Search

Adsorption-based separation is an important technology for C2 H2 purification due to the environmentally friendly and energy-efficient advantage. In addition to the high selectivity of C2 H2 /CO2 , the high uptake of C2 H2 also plays an important role in the separation progress. However, the trade-off between adsorption capacity and separation performance is still in a dilemma. Herein, we report a series of cage-like porous materials named FJI-H8-R (R=Me, Et, n Pr and i Pr) which all have high C2 H2 uptakes at 1 bar and 298 K. Dynamic breakthrough studies show that they all exhibit excellent C2 H2 /CO2 separation performance. Particularly, FJI-H8-Me possesses a long breakthrough time up to 90 min g-1 . Additionally, Grand Canonical Monte Carlo (GCMC) simulation reveals that the suitable pore space and geometry contribute much to the excellent separation performance.

Through a functional unit-transmutation strategy, a fatigue-free layered hybrid perovskite ferroelectric (C6H5CH2NH3)(2)CsPb2Br7 (BCPB) has been developed, which demonstrates stable spontaneous polarization (P-s) of 6.5 mu C cm(-2) and high Curie temperature up to 425 K. Meanwhile, BCPB shows splendid bulk photovoltaic effect (BPVE) properties with noticeable zero-bias photocurrent density (5 mu A cm(-2)), and high on/off switching ratio of current (over 3x10(5)); these merits even overmatch the most known ferroelectric semiconductor BiFeO3. The unique structure with self-regulated net electrical charged layers gives rise to the fatigue-free feature of P-s and BPVE (no significant fatigue after 10(8) polarity switching cycles), promoting the potential applications of BCPB in photovoltaic non-volatile memories. This work offers an efficient approach for exploring fatigue-free semiconducting ferroelectrics as well as excavates their further applications in next-generation electronic devices.

Birefringent materials are highly demanded for high-performance polarized optics. As compared with artificial anisotropic metamaterials, anisotropic crystals have advantages of low optical losses and easy processing, but their birefringence is still limited. Herein, based on first-principles studies, we identified a new type of functional anion units, (H

Luminescent stability is a vital factor that dictates the application of lanthanide luminescent materials. Designing luminescent lanthanide cluster nodes that form an extended framework with predictable linking patterns may help enhance the structural stability of the lanthanide complexes and hence lead to improved luminescent stability. Herein, we report a series of one-dimensional (1D) rare-earth metal-organic framework compounds, {Ln

{Ln4} cores outperform {Ln9} cores in achieving stable photoluminescence from double thiacalix[4]arene-capped lanthanide-oxo clusters.

Antiperovskites have been studied since the 1980s because of their rich physical and chemical properties, but their linear and second-order nonlinear optical responses remain largely unknown. Here we report a new polar crystal, Cs

Controllable arrangement of different ligands in a single assembly will not only bring increased complexity but also offers a new route to fine-tune the function of the designed architecture. We report here a combinatorial self-assembly with enPd(NO

Coordination hosts based on flexible ligands have received increasing attention due to their inherent adaptive cavities that often show induced-fit guest binding and catalysis like enzymes. Herein, we report the controlled self-assembly of a series of homo/heterometallic coordination hosts (Me

In this paper, a kind of fluorescent anti-counter feiting acrylate pressure-sensitive adhesive (PSA) label was prepared using 7-hydroxycoumarin and acrylate monomer. First,7-hydroxycoumarin was rea...

The design and synthesis of stable metal–organic frameworks (MOFs) have been a core obstacle in the widespread application of these functional crystalline porous materials, because of the stability...

Chiral ligands enabled palladium-catalyzed regio- and enantioselective C–H activation represents one of the current frontiers in transition metal catalysis. It has been extensively developed over the past decade as an important method for the synthesis of chiral molecules. Functional molecules bearing central, axial or planar chirality can be efficiently generated in good to excellent optical purities through this method. It has also been used as one of the most efficient methods for the rapid construction of various C–C and C–X bonds. In this review, we highlight the development of some representative chiral ligands in Pd-catalyzed enantioselective C(sp2)–H and C(sp3)–H functionalization reactions. Specifically, critical features of these novel Pd-catalyzed transformations assisted by chiral ligands such as monodentate phosphoramidites, chiral phosphoric acids (CPAs) and bifunctional mono-N-protected amino acids (MPAAs) will be discussed. The recent advances and limitations in this rapidly growing research area and its application in the total synthesis of natural products and pharmaceutical molecules will also be presented and discussed.

