High structural quality of crystalline organic semiconductors is the basis of their superior electrical performance. Recent progress in quasi two-dimensional (2D) organic semiconductor films challenges bulk single crystals because both demonstrate competing charge-carrier mobilities. As the thinnest molecular semiconductors, monolayers offer numerous advantages such as unmatched flexibility and light transparency as well  they are an excellent platform for sensing. Oligothiophene-based materials are among the most promising ones for light-emitting applications because of the combination of efficient luminescence and decent charge-carrier mobility. Here, we demonstrate single-crystal monolayers of unprecedented structural order grown from four alkyl-substituted thiophene and thiophene–phenylene oligomers. The monolayer crystals with lateral dimensions up to 3 mm were grown from the solution on substrates with various surface energies and roughness by drop or spin-casting with subsequent slow solvent evaporation. Our data indicate that 2D crystallization resulting in single-crystal monolayers occurs at the receding gas–solution–substrate contact line. The structural properties of the monolayers were studied by grazing-incidence X-ray diffraction/reflectivity, atomic force and differential interference contrast microscopies, and imaging spectroscopic ellipsometry. These highly ordered monolayers demonstrated an excellent performance in organic field-effect transistors approaching the best values reported for the thiophene or thiophene–phenylene oligomers. Our findings pave the way for efficient monolayer organic electronics highlighting the high potential of simple solution-processing techniques for the growth of large-size single-crystal monolayers with excellent structural order and electrical performance competing against bulk single crystals.

Requirements of speed and simplicity in testing stimulate the development of modern biosensors. Electrolyte-gated organic field-effect transistors (EGOFETs) are a promising platform for ultrasensitive, fast, and reliable detection of biological molecules for low-cost, point-of-care bioelectronic sensing. Biosensitivity of the EGOFET devices can be achieved by modification with receptors of one of the electronic active interfaces of the transistor gate or organic semiconductor surface. Functionalization of the latter gives the advantage in the creation of a planar architecture and compact devices for lab-on-chip design. Herein, we propose a universal, fast, and simple technique based on doctor blading and Langmuir–Schaefer methods for functionalization of the semiconducting surface of C8-BTBT-C8, allowing the fabrication of a large-scale biorecognition layer based on the novel functional derivative of BTBT-containing biotin fragments as a foundation for further biomodification. The fabricated devices are very efficient and operate stably in phosphate-buffered saline solution with high reproducibility of electrical properties in the EGOFET regime. The development of biorecognition properties of the proposed biolayer is based on the streptavidin–biotin interactions between the consecutive layers and can be used for a wide variety of receptors. As a proof-of-concept, we demonstrate the specific response of the BTBT-based biorecognition layer in EGOFETs to influenza A virus (H7N1 strain). The elaborated approach to biorecognition layer formation is appropriate but not limited to aptamer-based receptor molecules and can be further applied for fabricating several biosensors for various analytes on one substrate and paves the way for “electronic tongue” creation.

Friedel-Crafts acylation of tetrathienoacene (TTA) following by reduction reaction resulting in various octyl-substituted TTA derivatives is described for the first time. Varying conditions of the acylation reaction allowed controlling the...

To cite this article: Olena Yu. Poimanova, Sergii V. Radio, Katerina Ye. Bilousova, Vyacheslav N. Baumer & Georgiy M. Rozantsev (2014): Equilibria in the acidified aqueous-dimethylformamide solutions of tungstate-anion. Synthesis, crystal structure and characterization of decatungstate [BaThe formation and transformation of isopolytungstates in the system Na 2 WO 4 -HCl -NaCl -DMF -H 2 O with different dimethylformamide (DMF) concentrations have been studied by single-point pH-potentiometric titration and the subsequent modeling of the equilibria processes. The modeling of equilibria resulted in data necessary to synthesize barium decatungstate, [Ba(H 2 O) 2 (C 3 H 7 NO) 3 ] 2 [W 10 O 32 ]·(C 3 H 7 NO) 2 . The salt was characterized by elemental and EDX spectral analysis, SEM, FTIR spectroscopy, thermal analysis, single-crystal X-ray diffraction analysis in solid state, and by UV-Vis. spectroscopy in solution.

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