A　series　of　Dy3+-,　Tm3+-,　Eu3+　co-activated　Ba2CaLa(PO4)(3)　phosphors　were　synthesized　via　a　standard　solid　state　reaction　under　normal　ambient　air,　and　the　emission　colors　could　be　tuned　from　blue　to　white　and　then　to　red.　It　was　discovered　that　the　energy　is　transferred　from　Tm3+　to　Dy3+　by　directly　observing　overlap　of　the　excitation　spectrum　of　Dy3+　and　the　emission　spectrum　of　Tm3+　and　Dy3+.　By　utilizing　the　principle　of　energy　transfer,　we　have　demonstrated　that　with　appropriate　tuning　of　activator　content,　Ba2CaLa1-x-y-z(PO4)(3):xDy(3+)-yTm(3+)-zEu(3+)　phosphors　exhibit　great　potential　for　use　as　single-component　phosphors　for　warm　white　ultraviolet　light-emitting　diodes　(UV　LEDs).　(C)　2015　Elsevier　Ltd　and　Techna　Group　S.r.l.　All　rights　reserved.