran in the presence of molybdenum and tungsten sulphide Mo(W)S2. The aim of this work is to elucidate the reaction intermediates and to compare the activities of the two catalytic sites used in our reaction conditions. Our calculations show that the partial hydrogenation of the two molecules occurs preferentially in position (2,5). The hydrogenolysis reactions of the C-O bonds occur in two steps. The molybdenum sulphide exhibits higher catalytic activity.
Journal of Structural Chemistry, 2018
A theoretical study of hydrotreatment of the oxolane molecule without a catalyst and in the prese... more A theoretical study of hydrotreatment of the oxolane molecule without a catalyst and in the presence of a catalyst is performed by numerical DFT/B3LYP methods with 6-31G(d) and LanL2DZ basis sets. The catalyst used in this study is tungsten disulfide (WS 2) which is modeled by a three anionic vacancy site 3 3 WS H +. Hydrogenolysis of the oxolane molecule under hydrogen pressure is simulated through two sequential stages. The temperature and pressure experimental conditions taken in account in the study were 523 K, 573 K, and 623 K under 40 bar. The analysis of variations of diverse system parameters during the process reveals that oxolane undergoes a CO bonds cleavage at a ring opening at the end of both hydrogenolysis processes. The first hydrogenolysis process leads to the formation of a butan-1-ol molecule, which then undergoes second hydrogenolysis under the same pressure and temperature conditions. Finally, second hydrogenolysis produces water and butane molecules.
Journal of Materials Chemistry A, 2015
Quinoxaline fluorination leads to enhanced properties and efficiencies in PCPDTQx-based polymer s... more Quinoxaline fluorination leads to enhanced properties and efficiencies in PCPDTQx-based polymer solar cells.
Mediterranean Journal of Chemistry, 2020
Optoelectronics properties as helical molecular fingerprints have been investigated on a set of H... more Optoelectronics properties as helical molecular fingerprints have been investigated on a set of Helicenes molecules, which form a particular class of compounds and exhibit both π-electron delocalization and chiral properties. In this paper, we investigate the IR and Raman signatures of four representative Helicenes: Hexahilicene (Hexa-Helicene), tetrathia-[7]-helicene (Helicene-4S), and its pyrrole (Helicene-4N) and furan analogs (Helicene-4O), under the visible wavelength of 532 nm. Correctly, the impact of the method of calculation on these signatures has been pointed out. The simulation of the IR and Raman signatures involves two different steps: the evaluation of the vibrational frequencies and normal modes and the calculation of the Cartesian derivatives of electric properties. While most of the time, all the quantities are evaluated with a single method, we believe that this should not be the case since both steps have not the same requirements in terms of computational method...
Topics in Catalysis, 2020
Using DFT calculations, we have investigated the cycloaddition of thiophene with ethylene, follow... more Using DFT calculations, we have investigated the cycloaddition of thiophene with ethylene, followed by desulfurization of the produced heterobicyclic molecules at 373 K. The whole reaction process has been modeled in three steps: (i) the molecule adsorption on tungsten sulfide acting as a catalyst, (ii) the cycloaddition of the adsorbed molecule with ethylene, (iii) the elimination of the sulfur atom by hydrogenation of the cycloaddition products. Cycloaddition, in the presence or in the absence of catalyst, produced a bicyclic compound including a C-S bond. Its reaction with hydrogen led to the hydrogenolysis of C-S bonds. Without catalyst, the reaction of bicyclic compounds with hydrogen led to a double hydrogenolysis producing cyclohexa-1,2-diene and hydrogen sulfur. In the presence of catalyst, the reaction took place in two steps, leading to cyclohexene. With increasing the molecular weight of compounds, cycloaddition can allow the separation between light hydrocarbons from alkyl-thiophenic molecules with distillation, knowing that boiling temperature increases with the molecular weight. Although consuming more hydrogen, the reaction with catalysts led to an unsaturated cyclic product which can improve the octane number of fuels containing them.