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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]

Coordination cages with intrinsic enzyme-like activity are a class of promising catalysts for improving the efficiency of organic reactions. We present herein a viable strategy to conveniently construct multimetallic active sites into a coordination cage via self-assembly of a pre-formed sulfonylcalix[4]arene-based tetranuclear copper(II) precursor and an amino-functionalized dicarboxylate linker. The cage exhibits a "defective", partially open cylindrical structure and features coordinatively labile dimetallic Cu(II) sites. Modulated by this unique inner cavity environment, promising catalytic activity toward selective oxidation of primary alcohols to carboxylic acids at room temperature is achieved. Mechanistic studies reveal that the coordinatively labile dimetallic Cu(II) sites can efficiently capture and activate the substrate and oxidant to catalyze the reaction, while the confined nano-cavity environment modulates substrate binding and enhances the catalytic turnover. This study provides a new approach to designing biomimetic multifunctional coordination cages and environmentally friendly supramolecular catalysts. [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]

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]

Destructive quantum interference (DQI) provides a unique approach to controlling the leakage current in the OFF state of molecular devices. However, the DQI in π-conjugated molecular building blocks cannot exhibit ultralow conductance due to the existence of covalently bonded σ-transport channels. Thus, suppressing the σ-contribution via σ-DQI is essential for the fabrication of molecular junctions with high insulation and effective modulation of conductance in single-molecule junctions. Here, we demonstrate the existence of σ-DQI even in a simple series of CmCn ring molecules, with parallel chains of m and n alkyl units (where m, n=6, 8 or 10), by measuring their electrical conductance and Seebeck coefficients. Counterintuitively, the conductance of the symmetric CnCn rings is lower than that of the corresponding single chains (Cn), which is in contrast to the conductance superposition law in multi-channeled systems. Combined theoretical calculations reveal that the gauche conformation in a shorter chain fixed by another chain leads to the decreased conductance in alkyl rings, which originates from the phase-coherent tunneling and DQI in σ-conjugated systems. Our finding suggests that through appropriate conformation locking by cyclization, the covalent alkane system can exhibit DQI, which offers strategies for future designs of molecular electronic devices and materials. [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]

Narrow-band emission is crucial for high color purity in panel display. Nevertheless, attaining narrow-band emission is highly challenging because either thermally activated delayed fluorescence or phosphorescence in organic and metal-organic compounds originates primarily from multiple charge transfer transitions featured with broad bandwidths. In this work, a general tactic for achieving highly efficient narrow-band emission is proposed by the sensitization of ligand-centered phosphorescence through substantial intermetallic interaction. Relative to weak phosphorescence in mononuclear Pt(II) precursors, highly efficient ligand-centered phosphorescence is dramatically activated in Pt(II)-Au(I) heteronuclear complexes with quantum yield as high as 81% in solutions and 97% in doping films. High-efficiency solution-processed organic light-emitting diodes (OLEDs) with narrow-band emission are successfully attained with external quantum efficiency (EQE) of 21.6% and a full width at half maxima (FWHM) of 36 nm for yellow electroluminescence and EQE of 20.8% and FWHM of 32 nm for green electroluminescence. [ABSTRACT FROM AUTHOR]

Two heteroctanuclear Au4Ag4 cluster complexes of 4,5-diethynylacridin-9-one (H2L) were prepared through the self-assembly reactions of [Au(tht)2](CF3SO3), Ag(tht)(CF3SO3), H2L and PPh3 or PPh2Py (2-(diphenylphosphino)pyridine). The Au4Ag4 cluster consists of a [Au4L4]4− and four [Ag(PPh3)]+ or [Ag(PPh2Py)]+ units with Au4L4 framework exhibiting a twisted paper clip structure. In CH2Cl2 solutions at ambient temperature, both compounds show ligand fluorescence at ca. 463 nm as well as phosphorescence at 650 nm for 1 and 630 nm for 2 resulting from admixture of 3IL (intraligand) of L ligand, 3LMCT (from L ligand to Au4Ag4) and 3MC (metal-cluster) triplet states. Crystals or crystalline powders manifest bright yellow-green phosphorescence with vibronic-structured emission bands at 530 (568sh) nm for complex 1 and 536 (576sh) nm for complex 2. Upon mechanical grinding, yellow-green emission in the crystalline state is dramatically converted to red luminescence centered at ca. 610 nm with a drastic redshift of the emission after crystal packing is destroyed. [ABSTRACT FROM AUTHOR]

