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

Abstract

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.

Strong Electron–Phonon Coupling in β-Ga2O3: A Huge Broadening of Self-Trapped Exciton Emission and a Significant Red Shift of the Direct Bandgap

“…In terms of luminescent properties, different from conventional direct-bandgap semiconductors represented by zinc oxide (ZnO), gallium nitride (GaN), and aluminum nitride (AlN), the luminescence spectrum of β-Ga 2 O 3 does not show near-band emission (NBE) but strong broad luminescence characteristics composed of several emission components instead in the spectral range of 2.3–4.5 eV. , The lack of NBE is generally attributed to the formation of a self-trapped hole (STH), which is recombined with weakly localized electrons to contribute to a so-called self-trapped exciton emission (STE) in β-Ga 2 O 3 . − By studying the STE luminescence of β-Ga 2 O 3 , we can obtain useful physical parameters and information like the strength of electron–phonon coupling and exciton binding energy. Up to now, a detailed temperature-dependent study of the broad-spectrum STE luminescence of β-Ga 2 O 3 is still worth conducting, for which an in-depth study can help deepen the understanding of this STE luminescence mechanism.…”

Wide Concentration Range of Tb3+ Doping Influence on Scintillation Properties of (Ce, Tb, Gd)3Ga2Al3O12 Crystals Grown by the Optical Floating Zone Method

“…The excitation spectrum of Ce 3+ emission at 530 nm is composed of three sets of broad bands, which belong to the characteristic excitation transition of Ce 3+ and Tb 3+ ions, respectively. The band peaking at around 340 nm and 450 nm were commonly ascribed to 4f–5d 2 and 4f–5d 1 transition of the Ce 3+ , respectively [ 37 , 38 ]. The sharp lines observed at 302–313 nm are related to the characterized 8S 7/2 –6I j , 6P j excitation transition of Gd 3+ ion [ 39 ].…”

Rare-Earth Doping in Nanostructured Inorganic Materials

“…1029 Rare-earth halides, oxides, oxyhalides, oxysulfides, oxyorthosilicates, and perovskites possess excellent scintillation performance. 1030 In particular, Y, La, Gd, and Lu have been extensively studied as host lattices for controlling radioluminescence. 1031 Rare-earthdoped nanoscintillators with fast decay or persistent luminescence are being developed for specific applications.…”