Manabu Ihara

The absorption coefficient of the dye used in dye-sensitized solar cells is a major factor in the total energy efficiency of the cell. In this work, we increased the absorption coefficient of the dye cis-(NCS)2 bis(2,2‘-bipyridyl-4,4‘-dicarboxylate)ruthenium(II) used in such cells by having the dye adsorbed on silver islands. We studied the effect of the surface area of silver (per surface area of substrate) and the effect of dye concentration on this enhancement. This technique significantly en

The surface roughness of the c-TiO₂ layer help controls the perovskite grain size without any other parameter. The direct effect of perovskite grain size on PSC performance is clarified.

The reaction mechanism of the most commonly used anode material, Ni/yttria-stabilized zirconia (YSZ) cermets, in solid oxide fuel cells (SOFCs) was investigated. Because the reaction mechanism for the Ni/YSZ anode in has not been conclusively determined, we investigated the detailed dependence of dc polarization and interfacial conductivity of Ni/YSZ cermet anode on the partial pressure of hydrogen Based on our experimental results, we developed a model that links the chemical reactions on the a

A quickly rechargeable direct carbon solid oxide fuel cell (RDCFC) that uses a solid carbon fuel supplied by thermal decomposition of propane was developed. This RDCFC, after a fuel charging time of only , maintained a power density of for , had a maximum power density of , and exhibited these stable characteristics for at least six cycles of power generation and charging. This new type of solid oxide fuel cell can be used as a compact, portable power unit.

Diamond films were deposited on the silicon wafer at as low a temperature as 135 °C by filament-assisted chemical vapor deposition. Silicon wafer substrate scratched with diamond powder was cooled by a stream of water flowing around a substrate holder. The films were identified as diamond by Raman spectroscopy. Clearly faceted crystals were shown in scanning electron micrographs.

Diamond was deposited on substrates pre-etched with diamond powder using either a microwave plasma chemical vapor deposition method or a hot-filament-assisted chemical vapor deposition method. Density of residual diamond dust (i.e., number of diamond particles per unit area on the surface of a substrate) on the pre-etched substrates was determined using field emission scanning electron microscopy, and ranged from 3.3×107 to 6.6×1010 ♯/cm2. The diamond nucleation-site density (i.e., number of nuc

GaAs epitaxial growth by the open-tube AsCl3–Ga–N2 vapor-transport technique was thoroughly examined as to its growth conditions, with some discussion on an optimum condition supplemented. The results of Hall, impurity profile, and photoluminescence studies for both the epitaxial layers grown in the nitrogen carrier gas and in the hydrogen carrier gas were described for the sake of comparison. A number of experiments successfully revealed a residual impurity in an undoped epitaxial layer. It was

Single-crystal high-T/sub c/ BiSrCaCuO films were grown on

The photoluminescent intensities of nanocrystal ZnS:Tb and ZnS:Eu synthesized using a new technique were 2.5 and 2.8 times higher than those of bulk phosphors. Taking charge compensation into account, the luminescent efficiency of the nanocrystals can be improved. The cathodoluminescence of the nanocrystals was observed for the first time. These nanocrystal phosphors are promising for field emission display, electroluminescence, plasma‐display panels, and cathode ray tubes. © 2000 The Electroche

Nanocrystals of Tb- or Eu-doped ZnS were prepared using a new technique yielding high luminescent efficiency. The photoluminescent intensities of nanocrystal ZnS:Tb and ZnS:Eu were about three times higher than those of bulk phosphors. These nanocrystals were coated by a glass ingredient. The cathodoluminescent efficiency was improved by contriving the synthesis of glass-ingredient-coated nanocrystals. The cathodoluminescent intensities of the nanocrystals were more than ten times higher than th

Power‐generation experiments of solid‐oxide fuel cells with Ni/yttria‐stabilized zirconia cermet anodes were carried out by changing the water‐to‐methane ratio in the fuel. To separate the electrochemical reactions occuring on the three‐phase boundary of the anode from the steam‐reforming reactions, premixed gases corresponding to the composition at thermal equilibrium were used as the fuel. The reactions on the anode were quantitatively clarified at different steam‐to‐methane ratios by making a

Feed-forward neural networks (NNs) are a staple machine learning method widely used in many areas of science and technology, including physical chemistry, computational chemistry, and materials informatics. While even a single-hidden-layer NN is a universal approximator, its expressive power is limited by the use of simple neuron activation functions (such as sigmoid functions) that are typically the same for all neurons. More flexible neuron activation functions would allow the use of fewer neu