Shen Ye

The interface-sensitive spectroscopic method, sum frequency generation (SFG), has been used to investigate the interfacial water structure on a fused quartz surface modified by an octadecyltrichlorosilane (OTS) self-assembled monolayer in phosphate buffered solutions at various pHs. The experimental results demonstrate that the water molecules at the quartz/OTS surface flip while the water molecules at the OTS surface maintain their orientation when the solution pH is changed from neutral to aci

Several Zn-porphyrin (ZnP) derivatives were designed to build highly efficient dye-sensitized solar cells (DSC). It was found that solar cell efficiencies normalized for surface coverage (eta(rel)) are affected by the molecular spacer connecting the porphyrin core to the TiO2 surface, the sensitization conditions (solvent and time), and, to a lesser extent, the nature of the terminal group of the ZnP. Ultrafast transient absorption spectroscopy shows that electron transfer rates are strongly dep

The potential dependent structure change of a self-assembled monolayer of 11-ferrocenyl-1-undecanethiol (FcC11SH) on a gold electrode surface during the redox reaction of the terminal ferrocene group was investigated in 0.1 M HClO4 solution by electrochemical in situ Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS). A number of bands were observed in the 3200−1200 cm-1 region with p-polarization measurement, but no band was observed by s-polarization measurement when the

The structural changes in poly(2-methoxyethyl acrylate) (PMEA) thin films induced by the absorption of bisphenol A (BPA), which is suspected to be an endocrine disrupter disturbing the hormone balance in a living body, have been investigated by infrared reflection absorption spectroscopy (IRRAS) and sum frequency generation (SFG) measurements. BPA molecules are absorbed in PMEA thin film. By controlling the thickness of the intermediate polystyrene (PS) film between the PMEA and Au substrate, we

The adsorption structures of solvents on the surface of LiCoO2, which is the most widely used cathode material for Li-ion batteries, in contact with nonaqueous electrolyte solutions of carbonate esters have been characterized by in situ sum frequency generation (SFG) spectroscopy. The cyclic carbonate of ethylene carbonate (EC) is preferentially adsorbed on the LiCoO2 surface, in contrast to linear carbonates, such as dimethyl carbonate (DMC).

The molecular structures and their stabilities at the outmost-layer of the Langmuir-Blodgett (LB) films of stearic acid on solid substrates have been investigated by a highly surface-sensitive spectroscopic technique, sum frequency generation (SFG), in air and in aqueous solution, using the combination of both normal and deuterated stearic acid. Peaks observed in the SFG spectra are mainly attributed to the terminal methyl group at the outmost layer of the LB films. The SFG spectra in air are vi

To develop an efficient material for the cathode of the lithium-oxygen (Li-O₂) secondary battery, the oxygen reduction and evolution reactions (ORR and OER) on a well-defined graphene electrode have been investigated in a typical organic solvent, dimethyl sulfoxide (DMSO). The adsorption and desorption behaviors of the solvents on the graphene electrode surface were evaluated by an intrinsically surface-selective vibrational spectroscopy of sum frequency generation (SFG) during the OR

The surface molecular structures of Langmuir−Blodgett (LB) films of stearic acid with 1−12 layers formed on the hydrophilic substrates have been investigated in air by sum frequency generation (SFG). The SFG spectra of the even-numbered LB films were almost the same as those of the odd-numbered films, although it is expected that the molecular structures of the outermost layer for the even- and odd-numbered layers are different in the ideal model. In combination with AFM measurements, these expe

The anodic dissolution process of Au(111) in a 0.1 M perchloric acid (HClO4) solution containing chloride anion (Cl-) was investigated using an in situ scanning tunneling microscope. The initial dissolution of gold was observed at the step sites when the electrode potentials became more positive than +1.0 V. The rate of the anodic dissolution increased as the potential became more positive. When the potential became more positive than +1.35 V, dissolution on the terraces was also observed. The d

Until the mid 1980’s, there had been only few in situ methods available for structural determination of an electrode surface in solution at atomic and monolayer levels. Nowadays, many powerful in situ techniques, such as electrochemical scanning tunneling microscopy (EC-STM), infrared reflection absorption spectroscopy (IRAS), surface-enhanced Raman scattering (SERS), and surface-enhanced infrared reflection absorption spectroscopy (SEIRAS), second harmonic generation (SHG), sum frequency genera

The potential-dependent structure change and irreversible anodic decomposition reaction of a 2-(11-mercaptoundecyl)hydroquinone (H2QC11SH) monolayer on a gold electrode surface in 0.1 mol l–1 HClO4 solution has been investigated by electrochemical in situ FT-IRRAS. A number of bands with good signal-to-noise ratios have been observed at 1700–1100 cm–1 using p-polarization measurement but no bands were observed by s-polarization measurement when the potential was less than +1.2 V. The bands in th

The anodic dissolution process of a Au(11) oriented electrode in HCl04 solution containing various concentrations of chloride ion was investigated using an electrochemical quartz crystal microbalance (EQCM) under potential sweep and potentiostatic conditions. The in situ EQCM results clearly demonstrated that gold dissolves through a 3e oxidation process in the anodic potential region. No evidence for the le-dissolution was obtained in the present study.

The potential dependent structure change and mass transport at an 11-ferrocenyl-1-undecanethiol (FcC11SH) self-assembled monolayer on a gold electrode with various coverages were investigated by simultaneous Fourier transform infrared reflection absorption spectroscopy (IRRAS) and electrochemical quartz crystal microbalance (EQCM) measurements in 0.1 M HClO4 solution. As soon as the terminal ferrocene group was oxidized to a ferricenium cation (Fc+), a number of upward and downward IRRAS bands w