A π-conjugated nanosheet comprising planar nickel bis(dithiolene) complexes was synthesized by a bottom-up method. A liquid-liquid interfacial reaction using benzenehexathiol in the organic phase and nickel(II) acetate in the aqueous phase produced a semiconducting bulk material with a thickness of several micrometers. Powder X-ray diffraction analysis revealed that the crystalline portion of the bulk material comprised a staggered stack of nanosheets. A single-layer nanosheet was successfully realized using a gas-liquid interfacial reaction. Atomic force microscopy and scanning tunneling microscopy confirmed that the π-conjugated nanosheet was single-layered. Modulation of the oxidation state of the nanosheet was possible using chemical redox reactions.

The chemical structure of SiO ͑silicon monoxide͒ anodes has been analyzed using X-ray photoelectron spectroscopy ͑XPS͒. Vapor deposition was used to form SiO anodes on Cu film. XPS analysis was performed on anodes at each of three stages: after deposition, after initial charge, and after discharge. The results of this analysis were then evaluated in terms of the anode's respective electrochemical characteristics. It has been found that some Si remains oxidized in the full charge state and that lithium silicates are formed. The lithium silicates serve as a buffer with respect to changes in anode volume.The high energy density of lithium-ion rechargeable batteries would seem to make them especially promising candidates for meeting future requirements for large capacity batteries. However, the capacity of the material conventionally used for their anodes, graphite, is increasingly approaching its theoretical limit of 372 mAh/g, which would be insufficient for meeting the needs of future portable electronic equipment. 1,2 That is why much research has been devoted to the development of new anode materials, and substances which can absorb and retain lithium appear to be particularly promising in this respect. Silicon, which has a capacity ten times that of graphite, is one such substance. 3,4 Unfortunately, however, with silicon the expansion and contraction of lithium alloy during chargedischarge processes would lead to a pulverization of the active materials, and the resulting poor electrical contact between the current collector and the active materials would mean the degradation of capacity over a relatively small number of cycles. 5 As an alternative, SiO appears particularly promising because of its long cycle life. 6 It also has the advantage of absorbing and retaining a large quantity of lithium, which gives it a higher energy density than lithium-graphite. In order to determine the reasons for the good cycle characteristics of SiO, however, it is important to learn more about the chemical structure of SiO anodes. In this study, we have used X-ray photoelectron spectroscopy ͑XPS͒ to determine that chemical structure, and we have also investigated the electrochemical reaction of SiO with lithium. ExperimentalA SiO thin film about 2 m in thickness was prepared on a flat Cu film by vapor deposition. The background pressure was 1 ϫ 10 −6 Pa, and the deposition pressure was 1 ϫ 10 −4 Pa. X-ray diffraction ͑XRD͒ analysis of as-deposited SiO thin film was performed with Rigaku, RINT-2050. SiO anodes cut from this twolayer film were incorporated into coin-type electrochemical cells having lithium metal counter electrodes. The electrolyte was 1 M LiPF 6 in ethylene carbonate ͑EC͒:diethyl carbonate ͑DEC͒ ͑30:70 by volume͒. The electrochemical performance of these coin cells was measured for a 1/40 C current rate during initial charge and discharge operations, which were performed for a 0-2.5 V range. After initial charge and initial discharge, the anodes were removed in an Ar atmosphere, washed a number of times with DE...

We have used a codeposition technique to develop high-capacity metal-doped SiO anodes for use in Li-ion rechargeable batteries, and we have measured their electrochemical properties. Cycle maintenance rates were roughly 82% after 400 cycles with a manganese oxide cathode. Initial charge-discharge coulombic efficiencies were roughly 84% without Li addition and nearly 100% with Li addition to the anodes for their full performance using Li half-cells. The discharge capacities per unit weight of these anodes were about 3–4 times that of graphite. X-ray photoelectron spectroscopy analysis shows that the anodes have a different chemical structure from that of nondoped SiO anodes [ J. Electrochem. Soc. , 152 , A2089 (2005)] , that metal compounds are not formed in the doped metals, and that the valence of Si changed from 0 to 4+ , and back to 0, during initial charge and discharge. Doped-metal works as an electron transporter, helping diffusion of Li ions in the electrode, and improves the electrical properties of the material.

Formation of silicon-aryl and germanium-aryl direct bonds on the semiconductor surface is a key issue to realize molecular electronic devices, but the conventional methods based on radical intermediates have problems to accompany the side reactions. We developed the first example of versatile and efficient methods to form clean organic monolayers with Si-aryl and Ge-aryl bonds on hydrogen-terminated silicon and germanium surfaces by applying our original catalytic arylation reactions of hydrosilanes and hydrogermanes using Pd catalyst and base in homogeneous systems. We could immobilize aromatic groups with redox-active and photoluminescent properties, and further applied in the field of rigid π-conjugated redox molecular wire composites, as confirmed by the successive coordination of terpyridine molecules with transition metal ions. The surfaces were characterized using cyclic voltammetry (CV), water contact angle measurements, X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy, and atomic force microscopy (AFM). Especially, the AFM analysis of 17 nm-long metal complex molecular wires confirmed their vertical connection to the plane surface.

Photosensing performance of a system composed of photosystem I (PSI), vitamin K(1) (VK(1))-like molecular wire, and gold nanoparticles (AuNPs) in an aqueous solution was increased considerably by the addition of double surfactants, hexylamine and dodecylbenzenesulfonate.