Secondary doping: A new concept in conducting polymers

Phenomenologically, a primary dopant for a conducting polymer is a substance which drastically changes the electronic, optical, magnetic, and/or structural properties of the polymer and is accompanied by a large increase in conductivity. Phenomenologically, a secondary dopant is an apparently “inert” substance which, when applied to a primary‐doped polymer, induces still further changes in the above properties including a further increase in conductivity. The concept of secondary doping will be illustrated using polyaniline and its derivatives.