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.
Crystal structures of poly(di-n-butyl silane) and poly(di-n-pentyl silane)
The crystal structures of poly(di-n-butyl silane) and poly(di-n-pentyl silane) have been determined by comparing the experimental X-ray diffraction pattern with the theoretical pattern. The side-chain conformation is mostly determined by the intramolecular steric hindrance as well as the van der Waals interaction between the side chains. The Si backbone conformation of both crystals is a 7/3 helix, which is mainly determined by the intramolecular van der Waals interaction between the nearest-neighbour side chains. On the other hand. The Si backbone conformation of both crystals after a pressure treatment of 1500 MPa is all trans, which is caused by the van der Waals interaction between the side chains attached to the second-nearest-neighbour Si atoms; In all cases, one of the two C-Si-C-C groups in Si(C4H9)2 or Si(C5H11)2 is an essentially trans conformation. Whereas the other C-C-Si-C group has a cis-like conformation, which is different from that generally accepted.
Radiation-induced conductivity in poly(methylphenylsilylene) and poly(di-n-hexylsilylene) studied by time-resolved microwave conductivity
The transient conductibility change resulting on nanosecond pulsed irradiation of poly-(methylphenylsilylene) (PMPS) and poly(di-n-hexylsilylene) (PDHS) has been studied using the time-resolved microwave conductivity (TRMC) technique from nanoseconds to milliseconds after the pulse. The transients show a dispersive decay. In PMPS, where the hole is the major charge carrier, the mobility at room temperature appears to decrease with time from an initial value of at least 3×10 -8 m 2 /V-s on a nanosecond time scale to a value 1 order of magnitude less at milliseconds