Structural and photoluminescence properties of Sm3+ ions doped strontium yttrium tungstate phosphors for reddish-orange photonic device applications

Abstract

In the present research work, Sm3+ ions doped Strontium Yttrium Tungstate (Sr9Y2W4O24) phosphors entitled to emit reddish-orange light have been synthesized using the conventional solid-state reaction method and analyzed their structure and phase using X-ray diffraction (XRD) patterns. The diffraction peaks of the Sr9Y2W4O24 phosphor matches very well with the standard JCPDS pattern with card no. 49-0568. The morphological behaviour of the as-synthesized phosphor has been studied using scanning electron microscopy (SEM). Different vibrational bands present in the titled phosphor have been examined using Fourier Transform Infrared (FT-IR) spectroscopy. The optical band gap values of the as-synthesized phosphors have been measured using diffuse reflectance spectra (DRS). The photoluminescence (PL) spectral features recorded for Sm3+ ions activated Sr9Y2W4O24 phosphor under 405 nm excitation reveal strong visible reddish-orange emission at 604 nm pertaining to the 4G5/2 → 6H7/2 transition of Sm3+ ions. Also the PL spectra show concentration quenching at 2 mol% of Sm3+ ions doped in to them. From the recorded PL spectra, the CIE chromaticity coordinates estimated for Sr9Y2W4O24:2.0mol% of Sm3+ phosphor are falling in deep visible reddish orange region. The PL decay spectral profiles recorded at 604 nm emission under 405 nm excitation are showing double exponential behavior and the experimental lifetimes are found to be decreasing with increase in Sm3+ ions concentration in the assynthesized phosphors. The temperature-dependent PL (TD-PL) measurements demonstrate relatively better thermal stability for the as-synthesized phosphor. All the investigations carried out finally allows us to contemplate the suitability of Sm3+ ions doped Sr9Y2W4O24 phosphor for reddish-orange photonic device applications.