Interconfigurational 5d → 4f luminescence of Ce³⁺and Pr³⁺in Ca₉Lu(PO₄)₇

Abstract

Ca(9)Lu(PO(4))(7):Ce (3+) and Ca (9)Lu (PO (4))(7):Pr (3+) polycrystalline materials were synthesized by solid state reaction at high temperature. The materials were characterized by powder x-ray diffraction (XRPD). The luminescence spectroscopy and the excited state dynamics of these compounds were investigated upon excitation with UV/VUV synchrotron radiation. Both materials showed efficient and fast 5d-4f emission upon direct VUV excitation into the 5d levels but only Ca(9)Lu(PO(4))(7):Ce (3+) revealed luminescence upon excitation across the bandgap. The decay kinetics of the 5d-4f emission upon VUV intra-center excitation is characterized by a decay time of 29 ns for Ce (3+) and 17 ns for Pr (3+) with no significant build-up after the excitation pulse. For the both compounds, no significant temperature dependence of the 5d-4f emission lifetime was observed within the range 8-300 K.

Influence of magnesium on dielectric properties of Ca9–xMgxBi(VO4)7 ceramics

“…For example, magnesium for 1 calcium substitution in ferroelectric Ca 9 R(PO 4 ) 7 18 leads to Ca 8 MgR(PO 4 ) 7 possessing center of symmetry and electric polarization of antiferroelectric type. 20,21 Similar substitutions have not been studied yet for Ca 9 R(VO 4 ) 7 row of compounds especially for Ca 9 Bi(VO 4 ) 7 where maximum SHG was determined. 45 Earlier, it was found that in Ca 9 Bi(VO 4 ) 7 45,50 a portion of bismuth resides in tight M5O 6 octahedron, which restricts the contribution of a lone pair of Bi 3+ electrons to optical nonlinearity.…”

“…Calcium phosphates and vanadates of Ca 9 R (EO 4 ) 7 ( R = rare‐earth (RE), Bi, Y; E = P, V) belong to mineral whitlockite family . Most members of this family demonstrate interesting luminescent, optical nonlinear, ionic‐conductive, ferro‐ or antiferroelectric properties . In particular, the relevant phosphates are discussed as possible materials for light‐emitting diodes and also as luminescent bio‐probes in medicine .…”

Fast 5d-4f luminescence in Pr3+-doped K3Lu (PO4)2

“…As a result, the choice of the Pr 3 þ ion as an activator ion for wide band-gap hosts may constitute a promising alternative to the Ce 3 þ one in the development of new scintillator materials for applications requiring time-correlated registration of photons or working at higher count rate. Our search for novel materials showing fast 5d-4f emission of Pr 3 þ [6,7] has led us to the synthesis and investigation of the timeresolved spectroscopic properties of the double phosphate K 3 Lu(PO 4 ) 2 (KLuP) doped with this ion. KLuP is characterized by a high effective atomic number of $ 44.5, that is higher than one for Y 3 Al 5 O 12 (29.5) or YAlO 3 (31.4) widely used as scintillator materials, and potentially advantageous for X-and γ-rays detection.…”

A new hydrogen-containing whitlockite-type phosphate Ca9(Fe0.63Mg0.37)H0.37(PO4)7: hydrothermal synthesis and structure

“…Such biomaterials are slowly resorbed in the body to be replaced by natural bone. On this reason TCP and its variations were extensively studied as bioceramic [3] and luminescent [4][5][6] materials. In biomedicine, the mixture of TCP and hydroxyapatite is used as a biphasic calcium phosphate (BCP) being a bone-substitution ceramic due to different solubility of these calcium phosphates in aqueous systems [1].…”