Polysilane photophysics

Photochemistry and photophysics of polysilanes is also discussed in the Chapter by Zeigler, Harrah and Johnson in this volume, ref. 15. 

The dynamics of polysilane dendrimer excited states were also studied by Watanabe as mentioned above in a comparison with polysilynes,360,364 and suggested that a configuration coordinate model is applicable to the photophysics of branched silicon chains. Calculations showed a distorted geometry of the excited state localized at a branching point. 

The polysilanes can be regarded as one-dimensional analogs to elemental silicon, on which, of course, nearly all of modem electronics is based. The photophysical behavior of polysilanes is not approached by any other materials, save for the less stable and more costly polygermanes and polystannanes. The remarkable properties of polysilanes have led to intense interest, and to numerous proposed high-tech applications. But the great promise of polysilanes as materials has yet to be realized. Their only commercial use at present is as precursors to silicon carbide ceramics, an application which takes no advantage of their optical or electronic properties. 

Interest in polysilanes was reawakened in 1975, when Yajima and Hayashi found that permethylpolysilane could be transformed into silicon carbide by heating at high temperatures. Soon afterward, papers on soluble, meltable polysilanes began to appear. The literature on polysilanes has grown rapidly since that time. The early focus on the synthesis and simple characterization of polysilanes has given way to detailed physical studies of the structure of these polymers, and of their electronic and photophysical properties. 

Polysilanes have been studied extensively in recent decades because of their interesting photophysical properties and potential applications [1]. Yet, much fundamental knowledge about these interesting molecules is still lacking. In particular, relatively little is known about the... 

Polysilanes adopt a helical conformation. This class of polymers has the Si o conjugating backbone, which allows the conformational study by means of photophysical analysis of the polymers.30-220 226 Two polysilanes, 130 and 131, were synthesized by the Na-... 

The chemistry of the polysilane (polysilylene) high polymers is undergoing rapid development. These polymers have unique photophysical properties of intrinsic scientific interest and are acquiring technological applications in several areas. Poly(silylenes) were reviewed in 198610, and several useful chapters on polysilanes appear in a recent monograph83. 

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