Two-dimensional (2D) hybrid perovskites of Ruddlesden–Popper (RP) lattices are recently booming as a vigorous class of ferroelectrics, whereas their intrinsic van der Waals gaps exert weak interact...

A microporous supramolecular framework with high water and thermal stability can selectively absorb water molecules over methanol or ethanol due to the suitable channels. The model separation test on columns shows that an ultra-pure ethanol (99.9%) can be obtained from the mixture of ethanol/water (95:5). Additionally, after refluxing the desolvated sample in 95% ethanol at 60 °C for 5 h, the purity of ethanol rises up to 97.43%, which is obviously higher than 96.56% for 4 A molecular sieves.

Ferroelectricity-induced self-powered photodetection has emerged as an indispensable branch of new optoelectronic devices. Organometallic perovskites that combine ferroelectricity and semiconductor merits are promising. However, it remains a challenge to achieve self-powered photodetection with a low detection limit, due to the polarization deterioration caused by the leakage current of photoexcited carriers. Here, we exploit the high performance self-powered photodetection in the 2D perovskite ferroelectric, (C4H9NH3)2(NH2CHNH2)Pb2Br7 (1), driven by the switchable spontaneous polarization. Most strikingly, an extremely low detection limit of 82 nW cm−2 is achieved, far superior to those of many classical p–n junctions. Further studies disclose that such self-powered behaviors of 1 are related to its inherent photovoltaic effects, stemming from inversion symmetry breaking by ferroelectric polarization. This result advances the future potential of hybrid perovskite ferroelectrics as smart photoelectric devices.

The good thermal stability of a phosphor is crucial for its practical applications. Unfortunately, in the past decades, only the Gurney–Mott equation was available to describe the relation between the luminescence properties of a phosphor and temperature, which is, however, phenomenological and not precise. In this work, we introduced a hypothesis that the lowering of the luminescence efficiency of a phosphor is caused by the heat generated during the luminescence process and can be reduced if the luminescence site dissipates the heat away. We verified this hypothesis by evaluating the thermal conductivities κ of their luminescence sites, the Eu atoms, in the three phosphors, SrLiAl3N4:Eu2+, Sr2Si5N8:Eu2+ and SrSiN2:Eu2+, as well as those of the Sr atoms in their hosts SrLiAl3N4, Sr2Si5N8 and SrSiN2. It is suggested that our new approach can be employed as a practical criterion to search for phosphor materials with efficient luminescence properties.

Polarized-light photodetectors are the indispensable elements for practical optical and optoelectronic device applications. Two-dimensional (2D) hybrid perovskite ferroelectrics, in which the coupling of spontaneous polarization (Ps) and light favors the dissociation of photo-induced carriers, have taken a booming position within this portfolio. However, polarized-light photodetectors with a low detection-limit remain unexplored in this 2D ferroelectric family. In this work, the high-quality individual crystals of a 2D perovskite ferroelectric, BA2CsPb2Br7 (1, where BA+ is n-butylammonium), were used to fabricate ultrasensitive polarized-light detectors. Its unique bilayered structural motif results in quite strong electric and optical anisotropy with a large absorption ratio of αc/αa ≈ 3.2 (λ = 405 nm). Besides, the presence of ferroelectric Ps also endows high built-in electric field along the polar c-axis that favors photoelectric activities. Under an extremely low detectable limit of 40 nW/cm2, the detector of 1 exhibits a notable dichroism ratio (Iphc/Ipha ≈ 1.5), a large responsivity of ~39.5 mA/W and a specific detectivity of ~1.2 × 1012 Jones. Moreover, crystal-based devices of 1 also exhibit a fast response speed (~300 μs) and excellent anti-fatigue merits. This work highlights great potentials of hybrid perovskite ferroelectrics toward polarized-light photodetection.

