Zero-dimensional hybrid tin halides with stable broadband light emissions

Considering the instability and toxicity of 3D Pb-based perovskite nanocrystals, lead-free low-dimensional organic-inorganic hybrid metal halides have attracted widespread attention as potential substitutes. Herein, two new tin-based 0D halides [H4BAPP]SnBr5·Br and [H4BAPP]SnCl5·Cl·H2O (BAPP = 1,4-bis(3-aminopropyl)piperazine) were synthesized successfully based on [SnX5]3- as an emission center. Typically, [H4BAPP]SnBr5·Br and [H4BAPP]SnCl5·Cl·H2O display broadband yellow and yellow-green light emissions originating from the radiative recombination of self-trapped excitons (STEs). The photoluminescence quantum yields (PLQYs) of the two compounds were calculated to be 19.27% and 2.36%, respectively. Furthermore, the excellent chemical and thermal stability and broadband light emissions reveal their potential application in solid-state white lighting diodes.

Exploring 0D lead-free metal halide with highly efficient blue light emission and high-sensitivity photodetection

Environmentally friendly and highly efficient blue luminescent materials are an unremitting pursuit in the optoelectronic field. Herein, we assembled a new 0D lead-free metal halide of (F-PPA)ZnBr4, which exhibits narrow blue light emission with a remarkable PLQY of 50.15%, high stability and high detection sensitivity toward UV light. These results indicate the potential for the application of low-dimensional zinc-based halides in multiple optoelectronic devices.

Near-Unity Green Luminescent Hybrid Manganese Halides as X-ray Scintillators

The increasing demands in optoelectronic applications have driven the advancement of organic-inorganic hybrid metal halides (OIMHs), owing to their exceptional optical and scintillation properties. Among them, zero-dimensional (0D) low-toxic manganese-based scintillators have garnered significant interest due to their exceptional optical transparency and elevated photoluminescence quantum yields (PLQYs), making them promising for colorful light-emitting diodes and X-ray imaging applications. In this study, two OIMH single crystals of (Br-PrTPP)2MnBr4 (Br-PrTPP = (3-bromopropyl) triphenylphosphonium) and (Br-BuTPP)2MnBr4 (Br-BuTPP = (4-bromobutyl) triphenylphosphonium) were prepared via a facile saturated crystallization method. Benefiting from the tetrahedrally coordinated [MnBr4]2- polyhedron, both of them exhibited strong green emissions peaked at 517 nm owing to the d-d electron transition of Mn2+ with near-unity PLQYs of 99.33 and 86.85%, respectively. Moreover, benefiting from the high optical transparencies and remarkable luminescence properties, these manganese halides also exhibit excellent radioluminescent performance with the highest light yield of up to 68,000 photons MeV-1, negligible afterglow (0.4 ms), and linear response to X-ray dose rate with the lowest detection limit of 45 nGyair s-1. In X-ray imaging, the flexible film made by the composite of (Br-PrTPP)2MnBr4 and PDMS shows an ultrahigh spatial resolution of 12.78 lp mm-1, which provides a potential visualization tool for X-ray radiography.

A 0D hybrid lead-free halide with near-unity photoluminescence quantum yield toward multifunctional optoelectronic applications

Zero-dimensional (0D) hybrid metal halides have emerged as highly efficient luminescent materials, but integrated multifunction in a structural platform remains a significant challenge. Herein, a new hybrid 0D indium halide of (Im-BDMPA)InCl6·H2O was designed as a highly efficient luminescent emitter and X-ray scintillator toward multiple optoelectronic applications. Specifically, it displays strong broadband yellow light emission with near-unity photoluminescence quantum yield (PLQY) through Sb3+ doping, acting as a down-conversion phosphor to fabricate high-performance white light emitting diodes (WLEDs). Benefiting from the high PLQY and negligible self-absorption characteristics, this halide exhibits extraordinary X-ray scintillation performance with a high light yield of 55 320 photons per MeV, which represents a new scintillator in 0D hybrid indium halides. Further combined merits of a low detection limit (0.0853 μGyair s-1), ultra-high spatial resolution of 17.25 lp per mm and negligible afterglow time (0.48 ms) demonstrate its excellent application prospects in X-ray imaging. In addition, this 0D halide also exhibits reversible luminescence off-on switching toward tribromomethane (TBM) but fails in any other organic solvents with an ultra-low detection limit of 0.1 ppm, acting as a perfect real-time fluorescent probe to detect TBM with ultrahigh sensitivity, selectivity and repeatability. Therefore, this work highlights the multiple optoelectronic applications of 0D hybrid lead-free halides in white LEDs, X-ray scintillation, fluorescence sensors, etc.

