Tuneable luminescence of Pr3+-doped sodium aluminium gadolinium phosphate glasses for photonics applications

Abstract

Pr3+ doped sodium aluminium gadolinium phosphate (Pr:NaAlGdP) glasses were prepared to characterize on the structure, physical and especially spectroscopic properties. From XRD and FTIR results, synthesized glasses had the amorphous nature with phosphate complexes as the main structure units. The density, molar volume and refractive index of glass increased with increment of Pr2O3 concentration. The absorption spectra demonstrated the strong absorbance of Pr3+ dopant in visible light and near infrared region. The emission spectra recorded under 444, 468 and 481 nm excitation exhibited overlapping of Pr3+ emission from two emitting levels, 1D2 and 3P0. The 1D2→3H4 transition was of the highest intensity with emission maxima at 600 nm. The distinct excitation wavelengths caused the different emission patterns, resulting to the tuneable color of emission as pink, orange, and reddish orange. The optimum concentration of Pr2O3 in NaAlGdP glass is 0.1 mol% with the highest photoluminescence intensity and the 2nd longest decay time in hundred microsecond order. The non-single exponential decay profile and the reduction of decay time with added Pr2O3 content indicated the resonant energy transfer between Pr3+ ions. The high values of stimulated emission cross-section, branching ratio and quantum efficiency from Judd-Ofelt analysis confirmed the potential lasing action and light emitting with 600 nm from this glass. The radioluminescence study also represented the interesting ability of glass for X-ray detection. The Pr:NaAlGdP glass is a promising new photonics material for the tuneable light source, LED, display / screen, waveguide and laser medium.