Dy 3+ Activated Nearly White Emitting NaCdPO 4 as Potential Phosphors for Solid State Light Applications

A series of phosphate based phosphors NaCd1−xPO4: xDy3+(x = 0.02–0.1) are prepared by adopting conventional solid state reaction routes. The prepared phosphors are well characterized by x-ray diffraction to establish the phase purity while a field emission scanning electron microscope is used to detect the microstructure. The surface chemical composition, an important aspect of this work, is established by x-ray photoelectron spectroscopy. The photoluminescence excitation spectra are recorded at room temperature, in which the excitation maxima are observed at 347 nm, indicating a near ultraviolet (UV) excitation which can be useful for light emitting diodes with a UV chip. The emission spectra show three major emission lines at 480 nm (4F9/2 → 6H15/2) a blue emission, a yellow emission around 570 nm (4F9/2 → 6H13/2) and a red emission around 662 nm (4F9/2 → 6H11/2). The CIE 1931 color chromaticity diagram shows the color coordinates around (0.32, 0.31) and such phosphors can be useful for solid state lighting applications as the emission spectrum lies in the near white region in the color space.