Characterization of mixed halide scintillators: CsSrBrI2:Eu, CsCaBrI2:Eu and CsSrClBr2:Eu

Stand, Luis; Zhuravleva, Mariya; Chakoumakos, Bryan C.; Wei, Hua; Johnson, Jeffery L.; Martín, V.; Loyd, Matthew; Rutstrom, Daniel; McAlexander, W.; Wu, Yuntao; Koschan, Merry; Melcher, Charles L.

doi:10.1016/j.jlumin.2018.10.108

Cited by 26 publications

(12 citation statements)

References 52 publications

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“…Mixed halides constitute an important class of optical materials used as X-ray detection and storage phosphors, photon up- and downconverters, and light absorbers in photovoltaics. Well-known examples of this family of materials include alkali–alkaline-earth, alkaline-earth, − rare-earth, and alkali–lead halides. − The choice of the halogen source is determined by the form factor of the target mixed-halide (bulk, single crystal, nanocrystal, or thin film), the synthetic approach used (solid-state or solution), and also the ability to control the ratio between the two halide anions. Exercising stoichiometric control over this ratio enables fine-tuning of structural and electronic features governing the material’s optical response. , With this goal in mind, a variety of single halogen sources have been proposed; these include halide salts, , alkylammonium halides, , benzoyl halides, and alkylsilyl halides .…”

Section: Introductionmentioning

confidence: 99%

Accessing Mixed-Halide Upconverters Using Heterohaloacetate Precursors

et al. 2019

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A new type of organic−inorganic hybrid precursor to mixed-halide optical materials is described by using Ba 5 (CF 2 ClCOO) 10 •7H 2 O as an example. This heterohaloacetate belongs to the family of extended inorganic hybrids in which metal connectivity in three dimensions is achieved via metal−organooxygen−metal bridges. Thermolysis in the solid state and in solution yield crystalline BaFCl at temperatures below 300 °C. Chlorodifluoromethyl groups act as chlorine and fluorine source, making the organic moiety a de facto single-source precursor for the anionic portion of the target mixed halide. Solution thermolysis in the presence of Yb 3+ −Er 3+ sensitizing−activator pairs yields rare-earth-doped BaFCl nanocrystals capable of NIR-to-visible photon upconversion. Analyses of the composition, morphology, structure, and luminescence of these nanocrystals demonstrate that heterohalocetates serve as dual halogen sources for mixed-halide optical materials. Findings presented in this article enlarge the synthetic toolbox to access mixed halides at temperatures compatible with solution synthesis and processing.

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Section: Introductionmentioning

confidence: 99%

Accessing Mixed-Halide Upconverters Using Heterohaloacetate Precursors

et al. 2019

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“…To test this hypothesis, we introduced an antisite defect within orthorhombic CsSrI 3 (a = 4.81 Å, b = 15.78 Å, and 12.37 Å), a frequently studied s -block perovskite structure with a Cmcm space group (space group No. 63) [ 30 , 40 ]. This orthorhombic structure differs from the symmetric cubic structure due to (a) a different arrangement of atoms and (b) the tilted octahedra of [SrI 6 ] compared to the undistorted octahedral network in a cubic structure.…”

Section: Resultsmentioning

confidence: 99%

Role of Chemistry and Crystal Structure on the Electronic Defect States in Cs-Based Halide Perovskites

2021

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The electronic structure of a series perovskites ABX3 (A = Cs; B = Ca, Sr, and Ba; X = F, Cl, Br, and I) in the presence and absence of antisite defect XB were systematically investigated based on density-functional-theory calculations. Both cubic and orthorhombic perovskites were considered. It was observed that for certain perovskite compositions and crystal structure, presence of antisite point defect leads to the formation of electronic defect state(s) within the band gap. We showed that both the type of electronic defect states and their individual energy level location within the bandgap can be predicted based on easily available intrinsic properties of the constituent elements, such as the bond-dissociation energy of the B–X and X–X bond, the X–X covalent bond length, and the atomic size of halide (X) as well as structural characteristic such as B–X–B bond angle. Overall, this work provides a science-based generic principle to design the electronic states within the band structure in Cs-based perovskites in presence of point defects such as antisite defect.

