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Research Article
Theoretical Approach of the Rational Design of Methoxy Diphenylamine-Substituted Fluorine-Based HTMs for Highly Efficient Perovskite Solar Cells: DFT/TD-DFT
Issue:
Volume 14, Issue 2, December 2026
Pages:
34-48
Received:
3 July 2026
Accepted:
20 July 2026
Published:
10 August 2026
Abstract: Organic solar cells (OSCs) have attracted significant attention as a promising photovoltaic technology because of their low fabrication cost, lightweight nature, mechanical flexibility, and rapid improvement in power conversion efficiency (PCE). Despite these advances, the development of efficient hole-transporting materials (HTMs) remains a major challenge for further enhancing device performance. In this study, density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were employed to rationally design and investigate a series of four methoxy-substituted diphenylamine-based fluorine-containing hole-transporting materials (MDFM1–MDFM4) for photovoltaic applications. The molecular structures were engineered by functionalizing a fluorine-based core with methoxy diphenylamine donor units and terminal acceptor groups, connected via thiophene π-bridges, to improve their optoelectronic properties. The designed molecules were systematically evaluated for frontier molecular orbital energies, energy band gaps, reorganization energies, absorption spectra, charge-transfer characteristics, and photovoltaic parameters. The computational results reveal that structural modification significantly influences the electronic and optical properties of the investigated HTMs. Among the designed compounds, MDFM4 exhibits the most promising performance, with the smallest HOMO–LUMO energy gap (4.44 eV), the lowest electron reorganization energy (0.0144 eV), and the longest maximum absorption wavelength (455 nm in the gas phase), indicating enhanced charge transport and broader light-harvesting capability. In addition, MDFM4 demonstrates improved photovoltaic characteristics, including a higher predicted open-circuit voltage and superior overall photovoltaic performance compared with the reference molecule. These findings demonstrate that rational molecular engineering through terminal acceptor modification is an effective strategy for tuning the optoelectronic properties of fluorine-based HTMs. The present theoretical investigation provides valuable insights for the future design and development of high-performance hole-transporting materials for next-generation organic solar cells.
Abstract: Organic solar cells (OSCs) have attracted significant attention as a promising photovoltaic technology because of their low fabrication cost, lightweight nature, mechanical flexibility, and rapid improvement in power conversion efficiency (PCE). Despite these advances, the development of efficient hole-transporting materials (HTMs) remains a major ...
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Research Article
Quantitative Structure-Property Relationship Modeling of the Octanol/Water Partition Coefficient of a Series of Alkylpyridines Using Quantum Chemical Descriptors
Issue:
Volume 14, Issue 2, December 2026
Pages:
49-62
Received:
24 September 2026
Accepted:
24 October 2026
Published:
26 October 2026
Abstract: Lipophilicity is therefore the characteristic of certain substances of "liking" fatty substances. From a chemical standpoint, lipophilicity is a substance's affinity for non-polar solvents such as lipids. Lipophilicity is intimately linked to the concept of the partitioning of a molecule between an aqueous phase and a lipid phase. In this study, we modeled the octanol/water partition coefficient of a family of alkylpyridines using quantum-chemical molecular descriptors. Two molecular descriptors were calculated in this context: electronic energy (ET) and the energy gap (ΔEgap). QSPR (Quantitative Structure-Property Relationship) methods enabled us to correlate the octanol/water partition coefficient with these two molecular descriptors. The statistical and validation parameters are satisfactory. Statistical indicators have demonstrated a strong correlation between the octanol/water partition coefficient and these two independent variables. Validation parameters confirm that the established model is valid and performs effectively in predicting the octanol/water partition coefficient for the family of alkylpyridines studied. Consequently, it can be used to reliably predict the octanol/water partition coefficient for alkylpyridines within this same family provided they fall within the model's applicability domain at a 95% confidence level. From now on, designing new alkylpyridines with specific octanol/water partition coefficients requires only adjusting the two parameters of this model: electronic energy (ET) and the energy gap (ΔEgap). This work will thus simplify the task for experimental chemists synthesizing this family of molecules, provided they fall within the applicability domain of the developed QSPR model.
Abstract: Lipophilicity is therefore the characteristic of certain substances of "liking" fatty substances. From a chemical standpoint, lipophilicity is a substance's affinity for non-polar solvents such as lipids. Lipophilicity is intimately linked to the concept of the partitioning of a molecule between an aqueous phase and a lipid phase. In this study, we...
