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    Aggregation-induced enhanced emission and device applications of acrylonitrile derivatives
    (Elsevier, 2026) Ozen, Leyla Babali; Coban, Mustafa Burak; Ozen, Furkan; Ozkan, Gul; Ersanli, Cem Cuneyt; Ekici, Oner; Cin, Gunseli Turgut
    This study presents a comprehensive exploration of acrylonitrile derivatives 4(a-n) by integrating their structural, electronic, photophysical, and device-level characteristics. Building on our previous findings that demonstrated the suitability of acrylonitrile-based systems for optoelectronic applications, the present work extends the investigation to a wider series to elucidate structure-property-device correlations. The molecules adopt semi-planar conjugated architectures linking hydroxy-substituted phenyl rings through alpha,beta-unsaturated-C--- N linkages, promoting extended it-electron delocalization and efficient excited-state interactions.Frontier molecular orbital analysis and global reactivity parameters (HOMO, LUMO, omega, mu, eta) reveal that electron-withdrawing substituents, especially-CF3 groups, enhance molecular electrophilicity and polarization, whereas electron-donating substituents favor nucleophilic regions, consistent with molecular electrostatic potential (MEP) distributions.Photophysical investigations uncover prominent aggregation-induced emission (AIE) and aggregation-induced enhanced emission (AIEE) effects, displaying maximal radiative efficiency at specific DMSO-water compositions. Leveraging these luminescent properties, a functional p-Si/(4e)/Al Schottky diode was fabricated, exhibiting rectifying characteristics and a logarithmic enhancement in forward current under illumination.Overall, the results highlight that the synergistic combination of tunable electronic structure, strong excited-state emission, and device compatibility positions these acrylonitrile derivatives as promising candidates for advanced optoelectronic and photovoltaic applications.
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    Optical properties of BPP and DPP spiro-cyclotriphosphazenes: experimental and DFT insights
    (Springer Int Publ Ag, 2026) Ozen, Leyla Babali; Ozkan, Gul; Kurt, Erdal; Cin, Gunseli Turgut; Gunduz, Bayram; Ozen, Furkan
    Spiro-cyclotriphosphazenes such as 2,2-dichloro-4,4,6,6-bis[spiro(2',2''-dioxy-1',1''-biphenyl)]cyclotriphosphazene (DPP) and 2,2,4,4-tetrachloro-6,6-[spiro(2',2''-dioxy-1',1''-biphenyl)]cyclotriphosphazene (BPP) are well-established intermediates for functional phosphazene derivatives. However, their intrinsic optical and electronic properties have not been systematically explored under varying experimental conditions. In this work, DPP and BPP were synthesized and characterized to elucidate the correlation between structural parameters and photophysical behavior. A complementary experimental approach was employed: DPP optical properties were examined in solution as a function of molarity, while BPP properties were investigated in the solid state as a function of film thickness. This strategy enables a comparative evaluation of how intermolecular interactions and structural topology influence optical behavior. UV-Vis measurements revealed band-gap narrowing from 3.904 to 3.805 eV for BPP and from 3.921 to 3.830 eV for DPP, accompanied by red shifts. DFT calculations (B3LYP/6-31G(d,p)) reproduced the relative trends, with HOMO-LUMO gaps of 1.91 eV (BPP) and 0.92 eV (DPP); although absolute values differ from experiment, the calculations correctly predict the relative absorption onsets and tunable optical behavior. Molecular electrostatic potential (MEP) maps and conceptual DFT descriptors indicate that BPP is harder and more electrophilic, while DPP is softer and more polarizable, consistent with red-shifted absorption. These findings highlight the intrinsic optical robustness of both compounds and demonstrate that parameters such as film thickness, solution molarity, and ring topology can be used to tailor optoelectronic properties. The study establishes BPP and DPP as promising candidates for UV-blue optoelectronic devices, photodetectors, and wide-bandgap photonic materials.
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    Unveiling the temperature-dependent optoelectronic performance of acrylonitrile derivatives for organic semiconductors: A comprehensive DFT and experimental analysis
    (Pergamon-Elsevier Science Ltd, 2026) Ozen, Leyla Babali; Ekici, Oner; Ozkan, Gul; Ozen, Furkan; Gunduz, Bayram; Cin, Gunseli Turgut
    This study investigates the optoelectronic properties, crystal structures, and thermodynamic behaviors of two newly synthesized hydroxy-substituted phenylacrylonitrile derivatives (3a and 3b), starting from their synthesis. Experimental findings demonstrate that compound 3a exhibits superior optical semiconductor potential, particularly due to its lower band gap values. To better understand the mechanisms responsible for this superiority, the thermodynamic properties of the molecules-including heat capacity, entropy, enthalpy, and total energy-were systematically calculated using Density Functional Theory (DFT) at room temperature and over a temperature range. While the relationship between molecular dynamics and non-radiative decay is acknowledged in the literature, the quantitative impact of temperature-dependent thermodynamic parameters on the optoelectronic performance of organic semiconductors, as well as the mechanisms behind this effect, remains insufficiently explored. This research addresses this gap by demonstrating that the lower heat capacity, enthalpy, and entropy values of compound 3a, in comparison to 3b, are directly associated with reduced molecular dynamism and consequently enhanced optical efficiency. Linking electronic structure to thermodynamic rigidity reveals that reduced vibrational freedom in compound 3a extends exciton lifetimes, illuminating temperaturedependent decay pathways and highlighting its promise as a flexible optoelectronic active layer.