Two-dimensional (2D) hybrid lead halide perovskites are potential candidates for high light yield scintillators as they have small band gaps between 3 and 4 eV and large exciton-binding energy. Here, ...we discuss the scintillation properties from a total of 11 organic/inorganic hybrid perovskite crystals with two already reported crystals, (PEA)2PbBr4 and (EDBE)PbBr4. Their photoluminescence and X-ray luminescence (XL) spectra are dominated by narrow and broad band emissions, and they correspond to free exciton and self-trapped exciton, respectively. The lifetimes derived from time-resolved XL strongly vary from 0.6 to 17.0 ns. These values make this type of compound among the fastest scintillators. For the light yield derived from the XL, we found that only (PEA)2PbBr4, (EDBE)PbBr4, and (BA)2PbBr4 crystals have light yields between 10,000 and 40,000 photons/MeV. The mechanisms for thermal quenching and afterglow are discussed in order to optimize the light yields. With gamma-ray excitation, we reported the best energy resolution of 7.7% at 662 keV with excellent proportionality. Finally, this study paves the way toward the ultimate high light yield and fast scintillators for medical and homeland security applications.
Two-dimensional lead halide perovskites have demonstrated their potential as high-performance scintillators for X- and gamma-ray detection, while also being low-cost. Here we adopt lithium chemical ...doping in two-dimensional phenethylammonium lead bromide (PEA)
2
PbBr
4
perovskite crystals to improve the properties and add functionalities with other radiation detections. Li doping is confirmed by X-ray photoemission spectroscopy and the scintillation mechanisms are explored via temperature dependent X-ray and thermoluminescence measurements. Our 1:1 Li-doped (PEA)
2
PbBr
4
demonstrates a fast decay time of 11 ns (80%), a clear photopeak with an energy resolution of 12.4%, and a scintillation yield of 11,000 photons per MeV under 662 keV gamma-ray radiation. Additionally, our Li-doped crystal shows a clear alpha particle/gamma-ray discrimination and promising thermal neutron detection through
6
Li enrichment. X-ray imaging pictures with (PEA)
2
PbBr
4
are also presented. All results demonstrate the potential of Li-doped (PEA)
2
PbBr
4
as a versatile scintillator covering a wide radiation energy range for various applications.
Two-dimensional lead halide perovskites have shown great potential as X- and γ-ray scintillators due to their high light yield, fast decay rate, and low fabrication cost. Here, their versatility is expanded by achieving, via Li-doping,
α
-particle/γ-ray discrimination and thermal neutron detection.
Trends in scintillators that are used in many applications, such as medical imaging, security, oil-logging, high energy physics and non-destructive inspections are reviewed. First, we address ...traditional inorganic and organic scintillators with respect of limitation in the scintillation light yields and lifetimes. The combination of high–light yield and fast response can be found in Ce 3 + , Pr 3 + and Nd 3 + lanthanide-doped scintillators while the maximum light yield conversion of 100,000 photons/MeV can be found in Eu 3 + doped SrI 2 . However, the fabrication of those lanthanide-doped scintillators is inefficient and expensive as it requires high-temperature furnaces. A self-grown single crystal using solution processes is already introduced in perovskite photovoltaic technology and it can be the key for low-cost scintillators. A novel class of materials in scintillation includes lead halide perovskites. These materials were explored decades ago due to the large X-ray absorption cross section. However, lately lead halide perovskites have become a focus of interest due to recently reported very high photoluminescence quantum yield and light yield conversion at low temperatures. In principle, 150,000–300,000 photons/MeV light yields can be proportional to the small energy bandgap of these materials, which is below 2 eV. Finally, we discuss the extraction efficiency improvements through the fabrication of the nanostructure in scintillators, which can be implemented in perovskite materials. The recent technology involving quantum dots and nanocrystals may also improve light conversion in perovskite scintillators.
Two-dimensional (2D) hybrid lead bromide perovskites are candidates for high light yield, fast scintillators. In this paper, we discuss the effect of commensurate Lithium (Li)-doping (1 : 1 Li : Pb ...precursor ratio) on the scintillation properties of two previously reported high light yield 2D-perovskite crystals, PEA
2
PbBr
4
and BA
2
PbBr
4
. The effect of Li,
e.g.
light yield enhancement, is more prominent in PEA
2
PbBr
4
compared to BA
2
PbBr
4
. Both perovskite crystals show a broadening of the radioluminescence spectrum and a slightly longer afterglow, with residual scintillation below 2% after 5 s for both materials. The effects of Li on the negative thermal quenching exhibited by the perovskites are also discussed. Li doping increases the light yield of PEA
2
PbBr
4
by 78% and both perovskite materials show an improvement in their energy resolutions, with a record of 7.7% at 662 keV for the Li-doped PEA
2
PbBr
4
. Both perovskite crystals also show very fast gamma-ray excited scintillation decays, with average times of 12.9 ns and 8.0 ns for PEA
2
PbBr
4
and BA
2
PbBr
4
, respectively. This work shows that Li doping brings a significant improvement of the perovskite performance, making the perovskites more competitive for fast, high light yield applications in the medical, security or industrial sectors.
Commensurate Lithium doping of two-dimensional lead halide perovskites leads to improved scintillation properties, with enhanced light yield, narrower energy resolution, higher radiation hardness and faster scintillation decay.
