Structural and photoluminescence features of thermally stable red-emitting Pr3+-doped sodium calcium metasilicate phosphor for wLED applications

Microcrystalline pure phase praseodymium-doped Na4Ca4Si6O18 (NCMS: Pr3+) phosphors have been Synthesized and systematically characterized for implementation in wLED applications. High-temperature solid-state reaction methodology was opted to synthesize a series of NCMS: xPr(3+) (x = 0.0, 1.0, 2.0, 3.0 and 4.0 mol%) phosphor. X-ray diffraction pattern confirmed the phase purity and crystallinity of the as-prepared phosphor by comparing all the diffraction peaks with the standard pattern. The morphology of NCMS phosphor has been observed in the micrometre range and captured through the FE-SEM technique under 5 mu m resolution. Luminescence studies have been carried out in the visible region to illustrate the excitation and emission spectra of as-synthesized NCMS: Pr3+ phosphor. PL spectrum exhibits the radiative emission at 611 nm under the most intense excitation peak at 480 nm for 1.0 mol% of Pr3+-doped NCMS phosphors. The optimized concentration of dopant ion has been achieved by following the energy transfer-based concentration quenching mechanism and found to be 1.0 mol% for NCMS crystal. The chromaticity diagram represents the integrated emission colour of the optimized NCMS: 1.0 mol% Pr3+ phosphor, which falls in the red region with a colour purity of 97.0% when stimulated with blue light. Temperature-dependent luminescence studies are evident that the thermal stability of the prepared phosphor is quite high when utilized under the operating temperature of LEDs. Thus, the investigated outcomes encourage that the promising red-emitting NCMS phosphor can be utilized in wLED applications.