Synthesis and optical properties of Ba3Bi2 (PO4)4:Dy3+ phosphors for white light emitting diodes

The single-component Dy3+ activated Ba3Bi2 (PO4)(4) white light emitting phosphors were prepared by solid state reaction method. The phase formation of these phosphors was characterized by powder X-ray diffraction (PXRD) patterns. The photoluminescence properties and the surface morphology of these phosphors were investigated. The excitation spectrum of the Dy3+ characteristic emission at 575 nm exhibited narrow bands in the 300-450 nm range. Exciting the Ba3Bi2-x(PO4)(4):xDy(3+) x= 0.03, 0.06, 0.09, 0.12, 0.15, 0.18(here after abbreviated as BaBiPO:Dy3+) phosphor with 349 nm (near UV), the emission bands were observed at 470 nm (blue), 575 nm (yellow) and 664 nm (red) corresponding to the tran-sitions (F-4(9/2) -> H-6(15/2)), ((4)F9/2 -> H-6(13/)2), and (F-4(9/2) -> H-6(11/2)) respectively. The phosphor with x = 0.09 Dy3+ ion showed the maximum luminescence intensity. The luminescence lifetime of these phosphors were found to be in the millisecond range. The temperature dependent luminescence of BaBiPO:0.09Dy(3+) phosphor for 349 nm excitation was investigated and the calculated activation energy, Delta E, was 0.262 eV. The quantum efficiency and the colour rendering index were calculated. In addition, the Commission International del'Eclairagethe (CIE) chromaticity coordinates of these phosphors were found to be located in the near white region (x = 0.329, y = 0.349). These results indicate that the BaBiPO:Dy3+ phosphor has great potential as a single-component white-light-emitting phosphor for near-UV excitation. (C) 2018 Elsevier B.V. All rights reserved.