Optical and electrical properties of polycarbonate/MnCl2 composite films

The dependence of the absorption coefficient (alpha) on photon energy (hv) is determined in the spectral range from 200 to 800nm at room temperature for polycarbonate (PC)/MnCl2 composite films. The variation of the absorption coefficient (alpha), optical gap (E-opt), dielectric permittivity (epsilon '), dielectric loss (epsilon ''), loss tangent (tan delta), impedance (Z), AC conductivity (sigma(ac)), DC conductivity (sigma(dc)), and relaxation time (tau) with salt concentration and frequency are reported. The observed optical energy gap (Eopt) and energy gap tail (Delta E) is calculated from the measured absorption spectra. It is found that optical energy gap decreases with increasing MnCl2 concentration and the absorption coefficient reduces sharply (with reduction ratio of 79%) in the UV region at concentration of 20 wt% compared with the PC host. All measured electrical parameters of the composite sheets show frequency and content dependence. Both AC conductivity and DC conductivity increase with MnCl2 concentration while impedance decreases. Correlation between observed energy gap and AC conductivity is presented.