A new cadmium rare-earth oxyborate Cd4DyO(BO3)3 and luminescent properties of the Cd4Dy1-xSmxO(BO3)3 (0 ≤ x ≤ 0.8) phosphors

Abstract

Abstract A new cadmium-rare earth (Dy) oxyborate Cd4DyO(BO3)3 has been prepared by a high-temperature solution reaction at 950\xa0\u200b°C. The compound crystallizes in the space group Cm with a\xa0\u200b=\xa0\u200b7.9549(2) A, b\xa0\u200b=\xa0\u200b15.7792(3) A, c\xa0\u200b=\xa0\u200b3.4738(1) A, β\xa0\u200b= 100.183(2)°, V\xa0\u200b=\xa0\u200b429.166(17) A3, and Z\xa0\u200b=\xa0\u200b2. Its crystal structure consists of 1D [DyO4]n5n− chains of edge-sharing DyO6 octahedra and 1D [Cd2O6]n8n− double chains formed by corner- or edge-sharing CdO5 and CdO6 polyhedra. These chains are held together via common O atoms leading to a 3D [Cd4DyO10]n9n− network, with B atoms residing in channels of the network to balance charge, thus the final 3D network of Cd4DyO(BO3)3 is formed. IR and Raman studies support the presence of BO3 groups in the structure. Solid solutions of Cd4Dy1-xSmxO(BO3)3 (0\xa0\u200b≤\xa0\u200bx\xa0\u200b≤\xa0\u200b0.8) were prepared via solid-state reaction method and their photoluminescence properties were studied. It was found that under near-UV excitation, the luminescence color of Cd4Dy1-xSmxO(BO3)3 fluorescent powders can be tuned from yellowish white through white to purplish white by rationally controlling the Sm3+/Dy3+ concentration ratio. The Cd4Dy0.8Sm0.2O(BO3)3 phosphor excited at 364\xa0\u200bnm has CIE coordinates (0.338,0.328) and a CCT value of 5240\xa0\u200bK, which indicates that it has the potential to be used as a single-component white-emitting phosphor for commercial W-LEDs. Moreover, XPS and UV–vis absorption spectra of Cd4DyO(BO3)3 have also been investigated.