As low‐dimensional lead‐free hybrids with higher stability and lower toxicity than those of three‐dimensional lead perovskites, organic antimony(III) halides show great application potential in opt‐electronic field owing to diverse topologies along with exceptional optical properties. We report herein an antimony(III) hybrid (MePPh3)2SbCl5 with a zero‐dimensional (0D) structure, which exhibits brilliant orange emission peaked at 593 nm with near‐unity photoluminescent quantum yield (99.4 %). The characterization of photophysical properties demonstrates that the broadband emission with a microsecond lifetime (3.24 μs) arises from self‐trapped emission (STE). Electrically driven organic light‐emitting diodes (OLEDs) based on neat and doped films of (MePPh3)2SbCl5 were fabricated. The doped devices show significant improvement in comparison to non‐doped OLEDs. Owing to the much improved surface morphology and balanced carrier transport in light‐emitting layers of doped devices, the peak luminance, current efficiency (CE) and external quantum efficiency (EQE) are boosted from 82 cd m−2 to 3500 cd m−2, 1.1 cd A−1 to 6.8 cd A−1, and 0.7 % to 3.1 % relative to non‐doped devices, respectively. [ABSTRACT FROM AUTHOR]

As low‐dimensional lead‐free hybrids with higher stability and lower toxicity than those of three‐dimensional lead perovskites, organic antimony(III) halides show great application potential in opt‐electronic field owing to diverse topologies along with exceptional optical properties. We report herein an antimony(III) hybrid (MePPh3)2SbCl5 with a zero‐dimensional (0D) structure, which exhibits brilliant orange emission peaked at 593 nm with near‐unity photoluminescent quantum yield (99.4 %). The characterization of photophysical properties demonstrates that the broadband emission with a microsecond lifetime (3.24 μs) arises from self‐trapped emission (STE). Electrically driven organic light‐emitting diodes (OLEDs) based on neat and doped films of (MePPh3)2SbCl5 were fabricated. The doped devices show significant improvement in comparison to non‐doped OLEDs. Owing to the much improved surface morphology and balanced carrier transport in light‐emitting layers of doped devices, the peak luminance, current efficiency (CE) and external quantum efficiency (EQE) are boosted from 82 cd m−2 to 3500 cd m−2, 1.1 cd A−1 to 6.8 cd A−1, and 0.7 % to 3.1 % relative to non‐doped devices, respectively. [ABSTRACT FROM AUTHOR]

In this work, the synthesis, characterization, and phosphorescent properties of the coordination polymer, {Ag3(dppy)2[μ-SCN]3}n (1), are described. X-ray crystallography showed that the complex forms a one-dimensional infinite zipper-like chained structure linked by thiocyanate as the bridging ligand. The silver(I) complex exhibits a strong sky-blue phosphorescence with a high quantum yield of 70.2% in the solid state at ambient temperature. Additionally, following a temperature change from 418 to 77 K, the complex displays a remarkable luminescent thermochromic property. A novel 1D zipper-like silver(I) coordination polymer is constructed by 2-diphenylphosphinopyridine and thiocyanate. It exhibits strong sky-blue phosphorescence with high quantum yield of 70.2% in solid state at ambient temperature. Furthermore, its reversible thermochromism is demonstrated. [ABSTRACT FROM AUTHOR]