0D hybrid indium halide as a highly efficient X-ray scintillation and ultra-sensitive fluorescent probe

Halide perovskite nanocrystal (PNC) of 3D CsPbX3 as a scintillator has aroused intensive attention with advanced applications in radiation detection and X-ray imaging. However, the low light yield and serious toxicity of Pb2+ severely hinder advanced optoelectronic applications. To reduce these fatal shortcomings, a family of new environmentally friendly 0D hybrid lead-free indium halides of [DADPA]InX6·H2O (DADPA = 3,3'-diaminodipropylamine; X = Cl and Br) was prepared. Upon UV excitation, these halides display strong broadband yellow-orange light emissions, and the photoluminescence quantum yield (PLQY) can be optimized up to near unity through the Sb3+-doping strategy. Significantly, high PLQY, negligible self-absorption and low attenuation ability toward X-ray render extraordinary scintillation performance with a high light yield of 51 875 photons MeV-1 and ultralow detection limit of 98.3 nGyair s-1, which is far superior to typical 3D PNC scintillators. Additionally, the ultra-high spatial resolution of 25.15 lp mm-1, negligible afterglow time (2.75 ms) and robust radiant stability demonstrates excellent X-ray imaging performance. To the best of our knowledge, this is the first report on X-ray scintillation based on 0D indium halide materials.

High Emission Efficiency and Thermal Stability in Zero-Dimensional Hybrid Zinc Halide as a Blue Light Emitter

Exploring highly efficient blue-emissive lead-free halide materials is a significant and challenging objective in the study of luminescent materials. This study reports the synthesis of a new zero-dimensional (0D) hybrid zinc halide of [CYP]ZnBr4 (CYP = 1-cyclohexylpiperazine) containing an isolated [ZnBr4]2- tetrahedron. [CYP]ZnBr4 exhibits strong blue light emission with a high photoluminescence quantum yield (PLQY) of 79.22%, surpassing all previously reported 0D zinc halide counterparts. According to the theoretical and experimental studies, the blue light emission is attributed to intrinsic self-trapped excitons resulting from strong electron-phonon coupling and structural deformation. Importantly, [CYP]ZnBr4 demonstrates excellent structural and luminescence stability toward high temperatures (180 °C) over at least half a month. High luminescence efficiency and stability enable [CYP]ZnBr4 to be an efficient blue phosphor to fabricate white light-emitting diodes (LEDs), which produces high-quality white light with a color rendering index (CRI) of 93.1 and a correlated color temperature (CCT) of 5304 K, closely resembling natural sunlight. This white LED also exhibits consistent performance and stability across different drive currents, suggesting the potential for high-power optoelectronic applications. Overall, this study paves the way for the utilization of 0D hybrid halides in advanced solid-state lighting applications.

Reversible structural transformations and color-tunable emissions in organic manganese halides

Herein, we for the first time report a reversible conversion between green-emissive [DMPZ]MnCl4 and red-emissive [DMPZ]4(MnCl6)(MnCl4)2·(H2O)2 (DMPZ = 1,4-dimethylpiperazine) using kinetic and thermodynamic controlling strategies. Significantly, the synchronous structural and emission transformations in single-component organic manganese halides with adjustable emission colors are highlighted.

0D triiodide hybrid halide perovskite for X-ray detection

In the relentless pursuit of developing high-performance, stable and environmentally friendly materials for X-ray detection, we present a new class of Bi-based hybrid organic-inorganic perovskites. An X-ray detector based on a new zero-dimensional (0D) triiodide-induced lead-free hybrid perovskite, (DPA)2BiI9 (DPA = C₅H₁₆N₂²⁺), has been developed demonstrating outstanding detection performance, including high X-ray sensitivity (20 570 μC Gy_air^-1 cm^-2), low detectable dose rate (0.98 nGy_air s^-1), fast response time (154/162 ns) and excellent long-term stability.

Enhanced stability and tunable photoluminescence in Mn2+-doped one-dimensional hybrid lead halide perovskites for high-performance white light emitting diodes

Organic-inorganic hybrid low-dimensional lead halides have garnered significant interest in the realm of solid-state optical materials due to their unique properties and potential applications. In this study, we report the synthesis, characterization and application of Mn²⁺-doped one-dimensional (1D) [AEP]PbCl₅·H₂O hybrid lead halide perovskites with tunable photoluminescence properties. The Mn²⁺ doping leads to a redshift of the dominant emission wavelength from 463 nm to 630 nm, with the optimal doping concentration resulting in an enhanced photoluminescence quantum yield (PLQY) from less than 1% to 8.96%. The structural and optical stability of these doped perovskites have been thoroughly investigated revealing excellent performance under humid and high-temperature conditions. Perovskite-PVP composite films exhibit high crystallization and bright orange-red emission under UV excitation. Furthermore, we demonstrate the successful fabrication of a white LED device using the Mn²⁺-doped perovskite in combination with commercial green and blue phosphors. The fabricated LED exhibits a high color rendering index (CRI) of 87.2 and stable electroluminescence performance under various operating currents and extended operation times. Our findings highlight the potential of Mn²⁺-doped 1D hybrid lead halide perovskites as efficient and stable phosphors for high-performance white light emitting diodes and other optoelectronic applications.

