Synthesis and photoluminescence characteristics of a novel Eu and Tb doped LiMoO phosphor.

LiMoO:x Eu and LiMoO:xTb phosphors, where x = 0.5, 1, 2, 3, 5 and 7 wt%, were synthesized through a gel-combustion method. The XRD data reveals that Eu and Tb doped LiMoO phosphors exhibit a Rhombohedral structure belonging to the space group R3 which matched well with the standard JCPDS files (No.012-0763). We present photoluminescence (PL) spectra from Eu and Tb doped LiMoO under 349 nm Nd:YLF pulses laser excitation over the temperature range of 10-300 K. Undoped LiMoO shows a wide broad band around 600 nm because of the intrinsic PL emission of tetrahedral of MoO which was in good agreement with previous findings. Under the excitation of 394 nm, the as-synthesized phosphors exhibited sharp and strong intensity PL emission signals in the red (612 nm, D→F transition) and green (544 nm, D→F transition), respectively. The critical doping concentration of Eu and Tb ions in the LiMoO were estimated to be 2 wt%. The concentration quenching phenomena were discussed, and the critical distances for energy transfer have also been evaluated by the concentration quenching.