A red-emitting LiLa(2)O(2)BO(3):Sm(3+),Eu(3+) phosphor has been synthesized and characterized optically for white light-emitting diodes (LEDs). Because the oxyborate group (O(2)BO(3)(-7)) can contain high Eu(3+) concentration without concentration quenching, LiLa(2)O(2)BO(3) is a suitable host material for red-emitting phosphor for near-ultraviolet (n-UV) LEDs. When LiLa(2)O(2)BO(3):Eu(3+) was co-doped with Sm(3+), emission intensity of Eu(3+) was enhanced by similar to 30% than that of the sample without Sm(3+) owing to the energy transfer from Sm(3+) to Eu(3+). This energy transfer was confirmed by faster decay times of Sm(3+) as energy donors. LiLa(2)O(2)BO(3):Sm(3+),Eu(3+) showed a relative brightness of 334.7% of that of Y(2)O(2)S:Eu(3+), commercial red-emitting phosphor for n-UV LEDs. (C) 2008 The Electrochemical Society.