Zero-Dimensional Hybrid Cuprous Halide of [BAPMA]Cu2Br5 as a Highly Efficient Light Emitter and an X-Ray Scintillator

Lead halide perovskites have been explored as a new kind of promising X-ray with wide applications in radiation-associated fields, but low light yield and serious toxicity extremely restrict further applications. To address these issues, we herein demonstrated one new zero-dimensional (0D) organic-inorganic hybrid cuprous halide of [BAPMA]Cu₂Br₅ (BAPMA = N,N-Bis(3-aminopropyl) methylamine) containing discrete [Cu₄Br₁₀]^6- tetramers as excellent lead-free scintillators. Upon UV light excitation, [BAPMA]Cu₂Br₅ displays highly efficient broadband yellowish-green light emission with one dominant peak at 526 nm, a large Stokes shift of 244 nm, and a high photoluminescent quantum yield of 53.40%. Significantly, this broadband light emission can also be excited by higher-energy X-ray as radioluminescence with a high scintillation light yield of 43,744 photons/MeV. The detection limit of 0.074 μGy_air/s is also far less than the required value for regular medical diagnostics of 5.5 μGy_air/s. The solution-assembled hybrid structure facilely enables the [BAPMA]Cu₂Br₅-based scintillation screen to display high-performance X-ray imaging with a spatial resolution of 15.79 lp/mm showcasing potential application in X-ray radiography. In brief, combined merits of low toxicity and cost, negligible self-absorption, a low detection limit, considerable light yield, and spatial resolution highlight the excellent scintillation performance of 0D hybrid cuprous halide.

Stepwise Crystalline Structural Transformation in 0D Hybrid Antimony Halides with Triplet Turn-on and Color-Adjustable Luminescence Switching

Intelligent stimuli-responsive fluorescence materials are extremely pivotal for fabricating luminescent turn-on switching in solid-state photonic integration technology, but it remains a challenging objective for typical 3-dimensional (3D) perovskite nanocrystals. Herein, by fine-tuning the accumulation modes of metal halide components to dynamically control the carrier characteristics, a novel triple-mode photoluminescence (PL) switching was realized in 0D metal halide through stepwise single-crystal to single-crystal (SC-SC) transformation. Specifically, a family of 0D hybrid antimony halides was designed to exhibit three distinct types of PL performance including nonluminescent [Ph₃EtP]₂Sb₂Cl₈ (1), yellow-emissive [Ph₃EtP]₂SbCl₅·EtOH (2), and red-emissive [Ph₃EtP]₂SbCl₅ (3). Upon stimulus of ethanol, 1 was successfully converted to 2 through SC-SC transformation with enhanced PL quantum yield from ~0% to 91.50% acting as "turn-on" luminescent switching. Meanwhile, reversible SC-SC and luminescence transformation between 2 and 3 can be also achieved in the ethanol impregnation-heating process as luminescence vapochromism switching. As a consequence, a new triple-model turn-on and color-adjustable luminescent switching of off-on^I-on^II was realized in 0D hybrid halides. Simultaneously, wide advanced applications were also achieved in anti-counterfeiting, information security, and optical logic gates. This novel photon engineering strategy is expected to deepen the understanding of dynamic PL switching mechanism and guide development of new smart luminescence materials in cutting-edge optical switchable device.

Multiple Light Source-Excited Organic Manganese Halides for Water-Jet Rewritable Luminescent Paper and Anti-Counterfeiting

Rewritable luminescent paper is particularly crucial, considering the ultrahigh paper consumption and confidential information security, but a highly desirable stimuli-responsive smart luminescent material with excellent water solubility has rarely been studied. Herein, a new type of rewritable paper made by highly efficient green light emissive zero-dimensional (0D) organic manganese halides is rationally designed by virtue of the reversible photoluminescence (PL) off-on switching. Specifically, the green emission can be linearly quenched by water vapor in a wide humidity range and again recovered in a dry atmosphere, which make it a smart hydrochromic PL off-on switching and humidity sensor. Benefiting from the reversible luminescence off-on switch and excellent water solubility, rewritable luminescent paper is realized through water-jet security printing technology on 0D halide-coated commercial paper with high resolution. The printed/written information can be easily cleaned by slight heating with outstanding "write-erase-write" cycle capabilities. In addition, multiple light source-induced coincident green light emissions further provide convenience to realize anti-counterfeiting, encryption and decryption of confidential information, and so forth. This work highlights the superiority of dynamic ionic-bonded 0D organic manganese halides as reversible PL switching materials in rewritable luminescent paper, high-security-level information printing, storage and protection technologies, and so forth.

