Synthesis of novel Dy activated phosphate phosphors for NUV excited LED

The new trivalent dysprosium activated X₆AlP₅O₂₀ (where X=Sr, Ba, Ca and Mg) phosphors were prepared by the combustion method. The prepared phosphors are characterized by XRD, photoluminescence and SEM techniques. Excited by 350 nm near-ultraviolet (NUV) light, the phosphors show an efficient blue and yellow band emissions, which originates from the ⁴F_9/2→⁶H_15/2 and ⁴F_9/2→⁶H_13/2 transitions of Dy³⁺ ion, respectively. The excitation spectra of the phosphors are broadband extending from 340 to 400 nm, which are characteristics of NUV excited LED. The effect of the Dy³⁺ concentration on the luminescence properties of X₆AlP₅O₂₀:Dy³⁺ (where X=Sr, Ba, Ca and Mg) phosphors is studied. Ca₆AlP₅O₂₀ phosphors show strong PL emission intensity around 25 times more as compared to Ba₆AlP₅O₂₀, Sr₆AlP₅O₂₀ and Mg₆AlP₅O₂₀ phosphors. The investigated prepared phosphors are suitable for a NUV excited LED.