Photoluminescence properties and energy transfer of novel orange–red emitting phosphors:Ba_(3)Bi_(2)(PO_(4))_(4):Sm^(3+),Eu^(3+) for white light-emitting diodes

Sm^(3+), Eu^(3+)co-coped Ba_(3)Bi_(2)(PO_(4))_(4) phosphors,as potential phosphors for white light-emitting diode applications, were synthesized through the solid-state reaction method for the first time. The crystal structure,absorption spectra, photoluminescence properties, decay time, energy transfer mechanism, temperature-dependent properties, and Commission International De L’Eclairage(CIE) chromaticity coordinates were investigated systematically. The pure eulytite-type Ba_(3)Bi_(2)(PO_(4))_(4) phase was obtained after heating at 980 ℃ for 5 h. A notably enhanced absorption efficiency at 393 nm was observed when Sm^(3+), as a sensitizer, was doped into Ba_(3)Bi_(1.82)(PO_(4))_(4): 0.18 Eu^(3+)and the band gap of the Ba_(3)Bi_(2)(PO_(4))_(4) host was estimated to be 4.19 eV. The emission intensity of Ba_(3)Bi_(1.82)(PO_(4))_(4): 0.18 Eu^(3+)was significantly enhanced when Sm^(3+)was co-doped. The existence and mechanism of energy transfer from Sm^(3+) to Eu^(3+)were evaluated by photoluminescence spectra and decay time measurements. The CIE chromaticity coordinate of Ba3 Bi1.75(PO4)4: 0.07 Sm^(3+), 0.18 Eu^(3+) phosphor was calculated to be(0.5746, 0.4197), respectively.