Effect of dispersed Ag on the dielectric properties of sol–gel derived PbTiO3 thin films on ITO/glass substrate

Ag-dispersed PbTiO3 films were prepared on ITO/glass substrate by the sol–gel process. XRD was carried out to characterize the crystalline phases. A spectrophotometer and LCZ meter were used to measure the UV–VIS absorption spectra and dielectric properties of the films. Ag particles had formed in the PbTiO3 matrix. Their size and quantity increase with the increase in silver concentration. Ag particles are found to have an effect on the dielectric properties of PbTiO3 films. With the addition of Ag nanoparticles into PbTiO3 films initially, the dielectric constant of the films increases and the dissipation factor of the films decreases. Then with increasing of silver concentration, the dissipation factor of the film increases. However, the effect of the dispersed silver nanoparticles on dielectric constant gives different results at different frequency ranges. At low frequency it increases with the increase in silver concentration, which coincides well with percolation law. At high frequency, when silver concentration reaches 5 mol%, the dissipation factor markedly increases and the dielectric constant decreases, which departs from percolation law due to the interaction of ferroelectrics domains and silver particles.