Single-composition　(or　single-phase)　phosphors　have　been　proposed　as　a　new　strategy　to　overcome　the　concerns　of　emission　reabsorption　and　different　degradation　rates　of　the　three　primary　phosphors　for　light-emitting　diode　(LED)　applications.　A　series　of　Ce　3+　,　Sm　3+　and　Tb　3+　co-doped　NaSrBO　3　phosphors　were　synthesized　via　a　high　temperature　solid-state　reaction.　Upon　near　ultraviolet　(NUV)　excitation,　tunable　emission　from　violet　to　white　in　the　visible　region　was　realized　in　NaSrBO　3　:Ce　3+　,Sm　3+　,Tb　3+　phosphors　by　controlling　the　dopant　concentrations.　Particularly,　highly　efficient　white-light　emission　with　a　quantum　yield　as　high　as　48.2%　was　achieved.　The　energy　transfer　mechanism　between　Ce　3+　and　Sm　3+　ions　in　NaSrBO　3　was　found　to　be　predominantly　of　dipole-dipole　nature.　Moreover,　the　thermal　quenching　effect　on　the　photoluminescence　of　NaSrBO　3　:Ce　3+　,Sm　3+　,Tb　3+　was　comprehensively　surveyed　over　the　range　of　300-600　K,　showing　a　good　thermal　stability　for　LED　applications.　By　integrating　this　single-composition　white-emitting　NaSrBO　3　:Ce　3+　,Sm　3+　,Tb　3+　phosphor　with　a　360　nm　NUV　chip,　we　fabricated　a　high-performance　white　LED　(WLED),　which　exhibited　an　excellent　color　rendering　index　R　a　of　80.1　and　a　correlated　color　temperature　of　6731　K　with　CIE　coordinates　of　(0.311,　0.314).　These　findings　demonstrate　that　the　proposed　single-composition　white-emitting　NaSrBO　3　:Ce　3+　,Sm　3+　,Tb　3+　phosphors　can　serve　as　promising　phosphors　for　NUV-excited　WLEDs.　©　The　Royal　Society　of　Chemistry.