Yoshio Inuishi

Characteristics of Polythiophene Battery

A secondary battery utilizing polythiophene films as cathode and anode active materials in an electrolyte of TBABF4/MeCN is studied. The cell potential, energy density and maximum power density (based on the weight of cathode and anode films) are observed to be 3.1 V, 93 Wh/kg and 89 kW/kg, respectively, for the dopant concentration of 24 mol%.

Electrical Properties of Conducting Polymer, Poly-Thiophene, Prepared by Electrochemical Polymerization

Poly-thiophene perchlorate is prepared electrochemically in an electrolyte of 0.5 M AgClO4 and 0.2 M thiophene in acetonitrile. Dark greenish film with the complex of ca. [C4H2S(ClO4)0.26]x is obtained. The electrical conductivity along the film surface is about 0.6 Ω-1cm-1.

Electrical and optical properties of polythiophene prepared by electrochemical polymerization

Abstract Electrical conductivities and optical absorptions of neutral and oxidized polythiophene films polymerized by the electrochemical method are reported. The electrical conductivity of polythiophene borofluoride film shows metallic value of ca. 100 S cm−1 at room temperature and decreases over 1010 times into semiconductive regime by the electro-chemical or chemical undoping. Absorption spectrum of polythiophene changes by the undoping from the characteristic of metal to interband transition with absorption edge ca. 2.0 eV and maximum absorption coefficient of ∼ 105 cm−1 at 2.7 eV.

Proposal of Electro-Optical Switching and Memory Devices Utilizing Doping and Undoping Processes of Conducting Polymers

New optical switching and memory elements utilizing the spectral change of conducting polymers by electro-chemical doping and undoping are proposed.

Characteristics of Electro-Optic Device Using Conducting Polymers, Polythiophene and Polypyrrole Films

Detailed characteristics of electro-optic elements (color switching and memory) utilizing the spectral change of conducting polymers by electrochemical doping and undoping are studied. The response time of color switching, for example, red↔blue in polythiophene film in the electrolyte of LiBF4/acetonitrile is 30~100 msec under the applied voltages of -2.0↔+4.0 V vs. Li plate. More than 103 cycles of color switch are observed quite reproducibly. Three color states of yellow green, dark brown and blue are demonstrated for polypyrrole film.

Raman and Infrared Studies on Vibrational Properties of Ge–Se Glasses

Raman scattering and infrared absorption measurements have been performed on amorphous Ge x Se 1- x with 0≦ x ≦0.4 and crystalline GeSe 2 . Molecular model is applied to explain the vibrational spectra of amorphous GeSe 2 . Variation of Raman spectra in Ge x Se 1- x glasses with Ge composition shows that local order is not largely changed with the glass composition. The vibrational spectra, particularly infrared absorption spectra, of amorphous and crystalline GeSe 2 are very similar; suggesting that amorphous GeSe 2 may have the same local order as crystalline GeSe 2 .

Optical and Electrical Properties of Electrochemically Doped n- and p-Type Polythiophenes

Absorption spectra have been measured on polythiophene films subjected to electrochemical Bu4N+ doping. The spectra show essentially the same evolution as those for BF-4 doping, i.e., peaks at 0.6~0.7 eV and 1.5~1.8 eV appear upon doping in addition to the band-to-band absorption peak at 2.6 eV. Propagation velocities of electrochemical doping of Bu4N+ and BF-4 along polythiophene films were estimated to be on the order of 10-3 cm/sec.

Carrier Mobilities in Insulating Polymers Measured by Time of Flight Method

Carrier mobilities of several insulating polymers such as PET, PS were studied by the time of flight method using pulsed electron beam bombardment. For example, the mobilities obtained in an electric field of 1~2 MV/cm were 2×10-5 cm2/Vsec for the electron and 1×10-4 cm2/Vsec for the hole at 27 °C in PET with the activation energy around 0.3 eV. At low field mainly the slow carrier component due to detrapping was observed, which apparently gave a much lower mobility. The carrier lifetime was also estimated from the Hecht curve. It was found that the quantum yield (number of induced carriers per impinging electron) was influenced seriously by the molecular structure.

Influence of Inter-Carrier Scattering on Hot Electron Distribution Function in GaAs

Influences of carrier-carrier scattering on the electron distribution function in GaAs has been examined by the Monte Carlo calculation taking into account electron-electron and/or electron-hole scatterings. The calculated results were compared with the experimental distribution functions determined from the band-to-band recombination spectra under high electric fields.

Electron‐beam‐induced conduction in polyethylene

The electrical conduction in polyethylene induced by the irradiation of the short pulsed electron beam (100‐nsec time width) consists of the fast and the slow components. The former is attributed to the carrier transport in the crystalline part and the latter to that in the amorphous part. A logarithmic plot (Scher‐Montroll plot) of the slow part of the induced current versus time gives a knee at time Tr, which is thought to be the transit time of the carrier front between electrodes. Simple calculation by the formula μ=L/TrE gives the apparent slow carrier mobility μ of 5.6×10−7 and 3.2×10−7 cm2/V sec for the electron and the hole, respectively, at 343 K under a field E of 1.2 MV/cm for sample thickness L of 12 μm. These apparent slow carrier mobilities are dependent on both the thickness and the field strength. These behaviors are discussed in terms of Scher‐Montroll theory on transport in amorphous substances. The activation energy of the mobility is in good agreement with the apparent trap depth obtai...