Study of optical properties of Sr10(PO4)6F2 apatite kind phosphor prepared by co-precipitation method for W-LED applications

Sr 10 (PO 4 ) 6 F 2 doped with Eu and Dy and co-doped with Ce and Eu, is successfully synthesized by the low-temperature co-precipitation method for the first time using ammonia solution. The Rietveld refinement of the X-ray diffraction pattern confirms that it crystallized into hexagonal form and corresponds to the P63/m space group. SEM and EDS confirm that Sr 10 (PO 4 ) 6 F 2 formed with good morphology. As synthesized Sr 10 (PO 4 ) 6 F 2 :x% Eu 3+ luminescent material, it shows intense emission in the red region, while Sr 10 (PO 4 ) 6 F 2 :x% Dy 3+ shows emission in both the yellow and blue regions, which produces white emission with moderate concentration quenching approximately equal to 7 mol% and 5 mol%, respectively. The critical distance between Eu 3+ ions was determined to be 16.5878 Å and 18.56011 Å for Dy 3+ ions. From Dexter theory, we concluded that nonradiative dipole–dipole interaction is responsible for the concentration quenching effect for both activator emissions. Sr 10 (PO 4 ) 6 F 2 :7%Eu 3+ has comparatively longer lifetimes of the 7 F 0 → 5 L 6 shifts of Eu 3+ (≈3.52 ms), and Sr 10 (PO 4 ) 6 F 2 :5%Dy 3+ has an average lifetime equal to 1.42 ms for the ( 4 G 5/2 to 6 H 5/2 ) shift of Dy 3+ ions. Sr 10 (PO 4 ) 6 F 2 doped with 7% Eu 3+ has a comparatively lower band gap (3.9037 eV) than 5% Dy 3+ (3.9193 eV) obtained from the Tauc plot. The analysis of the optical characteristics of the Sr 10 (PO 4 ) 6 F 2 : Eu 3+ , Ce, and Dy 3+ phosphors proposed that this is a good candidate for applications as a red- and white-emitting luminescent material, respectively, for white LEDs and display applications.