Green Emission of Erbium Doped SYW Phosphors for Optical Thermometry And Solid-State Lighting

A series of Er3+ ions doped Sr9Y2W4O24 (SYW) phosphors have been synthesised using solid-state reaction technique. For optical thermometry and solid state lighting applications, the crystal structure, morphological, and luminescence features of the SYW : Er3+ phosphors were explored. X-ray diffraction (XRD) reveal that synthesized phosphors having single phase with a tetragonal crystal structure and I41/a space group. Scanning electron microscopy (SEM) was used to examine the morphological behaviour and presence of composition elements. The optical bandgap of the phosphor was evaluated using UV-Vis diffuse reflection spectra (DRS). The photoluminescence (PL) emission spectra were captured under 380 nm excitation, and the peak with the maximum intensity was identified at 563 nm ascribed to transition 4S3/2 -> 4I15/2, that emits green color in visible region. The temperature dependent PL (TD-PL) spectra show that SYW phosphor is substantially more thermally stable, having thermal activation energy of about 0.247 eV. Additionally, the fluorescence intensity ratio (FIR) was used to study the optical sensing characteristics of the thermal quenching transitions (2H11/2, 4S3/2) with maximum relative sensitivity (SR) and an absolute sensitivity (SA) being 1.33 % K-1and 0.307 % K-1, respectively. All of the aforementioned findings demonstrate that SYW : Er3+ ions doped phosphors have potential for optical thermometry and other photonic devices. Graphical abstract showing the photoluminescence studies (emission spectra) of Er3+ doped SYW phosphors. The emission spectra recorded under the 380 nm excitation wavelength in the range 500-700 nmimage