Enhancement of electrical conductivity associated with non-bridged oxygen defects in molybdenum phosphate oxide glass via doping of SrO

Based on the attractive properties of phosphate glass, improved molybdenum phosphate glasses of composition 40P 2 O 5 , 20MoO 3 , 15MgO, (25-x)Li 2 O, xSrO, [x = 0, 5, 10, 15 and 20 mol %] were prepared via the melt - quench technique. They were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–visible reflectance and Electron spin resonance (ESR). FTIR confirmed the existence of several structural phosphate groups other than MoO 4 and MoO 6 units. Optical analysis revealed the active species of molybdenum ions. SrO addition decreases the bandgap energy, converting the glass insulator features into semiconductor properties. The measured AC electrical conductivity (σ ac ) increased within the temperature range of 298–473(K) and decreased in the frequency range of 0.042 kHz–1 MHz. The estimated DC electrical conductivity increased with temperature, suggesting the semiconducting behavior. The highest electrical conductivity was found in base and 5% SrO samples. Therefore, it appears that the prepared glasses are viable candidates for opto-electronic applications.