Zero-Dimensional Hybrid Indium Halides with Efficient and Tunable White-Light Emissions

Two-dimensional hybrid lead perovskites have attracted a great deal of attention in white-light-emitting diodes, but the serious toxicity of Pb²⁺ and the limited photoluminescence quantum yield (PLQY) still restrict further optoelectronic application. To address these issues, a new combining photon strategy was proposed to achieve highly efficient broadband white-light emission in a new family of zero-dimensional (0D) indium halides based on an [InCl₆]^3- octahedron. Remarkably, these 0D halides display dual-band white-light emission derived from the synergistic work of blue- and yellow-light-emitting bands, which can be ascribed to the radiative recombination of bound excitons in organic cations and self-trapped excitons in inorganic anions, respectively, based on spectroscopy and theoretical studies. In-depth first-principles calculation demonstrates that the increased structural deformability effectively improves the PLQY from 7.01% to 18.56%. As a proof of concept, this work provides a profound understanding for advancing the rational design of novel single-component 0D lead-free halides as high-performance white-light emitters.

0D hybrid indium halides with highly efficient intrinsic broadband light emissions

Two new zero-dimensional (0D) hybrid indium halides of [H₂DMP]₂InX₇·2H₂O (X = Cl, Br) were designed based on [InX₆]^3- octahedra as optically active centers. Remarkably, these 0D halides display intrinsic broadband yellow-orange light emissions with highest quantum yield of 58.53% exceeding all previously reported 0D indium halides.

Zero-dimensional Hybrid Antimony Halide with Intrinsic Cyan Light Emission

Recently, zero-dimensional (0D) hybrid metal halides have attracted intensive attention with wide applications in solid-state lighting and display diodes. Herein, by using the facile wet-chemistry method, we prepared one new 0D hybrid antimony halide of [HMHQ] 2 SbCl 5 ·2H 2 O (MHQ = 2-methyl-8-hydroxyquinoline) based on discrete [SbCl 5 ] 2- unit. Remarkably, the bulk crystals of [HMHQ] 2 SbCl 5 ·2H 2 O exhibit strong cyan light emission with promising photoluminescence quantum yield (PLQY) of 18.92%. Systematical studies disclose that the cyan emission is mainly derived from the radiative recombination within conjugated organic cation. Benefiting from the promising luminescent performance, this 0D antimony halide can be utilized as an excellent down-conversion light emitting luminescent material to assemble white light-emitting diodes with high color rendering index (CRI) of 90.2.

Centimeter-sized lead-free iodide-based hybrid double perovskite single crystals for efficient X-ray photoresponsivity

Hybrid organic-inorganic lead halide perovskites (HOIPs) possess significant photoelectric characteristics for solar energy conversion, but the presence of lead causes issues for eco-friendly applications. Halide double perovskites represent a green option for application in the optoelectronic field, especially X-ray detection systems. Despite the great efforts, the exploration of large-size lead-free iodide-based hybrid double perovskite single crystals for X-ray detection has been unsuccessful. Herein, we demonstrate that a large single crystal of the 2D (two-dimensional) semiconducting perovskite (C₆H₁₆N₂)₂CuBiI₈·0.5H₂O can serve as an X-ray detection candidate. A perovskite crystal, as large as 35 × 31 × 3 mm³, was grown using a low-cost, simple cooling solution approach. To the best of our knowledge, this is the first time a centimeter-sized 2D BiCu iodide double perovskite single crystal has been used for X-ray detection. The perovskite crystal exhibited unique properties for X-ray detection, such as a significant X-ray absorption coefficient, considerable μτ product, and low trap density. Moreover, X-ray detection with a sensitivity of 5.51 μC Gy_air^-1 cm^-2 was achieved based on a single crystal. This work opens new ways to explore specially designed organic cations for stabilizing 2D HOIPs that show great potential in optoelectronics.

Applications of Halide Perovskites in X-ray Detection and Imaging

X-ray detection plays an extremely significant function in medical diagnosis, nondestructive testing, safety testing, scientific research, environmental monitoring and other practical applications. However, conventional inorganic semiconductors such as amorphous selenium,...