Polar hybrid perovskites have been explored for self-powered photodetection benefitting from prominent transport of photo-induced carriers and the bulk photovoltaic effect (BPVE). However, these self-powered photodetection ranges are relatively narrow depending on their intrinsic wide bandgaps (>2.08 eV), and the realization of broad-spectrum self-powered photodetection is still a difficult task. Herein, we successfully obtained a polar multilayered perovskite, (I-BA)2(MA)2Pb3I10 (IMP, MA+ = methylammonium and I-BA+ = 4-iodobutylammonium), via rational dimension reduction of CH3NH3PbI3. It features the narrowest bandgap of 1.71 eV in a BPV material. As a consequence, the integration of narrow bandgap and BPVE causes the self-powered photodetection to extend to 724 nm for IMP, and a repeatable photovoltaic current reaching 1.0 μA cm−2 is acquired with a high “on/off” ratio of ∼103 and photodetectivity (∼109 Jones) at zero bias. This innovative research provides a foothold for adjusting the physical properties of hybrid perovskites and will expand their potential for self-powered broad-spectrum detection., A polar hybrid perovskite with a wide-spectrum absorption extending to 724 nm was obtained . Benefitting from the narrow bandgap and bulk photovoltaic effects, self-powered broad-spectrum photodetection was achieved in hybrid perovskites.

By tuning the reaction solvents, two 3D luminescent MOFs based on Cu3I3S clusters, {[Cu3I3(TPSA)]·DEF}n (1) and {[Cu3I3(TPSA)]·DMF}n (2), have been obtained by utilization of a conformationally flexible ligand N,N′,N′′-tri(3-pyridine)thiotriamide phosphate (TPSA) under solvothermal conditions. They display different fluorescence on account of the proportions between two emission bands, of which, 1 is an orange-yellow-light-emitting phosphor and 2 is a single component white luminescent material. Moreover, the two cluster-based MOFs show multi-stimuli responsive luminescence towards temperature, solvents and nitro explosives.

Herein we report a two-fold interpenetrating pillar-layer microporous material, whose framework severely shrinks after losing guest molecules and transforms into a stable nonporous one. More importantly, the guest-free framework has rarely seen temperature-dependent gate-opening behaviours for C2 gases around room temperature.

Three similar ionic-type ligands which can provide ligand-centred charge transfer (LCCT) have been employed to synthesize three isostructural complexes, respectively. Due to the coordination of the ligands to the metal centres, all of the above mentioned complexes feature fluorescence and phosphorescence properties simultaneously. The mechanism of the luminous process is ligand-centred charge transfer (LCCT) combined with metal-to-ligand charge transfer (MLCT) processes. More interestingly, one compound manifests tunable colors from yellow to blue emissions involving white emission by varying the temperature and/or excitation wavelength directly. Experimental and computational results indicate that the differences in luminous properties originate from the ligand distortion combined with different electron states. Thus, this study provides a facile method to synthesize new single-component tunable-color luminescent coordination polymers with simultaneous fluorescence and phosphorescence.

Metal-organic frameworks showing successive magnetic ordering are far less common than inorganic compounds. Here, we report two metal-organic frameworks [CoII(ox)(bphy)•0.1(DMF)•0.1(MeOH)] n ( 1 ) and [CoII3(ox)3(bphy)2(DMF)2] n ( 2 ) comprised of zigzag and necklace CoII-ladders, respectively. Together with a previously reported compound [CoII(ox)(bphy)•0.2(DMF)] n ( 3 ) consisting of spiraling zigzag CoII-ladders, these three compounds provide a good system for comparative structural and magnetic studies. Comprehensive magnetic analysis reveals that the three compounds undergo long-range magnetic ordering at ~2.6 K but exhibit vastly different short-range magnetic correlations: compound 1 shows short-range spin-canted antiferromagnetism ordering at ~14.0 K; compound 2 demonstrates successive short-range antiferromagnetism ordering at ~15.5 and ~12.6 K; compound 3 shows slow magnetic relaxation with T b≈ 4.6 K. These results demonstrate long-range magnetic ordering is readily accessible in the frameworks of ox2− bridging CoII-ladders linked by bphy, where short-range magnetic correlations can be systematicly tuned by the CoII-ladder structures.

