Inexpensive and highly efficient luminescent materials based on multinary halides have received increased attention in recent years. Among those considered most promising are the perovskites such as CsPbX3 because of their highly efficient and tunable emission through precise control of chemical composition and nanostructuring. However, the presence of the toxic heavy metal Pb and relatively poor stability are among the major challenges for the introduction of lead-halide-based materials into the marketplace. Here, we report the optical properties of nontoxic and highly emissive one-dimensional (1D) all-inorganic halides CsCu2X3 (X = Cl, Br, I) and their mixed halide derivatives, which also show improved thermal and air stability. Photoluminescence (PL) measurements show tunable bright room temperature emission from green to yellow with photoluminescence quantum yields ranging from 0.37 (CsCu2Cl1.5Br1.5) to 48.0% (CsCu2Cl3). Temperature- and power-dependent PL measurements suggest that the emission results from self-trapped excitons induced by strong charge localization and structural distortions within the lD ribbon structure.

Low-dimensional hybrid organic–inorganic materials (HOIMs) are being widely investigated for their unique optoelectronic properties. Some of them exhibit broadband white-light (WL) luminescence upon UV excitation, providing a potential for the fabrication of single-component white-light-emitting diodes. Here, we report new examples of low-dimensional HOIMs, based on 4-aminopyridinium (4AMP) and group 12 metals (Hg and Zn), for single-component WL emission. The 4AMP cation containing structures feature HgBr4 and ZnBr4 isolated tetrahedra in (C5H7N2)2HgBr4·H2O (1) and (C5H7N2)2ZnBr4 (2), respectively. The presence of isolated molecular units in the zero-dimensional structures results in strongly localized charges and bright WL luminescence with corresponding Commission Internationale de l’Eclairage color coordinates of (0.34, 0.38) and (0.25, 0.26), correlated color temperatures of 5206 K (1) and 11 630 K (2), and very high color rendering indexes (CRI) of 87 (1) and 96 (2). The visibly bright WL emission at room temperature is corroborated with high measured photoluminescence quantum yield values of 14.87 and 19.18% for 1 and 2, respectively. Notably, the high CRI values for these new HOIMs exceed the commercial requirements and produce both “warm” and “cold” WL depending on the metal used (Hg or Zn). Based on temperature- and powder-dependent photoluminescence (PL), PL lifetimes measurements and density functional theory calculations, the broadband WL emission is assigned to the 4AMP organic molecules emission and self-trapped states.

Low‐dimensional halide perovskites with excellent luminescent properties have become leading candidates for optoelectronic and radiation‐detection applications. In this work, Tl cation is incorporated into 0D perovskite Cs3Cu2I5 host and an ultrabright and efficient scintillator is developed for X‐ray and γ‐ray detection. The Tl‐doped Cs3Cu2I5 crystals exhibit a high photoluminescence quantum efficiency of 79.2%. The radioluminescence emission of Cs3Cu2I5:Tl crystal under X‐ray excitation consists of a self‐trapped exciton emission at 440 nm and a Tl‐related emission at 510 nm at room temperature. With optimized Tl doping, the Cs3Cu2I5 not only demonstrates about five‐times enhanced steady‐state scintillation yield up to 150 000 photons/MeV and an improvement of X‐ray detection limit from 103.6 to 66.3 nGy s−1, but also maintains an extremely low afterglow of 0.17% at 10 ms after X‐ray cut‐off. The Cs3Cu2I5:Tl also possess a remarkable energy resolution of 3.4% at 662 keV and an ultrahigh light yield of 87 000 photons/MeV under 137Cs γ‐ray radiation.

We report syntheses, crystal and electronic structures, and characterization of three new hybrid organic–inorganic halides (R)ZnBr 3 (DMSO), (R) 2 CdBr 4 ·DMSO, and (R)CdI 3 (DMSO) (where (R) = C 6 (CH 3 ) 5 CH 2 N(CH 3 ) 3 , and DMSO = dimethyl sulfoxide). The compounds can be conveniently prepared as single crystals and bulk polycrystalline powders using a DMSO–methanol solvent system. On the basis of the single-crystal X-ray diffraction results carried out at room temperature and 100 K, all compounds have zero-dimensional (0D) crystal structures featuring alternating layers of bulky organic cations and molecular inorganic anions based on a tetrahedral coordination around group 12 metal cations. The presence of discrete molecular building blocks in the 0D structures results in localized charges and tunable room-temperature light emission, including white light for (R)ZnBr 3 (DMSO), bluish-white light for (R) 2 CdBr 4 ·DMSO, and green for (R)CdI 3 (DMSO). The highest photoluminescence quantum yield (PLQY) value of 3.07% was measured for (R)ZnBr 3 (DMSO), which emits cold white light based on the calculated correlated color temperature (CCT) of 11,044 K. All compounds exhibit fast photoluminescence lifetimes on the timescale of tens of nanoseconds, consistent with the fast luminescence decay observed in π-conjugated organic molecules. Temperature dependence photoluminescence study showed the appearance of additional peaks around 550 nm, resulting from the organic salt emission. Density functional theory calculations show that the incorporation of both the low-gap aromatic molecule R and the relatively electropositive Zn and Cd metals can lead to exciton localization at the aromatic molecular cations, which act as luminescence centers.