High color purity with narrow-band emission is a key factor for full-color displays. However, phosphorescent metal complexes typically exhibit broad emission with a full width at half maxima (FWHM) in the range of 80–100 nm. Here, we demonstrate a facile approach to achieve narrow-band emission by introducing electron-deficient moieties with electron-transport character into PtAg2 heteronuclear complexes. The as-synthesized PtAg2 complex 3 with dibenzo[b,d]thiophene 5,5-dioxide-3-acetylide shows extremely narrow emission with an FWHM of 25 nm in CH2Cl2 solution. The narrow-band emission is further verified by another two PtAg2 complexes containing electron-transport units such as oxadiazole (complex 4) and triphenyl-triazine (complex 5), in which the FWHM values are 26 nm for 4 and 28 nm for 5 in CH2Cl2 solution. TD-DFT studies suggest that the involvement of intra-ligand transition within an electron-deficient acetylide ligand is likely responsible for the narrow-band emission. Solution-processed OLEDs based on complex 4 exhibit excellent device performance with an FWHM of 37 nm in the electroluminescent spectrum and the highest current efficiency (CE) of 69.5 cd A−1, power efficiency (PE) of 50.5 lm W−1 and external quantum efficiency (EQE) of 18.2%. The narrow-band electroluminescence is also attained in complexes 3 and 5 with the FWHM values of 31 and 40 nm, respectively, which represent the narrowest electroluminescence for multinuclear metal complexes. This strategy of introducing electron-transport moieties not only improves the device performance but also narrows the emission width and thus enhances the color purity. [ABSTRACT FROM AUTHOR]

A dpppy-protected (dpppy = 2,6-bis(diphenylphosphino)pyridine) d10–d10 heterooctanuclear cluster complex [Ag3Cu5(ebzcz)6(dpppy)3](ClO4)2 (Hebzcz = 1-(3,6-di-tert-butylcarbazol-9-yl)-4-ethynylbenzene) was prepared by self-assembly reaction and characterized by single crystal X-ray diffraction. The diphosphine-supported Ag3Cu5 cluster structure is highly stabilized through substantial Cu–Ag and Cu–Cu intermetallic interactions. Since the Ag3Cu5 cluster is sufficiently shielded by bulky ligands (three ebzcz and three dpppy), thermally non-radiative relaxation is strongly prohibited so as to give brilliant photoluminescence under ambient conditions. As revealed by TD-DFT studies, the luminescence arises from metal cluster-centred 3[d → p/s] and 3[π (ebzcz) → π* (dpppy)] 3LLCT (ligand-to-ligand charge transfer) transitions. Taking advantage of Ag3Cu5 cluster complex as a phosphorescent dopant, a high-efficiency solution-processed organic light-emitting diode is achieved with a peak current efficiency of 38.1 cd A−1, a power efficiency of 29.9 lm W−1 and an external quantum efficiency of 14.7%. [ABSTRACT FROM AUTHOR]

Numerous mononuclear platinum(II) complexes are non-emissive or weakly emissive under ambient conditions, but the corresponding Pt–M (M = Cu(I), Ag(I), Au(I), etc.) heteronuclear assemblies could become intensely luminescent because of the inhibition of non-radiative relaxation and the promotion of intersystem crossing from singlet to triplet state through Pt–M intermetallic interactions. To this end, the fabrication of specifically structured Pt–M complexes by the use of slightly luminescent homonuclear Pt(II) precursors provides a promising approach to switching on phosphorescence as well as modulating emission energy and colour. This feature article is aimed at providing some typical examples for attaining highly phosphorescent Pt–M heteronuclear complexes using homonuclear Pt(II) precursors, focusing on the assembly strategy, the correlation of emissive properties to the structures, and the application of phosphorescence in sensing and light-emitting devices. [ABSTRACT FROM AUTHOR]