A Zero-Dimensional Hybrid Cadmium Perovskite with Highly Efficient Orange-Red Light Emission

Low-dimensional organic-inorganic hybrid metal halide materials have been extensively studied due to their excellent optoelectronic performances. Herein, by using the facile wet-chemistry method, we designed one new hybrid cadmium bromide of (H₃AEP)₂CdBr₆·2Br based on discrete octahedral [CdBr₆]^4- units. Remarkably, the bulk crystal of (H₃AEP)₂CdBr₆·2Br exhibits strong broadband orange-red light emission from the radiative recombination of self-trapped excitons (STEs) with a high photoluminescence quantum yield (PLQY) of 9%. Benefiting from the highly efficient luminescent performance, this 0D cadmium perovskite can be utilized as an excellent down-conversion red phosphor to assemble a white light-emitting diode, and a high color rendering index (CRI) of 93 is realized. As far as we know, this is the first orange-red light-emitting hybrid cadmium perovskite which promotes the full-color display in this system.

Bulk Mn2+ Doped 1D Hybrid Lead Halide Perovskite with Highly Efficient, Tunable and Stable Broadband Light Emissions

Mn²⁺ doped colloidal three-dimensional (3D) lead halide perovskite nanocrystal (PNC) has attracted intensive research attention; however, the low exciton binding energy and fatal optical instability of 3D PNC seriously hinder the optoelectronic application. Therefore, it remains significant to explore new stable host perovskite with strongly bound exciton to realize more desirable luminescent property. In this work, we utilized bulk one-dimensional (1D) hybrid perovskite of [AEP]PbBr₅  ⋅ H₂ O (AEP=N-aminoethylpiperazine) as structural platform to rationally optimize the luminescent property by a controllable Mn²⁺ doping strategy. Significantly, the series of Mn²⁺ -doped 1D [AEP]PbBr₅  ⋅ H₂ O show enhanced energy transfer efficiency from the strongly bound excitons of host material to 3d electrons of Mn²⁺ ions, resulting in tunable broadband light emissions from weak yellow to strong red spectral range with highest photoluminescence quantum yield up to 28.41 %. More importantly, these Mn²⁺ -doped 1D perovskites display ultrahigh structural and optical stabilities in humid atmosphere, water and high temperature exceeding the conventional 3D PNC. Combined highly efficient, tunable and stable broadband light emissions enable Mn²⁺ -doped 1D perovskite as excellent down-converting phosphor showcasing the potential application in white light emitting diode. This work not only provides a profound understanding of low-dimensional perovskites but also opens a new way to rationally design high-performance broadband light emitting perovskites for solid-state lighting and displaying devices.

Three-Dimensional Cuprous Iodide Framework with Intrinsic Broadband Red-to-Near-Infrared Light Emission

Herein, a new organic-inorganic hybrid cuprous iodide of [(Me)₂-DABCO]Cu₆I₈ was prepared and structurally characterized with a novel three-dimensional (3D) [Cu₆I₈]^2- framework. Significantly, this 3D cuprous iodide displays infrequent broadband red-to-near-infrared light emission (600-1000 nm) stemming from the radiative recombination of self-trapped excitons.

Enhancement of the photoluminescence efficiency of hybrid manganese halides through rational structural design

Five new zero-dimensional hybrid manganese halides based on discrete [MnCl4]2- tetrahedrons were prepared and used as highly efficient green-light emitters. Through rational management of organic cations to tailor the MnMn separation distances between neighboring [MnCl4]2- tetrahedrons, the photoluminescence quantum yield increased significantly from 7.98% to 81.11%.

Tunable Metal-Organic Frameworks Based on 8-Connected Metal Trimers for High Ethane Uptake

Metal trimers [M₃ (O/OH)](OOCR)₆ are among the most important structural building blocks. From these trimers, a great success has been achieved in the design of 6- or 9-connected framework materials with various topological features and outstanding gas-sorption properties. In comparison, 8-connected trimer-based metal-organic frameworks (MOFs) are rare. Given multiple competitive pathways for the formation of 6- or 9-connected frameworks, it remains challenging to identify synthetic or structural parameters that can be used to direct the self-assembly process toward trimer-based 8-connected materials. Here, a viable strategy called angle bending modulation is revealed for creating a prototypical MOF type based on 8-connected M₃ (OH)(OOCR)₅ (Py-R)₃ trimers (M = Zn, Co, Fe). As a proof of concept, six members in this family are synthesized using three types of ligands (CPM-80, -81, and -82). These materials do not possess open-metal sites and show excellent uptake capacity for various hydrocarbon gas molecules and inverse C₂ H₆ /C₂ H₄ selectivity. CPM-81-Co, made from 2,5-furandicarboxylate and isonicotinate, features selectivity of 1.80 with high uptake capacity for ethane (123 cm³ g^-1 ) and ethylene (113 cm³ g^-1 ) at 298 K and 1 bar.