Optical and scintillation characteristics of Mg2+-codoped Lu2Y(Al5-xGax)O12:Ce (x = 2, 3) multicomponent garnet crystals grown by the micro-pulling down method were investigated. At RT, the ...shortening of scintillation decay time and a decrease of light yield (LY) value measured for a higher Ga containing samples can be explained by thermal ionization of the Ce3+ 5d1 excited state. At 662 keV γ-rays, Lu2YAl3Ga2O12: Ce, 0.05%Mg exhibits high LY value of 29,000 ph/MeV along with scintillation decay times of 50 ns (86%) + 73 ns (14%). Co-doping with larger Mg2+ content leads to a decrease of LY value, scintillation decay time, and afterglow level. Radioluminescence quenching observed at low temperature region in correlation with large thermoluminescence peaks can be caused by trapping of electrons at intrinsic shallow traps.
•Luminescence and scintillation properties of Lu2Y(Al5-xGax)O12:Ce,Mg (x = 2, 3) crystals are investigated.•Temperature dependencies of photo-and radioluminescence are presented.•Lu2YAl3Ga2O12:Ce,0.05%Mg shows high light yield of 29,000 photons/MeV.•Lu2YAl3Ga2O12:Ce,0.05%Mg shows quenching temperature at 435 K due to thermal ionization.•Afterglow and thermoluminescence characteristics are investigated.
The scintillation properties of Mg 2+ -codoped Lu 0.6 Gd 2.4 Al 2 Ga 3 O 12 :Ce (LGAGG:Ce,Mg) single crystal grown by Czochralski's method are investigated. The light yield (LY), scintillation decay ...time, and coincidence time resolution are presented in comparison with a GAGG:Ce,Mg reference crystal. The LY of 26 200 photons/MeV obtained for LGAGG:Ce,Mg is lower than that of 39 600 photons/MeV for GAGG:Ce,Mg. Despite a lower LY value, the time resolution of LGAGG:Ce,Mg is comparable to that of GAGG:Ce,Mg due to its faster scintillation decay time. LGAGG:Ce,Mg exhibits a much faster afterglow decay and a lower thermally stimulated luminescence intensity with respect to GAGG:Ce,Mg.
A versatile new facility to study photoionization processes in impurity doped compounds is presented. In this new facility monochromatic light is coupled to a thermoluminescence reader, enabling a ...fully automated recording of glow curves as a function of photon excitation wavelength. It provides detailed information on the mechanism of trap filling preceding persistent luminescence. The technique is first demonstrated with a study on Lu
2SiO
5:Ce
3+ and then applied to commercial modern day double lanthanide doped SrAl
2O
4:Eu
2+,Dy
3+, Sr
4Al
14O
25:Eu
2+,Dy
3+, CaAl
2O
4:Eu
2+,Nd
3+; and to the classical ZnS:Cu
+ persistent luminescence phosphors. The presented data provide new insight into the mechanism of persistent luminescence.
► New set-up for measuring glow curves as a function of photon excitation wavelength. ► TL excitation spectra for Eu
2+ doped persistent luminescence phosphors are shown. ► Eu
2+ is the source of electrons liberated during daylight excitation.
Czochralski-grown β-Ga2O3 and β-Ga2O3:Si crystals with the free electron concentrations between 2.5·1016 and 4.3·1018 cm−3 have been characterized by means of pulse height and scintillation time ...profile measurements in order to assess their basic scintillation properties. At room temperature, with increasing free electron concentration in the studied range, the scintillation yields decrease from 8920 to 1930 ph/MeV, while the mean scintillation decay times pare down from 989 to 61 ns. However, when the brightest β-Ga2O3 sample is cooled down below 100 K, its scintillation yield exceeds 20000 ph/MeV.
•Czochralski-grown β-Ga2O3 and β-Ga2O3:Si crystals have been characterized.•Scintillation yield and decay times strongly depend on free electron concentration.•Scintillation yield clearly goes up with decreasing temperature towards liquid N2.
The scintillation characteristics of Lu 0.8 Gd 2.2 (Al 5- x Ga x )O 12 :Ce,Mg (<inline-formula> <tex-math notation="LaTeX">x = 2.6 </tex-math></inline-formula> and 3) single crystals grown by the ...micropulling down method are investigated. The light yield of 27600 photons/MeV obtained for Lu 0.8 Gd 2.2 Al 2 Ga 3 O 12 :Ce,Mg is higher than that of 25 400 photons/MeV obtained for Lu 0.8 Gd 2.2 Al 2.4 Ga 2.6 O 12 :Ce,Mg. The photoluminescence and scintillation decays measured at room temperature (RT) for Lu 0.8 Gd 2.2 Al 2 Ga 3 O 12 :Ce,Mg are faster than those for Lu 0.8 Gd 2.2 Al 2.4 Ga 2.6 O 12 :Ce,Mg. Temperature dependence of radioluminescence (RL) intensity indicates a lower quenching temperature for Lu 0.8 Gd 2.2 Al 2 Ga 3 O 12 :Ce,Mg. Coincidence time resolution of a Lu 0.8 Gd 2.2 Al 2 Ga 3 O 12 :Ce,Mg detector in coincidence experiment with a BaF 2 detector was measured to be 410 ps. The afterglow and thermally stimulated luminescence (TSL) characteristics below RT are also measured.
Low temperature thermoluminescence of β-Ga2O3, β-Ga2O3:Al and β-Ga2O3:Ce has been investigated. Glow curves have been analyzed quantitatively using a rate equations model in order to determine the ...traps parameters, such as activation energies, capture cross-sections and probabilities of recombination and retrapping.
•Undoped and doped β-Ga2O3 crystals have been grown by the Czochralski method.•Their glow curves between 10 and 350 K have been investigated.•Rate equations model has been used to determine traps parameters.
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