We describe herein a viable approach to enhance phosphorescence efficiency in PtCu2 complexes with aromatic acetylides by the use of bis(di-2-tolylphosphinomethyl)phenylphosphine (dTolmp) in place of bis(diphenylphosphinomethyl)-phenylphosphine (dpmp) as a supporting ligand. Relative to dpmp-supported PtCu2 complexes, dTolmp-supported complexes having the same acetylide ligands show not only a 16–36 nm red-shift of the emission peaks, but also a dramatic phosphorescence enhancement. The phosphorescence quantum yields of dTolmp-supported PtCu2 complexes are boosted to 6.6 and 11.6 times as high as those of the dpmp-supported ones in CH2Cl2 solutions and the solid state, respectively. From dpmp to dTolmp, introducing sterically hindered 2-methyl groups to phenyl rings not only improves the π-conjugation character of PtCu2 complexes, but also effectively inhibits the deactivation process of the triplet excited state through non-radiative relaxation. The phosphorescence properties were systematically modulated in a wide spectral range from 502 to 672 nm by introducing electron-donating or electron-withdrawing substituents into aromatic acetylides. [ABSTRACT FROM AUTHOR]

Seeking the strategies of designing highly conductive molecular structures is one of the core researches in molecular electronics. As asymmetric structure has manifested feasible properties in comprehensive fields, we introduce the structures of asymmetric platinum(II) complexes into the charge transport study at single-molecule scale for the first time. The single-molecule conductance measurement results reveal that, in platinum(II)-aryloligoynyl structures, the conductance of asymmetrically coordinated complexes is obviously higher than that of the symmetric isomers with the same molecular length, while the conductance is almost identical in symmetric and asymmetric platinum(II)-oligoynyl complexes Theoretical study uncovers that, upon connecting to the oligoynyl structure, the aromatic group effectively extends the π-system of the whole conductive backbone and gathers the HOMO population mainly on the longer oligoynyl ligand, which reduces the energy barrier in electron transport and enhances the conductance through HOMO energy lifting. This result provides feasible strategy for achieving high conductive molecular devices. [ABSTRACT FROM AUTHOR]

A triphosphine-supported Pt2Cu heterotrinuclear complex (1) constrained with 3,6-di-tert-butyl-1,8-diethynyl-9H-carbazole exhibits two-step phosphorescent mechanochromism due to intramolecular deformation. The stepwise phosphorescent mechanochromism following green → yellow → orange-red corresponds exactly to the phosphorescent emission observed in crystal morphs 1·4THF (green), 1·3acetone (yellow), and 1·4CH2Cl2 (orange-red), respectively, with different degrees of intramolecular deformation, as demonstrated by X-ray crystallography. [ABSTRACT FROM AUTHOR]

Three quinoline-based zinc(ii)–Schiff base complexes were synthesized and characterized by X-ray crystallography. They exhibit remarkable aggregation-induced emission enhancement (AIEE) in acetonitrile/diethyl ether mixtures due to the conversion of weak luminescence in homogeneous solution into strong emission in the nano-aggregated phase after increasing the fractions of diethyl ether. Interestingly, the AIEE performance can be significantly promoted by joining the two quinoline units through an alkoxy chain. Moreover, they show reversible mechanochromic luminescence behavior between dark and bright states during the grinding–fuming cycles, due to the modulation of morphologies between amorphous and crystalline states. Introducing an electron donating group in the para-position of aniline significantly improves the mechanochromic luminescence effect with a more accessible and distinct emission colour contrast. The molecular packing in the crystalline phase and time-dependent density functional theory (TD-DFT) calculations demonstrate that multiple intermolecular C–H…π and π–π interactions significantly strengthen the molecular rigidity and enhance the intramolecular charge-transfer (ICT) characteristics, leading to the effective emission enhancement in crystalline/nano-aggregated states. The novel AIEE and reversible mechanochromic luminescence properties point to the promising potential applications of these complexes in smart fluorescent materials. [ABSTRACT FROM AUTHOR]

