Photoluminescence properties and energy transfer of novel orange–red emitting phosphors: Ba <sub>3</sub> Bi <sub>2</sub> (PO <sub>4</sub> ) <sub>4</sub> : Sm <sup>3+</sup> , Eu <sup>3+</sup> for white light‐emitting diodes
Ruirui Cui, Xiang Guo, Xinyong Gong, Chaoyong Deng
Abstract
Abstract 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 °C 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 : 0.18Eu 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 : 0.18Eu 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 Ba 3 Bi 1.75 (PO 4 ) 4 : 0.07Sm 3+ , 0.18Eu 3+ phosphor was calculated to be (0.5746, 0.4197), respectively.