Lead chlorine cluster assembled one-dimensional halide with highly efficient broadband white-light emission

One new type of hybrid lead halide of [DTHPE]2Pb3Cl10 has been synthesized and characterized containing a one-dimensional (1D) wavelike [Pb3Cl10]4- chain based on a corner-shared [Pb3Cl11] cluster. Remarkably, this cluster-based 1D chain displays intrinsic broadband white light emission with a high quantum efficiency of 19.45% exceeding those of previously reported typical two-dimensional perovskites.

Combining Dual-Light Emissions to Achieve Efficient Broadband Yellowish-Green Luminescence in One-Dimensional Hybrid Lead Halides

In recent years, low-dimensional lead halides have emerged as some of most attractive photoelectric materials due to their intrinsic broadband emissions with a potential application in white-light emitting diodes. To achieve the desired performance, tremendous research has emphasized the modulation of inorganic components as optical centers; however, less work has paid attention to the direct contribution of the organic components. Herein, we successfully assembled two new hybrid lead halides of [H₂BPP]Pb₂X₆ (X = Br, 1, and Cl, 2) containing one-dimensional double [Pb₂X₆]^2- chains using optically active 1,3-bis(4-pyridyl)-propane (BPP) as an organic cation. Under UV-light excitation, compounds 1 and 2 exhibit broadband yellowish-green emissions, which were verified by promising photoluminescence quantum efficiencies (PLQEs) of 8.10% and 4.84%, respectively. The broadband light emissions are derived from the combination of dual higher-energy blue and lower-energy yellow light spectra, which can be attributed to the individual contributions of the organic and inorganic components, respectively, according to the time-resolved and temperature-dependent emission spectra as well as theoretical calculations. This work proves the great contribution of organic components to the photophysical properties and provides a new design strategy to realize broadband light emission by rationally combining the dual-emitting properties of different assembly blocks.

Organic cations directed 1D [Pb3Br10]4− chains: syntheses, crystal structures, and photoluminescence properties

To diversify the luminescence properties of 1D perovskites, different organic amine cations were combined with 1D [Pb₃Br₁₀]⁴⁻ chains leading to a series of A₂Pb₃Br₁₀ homologues, displaying broadband near white-light emissions with highest CRI of 96.

One-Dimensional Face-Shared Perovskites with Broad-Band Bluish White-Light Emissions

In recent years, two-dimensional (2D) hybrid lead halide perovskites based on corner-shared [PbX₆] octahedrons have received extensive attention with important potentials in single-component white-light emitting diodes (WLEDs) due to the soft and distorted crystal lattices. However, limited research focused on the one-dimensional (1D) perovskites although they possess similar structural superiorities to achieve this performance. Herein, by using different types of organic amine cations as structural direction reagents, we report one new type of hybrid 1D perovskites of APbCl₃ (A = (DTHPE)_0.5, DMTHP, DBN) based on the same 1D face-shared octahedral [PbCl₃]^- chains. Upon UV light excitation, these 1D APbCl₃ perovskites exhibit intrinsic broad-band bluish white-light emissions covering entire visible light spectra with the highest photoluminescence quantum yield (PLQY) of 6.99%, which catches up with the values of previously reported 2D perovskites. Through the systematical studies of time-resolved, temperature-dependent PL emissions, theoretical calculations, and so on, these broad-band light emissions can be ascribed to the radiative transition within conjugated organic cations. The facile assembly process, intrinsic broad-band light emissions, and high PLQYs enable these 1D APbCl₃ perovskites as new types of promising candidates in fabricating single-component WLEDs.

Improving Broadband White-Light Emission Performances of 2D Perovskites by Subtly Regulating Organic Cations

Recently, 2D organic-inorganic hybrid lead halide perovskites have attracted intensive attention in solid-state luminescence fields such as single-component white-light emitters, and rational optimization of the photoluminescence (PL) performance through accurate structural-design strategies is still significant. Herein, by carefully choosing homologous aliphatic amines as templates, isotypical perovskites [DMEDA]PbCl₄ (1, DMEDA=N,N-dimethylethylenediamine) and [DMPDA]PbCl₄ (2, DMPDA=N,N-dimethyl-1,3-diaminopropane) having tunable and stable broadband bluish white emission properties were rationally designed. The subtle regulation of organic cations leads to a higher degree of distortion of the 2D [PbCl₄ ]^2- layers and enhanced photoluminescence quantum efficiencies (<1 % for 1 and 4.9 % for 2). The broadband light emissions could be ascribed to self-trapped excitons on the basis of structural characterization, time-resolved PL, temperature-dependent PL emission, and theoretical calculations. This work gives a new guidance to rationally optimize the PL properties of low-dimensional halide perovskites and affords a platform to probe the structure-property relationship.