Mononuclear platinum(ii) complex trans-Pt(PPh3)2(C≡CC6H4SMe-4)2 (1-Pt) and its derivatives [PtM(dppm)2(C≡CC6H4SMe-4)2]+ (dppm = bis(diphenylphosphino)methane; M = Au, 2-PtAu; Ag, 2-PtAg; Cu, 2-PtCu) with “mono-gating” metal ions and [PtM2(dpmp)2(C≡CC6H4SMe-4)2]2+ (dppm = bis(diphenylphosphinomethyl)phenylphosphine; M = Au, 3-PtAu2; Ag, 3-PtAg2) with “dual-gating” metal ions were elaborately designed to modulate the conductance in platinum(ii) bis(σ-acetylide) complexes through “gating” d10 metal ions. The single-molecule conductance measurements by the STM-BJ technique demonstrate that the conductance follows 10−4.5 (1-Pt) ＞ 10−4.8 (2-PtAu) ＞ 10−4.9 (2-PtAg) ＞ 10−5.0 (2-PtCu) ＞ 10−5.1 (3-PtAu2) ＞ 10−5.3 (3-PtAg2) G0. Undoubtedly, charge transport along the platinum(ii) bis(σ-acetylide) backbone is progressively restricted by introducing one to two “gating” M ions to the mononuclear platinum(ii) molecule. As revealed by X-ray crystallography, the “gating” d10 metal ion is substantially bound to the acetylide and in fact the M–acetylide bonding is progressively enhanced in the order Au–Cacetylide→ Ag–Cacetylide→ Cu–Cacetylide, which coincides with a progressive decrease in the conductance as 10−4.8 (2-PtAu) ＞ 10−4.9 (2-PtAg) ＞ 10−5.0 (2-PtCu) G0. The M–acetylide coordination blocks the charge transport along the platinum(ii) bis(σ-acetylide) backbone so that the d10 metal ion behaves as a resistor to suppress the conductance. Theoretical studies confirm that the “gating” metal ions control the HOMO energy, which is lowered by the increased d orbital contribution of “gating” metal ions through Pt–M interactions. [ABSTRACT FROM AUTHOR]

A feasible synthetic approach to achieve Ag8, Ag16 and Ag29 silver(i) nanoclusters is reported by the use of 1,8-diethynyl-9H-carbazole (H3decz) as a directing ligand. The silver(i) nanoclusters exhibit room-temperature photoluminescence in both solution and solid state. The emission band shows stepwise red-shifts from visible to near-infrared region with the increase of cluster nuclearity following 2 (Ag8, λem = 571 nm) →3 (Ag16, λem = 651 nm) →4 (Ag29, λem = 916 and 875sh nm) in fluid CH2Cl2. [ABSTRACT FROM AUTHOR]

In order to develop solution-processable organic light-emitting diodes (OLEDs) with improved optical properties, PtAu3 heterometallic cluster complexes that exhibit narrow-band emission spectra were prepared through judicious molecular design. The brightly emissive PtAu3 complexes with robust chemical and thermal stability (＞290 °C) show photoluminescence quantum yields (PLQY) of 80.5% to 90.1% in doped films. The dihedral angle between the plane of the aromatic acetylide and the platinum(ii) coordination square plane exerts dramatic influence on the full width at half maximum (FWHM) of phosphorescent emission, in which the better the co-planarity, the narrower the FWHM. Theoretical studies suggest that the greater involvement of the acetylide-to-Pt 3LMCT state favors narrow-band emission. Solution-processed OLEDs based on narrow-band green emitters afford a maximum current efficiency (CE) of 38.7 cd A−1, power efficiency (PE) of 22.9 lm W−1 and external quantum efficiency (EQE) of 10.3% with an FWHM of 42 nm and CIE coordinates of (0.30, 0.61). The PtAu3 cluster complex with phenanthrene-fused carbazole-acetylide displays improved device performance due to its enhanced hole-carrier ability, with a peak CE of 62.2 cd A−1, PE of 30.3 lm W−1 and EQE of 16.6%. The elegant synthetic strategy combining electron and/or hole transport units enhances not only the device performance of the PtAu3 cluster complexes but also their charge carrier abilities, which were analyzed through space charge limited current measurements. [ABSTRACT FROM AUTHOR]

