Laser-induced generation of highly conducting areas in poly(bis-alkylthioacetylenes)

Abstract

This is the first report on physical studies of the laser-induced generation of highly conducting tracks in poly(bis-alkylthioacetylenes) (PATAC), which remain as an insulator ( σ = 10 −14 S cm −1) in the unexposed areas. The laser-produced permanent electrical conductivity lies in the range between 10 and 200 S cm −1 depending on the sample preparation and the laser irradiation conditions. To characterize the new materials and to study the modification processes, especially ESR, conductivity and Hall coefficient measurements were applied. The converted polymers are p-type semiconductors. At room temperature the estimated maximum Hall mobility is 10 cm −2V −1s −1. The electrical conductivity of the modified polymers is stable for a long time. The temperature coefficient of the resistance α is low and lies between 10 −3 and 10 −4K −1. The various properties of laser-modified PATAC allow one to state that on modification the product is intermediate between a semiconductor and a metal.