A three-dimensional cuprous lead bromide framework with highly efficient and stable thermochromic luminescence properties

The first 3D bimetallic halide of [H₂DABCO]₂Cu₆PbBr₁₂ based on two types of 6-connected nodes displays highly efficient thermochromic luminescence from broadband yellow to green light emissions.

Tetrameric cluster assembled one-dimensional hybrid lead halides with broadband light emission

A series of new types of 1D lead halide perovskites have been synthesized based on [Pb₄X₁₆] tetrameric clusters. The 1D crystal lattice exhibits broadband yellow light emission arising from the self-trapped excitons with potential application in WLEDs.

[Clinical value of MRI in the diagnosis of Brucellosis spondylitis]

Objective: To analyze the MRI characteristics of Brucellosis spondylitis (BS) and evaluate the clinical value of MRI in the diagnosis of BS. Methods: A total of 47 patients clinically diagnosed as BS from General Hospital of Jizhong Energy Xingtai Mining Industry Bloc and Xingtai Second Hospital from January 2015 to December 2017 were collected, including 32 males and 15 females, aged 24-77 years, with an average age of (57±11) years, and the course of disease was 1 month-2 years. Routine spinal MRI sequence were acquired for patients. Images were assessed by two senior imaging diagnostic physician independently. The evaluation included signal changes in the affected area of the vertebral body, vertebral body and intervertebral disc, the signal of paravertebral soft tissue, the signal of abscess around the vertebral body, whether the dural sac, spinal cord and nerve root were compressed or not, and its signal changes. Results: (1) Spinal involvement, in 47 patients with BS, 112 vertebral bodies were involved, including 11 cervical vertebrae (9.8%), 5 thoracic vertebrae (4.5%), 91 lumbar vertebrae (81.2%), and 5 sacral vertebrae (4.5%), the lumbar vertebrae was dominant. (2) MRI features, 112 vertebral bodies were involved, including 105 (93.8%) vertebral bodies morphology showed no significant changes, only 7 (6.2%) vertebral bodies showed mild collapse changes; 71 vertebral bodies showed diffuse destruction (63.4%), and 41 vertebral bodies showed localized destruction (36.6%). Among the 47 cases, 40 cases were continuous destruction of adjacent vertebral bodies, 6 cases showed non-adjacent damage; 37 cases of intervertebral disc involvement; 29 cases of narrowing of intervertebral space; 11 cases of paravertebral soft tissue swelling and 28 cases showed paravertebral abscess. Conclusion: MRI has certain characteristics in the diagnosis of Brucella spondylitis and has a high clinical value in the differential diagnosis of spinal disease.

Organic cation directed one-dimensional cuprous halide compounds: syntheses, crystal structures and photoluminescence properties

In recent years, organic-inorganic hybrid metal halides have emerged as a highly promising class of semiconducting light emitting diodes (LEDs) due to their fascinating photoluminescence properties. Here, by specifically selecting different organic cations as templates, a series of new hybrid cuprous halides have been solvothermally prepared, namely [Me-Py]CuI₂ (1), [(Me)₂-DABCO]Cu₂I₄ (2), [Me-MePy]Cu₂I₃ (3), and [H₂DABCO]Cu₃X₅ (X = I (4) and Br (5)). These hybrid cuprous halides feature one-dimensional (1D) [CuI₂]^-, [Cu₂I₃]^- and [Cu₃X₅]^2- (X = Br, I) chains surrounded and charge-balanced by organic cations. Under UV photoexcitation, these hybrid cuprous halides exhibit strong tunable photoluminescence from cyan (480 nm) to red (675 nm) emissions with large Stokes shifts (345 nm). The intrinsic nature of PL emissions is also investigated based on temperature-dependent PL emission, lifetime, photoluminescence quantum efficiencies, etc.

[Quantitative evaluation of the relationship between femoral trochlear dysplasia and the degeneration of the patellofemoral cartilage by using T2mapping]

