Dielectric and transport properties of bismuth sulfide prepared by solid state reaction method

We report synthesis of bismuth sulfide (Bi2S3) via conventional solid state reaction method at low temperature similar to 150 degrees C and ambient pressure. X-ray diffraction analysis confirmed the orthorhombic phase of prepared material. Transmission electron microscope images revealed the formation of nanorods having diameter similar to 20 nm and length similar to 100 nm to similar to 150 nm. Impedance and modulus plane plots from 20 Hz to 2 MHz show presence of bulk and grain boundary phases in Bi2S3 at each measurement temperature from 310 K to 400 K. An equivalent circuit model comprised of two resistance-R and constant phase element-Q (RQ) loops in series explains the electrical parameters (resistance and capacitance) and relaxation processes coupled with grains and grain boundaries. The conduction in Bi2S3 obeyed adiabatic small polaron hopping model. High and temperature dependent dielectric constant was observed in Bi2S3 suggesting it as an efficient material to be used in capacitive energy storage devices. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4781004]