Structural and optical properties of strontium/copper co-doped lithium borate glass system

Abstract

There is continuous search for materials having superior optical and structural properties in glass photonics, thermoluminescence dosimetry and phosphors fields. A new series of copper (Cu)/strontium (Sr) co-doped lithium borate glasses (LB:Sr, Cu) of composition (85 - x)H3BO3-15Li2CO3-2SrCO3-xCu2O, where x = 0.005 to 0.1 mol% were prepared using melt quenching method. Synthesized glasses are characterized to determine the concentration's effect of copper ions (Cu2+) on modification of the structural and optical properties. XRD patterns confirmed the amorphous nature and FESEM verified the homogeneous surface morphology. EDX spectra authenticated the accurate elemental traces. Glasses are thermally stable with Hurby parameter ~0.5. Glass density decreases with the increasing Cu2+ concentration. FTIR peaks in the range of 698-1070 cm-1 attribute to trigonal and tetrahedral stretching vibrations of BO3 and BO4 units. The direct/indirect band gap and Urbach energy vary from 3.1-2.8 eV/2.94-2.84 eV and 1.2-2.18 eV, respectively. The observed increase in refractive index ascribed to the conversion of BO4 into BO3 units. PL spectra under 280 nm excitations display two peaks centered at 482 and 526 nm accompanied by slight peak shift towards the lower wavelength. Excellent structural and spectroscopic characteristics of the present glass compositions indicate prospects for various photonic devices.