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A novel all-inorganic CsCu2I3 single-crystalline perovskite as a nonhygroscopic and efficient X-ray and γ-ray scintillator is described herein. It is featured by a one-dimensional (1D) perovskite structure with an orthorhombic system and a space group of Cmcm. The CsCu2I3 crystal emits yellow light peaking at 570 nm originated from strongly localized 1D exciton emission. It appears self-absorption free because of the large Stokes shift of 1.54 eV. The photophysics process of the self-trapped exciton was studied using temperature dependent photoluminescene spectra and decay kinetics measurements. The CsCu2I3 crystal exhibits an extremely low afterglow level of 0.008% at 10 ms under X-ray excitation. Under 137Cs γ-ray irradiation, its light yield is 16 000 photons/MeV with an energy resolution of 7.8% at 662 keV.

The zero-dimensional all-inorganic perovskites are self-activated blue emitters with slight hygroscopicity, scalable synthesis, and high radiation detection efficiency.

Organic-inorganic hybrid halide perovskites, represented by CH 3 NH 3 PbX 3 (X ¼ Cl, Br, I), have demonstrated excellent optoelectronic and radiation detection properties. [1-3] All-inorganic CsPbX 3 perovskites (X ¼ Cl, Br, I) with better long-term stability are also considered as promising materials for optoelectronic devices and semiconductor γ-ray detectors. [4-6] Recently, there has been a surge of interest in low-dimensional perovskites due to their high photoluminescence quantum yield (PLQY). For example, the crystal structure of Cs 4 PbBr 6 that consist of spatially isolated [PbBr 6 ] 4À octahedra surrounding with Cs þ ions can be regarded as a 0D structure at molecular level, which leads to an intense quantum confinement effect. Excitons are strongly confined at each [PbBr 6 ] 4À octahedron, enabling a high exciton binding energy of 353 meV and a high PLQY of between 42% and 45%. [7,8] Quite a few low-dimensional allinorganic perovskites with remarkable luminescent properties were also reported as sensitive and efficient scintillators. Bulk crystals of 0D Cs 4 CaI 6 :Eu, Cs 4 SrI 6 :Eu, and Cs 4 EuBr 6 perovskites, isostructural to K 4 CdCl 6 trigonal system, have excellent light yields from 51 800 to 78 000 photons MeV À1 and energy resolutions from 3.3% to 4.3% at 662 keV. [9,10] However, due to a small Stokes shift of Eu 2þ ions, these materials suffer from strong self-absorption effect when scaling-up crystal size. Nanocrystals of 0D CsPbBr 3 /Cs 4 PbBr 6 perovskites show a high light yield of 64 000 photons MeV À1 and a fast decay time of <10 ns. [11] Onedimensional materials were also reported as sensitive X-ray scintillators, such as Rb 2 CuBr 3 and Rb 2 CuCl 3. [12,13] In particular, the Rb 2 CuBr 3 , that is self-absorption free and nonhygroscopic, was reported to achieve an ultrahigh scintillation yield of 90 000 photons MeV À1. [12] All-inorganic 0D perovskite Cs 3 Cu 2 I 5 was recently reported as a highly efficient blue-emitting material with a PLQY of 91.2%, and regarded as promising for application in photodetectors, light-emitting diodes, and memristors afterward. [14-17] In 2020, Cs 3 Cu 2 I 5 nanocrystals were developed for X-ray imaging with a light yield of 80 000 photons MeV À1. [18] To the best of our knowledge, the X-ray and γ-ray detection capability of bulk Cs 3 Cu 2 I 5 single crystal has not been reported. Thus, the aim of this work is to study the physical and optical properties and the scintillation performance under X-ray and γ-ray radiation of high-quality Cs 3 Cu 2 I 5 perovskite single crystal grown by the Bridgman method. The 7 mm diameter single crystal of Cs 3 Cu 2 I 5 was grown by the vertical Bridgman method. High-purity powders of CsI (99.99%, Grirem Advanced Materials) and CuI (99.999%, Sigma-Aldrich) were used as raw materials. These starting materials were mixed consistent with stoichiometric ratio and loaded into a quartz ampoule in a glovebox with <0.1 ppm moisture and oxygen. The loaded ampoule was sealed under a vacuum of 10 À6 torr after drying at 180 C for ...