Photocarrier generation and transport in sigma -bonded polysilanes.

Polysilanes, even those containing no ..pi.. electrons, are found to be excellent photoconductors. In the materials studied to date, only holes are mobile but they have a well-defined mobility of about 10/sup -4/ cm/sup 2//VXat room temperature. In poly(phenylmethylsilane), the material we have studied most intensely, the hole-generation quantum efficiency is about 1% at high electric fields and the experimental results indicate that the holes are generated when excitons, formed when a photon is absorbed, diffuse to the surface of the film. The exciton diffusion length is found to be 500 A. These results help confirm the existence of extensive conjugation among sigma bonds in polysilanes.