Search for: All records

Abstract Zero‐dimensional (0D) organic metal halide hybrids (OMHHs) are emerging materials with significant potential for optoelectronic applications, including direct X‐ray detectors. While 0D OMHH single crystals exhibit excellent X‐ray detection properties, their scalability remains a significant challenge due to the time‐intensive growth process and difficulty in producing large single crystals exceeding a few centimeters. This limitation hinders their practicality for large‐area detector applications. Here, we report for the first time the development of amorphous 0D OMHH films via solution processing for efficient direct X‐ray detection. By reacting a non‐crystalline organic halide, triphenyl(9‐phenyl‐9H‐carbazol‐3‐yl)phosphonium bromide (TPPCarzBr), with zinc bromide (ZnBr₂), we have successfully produced amorphous 0D (TPPCarz)₂ZnBr₄films with controlled thickness via facile solution processing. The organic cations (TPPCarz⁺) feature a lower bandgap than the ZnBr₄²⁻anions, enabling efficient molecular sensitization, where ZnBr₄²⁻anions serve as X‐ray absorbers and TPPCarz⁺ cations as charge transporters. Direct X‐ray detectors based on 0D (TPPCarz)₂ZnBr₄films demonstrate outstanding performance, achieving a stable X‐ray detection sensitivity of 2,165 µC Gy_air⁻¹cm⁻²at 20 V mm⁻¹ and a detection limit of 6.01 nGy_air s⁻¹. The amorphous nature of these films enhances their processability, allowing for fabrication in various sizes and shapes, and making them highly adaptable for scalable detector applications. 

Abstract 0D organic metal halide hybrids (OMHHs) have recently emerged as a new generation of scintillation materials, due to their high luminescence quantum efficiency, sensitivity, stability, and cost‐effectiveness. While numerous 0D OMHH scintillators have been developed to date, most of them are based on solution grown single crystals that require time‐consuming synthesis and are limited in size. Here, high‐performance X‐ray scintillators based on facile solution processed 0D OMHH amorphous films are reported for the first time. By reacting triphenyl(9‐phenyl‐9H‐carbazol‐3‐yl) phosphonium bromide (TPPcarzBr) with manganese bromide (MnBr₂), 0D (TPPcarz)₂MnBr₄ amorphous films can be prepared via solution processing with mild thermal annealing, which exhibits green photoluminescence with an emission maximum ≈517 nm and a photoluminescence quantum efficiency of ≈87%. The X‐ray scintillation of 0D (TPPcarz)₂MnBr₄ amorphous films is characterized to exhibit a light yield of 44600 photon MeV⁻¹and an outstanding linearity with a low limit of detection of 32.42 nGy_airs⁻¹over a wide range of X‐ray dose rates. The versatile processability of 0D (TPPcarz)₂MnBr₄ is illustrated with remarkable recyclability, high cost‐effectiveness, and scalability for large‐scale production. By taking advantage of the amorphous nature of newly designed OMHHs, the approach opens up new opportunities for developing high‐performance, solution‐processable scintillators. 

Abstract Low dimensional (LD) organic metal halide hybrids (OMHHs) have recently emerged as new generation functional materials with exceptional structural and property tunability. Despite the remarkable advances in the development of LD OMHHs, optical properties have been the major functionality extensively investigated for most of LD OMHHs developed to date, while other properties, such as magnetic and electronic properties, remain significantly under‐explored. Here, we report for the first time the characterization of the magnetic and electronic properties of a 1D OMHH, organic‐copper (II) chloride hybrid (C₈H₂₂N₂)Cu₂Cl₆. Owing to the antiferromagnetic coupling between Cu atoms through chloride bridges in 1D [Cu₂Cl₆²⁻]_∞chains, (C₈H₂₂N₂)Cu₂Cl₆is found to exhibit antiferromagnetic ordering with a Néel temperature of 24 K. The two‐terminal (2T) electrical measurement on a (C₈H₂₂N₂)Cu₂Cl₆single crystal reveals its insulating nature. This work shows the potential of LD OMHHs as a highly tunable quantum material platform for spintronics. 

