Polymers in general are a class of materials known to be excellent insulators. However -conjugated polymers are different in that they possess semiconductor characteristic properties. They actually can be transformed into excellent conductors with conductivities close to those of good metals by doping. In addition to electrical conductivity, -conjugated polymers also show luminescence upon electrical or optical excitation. Furthermore stimulated emission is another crucial feature of such materials that provides the possibility of attaining laser action. The present work concentrates on a...