Enhanced emission of Eu3+ in lutetium tungsten molybdenum oxide phosphors: Synthesis, optical properties, thermal behavior, and LED packaging

By adjusting molar ratios of raw materials of Lu2O3 (Eu2O3) to WO3 and MoO3 as well as WO3 to MoO3, several lutetium tungsten molybdenum oxide phosphors Lu2W0.5Mo0.5O6, Lu2WxMoyO9 (x + y = 2), Lu2W1.5Mo1.5O12, and Lu6W0.5Mo0.5O12 were synthesized through a solid-state reaction method. The materials were characterized by X-ray diffraction (XRD) patterns, scanning electron microscope (SEM) images, energy-dispersive spectra (EDS), diffuse reflection (DR) spectra, room temperature photoluminescence (PL) excitation and emission spectra, luminescence decay curves, and temperature dependent PL spectra. Red shift excitation bands were recorded in Lu2WxMoyO9 (x + y = 2) phosphors with the concentration of Mo6+ increasing. Enhanced Eu3+ excitation and emission spectra were observed in the Lu2WxMoyO9 (x + y = 2) phosphors with the concentration of W6+ increasing. Possible energy transfer processes were proposed to explain the PL excitation and emission spectra. By combining phosphors with 365 nm ultraviolet (UV) chips, the obtained light emitting diodes (LEDs) gave bright red light under forward bias current. The results suggest that the obtained Eu3+ doped Lu2WMoO9 have potential applications in phosphor converted based UV LEDs.