Antiferroelectric materials, characterized by an antiparallel array of adjacent dipoles, are holding a bright future for solid-state refrigeration based on their electrocaloric (EC) effects. Despite great advances of inorganic oxides and some organic soft polymers, their EC effects are achieved under quite high electric fields that result in too low EC strengths for practical application. Currently, it is a challenge to exploit soft antiferroelectric with strong EC strengths. Here, by the mixed-cation alloying, we present a new perovskite-type soft antiferroelectric, (isopentylammonium)

Halide double perovskites have emerged as remarkable semiconductors owing to their nontoxicity and superior optoelectronic features. Despite recent exciting progress, halide double perovskites with...

The development of practical porous materials for the selective capture of CO2 from flue gas and crude biogas is highly critical for both environment protection and energy safety. Here, a novel met...

The pore engineering of microporous metal-organic frameworks (MOFs) has been extensively investigated in the past two decades, and an expansive library of functional groups has been introduced into various frameworks. However, the reliable procurement of MOFs possessing both a targeted pore size and preferred functionality together is less common. This is especially important since the applicability of many elaborately designed materials is often restricted by the small pore sizes of microporous frameworks. Herein, we designed and synthesized a mesoporous MOF based on Zr

Lanthanide-doped inorganic upconversion nanocrystals (UCNCs) are promising as fluorescent diagnostic and therapeutic agents for in vivo applications ranging from biological imaging to disease theranostics. However, all currently available lanthanide-doped inorganic UCNCs are not biodegradable and thus cannot be harmlessly eliminated from the body of living organism during a reasonable period of time, making their clinical translations nearly impossible. Here, we report a class of red-emitting biodegradable UCNCs based on Yb3+/Er3+-doped inorganic potassium heptafluozirconate (K3ZrF7:Yb/Er) that features a dynamically "soft" crystal lattice containing water-soluble [ZrF7]3- cluster and a K+ cation. The red-emitting K3ZrF7:Yb/Er UCNCs exhibit a pH-dependent biodegradation capability upon exposure to water both in vitro and in vivo, and the rapid biodegradation rate, monitored using the intrinsic red upconversion luminescence, can be tuned particularly in a mild acidic tumor microenvironment (pH ∼5-6). More importantly, the final biodegradation products of K3ZrF7:Yb/Er UCNCs can be excreted from the body of mice in a short period of time with no evidence of toxicity, in stark contrast to the nondegradable β-NaYF4:Yb/Er UCNCs that primarily accumulate in the main organs of mice. These findings described here unambiguously would benefit the future biomedical applications and clinical translations of lanthanide-doped inorganic UCNCs.

Although two-dimensional (2D) metal-halide double perovskites display versatile physical properties due to their huge structural compatibility, room-temperature ferroelectric behavior has not yet been reported for this fascinating family. Here, we designed a room-temperature ferroelectric material composed of 2D halide double perovskites, (chloropropylammonium)4 AgBiBr8 , using an organic asymmetric dipolar ligand. It exhibits concrete ferroelectricity, including a Curie temperature of 305 K and a notable spontaneous polarization of ≈3.2 μC cm-2 , triggered by dynamic ordering of the organic cation and the tilting motion of heterometallic AgBr6 /BiBr6 octahedra. Besides, the alternating array of inorganic perovskite sheets and organic cations endows large mobility-lifetime product (μτ=1.0×10-3 cm2 V-1 ) for detecting X-ray photons, which is almost tenfold higher than that of CH3 NH3 PbI3 wafers. As far as we know, this is the first study on an X-ray-sensitive ferroelectric material composed of 2D halide double perovskites. Our findings afford a promising platform for exploring new ferroelectric materials toward further device applications.

