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Spatial resolution of scintillator is crucial for high‐quality X‐ray imaging, especially in tiny and complicated electronic component. In this work, PrPP2MnBr4 single crystal is obtained by dual‐solvent evaporation method, which gives an unprecedented high spatial resolution of 104.3 lp/mm, representingstate of the art among non‐lead metal halides. The study also conducts the preparation of large area scintillation screen (10 cm × 10 cm) by solidifying melted salt PrPP2MnBr4, thus giving an excellent X‐ray imaging with spatial resolution of 53.5 lp mm−1, which demonstrates its application on large area detection. [ABSTRACT FROM AUTHOR]

Developing highly sensitive optical thermometers is of great significance due to their capability to enable remote and non-contact temperature measurements, rendering them highly applicable in diverse and harsh environments. Herein we report a temperature-dependent phosphor of 0D metal halide hybrid by incorporating Bi3+ into the (MePPh3)2ZnCl4 matrix. Through Bi3+ doping, the initially non-luminescent (MePPh3)2ZnCl4 matrix exhibits a deep-blue emission centered at 453 nm, with a photoluminescence quantum yield (PLQY) of 5.71% and a Stokes shift of 75 nm at room temperature. Experimental characterization demonstrates that exciton-like luminescence of Bi3+ is mainly responsible for the blue emission. Single crystals of Bi3+-doped (MePPh3)2ZnCl4 show an unusual correlation between photoluminescence (PL) lifetime and temperature. Particularly, the dependence of luminescence lifetime on temperature is most remarkable in the temperature range of 80 to 100 K with an exceptional sensitivity up to 0.09 K−1, representing one of the best levels for thermometry based on PL decay lifetime. Our work not only provides a viable strategy for designing a novel, environmentally friendly, and stable blue emitter, but also paves the way for precise thermometric application at low temperature. [ABSTRACT FROM AUTHOR]

For designing single-molecule devices that have both conjugation systems and structural flexibility, a hyperconjugated molecule with a σ–π bond interaction is considered an ideal candidate. In the investigation of conductance at the single-molecule level, since few hyperconjugation systems have been involved, the strategy of building hyperconjugation systems and the mechanism of electron transport within this system remain unexplored. Based on the skipped-conjugated structure, we present a rational approach to construct a hyperconjugation molecule using a hydroxyl group, which serves as a bridge to interact with the conjugated fragments. The measurement of single-molecule conductance reveals a two-fold conductance enhancement of the hyperconjugation system having the 'bridging' hydroxyl group compared to hydroxyl-free derivatives. Theoretical studies demonstrate that the hydroxyl group in the hyperconjugation system connects the LUMO of the two conjugated fragments and opens a through-space channel for electron transport to enhance the conductance. [ABSTRACT FROM AUTHOR]

It is imminent to develop phosphors with multiple stimuli responses due to the increasing demand on anti‐counterfeiting and information encryption technologies. Here, a zero dimensional (0D) organic–inorganic hybrid (DPPE)2MnBr4·H2O (DPPE = 4,4‐Difluoropiperidine, 1), which emits green light and exhibits reversible thermo‐ and vapor‐luminescence responses to heat and organic solvents is reported. Specifically, when heated above 100 °C for 30 s, hybrid 1 transforms into yellow‐emitting hybrid 2. Upon exposure to dichloromethane (DCM), it transforms into a red‐emitting hybrid 3. Experimental analysis reveals that Mn2+‐Mn2+ magnetic coupling interactions and coordination configuration transformation are responsible for the obvious switching of photoluminescence. Owing to its extraordinary triple‐mode switching characteristics, enabling luminescence‐adjustable transformations such as green to yellow, green to red, and yellow to red emission, this metal‐halide hybrid is promising for the application in anti‐counterfeiting and information encryption. [ABSTRACT FROM AUTHOR]

Circularly polarized electroluminescence (CPEL) is an active area of research because of its wide application in 3D displays and anti‐counterfeiting. However, it is not trivial to obtain a high asymmetry factor for highly efficient CPELs. Herein, a highly efficient CPEL is demonstrated with a superior asymmetry factor by using a chiral phosphine‐oxide‐passivated perovskite film as an emitter. An in situ‐formed perovskite nanocrystalline (NC) film is obtained by passivation of the chiral phosphine oxide. The as‐formed film exhibits much‐enhanced photoluminescence compared with the pristine film. More importantly, the NC film exhibits excellent chiral photoluminescence with a luminescence dissymmetry factor glum as high as 5.6 × 10−3. Electrically driven light‐emitting diodes based on the NC film exhibited superior device performance with a maximum brightness of 18,783 cd m−2 and a peak external quantum efficiency of 3.6%. More encouragingly, an unprecedented electroluminescence asymmetry factor gEL of up to 0.18 is achieved because of the chiral lattice distortion of the perovskite, which is the state‐of‐the‐art among hybrid materials. [ABSTRACT FROM AUTHOR]

