An intense red-emitting phosphor Sr 3 Lu(PO 4 ) 3 :Eu 3+ for near ultraviolet light emitting diodes application

Abstract A series of Sr 3 Lu(PO 4 ) 3 :Eu 3+ phosphors were successfully prepared via the solid-state method, and their luminescence properties were investigated. The excitation and emission spectra show that this phosphor can be effectively excited by near ultraviolet (NUV) light, and produces strong and prevailing red emissions at 612 nm belonging to the 5 D 0 → 7 F 2 electric dipole transition. Eu 3+ ion was heavy doped in Sr 3 Lu(PO 4 ) 3 host and the optimal concentration of Eu 3+ was found as 0.8. The critical transfer distance of Eu 3+ was determined to be 8.5 A. The concentration quenching was demonstrated to be caused by the energy transfer among the nearest-neighbor ions in the Sr 3 Lu(PO 4 ) 3 :Eu 3+ phosphor. Under excitation of 394 nm, the integral emission intensity of Sr 3 Lu 0.2 (PO 4 ) 3 :0.8Eu 3+ is about 6 times that of Y 2 O 3 :Eu 3+ . The CIE color coordinates of Sr 3 Lu 0.2 (PO 4 ) 3 :0.8Eu 3+ was (0.636, 0.354) located in red region. In addition, good thermal stability was also identified in Sr 3 Lu 0.2 (PO 4 ) 3 :0.8Eu 3+ and its emission intensity was reduced to 88% of its initial value at 100 °C and 70% at 200 °C. The current research suggests that Sr 3 Lu(PO 4 ) 3 :Eu 3+ could be a promising red phosphor for white LEDs and display devices.