Preparation of Pr- and Dy-Doped Rb1 − x M x Pb2Cl5 − y Br y (M = K, Cs) crystals

We have demonstrated for the first time the possibility of preparing high-purity and praseodymium- and dysprosium-doped solid solutions based on lead halides and alkali metals: Rb1 − xCsxPb2Cl5, Rb1 − xCsxPb2Br5, Rb1 − xKxPb2Cl5, and RbPb2Cl5 − yBry. According to X-ray diffraction data, Rb1 − xCsxPb2Cl5 and Rb1 − xCsxPb2Br5 crystals in the solid solution range are isostructural with the constituent double salts RbPb2Cl5 and RbPb2Br5, respectively. The double salt Rb0.5K0.5Pb2Cl5 is isostructural with KPb2Cl5, and the double mixed salt RbPb2Cl2.5Br2.5 is isostructural with RbPb2Br5. The Pr3+ and Dy3+ concentrations in crystals of the solid solutions and mixed salts were determined by inductively coupled plasma mass spectrometry (ICP-MS). In the Rb1 − x (Cs, K)xPb2Hal5 (Hal = Cl, Br) solid solutions, the dopants were observed to be nonuniformly distributed over the host. According to ICP-MS analysis data and absorption spectra, the Pr3+ and Dy3+ concentrations in the RbPbCl2.5Br2.5 crystals were higher than those in RbPb2Br5.