We report here a new approach to achieve thermochromic luminescence through thermally induced ligand-field transformations. A one-dimensional chain manganese(ii) complex exhibits thermochromic luminescence from blue-green (502 nm) to red (617 nm) emission in a wide range of temperatures (480–80 K), ascribed to the conversion of a tetrahedronal to trigonal bipyramidal ligand-field via two-step single-crystal to single-crystal transformations. [ABSTRACT FROM AUTHOR]

A family of highly phosphorescent PtM3 (M = Au, Ag) aromatic acetylide cluster complexes supported with tetraphosphine and stabilized by μ-chloride were synthesized by the use of weakly luminescent mononuclear Pt(PPh3)2(C≡CR)2 (R = aryl) as precursors. The formation of PtM3 cluster complexes involves the abstraction of chloride from dichloromethane. The dramatic difference between PtAg3 and PtAu3 cluster structures arises from the location of the Pt atom, which is at the center of the triangle-planar PtM3 cluster for M = Ag whereas at one of the three corners in the PtM3 triangle plane for M = Au. Perturbation of the chloride ion in complexation by using a halide-abstracting agent results in the formation of PtM2 heterotrinuclear structures as demonstrated by X-ray crystallography. The PtAu3 complexes display intense phosphorescence with quantum yields of over 90% in doped films. High-efficiency OLEDs based on PtAu3 complexes were attained with an external quantum efficiency (EQE) over 18%. Most importantly, the optimized devices exhibit extremely small efficiency roll-off (less than 1%) at a practical brightness over 1000 cd m−2, which is one of the best performances for solution-processable phosphorescent OLEDs. [ABSTRACT FROM AUTHOR]

We demonstrate a proof-of-concept design of a new platform for proton recognition and modulation. The new proton receptors are derived from a unique class of synthetic supercontainers that exhibit exceptional proton binding capacity (over 50 equiv.) and intriguing proton-dependent fluorescent switching behavior. Experimental and computational studies suggest that the proton-responsive event involves a two-step mechanism pertaining to proton binding by both amino and pyrenyl moieties of the supercontainer constructs. The high proton binding capacity of the supercontainers can be further modulated via small-molecule “regulators” that compete for the proton-binding sites, opening exiting new opportunities for proton manipulation in both chemistry and biology. [ABSTRACT FROM AUTHOR]

A new sulfonylcalix[4]arene-based dinuclear terbium molecular container (1) was conveniently synthesized and utilized as a fluorescence probe for the detection of a well-known biomarker 1-hydroxypyrene (1-OHP), which is used for the evaluation of polycyclic aromatic hydrocarbons (PAHs). The sulfonylcalix[4]arene ligand could not only serve as an efficient antenna ligand to promote the ligand-to-metal energy transfer but also provide a suitable cavity to accommodate 1-OHP. Promising fluorescence quenching effects were well established during the titration of the compound 1 with 1-OHP, and these effects were due to the enhancement in the host–guest intermolecular charge transfer and the decrease in the ligand-to-metal energy transfer after the formation of the stable host–guest complex. The fluorescence sensing mechanism was clearly understood through the titration experiments, and the data could be fit with the Benesi–Hildebrand and Stern–Volmer models. The TbIII-TBSC-based luminescent sensor exhibited quick response, high sensitivity, and specific selectivity to 1-OHP, even in the presence of other constituents in urine, thus providing a new sensing platform for the clinical diagnosis of human exposure to PAHs. [ABSTRACT FROM AUTHOR]

Abstract: A series of novel diiridium complexes (1–4) bearing both functional 2‐pyrazolyl‐6‐phenyl pyridine chelate and bidentate phenyl imidazolylidene chelate are synthesized, for which the pyrazolate fragment of the tridentate 2‐pyrazolyl‐6‐phenyl pyridine also behaves as the bridge to hold two iridium atoms in close vicinity. Their structure is unambiguously confirmed using X‐ray structure determination on the corresponding derivative 2a bearing 1,3‐bis(4‐fluorophenyl)‐1H‐Imidazolyl cyclometalate. Their photophysical and electrochemical properties are studied and further affirmed by the computational approaches. All these Ir(III) metal complexes 1–4 are very stable in both solution and solid film with near unity emission quantum efficiency. As opposed to most of diiridium complexes documented in literature, 1–4 are volatile and suitable for fabrication of organic light emitting diodes (OLEDs) under vacuum evaporation. The corresponding electroluminescent devices exhibit superior performance, among which external quantum efficiency of 27.6% using 2 as dopant stands for the record high of OLEDs using dinuclear Ir(III) complexes. They also offer a low roll‐off at high luminance, demonstrating their potential en route to high performance OLEDs. [ABSTRACT FROM AUTHOR]

