Sr3Lu (VO4)3: Eu3+ red-emitting phosphors for warm white LEDs

A series of novel red emission phosphors Sr3Lu1-x(VO4)(3):xEu(3+)(x = 0.007, 0.009, 0.02, 0.04, 0.06) were synthesized successfully by traditional high-temperature solid-state reaction. The results of X-ray diffraction (XRD) reveal the doped Eu3+ ions have replaced the lattice sites of Lu3+ ions. The diffuse reflectance spectra illustrate the energy gap of Sr3Lu(VO4)(3) host is 3.61 eV. The room-temperature steady-state fluorescence spectra show that these phosphors can be effectively pumped by the charge-transfer band (CTB) of the host in near ultraviolet (NUV) spectral region and then produce strong and pure red emission at 615 nm originated from D-5(0) -> F-7(2) electric dipole transition of Eu3+. The Commission Internationale de L'Eclairage (CIE) coordinates of Sr3Lu0.96(VO4)(3):0.04Eu(3+) are (x = 0.65, y = 0.35), which are very close to the red standard of National Television Standards Committee NTSC (0.67, 0.33). The fabricated warm white-light-emitting diodes (LED) demonstrate high color-rendering index Ra as 93. The results imply the red-emitting Sr3Lu(VO4)(3):Eu3+ phosphors could be potentially utilized in the fields of solid-state lighting.