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

Scintillator materials convert high-energy radiation into photons in the ultraviolet to visible light region for radiation detection. In this review, advances in X-ray emission dynamics of inorganic scintillators are presented, including inorganic halides (alkali-metal halides, alkaline-earth halides, rare-earth halides, oxy-halides, rare-earth oxyorthosilicates, halide perovskites), oxides (binary oxides, complex oxides, post-transition metal oxides), sulfides, rare-earth doped scintillators, and organic-inorganic hybrid scintillators. The origin of scintillation is strongly correlated to the host material and dopants. Current models are presented describing the scintillation decay lifetime of inorganic materials, with the emphasis on the short-lived scintillation decay component. The whole charge generation and the de-excitation process are analyzed in general, and an essential role of the decay kinetics is the de-excitation process. We highlighted three decay mechanisms in cross luminescence emission, exitonic emission, and dopant-activated emission, respectively. Factors regulating the origin of different luminescence centers controlling the decay process are discussed.

Tb3Pd2, Er3Pd2 and Er6Co5–x : structural variations and bonding in rare-earth-richer binary intermetallics

The three binary Tb/Er-rich transition metal compounds Tb3Pd2 (triterbium dipalladium), Er3Pd2 (trierbium dipalladium) and Er6Co5–x (hexaerbium pentacobalt) crystallize in the space groups Pbam (Pearson symbol oP20), P4/mbm (tP10) and P63/m (hP22), respectively. Single crystals of Tb3Pd2 and Er6Co5–x suitable for X-ray structure analysis were obtained using rare-earth halides as a flux. Tb3Pd2 adopts its own structure type, which can be described as a superstructural derivative of the U3Si2 type, which is the type adopted by Er3Pd2. Compound Er6Co5–x belongs to the Ce6Co2–x Si3 family. All three compounds feature fused tricapped {TR 6} (R = rare-earth metal and T = transition metal) trigonal prismatic heterometallic clusters. R 3Pd2 is reported to crystallize in the U3Si2 type; however, our more detailed structure analysis reveals that deviations occur with heavier R elements. Similarly, Er6Co5–x was assumed to be stoichiometric Er4Co3 = Er6Co4.5. Our studies reveal that it has a single defective transition-metal site leading to the composition Er6Co4.72(2). LMTO (linear muffin-tin orbital)-based electronic structure calculations suggest the strong domination of heteroatomic bonding in all three structures.

Facile synthesis of high purity anhydrous complex rare earth halides by the modified mixed-salt-dehydration method

A novel and facile method to produce high purity anhydrous complex rare earth halides was introduced.

Homoleptic organolanthanide compounds supported by the bis(dimethylsilyl)benzyl ligand

A β-SiH functionalized benzyl anion [C(SiHMe2)2Ph]− reacts with early rare earth halides to provide homoleptic tris(alkyl)lanthanides containing secondary interactions in an efficient and high yielding route.

White light emission and temperature dependent chromaticity shifts by modification of luminescent ZrO(FMN) nanoparticles with rare earth halides

White light emission of composite suspensions is achieved by functionalization of ZrO(FMN) nanoparticles with lanthanide chlorides resulting in core–shell systems and a temperature dependent chromaticity shift.