Silver nanocolloid, a dense suspension of ligand-encapsulated silver nanoparticles, is an important material for printing-based device production technologies. However, printed conductive patterns of sufficiently high quality and resolution for industrial products have not yet been achieved, as the use of conventional printing techniques is severely limiting. Here we report a printing technique to manufacture ultrafine conductive patterns utilizing the exclusive chemisorption phenomenon of weakly encapsulated silver nanoparticles on a photoactivated surface. The process includes masked irradiation of vacuum ultraviolet light on an amorphous perfluorinated polymer layer to photoactivate the surface with pendant carboxylate groups, and subsequent coating of alkylamine-encapsulated silver nanocolloids, which causes amine–carboxylate conversion to trigger the spontaneous formation of a self-fused solid silver layer. The technique can produce silver patterns of submicron fineness adhered strongly to substrates, thus enabling manufacture of flexible transparent conductive sheets. This printing technique could replace conventional vacuum- and photolithography-based device processing.

The quasi-Werner-type copper(II) complex, [Cu(PF 6 ) 2 (4-mepy) 4 ] (1), in which 4-mepy is the 4-methylpyridine ligand, has flexible and polar axial bonds of Cu-PF 6 . Flexibility of the Cu-PF 6 bonds induces diverse and unprecedented guest-inclusion structures, such as. Exposure of the dense form, a-1, to benzene vapor affords the benzene-inclusion complex {[Cu(PF 6 ) 2 (4-mepy) 4 ]•2benzene} (g-1…2benzene), all benzene guests of which are easily removed by vacuum drying, reforming guest-free, dense a-1¢ with smaller sized crystals than a-1. In contrast to a-1, which shows almost no CO 2 adsorption, a-1¢ adsorbs CO 2 gas with structural transformations, this being the first example that exhibits adsorption of gas in a dense Werner-type complex and a drastic change in adsorption properties depending on the size of the crystals.

We report the syntheses and crystal structures of novel porous assemblies of coordination complexes (PACs) with/without guest molecules, α-[Cu(A)₂(py)₄] (α-PAC-2-A (A = PF₆, BF₄, CF₃SO₃, and CH₃SO₃); py = pyridine), γ-{[Cu(PF₆)₂(py)₄]·2guest} (γ-PAC-2-PF₆ ⊃ 2guest (guest = acetone and py)), γ-{[Cu(BF₄)₂(py)₄]·2acetone} (γ-PAC-2-BF₄ ⊃ 2acetone), and β-{[Cu(CH₃SO₃)₂(py)₄]·2.67H₂O} (β-PAC-2-CH₃SO₃ ⊃ 2.67H₂O). The single-crystal X-ray diffraction analyses of α-PAC-2-A show that α-PAC-2-A have dense packing structures, in which anions of the discrete coordination complexes form weak hydrogen-bonding and anion-π interactions. In contrast, γ-PAC-2-PF₆ ⊃ 2guest, γ-PAC-2-BF₄ ⊃ 2acetone, and β-PAC-2-CH₃SO₃ ⊃ 2.67H₂O form guest-including structures with coordination environments around the Cu(II) atoms similar to the α-forms. The vapour adsorption measurements for MeCN and acetone in α-PAC-2-A suggest that the adsorption associated with structural transformations is induced by weak Lewis-base PF₆⁻ and BF₄⁻ anions covered only with fluorine atoms, which weaken the host-host interactions.

The modification of printed silver electrode surfaces for use as the bottom-contact electrodes of organic thin-film transistors (OTFTs) is reported. Printed silver electrodes fabricated using the surface photoreactive nanometal printing (SuPR-NaP) technique are inevitably covered with an inert surface layer of alkylamines that is originally used for encapsulation of the silver nanoparticles (AgNPs). However, it may act as a built-in protective layer against carrier injections. We demonstrate that a simple vapor exposure method is sufficient for converting the protective layer into a layer that assists carrier injection. As modifiers, we used various types of fluorinated benzenethiols that exhibit a stronger coordination with the silver surfaces than the alkylamimes. We detected the chemical conversion from alkylamine encapsulation to thiol coordination by surface enhanced Raman spectroscopy (SERS) and evaluated the improvement in the carrier injection using a transfer length method (TLM) for the OTFTs. Among the modifiers, the pentafluorobenzenethiol (PFBT) treatment significantly improves the device performance and stability of the OTFTs.

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