Towards Solid State Investigations on Polyacetylene

Abstract

Even when single crystals of conventional semiconductors and metals became available, quantitative, reproducible measurements of their optical properties posed serious problems to the investigator. For a long time, reflectivity data have been dominated by the surface properties (roughness, adsorbed impurities etc.) until improved preparation techniques were developed. Many of the optical measurements on polyacetylene have been performed under very ill-defined conditions (surface as prepared, in air etc.) and and also neglecting the specific morphology of the Shirakawa-type material. Our improved synthesis allows the preparation of highly oriented polyacetylene (cis and trans) with well-defined bulk properties as well as a sample surface with a sufficient quality for optical investigations in a wide spectral range. Careful experiments allowing a quantitative evaluation of optical properties are decribed, which are indispensible for the determination of other physical properties.