Structures composed of SiOxF6-x (x = 1, 2, 3, 4, 5) or SiOxF4-x (x = 1, 2, 3) species have thus far been observed in only a few compounds, and their functional properties are completely unknown in silicate chemistry. By introducing the least electronegative element, cesium, and the most electronegative element, fluorine, into the silicophosphate system, we successfully designed the first noncentrosymmetric fluorooxosilicophosphate with Si-F bonds, CsSiP2O7F, whose structure consists of an unprecedented SiP2O10F moiety containing hexacoordinate SiO5F species. The experimental results highlight CsSiP2O7F as the first fluorooxosilicophosphate deep-UV nonlinear optical (NLO) material. The first-principles calculations reveal that the SiP2O10F moiety is a new type of NLO-active unit and that both cesium and fluorine increase the deep-UV transparency of CsSiP2O7F. This work provides a new source of deep-UV NLO materials and insights into obtaining noncentrosymmetric structures that are indispensable to functional materials in nonlinear optics, piezoelectricity, ferroelectric, pyroelectricity, etc.

3D perovskite CsPbBr3 has recently taken a blooming position for optoelectronic applications. However, due to the lack of natural anisotropy of optical attributes, it is a great challenge to fulfil polarization-sensitive photodetection. Here, for the first time, we exploited dimensionality reduction of CsPbBr3 to tailor a 2D-multilayered hybrid perovskite, (TRA)2 CsPb2 Br7 (1, in which TRA is (carboxy)cyclohexylmethylammonium), serving as a potential polarized-light detecting candidate. Its unique quantum-confined 2D structure results in intrinsic anisotropy of electrical conductivity, optical absorbance, and polarization-dependent responses. Particularly, it exhibits remarkable dichroism with the photocurrent ratio (Ipc /Ipa ) of ≈2.1, being much higher than that of the isotropic CsPbBr3 crystal and reported CH3 NH3 PbI3 nanowire (≈1.3), which reveals its great potentials for polarization-sensitive photodetection. Further, crystal-based detectors of 1 show fascinating responses to the polarized light, including high detectivity (>1010 Jones), fast responding time (≈300 μs), and sizeable on/off current ratios (>104 ). To our best knowledge, this is the first study on 2D Cs-based hybrid perovskite exhibiting strong polarization-sensitivity. The work highlights an effective pathway to explore new polarization sensitive candidates for hybrid perovskites and promotes their future electronic applications.

Antimony(III) borates with a stereochemical active lone pair remained unknown, although the first antimony borate was reported more than twenty years ago. Now, the first antimony(III) borate in a closed system is successfully synthesized, namely SbB3 O6 . Remarkably, SbB3 O6 not only exhibits an exceptional linear optical response, that is, birefringence of Δn=0.290 at the wavelength of 546 nm, which is the largest among borates, but also has a strong nonlinear optical response of 3.5 times larger than the benchmark KH2 PO4 , exceeding those of most borates. Theoretical calculations reveal that the coexistence of strong linear and nonlinear optical responses in SbB3 O6 should be attributable to the synergistic effect of π-conjugated B-O anionic groups and Sb3+ with stereochemically active lone pair. This work provides a new class of optical bi-functional materials with potential prospects in integrated optical devices.

The separation of C

Selective separation using porous adsorbents is an energy-efficient alternative to traditional separation techniques. Stacked porous organic molecular frameworks (POMFs) capable of noncovalent π⋅⋅⋅π interactions are emerging as a new kind of adsorbents that facilitate green separation. Here we report a robust porous molecular crystal (TAPM-1), which is stabilized by multiple intermolecular π⋅⋅⋅π interactions. With its long-range π-stacking, TAPM-1 has excellent hydrophobicity, thermostability, recyclability, and high selectivity for aromatics over the corresponding cyclic aliphatics. This enables TAPM-1 to serve as the stationary phase in the high-resolution gas chromatographic separation of benzene and cyclohexane or toluene and methylcyclohexane.

