Zero‐Dimensional Gua₃SbCl₆ Crystals as Intrinsically Reabsorption‐Free Scintillators for Radiation Detection

Abstract

The search for efficient, re‐absorption‐free scintillators has recently focused the attention on antimony‐based halides, which exhibit largely Stokes shifted luminescence due to radiative recombination of excitons self‐trapped (STE) in strongly Jahn–Teller distorted Sb3+ color centers. Here, the synthesis of a hybrid structure is reported with chemical formula (C13H14N3)3SbCl6 consisting of spatially isolated [SbCl6]3− octahedra separated by organic N,N'‐diphenylguanidinium (Gua) molecules. The optical properties of this material are mainly determined by the inorganic component and are characterized by a pronounced Stokes shift of ≈1.3 eV and a room‐temperature photoluminescence (PL) efficiency of up to 85%. Remarkably, highly efficient radioluminescence (RL) is observed with scintillation light yields of ≈2000 ph MeV−1 using both soft X‐rays and a 124 keV gamma source. Temperature‐dependent PL and RL measurements confirm the minor role of non‐radiative channels, which are completely suppressed below 100 K. Thermally stimulated luminescence measurements suggest that the traps in Gua3SbCl6 crystals have a significantly large energy depth distribution below the absorbing state.

Multiexcitonic Emission of Organic–Inorganic (C4H12N)2ZrCl6:Sb3+ Perovskites across the Full Visible Region for Anticounterfeiting Applications

“…As shown in Figure 3a, broadband emission at 470 nm of the (TMA) 2 ZrCl 6 crystals exhibited a single-exponential decay with a long lifetime of 4.46 μs, consistent with STE emission. 2,7,8 The emission wavelength scanning decay of (TMA) 2 ZrCl 6 further indicates that there was only one PL component in the corresponding wavelength range (Figure 3b). To measure the lifetime of the 470 nm emission from the Sb 3+ -doped sample, the excitation wavelength was set to 250 nm to avoid generating the 490 nm emission and to exclude its interference (Figure S8).…”

“…O rganic−inorganic metal halide perovskites have recently emerged as promising light-emitting materials; widespread attention on these perovskites is because of their wide variety of available organic ligands and metal centers that result in structural diversity as well as optical tunability. 1,2 These perovskites can be classified into three-, two-, one-, and zerodimensional (0D) compounds, based on the spatial arrangement of the confined anionic inorganic blocks and surrounding organic cations. 3,4 Materials with low dimensionality typically trap excitons in the confined inorganic blocks and thus facilitate self-trapping of excitons, which typically exhibit broadband emission.…”

“…Organic–inorganic metal halide perovskites have recently emerged as promising light-emitting materials; widespread attention on these perovskites is because of their wide variety of available organic ligands and metal centers that result in structural diversity as well as optical tunability. , These perovskites can be classified into three-, two-, one-, and zero-dimensional (0D) compounds, based on the spatial arrangement of the confined anionic inorganic blocks and surrounding organic cations. , Materials with low dimensionality typically trap excitons in the confined inorganic blocks and thus facilitate self-trapping of excitons, which typically exhibit broadband emission. , Because of strong quantum confinement effects, these low-dimensional halide perovskites usually exhibit strongly Stokes-shifted broadband emission with excellent photoluminescence (PL) and are promising materials for, e.g., solid-state lighting and X-ray scintillation, as well as thermography. − However, such perovskite materials typically exhibit a single broadband self-trapped exciton (STE) emission; transport and recombination of excitons are strongly affected by exciton–phonon coupling, which imparts difficulties to directly tuning the intrinsic properties of STEs and thus achieve tunable emission across the full visible region …”

Ultrafast and Radiation-Hard Lead Halide Perovskite Nanocomposite Scintillators

“…It follows that any improvement in the so-called coincidence time resolution (CTR) has a direct beneficial effect on the resolution of TOF-PET images, thus motivating the technology race toward a CTR < 10 ps, corresponding to millimeter resolution, which represents a more than 10-fold improvement compared to state-of-the-art commercial TOF-PET scanners . Finally, for rapid industrial technology transfer and large-scale applications, it is essential that scintillators can be manufactured in large sizes and/or quantities using methods that are affordable in terms of both process energy and raw materials …”

“…23 Finally, for rapid industrial technology transfer and large-scale applications, it is essential that scintillators can be manufactured in large sizes and/or quantities using methods that are affordable in terms of both process energy and raw materials. 32 Recently, so-called nanocomposite scintillators based on high-Z scintillator nanocrystals (NC) embedded in polymeric matrices have emerged as promising alternatives to traditional materials, 33 such as inorganic scintillator crystals�which are prohibitively expensive and energy-intensive and cannot be produced in large sizes/volumes 19 �or plastic scintillators, 34 which can be produced cheaply in large sizes and customized shapes but are radiation-soft 22 and have lower energy resolution. 35 By exploiting the efficient and fast scintillation of NCs 36,37 in combination with the flexibility of plastic fabrication, nanocomposite scintillators hold promise to bridge the gap between the single crystal and plastic approaches, thus enabling a leap forward in radiation detection schemes.…”