Photoluminescence properties of Sm3+-doped La2O3 powders

The Sm3+-doped La2O3 powders were prepared by precipitation method. The room temperature photoluminescence (PL) spectra of Sm3+-doped La2O3 powders doped with different Sm3+ concentration excited at 405 nm have been investigated. The PL spectra showed three main strong emissions peaks at near 572, 613, and 657 nm, which were due to the f-f forbidden transitions of the 4f electrons of Sm3+, corresponding to (4)G(5/2)-> H-6(5/2) (572 nm), H-6(7/2)(613 nm), and H-6(9/2)(657 nm), respectively. The optimum Sm3+ concentration in La2O3 powders for optical emission was determined to be 2.0%. Since the 2% Sm-doped La2O3 offer a rather strong f-f transition excitation in near the UV region, the as-prepared phosphors are likely to be used as potential red phosphors for near-ultraviolet (370-410 nm) light-emitting diodes (LEDs).