Energy transfer and luminescence properties of BaSr2Gd1-xMx(PO4)3 (M= Dy, Tm, Eu) phosphors for warm white UV LEDs

Abstract Novel single-phased white-light-emitting and color tunable BaSr 2 Gd(PO 4 ) 3: Dy 3+ , Tm 3+ , Eu 3+ phosphors were synthesized by solid-state reaction method and characterized with power X-ray diffraction (XRD), photoluminescence excitation (PLE), photoluminescence (PL) and PL delay spectral measurement. Under the excitation of ultraviolet, dual energy transfer, namely, Dy 3+ to Tm 3+ and Dy 3+ to Eu 3+ , exists in the system of BaSr 2 Gd(PO 4 ) 3 :Dy 3+ ,Tm 3+ ,Eu 3+ . The emission color of these phosphors can be accurately changed from greenish blue to blue via ET of Dy 3+ to Tm 3+ and from yellowish green to yellow via ET of Dy 3+ to Eu 3+ . Under the excitation at 388 nm, BaSr 2 Gd 0.91 (PO 4 ) 3 :0.04Dy 3+ ,0.03Eu 3+ ,0.02 Tm 3+ phosphor showed bright a white light with chromatic coordinate of (0.329,0.349). The as-prepared phosphors have a great potential as a credible candidate for near ultra-violet excited white light emitting phosphor.