Temperature dependent charge transport and dielectric relaxation of Two-Dimensional RbPb2Br5 Layered-Halide

We have reported fundamental aspects on the vacancy mediated conduction and relaxation mechanisms of charge carriers in 2D RbPb2Br5 layered-halide synthesized via wet chemical method as well as its application in resistive switching devices. The structural deformation and phase transition are not observed in RbPb2Br5 layered-halide from temperature dependence of the XRD and DSC results respectively. The electronic band structure and TDOS are theoretically calculated and the obtained band gap from the calculation is around ~ 2.89 eV. The impedance results provide the grain and grain boundary contributions to the effective impedance in details. The temperature dependence of the DC conductivity (sDC) and the hopping frequency (wH) in the different temperature regions is explained by the predominance of the vacancy-mediated charge carrier conduction and relaxation due to the trap states formed by various defects in the layered-halide. The calculated activation energy for the DC conductivity in the low temperature region (Es,LTR ~ 0.073 eV) is comparatively lower than those obtained in the mid temperature (Es, MTR ~ 0.61 eV) and high temperature regions (Es, HTR ~ 1.07 eV). The high value of the activation energy at high temperatures is observed due to onset of the vacancy mediated charge carrier conduction leading to high DC conductivity. Furthermore, the value of the activation energy obtained from the DC conductivity is much closer to those obtained for the hopping frequency and the dielectric relaxation time in different temperature regions.