Room temperature electrical analysis of Pr³⁺ doped silicate glasses for energy storage applications

Composite glasses possessing amorphous nature and high dielectric constants exhibit properties suitable for optoelectronic and electrochemical applications. Multi-component silica calcium phosphate glasses doped with 0.5 and 1 mol% of trivalent praseodymium (Pr³⁺) were synthesized by the sol-gel method. The Pr³⁺ doped and undoped glasses were compared at room temperature (300 K) for analyzing their electrical variations. Dielectric studies predicted an increase in the dielectric constant and conductivity in the doped sample when compared to the undoped glass. A high dielectric constant of 89.2 was observed in the optimally doped glass at 1 kHz. The value of the capacitance increases to the order of nanofarads as the concentration of Pr³⁺ increases, indicating enhanced storage in the material. The AC conductivity of the highly doped sample evidenced a high value of 2.9 x 10^-5 S/cm at 10 MHz. The Cole-Cole plot of the glasses demonstrated a single flattened semicircle due to the lack of grains. The equivalent circuitry constitutes a constant phase element (CPE) in series to a parallel circuit of a resistor and CPE. The behavior is indicative of the suitability of the glasses as cathodes. The increase of capacitance with doping in the low-frequency region suggests the use of glasses as energy storage dielectric materials in condensers.