•Electroless-plated gold and platinum films are introduced for printed organic transistors.•High-performance solution-processed organic transistors are built with the printed electrodes.•With solution crystallized thin-films of C10-DNTT, mobility reaches 6.0 cm2 V−1 s−1, offering practical printing techniques.Electroless-plated gold and platinum films are used as source and drain electrodes in high-performance solution-processed organic field-effect transistors (OFETs), representing a promising large-area, near-room-temperature and vacuum-free technique to form low-resistance metal-to-semiconductor interfaces in ambient atmosphere. Developing non-displacement conditions using a Pt-colloidal catalyst for soft electroless plating, the electrodes are deposited on crystallized thin films of 2,9-didecyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (C10-DNTT) without significant damage to the semiconductor material. The top-contact OFETs show remarkable performance, with a mobility of 6.0 cm2 V−1 s−1. The method represents a practical fabrication technique to mass-produce circuitry arrays of nearly best-performing OFETs for the printed electronics industry.

We report a novel solution-crystallization method to grow two-dimensional platelet-shaped single-crystals of well-known insoluble organic semiconductors via thermal conversion of their precursor molecules dissolved in ionic liquids (ILs). By optimizing conditions of the crystal growth regarding physical properties of ILs such as density and viscosity, we successfully and reproducibly obtained thin platelets of pentacene and dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) single-crystals, with which nearly the best performing field-effect transistors are constructed for the two compounds. The prompt and simple technique has opened the way to use practically insoluble organic semiconductor materials for high-performance printed electronics, which enables mass-producible and large-area organic circuitry devices.Graphical abstractHighlights► We develop a novel solution-crystallized method to grow 2D crystals in ionic liquids. ► We convert soluble precursors to insoluble organic materials via thermal conversion. ► We obtain the single-crystals of well-known pentacene and DNTT semiconductors. ► These obtained crystals nearly exhibit the best-reported FET performance. ► The simple technique has opened the way to use practically insoluble materials.

Benzopyrazine-fused tetracene (TBPy) and its disulfide (TBPyS) bearing alkoxy groups (OCH3, OC8H17) were designed and synthesized to obtain π-expanded tetracene derivatives. These derivatives are featured with long-wavelength light absorption property (λonset: up to 820 nm), photooxidative stability (half-lives (τ1/2): 11 times longer than tetracene), and solubility for solution process. The methoxy compounds (TBPy-C1 and TBPyS-C1) were used for single-crystal X-ray crystallographic analysis and single-crystal organic field-effect transistor (OFET) devices showing relationship between packing structures and hole mobilities. The octyloxy compounds (TBPy-C8 and TBPyS-C8) were investigated on solution-processed thin-film formation and hole transport property in thin-film OFET devices. Crystalline mesophase of TBPy-C8 and TBPyS-C8 was characterized by differential scanning calorimetry analysis showing endothermic peaks at 98 and 198 °C on its second heating process and exothermic peaks at 177 and 76 °C on its second cooling process for TBPyS-C8, and played crucial roles in thin-films formation. Hole mobility of 1.7 × 10−2 cm2/V s (with Vth = −30 V and ION/IOFF = 104) was obtained for the thin-film OFET device of TBPyS-C8.Graphical abstractHighlights► New tetracene derivatives bearing benzopyrazine acceptor and disulfide donor units were synthesized. ► These compounds are low-bandgap materials giving wavelength light absorption property up to 820 nm. ► These compounds showed hole transport property in field-effect transistors. ► Two alkoxy chains on the benzopyrazine unit influences thermal property and film forming ability. ► An octyloxyl derivative has mesophase between ca. 90 and 190 °C, and thin-film formation is possible at the mesophase.

We here report naphtho[2,1-b:6,5-b′]difuran derivatives as new p-type semiconductors that achieve hole mobilities of up to 3.6 cm2 V–1 s–1 along with high Ion/Ioff ratios in solution-processed single-crystal organic field-effect transistors. These features originate from the dense crystal packing and the resulting large intermolecular π-orbital overlap as well as from the small reorganization energy, all of which originate from the small radius of an oxygen atom.

Air-stable and high-mobility polymer-based organic thin-film transistors are developed by employing low-surface-energy self-assembled monolayers and prolonged post-annealing. Carrier mobility in spin-coated thin films of a high-ionic-potential polymer semiconductor poly(2,5-bis(2-thienyl)-3,6-dihexadecyltheino[3,2-b]thiophene) reaches (0.08–0.17 cm2/V s with decyltriethoxysilane monolayers and 0.4–0.8 cm2/V s with (heptadecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane monolayers. The values become higher with longer annealing above the glass-transition temperature. The mobility, threshold voltage and on–off ratio are stable in humid air during the whole period of the experiment for more than 2 weeks. The high-performance and the air-stability demonstrated in the polymer thin-film transistors have enhanced their applicability in large-area, low-cost and flexible electronic devices.