Coordination cages sustained by metal–ligand interactions feature polyhedral architectures and well-defined hollow structures, which have attracted significant attention in recent years due to a variety of structure-guided promising applications. Sulfonylcalix[4]arenes-based coordination cages, termed metal–organic supercontainers (MOSCs), that possess unique multi-pore architectures containing an endo cavity and multiple exo cavities, are emerging as a new family of coordination cages. The well-defined built-in multiple binding domains of MOSCs allow the efficient encapsulation of guest molecules, especially for drug delivery. Here, we critically discuss the design strategy, and, most importantly, the recent advances in research surrounding cavity-specified host–guest chemistry and biomedical applications of MOSCs. [ABSTRACT FROM AUTHOR]

Metal halides are considered as an emerging class of X-ray scintillation materials with typical advantages of high-resolution scintillating imaging, low-cost and facile preparation. Here, we report ultra-high spatial resolution X-ray imaging by using a 2D copper(I)-based cluster (CISDM)4[Cu4I8]·2H2O (CISDM = cis-2,6-dimethylmorpholine) as a scintillator material. Thin single crystals were grown by slowly evaporating a solution containing CuI and CISDMI, and determined as a 2D layered structure with the [Cu4I8]4− cluster polyhedrons connected to each other and surrounded by CISDM cations. 2D (CISDM)4[Cu4I8]·2H2O exhibits bright yellow luminescence at 588 nm and a photoluminescence quantum yield as high as 87.2%. X-ray scintillation investigation shows that this 2D hybrid displays a good linear response to X-ray dose rates and a light yield of about 41 042 photons MeV−1 as well as a low detection limit of 86.8 nGy s−1. Most encouragingly, it gives an exceptional spatial resolution of 108 lp mm−1, representing the state of the art value among those of the reported lead-free metal halide hybrids. Our work provides a design concept of copper(I)-based single crystals for the application in high spatial resolution scintillators. [ABSTRACT FROM AUTHOR]

Ultra‐long room temperature phosphorescence (ULRTP) materials show valuable applications in encryption, biological imaging, and many other fields. Amazingly, the concomitant impurities from raw materials that are normally ignored contribute dramatically to the ULRTP. In this study, CzPMB [9‐(4‐bromo‐3‐methylphenyl)‐9H‐carbazole] with phosphorescent quantum efficiency of 64% is prepared from commercial carbazole, but the phosphorescent efficiency is drastically reduced to < 2% once trace impurity (5‐(4‐bromo‐3‐methylphenyl)‐5H‐benzo[b]carbazole) is separated. HPLC studies demonstrated the separated impurity is a byproduct derived from trace benzocarbazole in commercial carbazole. Subsequently, the ULRTP for the CzPMB synthesized from lab‐made carbazole is totally unobserved, strongly confirming the dramatic impact of impurity. A defect trapping mechanism in multicomponent system rather than heavy atom effect is proposed for highly efficient ULRTP after carefully analyzing the crystal packings and molecular energy levels. Inspired by this discovery, a series of effective ULRTP bi‐component systems with the highest phosphorescence efficiency of 64.1% are reproduced by directed host‐guest doping. This strategy paves a viable path for the design of organic materials with highly efficient ULRTP. [ABSTRACT FROM AUTHOR]

Herein, we describe an efficient method involving the synthesis of diverse quinoxalines using the DMSO/tBuONa/O2 system as a single-electron oxidant to form α-imino radicals and nitrogen radicals for the direct construction of C–N bonds. This methodology provides a novel approach to form α-imino radicals with good reactivity. [ABSTRACT FROM AUTHOR]

