Synthesis, crystal structure and luminescent properties of a quinary borate-phosphate compound CsNa2Dy2(BO3)(PO4)2

Abstract Borate-phosphates exhibit a wide range of compositional and structural diversity, making them ideal hosts for luminescent materials. In this work, a new borate-phosphate compound CsNa 2 Dy 2 (BO 3 )(PO 4 ) 2 has been prepared under high temperature solution growth method. It crystallizes in an orthorhombic space group Cmcm with the following lattice parameters determined by single-crystal X-ray diffraction: a = 6.9709(5), b = 14.9699(11), c = 10.6480(8) Å, z = 4. Its structure contains isolated BO 3 planar triangles and PO 4 tetrahedra, which are interconnected by Cs + , Na + and Dy 3+ ions. Solid solutions of CsNa 2 Y 2(1− x ) Dy 2 x (BO 3 )(PO 4 ) 2 ( x = 0 − 0.08) are prepared and exhibit a yellow emissive luminescence by near-UV excitation due to the 4 F 9/2 → 6 H (13/2, 15/2) transitions of Dy 3+ . The optimized concentration of Dy 3+ is x = 0.01, and if over this critical value, the luminescent intensity will decrease due to concentration quenching. The Commission International de L’Eclairage (CIE) coordinates for CsNa 2 Y 1.98 Dy 0.02 (BO 3 )(PO 4 ) 2 are ( x = 0.377, y = 0.404), corresponding to yellow color. The prepared phosphor may serve as a yellow phosphor for NUV-excited LEDs.