Synthesis and Characterization of CaAl2O4: Dy3+ and CaAl2O4: Sm3+ Phosphor Powders

Abstract

Calcium aluminate, CaAl2O4 is efficient and well known host material for inorganic phosphors. Although this host structure is mostly doped with Eu2+, different types of rare earth ions have also been studied. In this study, attention was drawn to CaAl2O4 type phosphors doped with Dy3+ and Sm3+ at different concentrations. Ca1-xAl2O4: Dy3+x (x= 0.008, 0.012, 0.02, 0.03) and Ca1-yAl2O4: Sm3+y (y= 0.008, 0.012, 0.02, 0.03) phosphors were synthesized as powder samples through the solid-state reaction method. After heat treatments, monoclinic CaAl2O4 structure was confirmed for all rare earth doped samples by the XRD analysis. PL characteristics of samples depend on activator ion. The PL emission spectra of Dy3+ doped powder samples show two strong bands at 484 nm and 577 nm which are attributed to a typical 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3+ ions. Sm3+ activated phosphors have the emission peaks at 565 nm, 604 nm, 649 nm, and 712 nm which are assigned to Sm3+ transitions: 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2, 4G5/2 → 6H11/2, respectively. The Commission International De IEclairage (CIE) 1976 chromaticity coordinates were evaluated from the emission spectra in two different rare earth ion doped phosphors, the values (uꞌ = 0.21805, vꞌ = 0.52537) and (uꞌ = 0.36078, vꞌ = 0.54567) were colors of yellow-orange and brick red, respectively. Consequently, synthesized Ca1-xAl2O4: Dy3+x (x= 0.008) and Ca1-xAl2O4: Sm3+y (y= 0.008) phosphors emitting in different color regions can be useful for LED’s and display applications.