Birefringent crystals that can modulate the polarization of light play a significant role in modern optical devices including polarizing microscopes, optical isolators, and achromatic quarter-wave plates. To date, commercial birefringent crystals are exclusively limited to purely inorganic compounds. Here we report a new organic-inorganic hybrid halide, MLAPbBr

The photodynamic therapy (PDT) as a promising antitumor therapy technique is greatly hampered by the low tissue penetration of light and the photothermal effect of prolonged irradiation. Near-infrared (NIR) persistent luminescence nanoparticles (NPLNPs) possess the potential for application in next-generation PDT. However, owing to the low re-excitation efficiency of NPLNPs in deep tissue, the current PDT nanoplatform based on NPLNPs is faced with the disadvantage of decreased PDT efficiency induced by persistent luminescence (PersL) decay at the lesion site. Herein, NPLNPs, Zn

Accurately designing and synthesizing new deep-ultraviolet (deep-UV) nonlinear optical (NLO) crystals that are limited by the so-called "200 nm wall" on their transparency windows remain challenging. On the basis of a bandgap-directed computer-aided material design approach, two new NLO sulfates, KMgSO

Linear dichroic anisotropic photonic materials are highly attractive due to their great potentials in many applications, which in combination with the ferroelectric properties could broaden their research and applications. However, to date, the linear dichroism conversion phenomenon has not been observed in one-dimensional (1D) large-size single-crystal materials: in particular, lead-free perovskite ferroelectric crystals. Here, we propose a new ferroelectric design strategy: namely, partial organic cation substitution for precisely designing 1D polarization-sensitive perovskite ferroelectrics. As an example, the 1D mixed-cation perovskite ferroelectric (n-propylammonium)(methylammonium)SbBr5 was synthesized, which exhibits a fascinating ferroelectricity with a notable reversible polarization of 2.9 μC/cm2 and a large ferroelectricity-driven polarization ratio of 6.9. Importantly, the single-crystalline photodetectors also exhibit superior optoelectronic anisotropic performances at the paraelectric phase, having a large photoelectric anisotropy ratio (∼35), an excellent polarization-sensitive dichroism ratio (∼1.31), highly sensitive detectivity up to ∼109 Jones, and a fast response rate (∼45/68 μs). This finding provides a significant and effective pathway for the targeted design of new functional lead-free linear dichroic anisotropic photonic ferroelectrics.

It remains a challenge to develop UV nonlinear optical (NLO) crystals that can achieve a desirable trade-off on UV absorption edge, second harmonic generation (SHG), and birefringence. Here we report a thiosulfate UV NLO crystal of a 2D van der Waals layered structure, [C(NH

Benefiting from their structural flexibility and solution processability, organic–inorganic metal halide hybrids with efficient white-light emission present a great promise for solid-state lighting...

Polarized light detection is attracting increasing attention for its wide applications ranging from optical switches to high-resolution photodetectors. Two-dimensional (2D) hybrid perovskite-type ferroelectrics combining inherent light polarization dependence of bulk photovoltaic effect (BPVE) with excellent semiconducting performance present significant possibilities. Now, the BPVE-driven highly sensitive polarized light detection in a 2D trilayered hybrid perovskite ferroelectric, (allyammonium)(2)(ethylammonium)(2)Pb3Br10 (1), is presented. It shows a superior BPVE with near-band gap photovoltage of ca. 2.5 V and high on/off switching ratio of current (ca. 10(4)). Driven by the superior BPVE, 1 exhibits highly sensitive polarized light detection with a polarization ratio as high as ca. 15, which is far more beyond than those of structural anisotropy-based monocomponent devices. This is the first realization of BPVE-driven polarized light detection in hybrid perovskite ferroelectrics.

The second harmonic generation (SHG) responses of the paraelectric and ferroelectric phases of KH2PO4 (KDP) were calculated by first-principles density functional theory (DFT) calculations, and the individual atom contributions to the SHG responses were analyzed by the atom response theory (ART). We show that the occurrence of static polarization does not enhance the SHG responses of the ferroelectric KDP, and that the Kleinman symmetry is reasonably well obeyed for the paraelectric phase, but not for the ferroelectric phase despite that the latter has a larger bandgap. This is caused most likely by the fact that the ferroelectric phase has lower-symmetry local structures than does the paraelectric phase. The contribution to the SHG response of an individual K+ ion is comparable to that of an individual O2− ion. The contributions of the O2− and K+ ions arise overwhelmingly from the polarizable parts of the electronic structure, namely, from the valence bands of the O-2p nonbonding states and from the conduction bands of the K-3d states.