Assessing of photoluminescence and structural properties of Dy+3 doped cadmium tantalate phosphor

According to the charge balance, trivalent dysprosium doped Cdx-1Ta2O6:xDy3+ (x=0.5, 1, 2, 3, 5) phosphor series was fabricated by solid state reaction route at 1100 C for 8 h. The synthesized phosphors were investigated by XRD (X-ray diffraction), SEM (scanning electron microscopy), and PL (photoluminescence) analyses. XRD and SEM analyzes revealed the orthorhombic colombite crystal structure and the presence of oval-like and shapeless morphology with submicron and several micron grain sizes, respectively. With the excitation of 387.8 nm, the phosphors exhibited blue and yellow emissions at 482.4 nm and 578.5 nm depending on the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions of Dy3+, respectively. The concentration quenching did not occur because the improvement in the charge balance reduced the structural defects and decreased the conversion of excitation energy to non-radiative transitions. The emission intensity of cadmium tantalate phosphor increased with increasing Dy3+ ion concentration up to x=5 value, and did not occurred the concentration quenching which reduces emission intensity. The Commission Internationale d’Eclairage (CIE) coordinates of Cdx-1Ta2O6:xDy3+ (x=0.5, 1, 2, 3, 5) phosphors were found near the white region in the chromaticity diagram