Reaction of [Au(tht)2](ClO4) (tht = tetrahydrothiophene), [Cu(CH3CN)4](ClO4), 3,6-di-tert-butyl-1,8-diethynyl-9H-carbazole (H3decz), and bis(2-diphenylphosphinophenyl)ether (POP) in the presence of triethylamine (NEt3) gave the cluster complex Au4Cu2(decz)2(POP)2 as yellow crystals. As revealed by X-ray crystallography, the Au4Cu2 cluster exhibits scissor-like structure sustained by two decz and two POP ligands and stabilized by Au-Cu and Au-Au interactions. The Au4Cu2 cluster shows bright yellow to orange photoluminescence upon irradiation at >300 nm, arising from 3[π (decz)→5d (Au)] 3LMCT (ligand-to-metal charge transfer) and 3[π→π* (decz)] 3IL (intraligand) triplet states as revealed by theoretical and computational studies. When it is mechanically ground, reversible phosphorescence conversion from yellow to red is observed owing to more compact molecular packing and thus stronger intermetallic interaction. Variable-temperature luminescence studies reveal that it displays distinct red-shifts of the emission whether the temperature is elevated or lowered from ambient temperature, suggestive of exceptional thermochromic phosphorescence characteristics. [ABSTRACT FROM AUTHOR]

Sb3+ doping strategy has proved to be an effective way to regulate the band gap and improve the photophysical properties of metal halides. Herein, Sb3+‐doped lead‐free indium halide hybrid InCl6(C4H12N2)2Cl·H2O:xSb3+ (0 ≤ x ≤ 1) is reported. Upon Sb3+‐doping, the weak emission of InCl6(C4H12N2)2Cl experiences a significant enhancement in emission intensity with near‐unity photoluminescence quantum yield (PLQY). The photophysical data fitted by the power‐law equation verifies self‐trapped exciton emission for the broadband emission. Interestingly, the emission experiences a gradual red‐shift with emission color changing from green to yellow and finally to orange as the Sb3+‐doped concentration increases. The single crystal X‐ray diffraction, excitation wavelengths‐dependent emission spectra, and the distortion degree calculation of InCl6(C4H12N2)2Cl·H2O:xSb3+ (0 ≤ x ≤ 1) indicate that the Sb3+ concentration dependent luminescence results from the synergistic effect of crystal phase transition, change of luminescence center, and the distortion of crystal structure. This achievement represents a successful strategy to achieve the photophysical properties modulation of metal halides for versatile optical applications. [ABSTRACT FROM AUTHOR]

The emerging lead halide perovskites show great potential for their use as emitters in electrically driven light-emitting diodes (LEDs) with external quantum efficiency (EQE) over 25%. While the toxicity of lead and inferior device stability are the main obstacles for their commercialization, replacing Pb2+ with low- or non-toxic metal ions to form low- or zero-dimensional structures provides an alternative approach to effectively tackle these issues. Recently, luminescent lead-free metal halides have been increasingly developed toward eco-friendly and highly efficient electroluminescence. In this feature article, we give a brief overview of recent advances in luminescent lead-free metal halides and their applications in electrically driven LEDs. The challenges and prospects in this field are outlined at the end. [ABSTRACT FROM AUTHOR]

A highly sensitive and specific acetic acid probe is desirable to distinguish acetic acid from other fatty acids. Herein, we designed and synthesized two zinc complexes, H2tBuCarPyZn2Br4(AcO)2·AcOH (1) and H2tBuCarPyZn2Br4(AcO)2 (2). Both complexes exhibit fluorescence with emission peaks at 500 nm for complex 1 and 550 nm for complex 2, respectively. The DFT calculation shows that the transition from Br to the H2tBuCarPy ligand is mainly responsible for the yellow emission of complex 2, while for complex 1 the valence band consists of Br and acetic acid solvent, and the participation of acetic acid in complex 1 could result in the blue-shift of emission compared with that of complex 2. Interestingly, an obvious blue-shift of emission was observed when complex 2 was exposed to an acetic acid atmosphere. Besides, the as-exposed complex 2 could recover to the initial state once the acetic acid atmosphere was removed. PXRD results demonstrate that the phase change from complex 2 to complex 1 after absorbing the acetic acid vapor accounts for the vapor-chromism. Then complex 2 was developed as an acetic acid probe, exhibiting high sensitivity and selectivity and excellent fatigue resistance. [ABSTRACT FROM AUTHOR]

