Structural and luminescent properties of dysprosium ions-doped tungstate phosphor for w-LEDs

Abstract

In the present research work, a Dy3+ doped Tungstate phosphor that emits light in white region has been synthesized using conventional solid-state reaction. An X-ray diffraction (XRD) pattern for the as-synthesized phosphor material was recorded for structural analysis and phase identification. The diffraction peaks of the tungstate phosphor match very well with the standard JCPDS pattern. The optical band gap value of the as-synthesized phosphor has been measured using diffuse reflectance spectra (DRS). The photoluminescence (PL) spectral features recorded for the Dy3+ ions activated tungstate phosphor under 360 nm excitation reveal strong emission peaks in blue (490 nm), a relatively less intense peak in the yellow region (580 nm) and a significantly less intense red peak (683 nm). From the recorded PL spectra, the CIE chromaticity coordinates (0.33046, 0.37422) estimated for 1.0 mol% doping concentration of Dy3+ ions in the as-prepared phosphor material are falling in the white region. CCT value (5580K) signifies its application for cool white light-emitting diode (w-LEDs). The PL decay spectral profile recorded at 480 nm emission under 360 nm excitation shows double exponential behaviour. The temperature-dependent PL (TDPL) measurements demonstrate relatively better thermal stability for the as-synthesized phosphor. All the investigations carried out finally allow us to contemplate the suitability of Dy3+ ions doped tungstate phosphor for w-LED.