Temperature dependence of direct current conductivity in Ag-ED20 nanocomposite films

Resumo

The effect of silver nanoparticles (NPs) in the concentration range of ≤0.8 wt % have on direct current conductivity σ_dc of Ag-ED20 nanocomposite is studied by method of broadband dielectric spectroscopy (10⁻²–10⁵ Hz) method of broadband dielectric spectroscopy. It is found that temperature dependence σ_dc consists of two sections: above the glass transition temperature (T_g), the dependence corresponds to the empirical Vogel–Fulcher–Tammann law (Vogel temperature T₀ does not depend on the NP concentration); below T_g, the dependence is Arrhenius with activation energy E_a ≈ 1.2 eV. In the region where T > T_g, the σ_dc value grows along with NP concentration. It is concluded that the observed broken form of the temperature dependence is apparently due to a change in the conduction mechanism after the freezing of ion mobility at temperatures below T_g.