White light emitting thermally stable bismuth phosphate phosphor Ca <sub/>3</sub> Bi( <scp>PO</scp><sub/>4</sub> ) <sub/>3</sub> :Dy ³⁺ for solid state lighting applications

摘要： White light emitting dysprosium doped Ca3Bi(PO4)3 phosphor was successfully synthesized via co-precipitation method for the first time and the structural, vibrational, morphological and luminescent properties have been investigated for solid state lighting applications. The X-ray diffraction (XRD) and structural refinement studies reveal that the synthesized phosphors consist of single phase with cubic structure. The field emission scanning electron microscopy (FE-SEM) images reveal that the as-synthesized phosphor has micron size with an irregular shape. Under near ultraviolet (n-UV) and blue excitation, the phosphor exhibits white light emission via a combination of blue (~451 nm) and yellow (~575 nm) emission bands. The optimized concentration of Dy3+ ions is 6.0 mol % after which the concertation quenching takes place. The process of energy transfer between Dy3+ ions is due to dipole-dipole interaction, which was confirmed by applying Dexter and Reisfeld’s Energy Transfer (ET) formula. The CIE chromaticity coordinates for the optimized phosphor were (0.329, 0.377), which lie in the white light region. The emission intensity remains to 83.41% at 373 K to that of at room temperature, which indicates good thermal stability. The above mentioned results demonstrate that Ca3Bi(PO4)3 is a potential phosphor for solid state lighting applications.