Abstract Scintillators, one of the essential components in medical imaging and security checking devices, rely heavily on rare‐earth‐containing inorganic materials. Here, a new type of organic‐inorganic hybrid scintillators containing earth abundant elements that can be prepared via low‐temperature processes is reported. With room temperature co‐crystallization of an aggregation‐induced emission (AIE) organic halide, 4‐(4‐(diphenylamino) phenyl)‐1‐(propyl)‐pyrindin‐1ium bromide (TPA‐PBr), and a metal halide, zinc bromide (ZnBr₂), a zero‐dimensional (0D) organic metal halide hybrid (TPA‐P)₂ZnBr₄with a yellowish‐green emission peaked at 550 nm has been developed. In this hybrid material, dramatically enhanced X‐ray scintillation of TPA‐P⁺is achieved via the sensitization by ZnBr₄²⁻. The absolute light yield (14,700 ± 800 Photons/MeV) of (TPA‐P)₂ZnBr₄is found to be higher than that of anthracene (≈13,500 Photons/MeV), a well‐known organic scintillator, while its X‐ray absorption is comparable to those of inorganic scintillators. With TPA‐P⁺as an emitting center, short photoluminescence and radioluminescence decay lifetimes of 3.56 and 9.96 ns have been achieved. Taking the advantages of high X‐ray absorption of metal halides and efficient radioluminescence with short decay lifetimes of organic cations, the material design paves a new pathway to address the issues of low X‐ray absorption of organic scintillators and long decay lifetimes of inorganic scintillators simultaneously. 

A computational investigation is presented, in conjunction with synthesis and experimental characterization, into the structural, electronic, and optical properties of layered two‐dimensional organic lead bromide perovskites. Materials based on the chiral (R/S)‐4‐fluoro‐α‐methylbenzylammonium (R/S‐FMBA), which have been shown to lead to bright room‐temperature circularly polarized luminescence, are contrasted with the similar achiral 4‐fluorobenzylammonium (FBA). Using density functional theory (DFT) with van der Waals (vdW) corrections, relaxed structures (compared with X‐ray diffraction, XRD) and optical absorption spectra (compared with experiments) are studied, as well as band structure and orbital character of transitions. A Python code is developed and provided to calculate octahedral distortions and compare DFT and XRD results, finding that vdW corrections are important for accuracy and that DFT overestimates octahedral tilt angles. (FMBA)₂PbBr₄shows among the largest tilt angle differences (often termed ) reported, 14°–15°, indicating strong inversion symmetry‐breaking, which enables its chiral emission. A large resulting Dresselhaus spin‐splitting effect is found. The lowest‐energy optical transitions involve the perovskite only and are polarized within the layer. This work furthers understanding of structure‐property relations with applications to optoelectronics and spintronics. 

An AIE organic zinc chloride complex scintillator, in which the metal halide serves as X-ray sensitizer for the organic component, is discovered to exhibit a light yield of 13 423 Photon per MeV and a radioluminescence decay lifetime of 5.24 ns. 

Organic metal halide hybrids with low-dimensional structures at the molecular level have received great attention recently for their exceptional structural tunability and unique photophysical properties. Here we report for the first time the synthesis and characterization of a one-dimensional (1D) organic metal halide hybrid, which contains metal halide nanoribbons with a width of three octahedral units. It is found that this material with a chemical formula C 8 H 28 N 5 Pb 3 Cl 11 shows a dual emission with a photoluminescence quantum efficiency (PLQE) of around 25%. Photophysical studies and density functional theory (DFT) calculations suggest the coexisting of delocalized free excitons and localized self-trapped excitons in metal halide nanoribbons leading to the dual emission. 

1D organic metal halide hybrids (OMHHs) exhibit strongly anisotropic optical properties, highly efficient light emission, and large Stokes shift, holding promise for novel photodetection and lighting applications. However, the fundamental mechanisms governing their unique optical properties and in particular the impacts of surface effects are not understood. Herein, 1D C₄N₂H₁₄PbBr₄by polarization‐dependent time‐averaged and time‐resolved photoluminescence (TRPL) spectroscopy, as a function of photoexcitation energy, is investigated. Surprisingly, it is found that the emission under photoexcitation polarized parallel to the 1D metal halide chains can be either stronger or weaker than that under perpendicular polarization, depending on the excitation energy. The excitation‐energy‐dependent anisotropic emission is attributed to fast surface recombination, supported by first‐principles calculations of optical absorption in this material. The fast surface recombination is directly confirmed by TRPL measurements, when the excitation is polarized parallel to the chains. The comprehensive studies provide a more complete picture for a deeper understanding of the optical anisotropy in 1D OMHHs.