A series of Ag(i) and Cu(i) complexes [Ag3(L1)2][PF6]3 (8), [Ag3(L2)2][PF6]3 (9), [Cu(L1)][PF6] (10) and [Cu(L2)][PF6] (11) have been synthesized by reactions of the tridentate amine-bis(N-heterocyclic carbene) ligand precursors [H2L1][PF6]2 (6) and [H2L2][PF6]2 (7) with Ag2O and Cu2O, respectively. Complexes 10 and 11 can also be obtained by transmetalation of 8 and 9, respectively, with 3.0 equiv. of CuCl. A heterometallic Cu/Ag–NHC complex [Cu2Ag(L1)2(CH3CN)2][PF6]3 (12) is formed by the reaction of 8 with 2.0 equiv. of CuCl. All complexes have been characterized by NMR, electrospray ionization mass spectrometry (ESI-MS), and single-crystal X-ray diffraction studies. The luminescence properties of 10–12 in solution and the solid state have been studied. At room temperature, 10–12 exhibit evident luminescence in solution and the solid state. The emission wavelengths are found to be identical at 483 nm in CH3CN, but they are 484, 480 and 592 nm in the solid state for 10–12, respectively. These results suggest that 12 dissociates into two molecules of 10 and Ag(i) ions in solution. Complex 12 is the first luminescent heterometallic Cu/Ag–NHC complex. [ABSTRACT FROM AUTHOR]

Abstract: An elaborately designed pyridinium‐functionalized octanuclear zinc(II) coordination container 1‐Zn was prepared through the self‐assembly of Zn2+, p‐tert‐butylsulfonylcalix[4]arene, and pyridinium‐functionalized angular flexible dicarboxylate linker (H2BrL1). The structure was determined by a single‐crystal X‐ray diffractometer. 1‐Zn displays highly sensitive and specific recognition to 2‐picolylamine as revealed by drastic blueshifts of the absorption and emission spectra, ascribed to the decrease of intramolecular charge transfer (ICT) character of the container and the occurrence of intermolecular charge transfer between the host and guest molecules. The intramolecular charge transfer plays a key role in the modulation of the electronic properties and is tunable through endo‐encapsulation of specific guest molecules. [ABSTRACT FROM AUTHOR]

Abstract: Developing ternary metal oxides as electron transport layers (ETLs) for perovskite solar cells is a great challenge in the field of third‐generation photovoltaics. In this study, a highly mesoporous Zn2Ti3O8 (m‐ZTO) scaffold is synthesized by ion‐exchange method and used as ETL for the fabrication of methyl ammonium lead halide (CH3NH3PbI3) perovskite solar cells. The optimized devices exhibit 17.21 % power conversion efficiency (PCE) with an open circuit voltage (Voc) of 1.02 V, short‐circuit current density (Jsc) of 21.97 mA cm−2 and fill factor (FF) of 0.77 under AM 1.5G sunlight (100 mW cm−2). The PCE is significantly higher than that based on mesoporous ST01 (m‐ST01; 10 nm TiO2 powder) layer (η=14.93 %), which is ascribed to the deeper conductive band of ZTO nanoparticles, better light absorption and smaller charge recombination. The devices stored for 100 days at ambient temperature with humidity of 10 % showed excellent stability with only 12 % reduction of the PCE. The charge transmission kinetic and long‐term stability parameters of the ZTO‐based perovskite film growth are discussed as well. [ABSTRACT FROM AUTHOR]