There is provided a material comprising a n-doped electrically conductive polymer comprising at least one electron-deficient aromatic moiety, each electron-deficient aromatic moiety having a gas-phase electron affinity (E A ) of 1-3 eV; and at least one counter-cation covalently bonded to the polymer or to a further polymer comprised in the material, the polymer being n-doped to a charge density of 0.1-1 electron per electron-deficient aromatic moiety, the polymer being capable of forming a layer having a vacuum workfunction (WF) of 2.5-4.5 eV, and wherein all the counter-cations comprised in the material are immobilised such that any electron in the polymer cannot significantly diffuse or migrate out of the polymer. There is also provided a method of preparing the material.