Dielectric properties and relaxation mechanism of organic trans-stilbene and p-terphenyl molecular crystals using impedance spectroscopy

•Dielectric properties of trans-stilbene and p-terphenyl are studied from 1 Hz–1 MHz.•Dielectric constant and loss spectra show quality and homogeneity of the crystals.•Electronic and molecular relaxation mechanisms were observed in trans-stilbene.•Secondary relaxation mechanisms were not presented in the p-terphenyl crystals.

Dielectric properties of trans-stilbene and p-terphenyl have been studied in the frequency range (1 Hz–1 MHz) at room temperature (300 K). The results of dielectric constant and loss spectra have revealed high quality and high homogeneity of the single crystalline phase of the crystals grown with negligible impurity and defect concentrations. The electrical modulus clearly shows a low frequency maximum indicating that the electronic relaxation processes were presented in the both crystals. The molecular relaxation mechanisms were also observed in the trans-stilbene crystals and no other secondary relaxation mechanisms were presented in the p-terphenyl crystals.