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“…Mineral oil is widely used in the manufacturing and characterization of scintillator crystals. [ 28 ] For example, mineral oil can be used as a lubricant for crystal cutting and polishing. Meanwhile, it uses a simple and convenient solution to keep the crystal insulated from the environment, and is used as a packaging material for temporary and long‐term storage of crystal materials.…”

Section: Challenges and Outlookmentioning

confidence: 99%

“…Scintillators generally consisted of high‐density heavy elements. [ 27–29 ] However, the traditional scintillator is generally a large inorganic crystal that can only be grown in a high‐temperature environment, which greatly increases the production cost and preparation difficulty. [ 30 ] Besides, due to the limitations of low efficiency or afterglow effects, the luminescence of most traditional scintillators is hard to adjust in the visible spectrum.…”

Section: Introductionmentioning

confidence: 99%

Halide Perovskite, a Potential Scintillator for X‐Ray Detection

et al. 2020

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the coincidence efficiency. This indicates that the solid angle controlled by the PET system and the efficiency of the intrinsic detector are greater. [11,12] More significantly, the Compton events in the pulse height spectrum are mainly caused by scattering in the scintillator. Therefore, these deficiencies can be avoided by lowering the threshold. However, the signal provided by Compton scattering quanta in adjacent crystals may be higher than the threshold, and thus may affect the position resolution and make it worse. In X-ray computed tomography (CT), the body is mainly irradiated continuously from multiple directions by fan-shaped X-rays, while attenuation profiles are recorded, and finally reconstructed from the cross-sectional view of the body. [13] This technology mainly uses complex scanning methods in the field of clinical practice. At present, the realized way of X-rays detector can be roughly divided into two types, direct and indirect. The former one directly absorbs incident X-rays, generates electronic signals through semiconductors or engenders chemical signals through thin films. [14-17] This method can directly convert X-rays into visible light without going through other processes. Therefore, an X-ray detector with a wide linear response range, fast pulse rise time, high-energy resolution, and spatial resolution can be obtained, which makes it copiously applied in X-ray detection. [18-21] However, X-ray detectors based on semiconductors face the challenges of high cost and low efficiency. In addition, although the film is cheap, it is difficult to apply in digital form, which may limit its further development. The latter one refers to the conversion of X-rays (in the highenergy radiation, in addition to X-rays, α, β, and γ rays are also included) into ultraviolet visible (UV) light through scintillators which can be further captured by optical devices. [22-24] It consists of a scintillator and an array photodiode (PD). In contrast, since the scintillator that converts X-rays indirectly is cheap, it is easier to implement in the industry than direct detectors, and has the characteristics of low cost and abundant options, stability, and flexible conversion rate. [25,26] At present, indirect X-ray detectors are widely used in ordinary flat panel X-ray detectors. Moreover, it can be flexibly combined with commercially mature sensor arrays (e.g., amorphous silicon PDs, thin film transistor arrays, photomultiplier tubes, complementary metal oxide semiconductors, silicon avalanche PDs, and X-ray imaging charge-coupled devices [CCD]), therefore, they have attracted more attention. Scintillator is a unique class of luminescent materials, which is extensively used in many fields such as nondestructive testing, medical imaging, space probes, etc. Compared with the disadvantages of traditional scintillator materials which have high cost, are fragile, have long response time and low spatial resolution disadvantages, metal halide perovskites are considered to be the most potential scintillator materials in ...

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Characterization of mixed halide scintillators: CsSrBrI2:Eu, CsCaBrI2:Eu and CsSrClBr2:Eu

Cited by 26 publications

References 52 publications

Accessing Mixed-Halide Upconverters Using Heterohaloacetate Precursors

Accessing Mixed-Halide Upconverters Using Heterohaloacetate Precursors

Role of Chemistry and Crystal Structure on the Electronic Defect States in Cs-Based Halide Perovskites

Halide Perovskite, a Potential Scintillator for X‐Ray Detection

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