Photoluminescence properties and energy transfer of novel orange–red emitting phosphors: Ba3Bi2(PO4)4: Sm3+, Eu3+ for white light-emitting diodes

Abstract

Sm3+, Eu3+ co-coped Ba3Bi2(PO4)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 Ba3Bi2(PO4)4 phase was obtained after heating at 980 °C for 5 h. A notably enhanced absorption efficiency at 393 nm was observed when Sm3+, as a sensitizer, was doped into Ba3Bi1.82(PO4)4: 0.18Eu3+ and the band gap of the Ba3Bi2(PO4)4 host was estimated to be 4.19 eV. The emission intensity of Ba3Bi1.82(PO4)4: 0.18Eu3+ was significantly enhanced when Sm3+ was co-doped. The existence and mechanism of energy transfer from Sm3+ to Eu3+ were evaluated by photoluminescence spectra and decay time measurements. The CIE chromaticity coordinate of Ba3Bi1.75(PO4)4: 0.07Sm3+, 0.18Eu3+ phosphor was calculated to be (0.5746, 0.4197), respectively.