Browsing by Author "Usta, H."

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Achieving Extreme Solubility and Green Solvent-Processed Organic Field-Effect Transistors: A Viable Asymmetric Functionalization of [1]Benzothieno[3,2-B][1]Benzothiophenes
(American Chemical Society, 2025) Yıldız, T.A.; Deneme, İ.; Usta, H.
Novel structural engineering strategies for solubilizing high-mobility semiconductors are critical, which enables green solvent processing for eco-friendly, sustainable device fabrication, and unique molecular properties. Here, we introduce a viable asymmetric functionalization approach, synthesizing monocarbonyl [1]benzothieno[3,2-b][1]benzothiophene molecules on a gram scale in two transition-metal-free steps. An unprecedented solubility of up to 176.0 mg·mL–1(at room temperature) is achieved, which is the highest reported to date for a high-performance organic semiconductor. The single-crystal structural analysis reveals a herringbone motif with multiple edge-to-face interactions and nonclassical hydrogen bonds involving the carbonyl unit. The asymmetric backbones adopt an antiparallel arrangement, enabling face-to-face π-π interactions. The mono(alkyl-aryl)carbonyl-BTBT compound, m-C6PhCO-BTBT enables formulations in varied green solvents, including acetone and ethanol, all achieving p-channel top-contact/bottom-gate OFETs in ambient conditions. Charge carrier mobilities of up to 1.87 cm2/V·s (μeff≈ 0.4 cm2/V·s; Ion/Ioff≈ 107–108) were achieved. To the best of our knowledge, this is one of the highest OFET performances achieved using a green solvent. Hansen solubility parameters (HSP) analysis, combined with Scatchard–Hildebrand regular solution theory and single-crystal packing analysis, elucidates this exceptional solubility and reveals unique relationships between molecular structure, interaction energy densities, cohesive energetics, and solute–solvent distances (Ra). An optimal solute–green solvent interaction distance in HSP space proves critical for green solvent-processed thin-film properties. This asymmetric functionalization approach, with demonstrated unique solubility insights, provides a foundation for designing green solvent-processable π-conjugated systems, potentially advancing innovation in sustainable (opto)electronics and bioelectronics. © 2025 Elsevier B.V., All rights reserved.
Labyrinthine Microstructures With a High Dipole Moment Boron Complex for Molecular Physically Unclonable Functions
(American Chemical Society, 2025) Yıldız, T.A.; Kiremitler, N.B.; Kayacı, N.; Kalay, M.; Özcan, E.; Deneme, I.; Usta, H.
The design and development of novel molecular-physically unclonable functions (PUFs) with advanced encoding characteristics and ease of fabrication have recently attracted attention in cryptography, secure authentication, and anticounterfeiting. Here, we report the development of a new high dipole-moment small molecule, InIm-BF2, a difluoroborate complex of an indolyl-imine ligand, and the fabrication of unique labyrinthine patterns through a facile two-step thin film process under ambient conditions. The new molecule has a dipolar, coplanar π-backbone and arranges in the solid state with antisymmetric cofacial π-stackings (3.86 Å). These properties, along with short C–H···π contacts (2.74–2.88 Å) and nonclassical C–H···F hydrogen bonds (2.47–2.51 Å) (23.4% and 11.5% of the Hirshfeld surfaces, respectively), drive the formation of amorphous molecular PUF patterns with disordered, short-range interactions. Spin-coating followed by thermal annealing at a moderate temperature produces nanoscopic molecular thin films with intricate labyrinthine patterns. These patterns, characterized by interconnected, irregularly shaped, micron-sized (≈50–100 μm) features, exhibit excellent PUF characteristics, verified through advanced image analysis and computational algorithms. Unlike randomly positioned isolated features in classical binarized keys, the interconnected labyrinthine patterns possess rich entropy and complex features, directly authenticated via deep-learning methodologies. Our work not only demonstrates a facile, promising approach to fabricating unique high-entropy PUF patterns but also provides critical insights into designing advanced molecular materials for next-generation security applications. © 2025 The Authors. Published by American Chemical Society