Development of colour tunable phosphor via rare earth doping in eulytite type Ba3Bi2(PO4)4 host material

Recently, Eulytite type Ba3Bi2(PO4)(4) host material has shown promising characteristics of efficient and thermally stable photoluminescence (PL). In the present work, Ba3Bi2(PO4)(4) host material doped singly, doubly and triply with rare earth ions (Dy3+, Eu3+ and La3+) phosphors were prepared by conventional solid-state reaction method. Resultant phosphors were characterized by X-ray diffraction, fourier transform infrared (FTIR) and PL techniques. FTIR spectra shows the characteristic stretching vibrations of PO4 tetrahedron at 1300 and 675 cm(-1). All of the doped and co-doped phosphors show the effective excitation in near UV and blue region. The PL emission spectra of Dy3+ doped Ba3Bi2(PO4)(4) phosphors showed two characteristic peaks in blue and yellow region and Eu3+ doped Ba3Bi2(PO4)(4) phosphors PL emission spectra dominated by the peaks in orange-red region. The spectral tuning is achieved via single, double and triple doping of Dy3+, Eu3+ and La3+ ions in Ba3Bi2(PO4)(4) host lattices. Critical distance of energy transfer and the type of multipolar interaction responsible for concentration quenching in Dy3+ and Eu3+ ion doped phosphors were estimated. CIE co-ordinates of all synthesized phosphors were obtained: Dy3+ ions doped phosphor show faint cyan hue (0.2739, 0.3409), Eu3+ ions doped phosphor show orangish colour (0.5177, 0.4720), doubly (Dy3+, Eu3+) doped phosphor show faint orange colour (0.3999, 0.3531) and La3+ ions doubly doped phosphor show white colour with an orangish shade (0.3585, 0.3548). Correlated colour temperature around 4525 K which is less than 5000 K which makes it a suitable candidate for warm white light for indoor lighting purpose. Studied phosphors shows tuning of the colour with changing the rare earth doping and co-doping ions. With the sharp excitation in near UV and blue region and color tuning makes this phosphor eligible for further exploration for the application in phosphor converted-LED.