Effect of Ce3+ ion on Dy3+ or Mn2+ in KMgSO4Cl synthesized by centrifuge method

In this paper effect of Ce3+ ion on Dy3+ and Mn2+ ions in microcrystalline KMgSO4Cl host prepared by ethanol (centrifuge technique) method has been discussed. In KMgSO4Cl sample X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) characteristics have been studied. Powder X-ray diffraction analysis shows the crystalline nature of the phosphor prepared by this new route. The morphological structures of the samples were conducted using SEM technique. An average crystallite size was found to be 5 μm. Photoluminescence in KMgSO4Cl:Ce3+ is observed at 324 nm and 344 nm along with red emission broad band at around 644 nm. In KMgSO4Cl: Ce, Dy phosphor Ce3+ emission around 324 and 344 nm overlaps rather well with Dy3+ excitation. The addition of Ce3+ showed higher photoluminescence (PL) intensity for the Dy3+ emissions around 482 and 576 nm excited via Ce3+ ions at 284 nm due to 4F9/2 to 6H15/2 and 6H13/2 levels. Ce3+→Mn2+ energy transfer process occurs in KMgSO4Cl host. KMgSO4Cl: Mn does not give PL at 284 nm excitation but for co-doped samples with cerium, Mn2+ ions exhibits efficient fluorescence at around 560 nm due to 4T1-6A1 transition. KMgSO4Cl: Dy or KMgSO4Cl: Mn directly exciting does not show any emission while addition of Mn2+, enhances red emission of Ce3+ at 644 nm. The CIE co-ordinates of KMgSO4Cl:Ce; KMgSO4Cl:Ce, Dy and KMgSO4Cl:Ce, Mn phosphors reveals that the emission colour varies from blue to deep-red. Hence this material may be a potential lamp phosphor.