Electrical transport in ethyl cellulose-chloranil system

The charge-transport behaviour in pure and chloranil (Chl) doped ethyl cell ulose (EC) system has been studied by measuring the dependence of current o n field, temperature, electrode material and dopant concentration. The role of doping molecular concentration in the polymer matrix and modification i n the conduction characteristics are studied. Lowering of the activation en ergy due to doping was observed. The current was found to increase with an increase in the chloranil concentration. An explanation for this has been a ttempted on the basis of formation of molecular aggregates between chlorani l molecules and ethoxy groups of ethyl cellulose. It is suggested that chlo ranil occupies interstitial positions between the polymer chains and assist s in carrier transportation by reducing the hopping barriers. The current-v oltage characteristics of different samples are analyzed using space charge limited current theory and quantitative information about the transport pa rameters is derived. The values of effective drift mobility and trapped cha rge carrier concentration which result in the build up of space charge have been calculated.