VUV-vis photoluminescence, X-ray radioluminescence and energy transfer dynamics of Ce3+ and Pr3+ doped LiCaBO3

Abstract

A series of LiCaBO₃:Ce³⁺/Pr³⁺ phosphors were prepared by a high-temperature solid state reaction method. A structure refinement for the LiCaBO₃ compound was performed based on powder X-ray diffraction (XRD) data. The energies of the crystal field split excited 5d states of Ce³⁺ and Pr³⁺ in LiCaBO₃ were determined from synchrotron radiation VUV-UV excitation spectra. Furthermore, the influence of the doping concentration and temperature on the emission properties of Ce³⁺ was investigated, and the vacuum referred binding energy (VRBE) scheme for all lanthanide 4f and 5d states in LiCaBO₃ was constructed to estimate the thermal activation energy of Ce³⁺ luminescence quenching. The Pr³⁺ to Ce³⁺ energy transfer (ET) and its influence on luminescence decays of Pr³⁺ and Ce³⁺ were studied in detail. Finally, the X-ray excited luminescence spectra were measured to evaluate the possible X-ray detection applications.