Study of vacuum-evaporated poly(di-methyl silane) thin film and its application to dye-sensitized solar cell
Organopolysilanes are expected to be used for future optical and electronic devices. Poly(di-methyl silane), [Si(CH/sub 3/)/sub 2/]/sub n/, the most fundamental organopolysilane, is not solved in organic solvent at room temperature. Therefore, we have proposed the vacuum evaporation technique in order to obtain thin films of poly(di-methyl silane). In this paper, optical and electrical properties of poly(di-methyl silane) thin films are examined. As a result, it is found that the electric conductivity parallel to the Si backbone is larger by about three orders of magnitude than that perpendicular to the Si backbone. Moreover, highly oriented poly(di-methyl silane) thin film prepared by the vacuum evaporation technique is applied to the dye-sensitized solar cell, and we have succeeded in fabricating the perfectly solid-state dye-sensitized solar cell using poly(di-methyl silane) thin film.
Orientation of films prepared by the evaporation of poly(dimethyl silane)
This paper describes highly oriented films prepared by the evaporation of poly(dimethyl silane). The specimens are prepared at various evaporation speeds and substrate temperatures. The polymer is divided into species of about 2 nm length on the evaporation heater, and the species recrystallize on the substrate. The structure and orientation of the films are investigated using wide-angle X-ray diffraction and ultraviolet absorption methods. The substrates used are single-crystal silicon (100) for the X-ray diffraction measurement and fused silica for the ultraviolet absorption measurement. The polymer exhibits the same orientation on both substrates. It is found that most of the silicon chains are perpendicular to the substrate surface in the film prepared under the condition whose growth rate is lower than 20 nm min-1. On increasing the substrate temperature, the number of silicon chains whose orientation is normal to the substrate surface increases.
Investigations of dielectric gratings using electrodynamic models based on volume integral equations
Eigenmodes of planar and cylindrical dielectric gratings (DGs) and electromagnetic wave scattering from multiplayer DGs are investigated. The DG characteristics are calculated using numerical-analytical solution of integral equations (IEs).