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Research Article
Correlating Structural Properties and Performance in Thiophene-Bridged Benzodithiophene Donors for Bandgap Narrowing and Efficient Charge Transport in Organic Photovoltaics Cells (OPVCs): Insights from DFT/TD-DFT
Issue:
Volume 14, Issue 2, December 2026
Pages:
63-83
Received:
18 September 2026
Accepted:
4 October 2026
Published:
29 October 2026
Abstract: Studying correlating structural properties and performance is critical for the rational advancement of donor materials in organic photovoltaics cells (OPVCs). In this study, thiophene-bridged benzodithiophene (BDT) donors were strategically engineered to probe the impact of π-bridge modulation on electronic structure, optical transitions, and photovoltaic-relevant descriptors using density functional theory (DFT) and time-dependent DFT (TD-DFT). Systematic extension of π-conjugation induces substantial bandgap narrowing from 1.68 to 2.01 eV through enhanced frontier orbital delocalization and reduced HOMO-LUMO separation. This structural modulation produces a pronounced bathochromic shift in absorption maxima up to 815 nm, enabling near-infrared light harvesting. Frontier orbital and density of states analyses reveal intensified intramolecular charge transfer from the electron-rich BDT core to electron-deficient terminals, promoting effective charge separation. Increased dipole moments and oscillator strengths further support improved excitonic dissociation propensity. Theoretical evaluation of open-circuit voltage (Voc) and exciton binding energy (Eb) derived from calculated energy levels suggests favorable donor-acceptor energetic alignment and reduced Coulombic binding. These findings establish π-bridge engineering as a decisive molecular strategy for governing bandgap modulation and charge transport potential in next-generation BDT-based OPVCs systems.
Abstract: Studying correlating structural properties and performance is critical for the rational advancement of donor materials in organic photovoltaics cells (OPVCs). In this study, thiophene-bridged benzodithiophene (BDT) donors were strategically engineered to probe the impact of π-bridge modulation on electronic structure, optical transitions, and photo...
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Research Article
Structural, Electronic, and Spectroscopic Effects of Ligand Modification in RuCl2L2 Complexes: A Comparative DFT and TD-DFT Study
N’guessan Kouakou Nobel,
Ouattara Wawohinlin Patrice,
Bléhoué Clémence Ingrid,
Koné Mamadou Guy-Richard*
,
Koudjina Simplice,
Ouattara Lamoussa,
Dembélé Georges Stéphane,
Bamba Kafoumba,
Ziao Nahossé
Issue:
Volume 14, Issue 2, December 2026
Pages:
84-98
Received:
17 September 2026
Accepted:
27 September 2026
Published:
5 November 2026
DOI:
10.11648/j.ijctc.20261402.14
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Abstract: The nature of the heterocyclic rings in azo ligands plays a crucial role in modulating the physicochemical properties of ruthenium complexes. However, the effects of replacing an azopyridine ligand with an azopyrrole analogue on the structural, thermodynamic, electronic, and photophysical properties of ruthenium complexes remain insufficiently understood. This study investigates the influence of ligand ring modification on the properties of RuCl2L2 complexes, where L denotes either 2-phenylazopyridine (azpy) or 2-cyclopentadienylazopyrrole (azopyrrole). Ground-state geometries were optimized at the B3LYP/LANL2DZ level and characterized by vibrational frequency calculations. Thermodynamic and electronic properties were examined using Density Functional Theory (DFT), Natural Bond Orbital (NBO) analysis, and Time-Dependent DFT (TD-DFT) calculations. The results indicate that ligand substitution has a limited effect on the coordination geometry around the ruthenium center but significantly modifies the electronic distribution within the complexes. Among the three investigated isomers, the α-Cl isomer is predicted to be the most stable in both series. The formation of RuCl2(azpy)2 is thermodynamically favorable, whereas the formation of RuCl2(azopyrrole)2 is unfavorable at 298 K under the computational conditions considered. Frontier molecular orbital analysis reveals predominantly Metal-to-Ligand Charge-Transfer (MLCT) character for the azpy complexes, while the azopyrrole complexes exhibit a stronger Ligand-to-Metal Charge-Transfer (LMCT) contribution. The latter also display lower HOMO–LUMO gaps and chemical hardness values, together with higher electrophilicity indices. TD-DFT calculations predict absorption bands in the visible and near-infrared regions, highlighting ligand modification as a promising strategy for tuning the electronic and photophysical properties of ruthenium complexes.
Abstract: The nature of the heterocyclic rings in azo ligands plays a crucial role in modulating the physicochemical properties of ruthenium complexes. However, the effects of replacing an azopyridine ligand with an azopyrrole analogue on the structural, thermodynamic, electronic, and photophysical properties of ruthenium complexes remain insufficiently unde...
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