Nd3+ and Pr3+ doped anti-zeolite matrix-LiBa12(BO3)7F4: Crystal structures, luminescence properties

Abstract

The LiBa12(BO3)7F4 crystals doped Nd3+ and Pr3+ were grown from high-temperature solution melts, using the TSSG method. All the samples have the wide absorption band in the visible range of 350–650 nm related to the dichroism, which is typical for other colored “antizeolites”. Strong radiation bands are associated with well known electronic transitions of Pr3+ (3P0 → 3H6 at 630 nm, 3P0 → 2F2 at 670 nm) and Nd3+ (4F3/2 → 4I9/2 at 875 nm, 4F3/2 → 4I11/2 at 1054 nm). In addition crystals of Nd-doped barium fluoride borate solid solutions NdxBa12(BO3)8-xF6x were grown from high temperature solution. Using X-ray single-crystal diffraction, the structure was solved and refined in I4/mcm space group that are similar to other colored “antizeolites” built with the positively charged framework of [Ba12(BO3)6]6+ cation pattern which contains channels built of alternating barium cubes and anticubes. According to the structure refinement of NdxBa12(BO3)8−xF6x, cube channel segments are populated mainly by [F4]4– and [NdF4]– clusters, whereas anticube ones – by (BO3)3– anions.