Luminescence of Rare Earth Activated Lutetium Oxyhalide Phosphors

Abstract

Lutetium oxychloride and oxybromide phosphors have been prepared using Tb3+, Tm3+, Ce3+, Sm3+, and Dy3+activators. In general, luminescent characteristics are similar to those found for corresponding lanthanum oxyhalide phosphors. The stability of lutetium oxyhalides is markedly decreased apparently due to the effect of the lanthanide contraction phenomenon. Apparently for the same reason, emissions from the Tm3+ 3P0 excited states occur about 10 nm lower than those for corresponding lanthanum oxyhalide phosphor emissions. Tb3+, Tm3+, and Ce3+ activated phosphors are efficient under x‐ray excitation and may have use in image intensifiers for high kilovolt peak applications in medical radiography. Emissions from the Tm3+ 3P0 have a broad‐band character similiar to that found in normalLaOBr:normalTm phosphors.

Room-temperature scintillation properties of cerium-doped REOX (RE=Y, La, Gd, and Lu; X=F, Cl, Br, and I)

“…The oxyfluoride and LuOCl materials have three-dimensional structures, which could contribute to their lack of fast, exponential decays, and efficient cerium luminescence upon doping. In particular, Rabatin [14] also observed "different" emission in LuOCl: Ce 3+ relative to LuOBr: Ce…”

“…Yttrium, lanthanum, gadolinium, and lutetium oxychlorides and oxybromides doped with trivalent cerium have been previously studied for use in cathodoluminescent and X-ray intensifying screens [12], [13], [14] and [15]. Here we report the scintillation properties (emission spectra, decay curves, and decay times) of these materials and added those of the oxyfluorides and oxyiodides, following the general formula REOX (RE=Y, La, Gd, and Lu; X=F, Cl, Br, and I).…”

A Review on X-ray Excited Emission Decay Dynamics in Inorganic Scintillator Materials

“…The hygroscopic nature of each RE oxyhalide is inversely related to the ionic size of their rare earth. For the same reason, Rabatin [44] found lutetium oxyhalides compounds were much less stable compared to lanthanum oxyhalides, causing decrease in the phosphor light emission intensity. The RE oxyhalides provide an appropriate host matrix for lanthanide doping.…”

Blue-Emitting Eu2+-Activated LaOX (X = Cl, Br, and I) Materials: Crystal Field Effect

“…For the application of X-ray image converter, especially in medical radiography, it is necessary that phosphor materials should response rapidly and have high brightness for conversion of the X-rays to visible light. So, lanthanide oxyhalide phosphors have been widely studied for improved luminescent materials with high sensitivity and efficiency to X-rays. − It is well-known that divalent europium ions (Eu 2+ ) in phosphor materials have been widely used as very important and useful activators that exhibit broad emission bands between ultraviolet (UV) and the red spectral range, corresponding to the 4f 6 5d 1 → 4f 7 transition. − We reported, for the first time, a novel blue-emitting Eu 2+ activated LaOCl phosphor synthesized using the solid-state reaction between La 2 O 3 and excess NH 4 Cl at 1000 °C under a reducing atmosphere (4% H 2 –Ar mixture gas) . XRD measurements revealed that the LaOCl:Eu 2+ polycrystalline particles are well-oriented along the [001] axis above 2.5 mol ratio (mol (NH 4 Cl)/mol (La 2 O 3 )).…”