Electrical Conductivity and Dielectrical Properties of Bulk Methylene Green
Thermal stability, direct current conductivity (σDC), alternating current electrical conductivity (σAC) and dielectric properties of bulk methylene green (MG) have been investigated. The thermal stability of MG wasstudied by differential scanning calorimetry and thermogravimetrytechniques.Temperature dependence of σDC showed that the MG has semiconductor behavior with two activation energies determined as 0.12 and 0.31 eV in the temperature range 303-343 and 363-463 K, respectively. The σAC of bulk MG was performed in frequency range 150 Hz–5 MHz and temperature range 303–463 K. The dependence of AC conductivity on frequency for MG is found to satisfyJonscher’s universal power law especially at high frequencies.The correlated barrier hopping model is found to be applicable in which the density of localized states is determined. The σAC is thermally activated and the activation energy decreases with the increases in frequency. The variation of the real and imaginary parts of the dielectric constant with the frequency and temperature is explained.
Keywords- Methylene green; Thermal properties; Electrical conductivity; Correlated barrier hopping; Dielectric properties.