The Fano resonance in single‐molecule junctions could be created by interaction with discrete and continuous molecular orbitals and enables effective electron transport modulation between constructive and destructive interference within a small energy range. However, direct observation of Fano resonance remains unexplored because of the disappearance of discrete orbitals by molecule‐electrode coupling. We demonstrated the room‐temperature observation of Fano resonance from electrochemical gated single‐molecule conductance and current–voltage measurements of a para‐carbazole anion junction. Theoretical calculations reveal that the negative charge on the nitrogen atom induces a localized HOMO on the molecular center, creating Fano resonance by interfering with the delocalized LUMO on the molecular backbone. Our findings demonstrate that the Fano resonance in electron transport through single‐molecule junctions opens pathways for designs of interference‐based electronic devices. [ABSTRACT FROM AUTHOR]

It is desirable to develop semiconductors with simultaneously multiple responses to single stimuli. Herein, a thermally responsive hybrid semiconductor (AEV)[Pb2Br8] (AEV4+ = 1,1′‐bis(2‐ammonioethyl)‐[4,4′‐ bipyridine]‐1,1′‐diium) is successfully prepared by introducing functionalized organic cations into 1D lead(II) chains. The lead(II) chain contains an edge‐sharing PbBr6 octahedron with highly electron‐deficient cations distributed in the interspace of the inorganic framework. Interestingly, the as‐formed hybrid exhibits extraordinary thermochromic behavior along with intriguing temperature‐dependent conductivity and thermal conductivity due to the thermal motion of the electrons in the hybrid. Specifically, the color of the pristine hybrid changes from yellow to brown when the temperature rises to 70 °C, and gradually deepens as the temperature continues to rise, accompanied by the continuous decline in electric conductivity and thermal conductivity. Once heating is stopped, the color and conductivity recover to the original state in a few minutes. As demonstrated by electron paramagnetic resonance and X‐ray photoelectron spectroscopy studies, the thermal‐induced electron transfer is likely responsible for the intriguing thermally responsive behaviors. This work provides a paradigm for the modular and functional design of hybrid materials that manifest potential applications in semiconductor refrigeration, thermal power generation, intelligent circuit, and other opt‐electronic devices. [ABSTRACT FROM AUTHOR]

Circular polarized luminescence (CPL)‐active materials attract great attentions owing to their widely applications in 3D optical displays and encrypted transmission. Inspired by the strategies adopted in perovskite based CPL materials, herein, CPL‐active hybrids (D)‐ and (L)‐(tert‐butyl prolinate)MnCl3 were successfully prepared by assembling chiral D/L tert‐butyl prolinate with manganese (II) chloride. Single crystal structures show the as‐formed hybrids possess one‐dimensional (1D) structure containing linear chains of face‐sharing MnCl6 octahedral surrounded by prolinate cations. The 1D Mn(II) hybrids display strong red emission peaked at 646 nm with PLQY of 67.1 % and 57.2 % for d‐type and l‐type, respectively, representing the highest PLQY for 1D MnII hybrids. Interestingly, the 1D Mn(II) hybrids exhibit prominent circular dichroism (CD) signals and remarkable CPL activity with the dissymmetry factor g of 6.1*10−3 and −6.3*10−3 from 550 to 800 nm for (D)‐ and (L)‐(tert‐butyl prolinate)MnCl3, respectively, owing to the existence of chiral cations. It is worthy noted the obtained g represents the highest value for non‐lead organic–inorganic hybrids. [ABSTRACT FROM AUTHOR]

Chiral materials with circularly polarized luminescence (CPL) are currently attracting great attention for their wide applications in bioresponsive imaging, 3D displays, and storage of information. Herein, CPL‐active enantiomorphic hybrids (R)‐ and (S)‐C6H15Cl2NO⋅SbCl5 are obtained by self‐assembling chiral R/S‐(3‐chloro‐2‐hydroxypropyl)trimethylammonium chloride with antimony(III) chloride, giving a 0D structure with SbCl5 pyramids isolated by (3‐chloro‐2‐hydroxypropyl)trimethylammonium chloride cations. The formed enantiomers exhibit brilliant orange emission peaked at 604 nm with photoluminescence quantum yield as high as 71.2%, originating from the self‐trapped exciton emission demonstrated by photophysical characterization. Due to the existence of chiral organic cations, the enantiomers exhibit strong chiral‐optical properties with mirror‐image circular dichroism signals in ground state and obvious CPL activity with the dissymmetry factor glum of 2.5 × 10−4 and −1.6 × 10−4 for R‐type and S‐type, respectively. It should be mentioned that these are the first reported 0D hybrids with CPL‐activity. This work paves an avenue for developing eco‐friendly CPL materials with highly ‐efficient luminescence. [ABSTRACT FROM AUTHOR]