Objective: To evaluate the relationship between the femoral trochlear dysplasia(FTD) and the degeneration of the patellofemoral cartilage by using MR T2mapping technique. Methods: Sixty two subjects with FTD(aged 18-45 years) were enrolled in Tianjin First Center Hospital from January 2016 to December 2017,the controls which both age and gender were matched.T2mapping scan were aquired for each subject and control. Compare the differences of the T2mapping values for each area between subjects and controls, and compare Dejour types of femoral trochlear in different age groups, respectively. Results: The T2mapping value of subjects was significant lower than controls: the superficial-femoral-lateral layer (sFL) (P=0.000) and the superficial-patella-lateral layer (sPL) (P=0.009). In the group of age less than 30 years, the T2mapping value of subjects was significant lower than controls:sFL (P=0.001) and sPL (P=0.015). In group of age greater than 30 years, the T2mapping value of subjects was significant lower than controls: sFL (P=0.035). In difference Dejour types of FTD, the T2mapping value of type B-D was lowest in sFL(P=0.014),sPL(P=0.000), the superficial-patella-medial layer (sPM) (P=0.020) and the the T2mapping value of type B-D was highest in the deep-femoral-medial layer (dFM) (P=0.006). The difference was statistically significant, P<0.05. Conclusion: The FTD might cause the early degeneration of patellofemoral cartilage, which significantly appear in the young age; The type B-D of FTD is more likely to cause the wider range of superficial cartilage injure and involved some part of deep layer; the injure shows dehydration change in superficial cartilage and edema in deep layer.

Spin-reorientation critical dynamics in the two-dimensional XY model with a domain wall

In recent years, static and dynamic properties of non-180^{∘} domain walls in magnetic materials have attracted a great deal of interest. In this paper, spin-reorientation critical dynamics in the two-dimensional XY model is investigated with Monte Carlo simulations and theoretical analyses based on the Langevin equation. At the Kosterlitz-Thouless phase transition, the dynamic scaling behaviors of the magnetization and the two-time correlation function are carefully analyzed, and critical exponents are accurately determined. When the initial value of the angle between adjacent domains is slightly lower than π, a critical exponent is introduced to characterize the abnormal power-law increase of the magnetization in the horizontal direction inside the domain interface, which is measured to be ψ=0.0568(8). In addition, the relation ψ=η/2z is analytically deduced from the Langevin dynamics in the long-wavelength approximation, well consistent with numerical results.

Transition metal complex dye-sensitized 3D iodoplumbates: syntheses, structures and photoelectric properties

The first types of transition metal complex cationic dye-sensitized 3D hybrid porous iodoplumbates exhibiting outstanding visible light-driven photoelectric properties.

Organic cation directed hybrid lead halides of zero-dimensional to two-dimensional structures with tunable photoluminescence properties

A series of new inorganic–organic hybrid lead halides have been solvothermally synthesized and characterized with tunable luminescence properties from yellow, orange to red emissions with the largest reported Stokes shift.

[Value of mDIXON-Quant sequence, diffusion-weighted imaging in quantitatively diagnosing the sacroiliitis stages]

Objective: To evaluate the value of mDIXON-Quant sequence, diffusion-weighted imaging (DWI) in quantitative diagnosing of the sacroiliitis stages in patients with ankylosing spondylitis (AS). Methods: Based on the Bath Ankylosing Spondylitis Activity Index (BASDAI) and laboratory parameters, a total of 51 patients were diagnosed with AS. They were divided into two groups as early active group (n=20) and chronic active group (n=31), and at the same time, 25 healthy people from Tianjin were included as control group. The regular MRI sequences and mDIXON-Quant sequence, DWI were obtained. The apparent diffusion coefficient (ADC) and fat-signal fraction (FF) value of bone marrow with edema of the sacroiliac joints in early active group and chronic active group and of subchondral bone marrow of sacroiliac joint in control group all were measured by ADC maps and FF maps. Mean (FF, ADC) values were compared between groups. Results: The ADC value of the early active group, chronic active group and the control group is (1.07±0.20)×10(-3)mm(2)/s, (1.00±0.22)×10(-3)mm(2)/s, (0.25±0.07)×10(-3)mm(2)/s, respectively, and the differences of ADC value between early active group and control group, chronic active group and control group were significant (P<0.01), but the difference of the ADC value between early active group and chronic active group was not significant (P=0.394). That is to say, the ADC value can't distinguish the early active group and chronic active group. The differences of FF value between groups was significant (P<0.01), and the FF value of bone marrow with edema in chronic active group were higher than that in early active group. Conclusions: The mDIXON-Quant sequence can quantitatively diagnose early active group and chronic active group, and the diagnostic value is better than DWI. Thus, it can provide guidance for clinical treatment and prognosis.

Di-pyridyl organic cation directed hybrid cuprous halogenides: syntheses, crystal structures and photochromism and photocatalysis

A series of organic–inorganic hybrid cuprous halogenides have been solvothermally prepared and feature photochromism behavior and visible light driven photocatalytic activities.

Comparison studies of hybrid lead halide [MPb2X7]2− (M = Cu, Ag; X = Br, I) chains: band structures and visible light driven photocatalytic properties

A series of inorganic–organic hybrid heterometallic halides of [TM(2,2-bipy)₃]MPb₂X₇ (M = Ag/Cu, X = Br, I) have been solvothermally prepared with visible light driven photocatalytic properties.