Optoelectrical Properties of Ferroelectric PC/Ceramic Composites

Polycarbonate (PC)/ceramic (YSiBTS) composites were prepared using the casting technique. The dependence of the absorption coefficient (alpha) on photon energy (h upsilon) was determined in the spectral range from 200nm to 800nm at room temperature. The variation of the absorption coefficient (alpha), optical gap (E-opt), relative permittivity (epsilon'), AC conductivity (sigma(AC)) with YSiBTS ceramic concentration and frequency are reported. The observed optical energy gap (Eopt) was calculated from the measured absorption spectra. It was found that optical energy gap decreases with ceramic concentration and the absorption coefficient highly increases in the UV region at concentration of 18wt% compared with the PC host. The dielectric constant and AC conductivity was measured for PC/ceramic composites at temperature range between 25 degrees C to 140 degrees C and at different frequency values (120 Hz, 1 kHz, 10 kHz, and 100 kHz). The obtained results indicate that PC modifies the dielectric properties of ceramic. At the same time addition of ceramic to PC polymer enhanced both dielectric constant and the polar character of PC matrix. It is also shown that at high ceramic content, the dielectric constant is independent of temperature between 30 degrees C and 90 degrees C. Additionally, there is agreement between the optical energy gap and AC conductivity results. Correlation between obtained results and SEM results is presented.