Luminescence of dimer lead centers in aluminium perovskites and garnets

Abstract

Steady‐state emission and excitation spectra and luminescence decay kinetics were studied at 80–300 K under excitation in the 2.5–6.0 eV energy range for undoped and Ce3+‐doped aluminium garnet (Lu3Al5O12, Y3Al5O12) and aluminium perovskite (LuAlO3, YAlO3) single crystalline films (SCF) grown by Liquid Phase Epitaxy method from the PbO‐based flux. The aim of the work was to identify spectral bands, arising from lead‐induced centers of different types, and to clarify their influence on scintillation characteristics of Ce3+ centers. It was found that in the perovskite SCF studied, the concentration of single Pb2+‐based centers is comparatively small. In the SCF of garnets, in YAG SCF their concentration is considerably smaller than in LuAG SCF. The lead‐induced emission at about 3.1–3.2 eV excited around 3.9 eV was observed in all the SCF studied and ascribed to the dimer lead centers of the type of {Pb2+ – oxygen vacancy – Pb2+}. In Ce3+‐doped perovskite SCF, due to a strong overlap of the excitation band of the dimer centers and the emission band of Ce3+ centers, a considerable influence of dimer lead centers on the scintillation characteristics of these materials is expected. In the SCF of garnets, the influence of dimer lead centers on the characteristics of Ce3+ centers is negligible. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Influence of lead-related centers on luminescence of Ce3+ and Pr3+ centers in single crystalline films of aluminium perovskites and garnets

“…Both the single and the dimer Pb 2þ -based centers can exist in the SCF. The emission and excitation bands of these centers, identified by Babin et al (2007Babin et al ( , 2009, can overlap with the Ce 3þ -or Pr 3þ -related bands. This leads to the energy transfer processes between mentioned centers and has a negative influence on the scintillation properties of these SCF.…”

Origin of Bi3+‐related luminescence centres in Lu3Al5O12:Bi and Y3Al5O12:Bi single crystalline films and the structure of their relaxed excited states

“…The studies of ns 2 -ions-doped alkali halides (see, e.g., [16,17]) and aluminum perovskites and garnets [18] showed that the spectral bands of dimer impurity centers are usually noticeably shifted to lower-energies with respect to the bands of the corresponding single centers. (Fig.…”

Luminescence and scintillation characteristics of YAG:Ce single crystalline films and single crystals

“…Increasing the lead content in SCF accelerates the decay of the Ce 3þ emission in YAG:Ce (PbO) SCF (Fig. 3, curve 3 for C3 sample) which can be caused by the energy transfer from the Ce 3þ ions to Pb 2þ -based complex centers (Babin et al, 2009). The decay of the Ce 3þ luminescence in YAG:Ce (BaO) SCF is close to the singleexponential course within one decade but may contain another slower components, the origin of which is not understood and has not been observed in another YAG:Ce (BaO) SCF samples in (Kucera et al, 2008).…”