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Metal-organic frameworks (MOFs) show great potential for various applications, but many of them suffer from the drawbacks of hydrolysis propensity and poor processability. Herein, we employ polymers of intrinsic microporosity (PIMs) with hydrophobic pores to decorate MOFs toward substantially improved water stability and shapeability. Through simple PIM-1 decoration, the sub-5 nm polymer layers can be uniformly deposited on MOF surfaces with almost no deterioration in porosity. Owing to the existence of superhydrophobic coating and the obstruction of water entrance into MOFs, the PIM-1 coated CuBTC exhibits impressive water resistance and excellent pore preservation ability after exposure in water, even in acidic and alkaline solutions. Moreover, polymer decoration improves the processability of MOFs, while various MOF/PIM-1 bulk wafers and oil-water separators can be obtained straightforwardly.

Molecular design is one of the fundamental strategies to improve the photovoltaic performance of organic solar cell (OSC) devices. The alkyl side chains of materials play an essential role in optim...

Semiparametric models are often used to analyze panel data for a good trade-off between parsimony and flexibility. In this paper, we investigate a fixed effect model with a possible varying coefficient component. On the basis of empirical likelihood method, the coefficient functions are estimated as well as their confidence intervals. The estimation procedures are easily implemented. An important problem of the statistical inference with the varying coefficient model is to check the constant coefficient about the regression functions. We further develop checking procedures by constructing empirical likelihood ratio statistics and establishing the Wilks theorems. Finally, some numerical simulations and a real data analysis is presented to assess the finite sample performance.

A vapor-phase grafting strategy is developed for the postsynthetic modification of metal-organic frameworks (MOFs). On the basis of the Schotten-Baumann reaction between acyl chloride (-COCl) and amino (-NH2) groups and hydrolysis of -COCl, the carboxylated MOFs could be prepared through simple exposure in vaporized acyl chloride molecules and immersion in water. The modified MOFs have well-maintained crystalline structures and porosities and show substantially improved fluoride removal performance.

This article aimed to establish a prediction model of grayscale sonography and ultrasound elastography for malignant sub-pleural solid masses and evaluate its diagnostic value. The study included 153 patients, including 89 patients with malignant tumors and 64 patients with benign diseases. Statistical differences between the malignant and benign groups were found in the factors of age, air bronchogram, borderline, shape and elasticity score (p0.05). Age, elasticity score and borderline were effective factors for predicting malignant sub-pleural solid masses, offering an area under the receiver operating characteristic curve (AUROC) value of 0.72 (95% confidence interval [CI] 0.64-0.80), 0.73 (95% CI 0.65-0.79) and 0.70 (95% CI 0.62-0.77), respectively. The AUROC value of the prediction model for malignant sub-pleural solid masses was 0.88 (95% CI 0.81-0.92), which indicates that the prediction model was able to improve the diagnostic accuracy and that it may prove a useful auxiliary diagnostic tool for malignant sub-pleural solid masses, especially in primary health care institutions in developing countries.

In this paper, the empirical likelihood-based inference is investigated with varying coefficient panel data models with fixed effect. A naive empirical likelihood ratio is firstly proposed after th...

Graphene oxide (GO) membranes show great potential in molecular separation for water treatment. However, the inferior stability of GO membranes is a major bottleneck for practical applications. In this study, bio-inspired polydopamine (PDA) deposition is reported for enhancing the stability of GO membranes. Through simple and mild immersion, PDA is self-polymerized on GO membranes. The blocking of PDA chains to membrane defects improves the rejections for various molecules. Because the inherently strong adhesion and crosslinking of PDA greatly strengthen the interactions of substrates to GO layers and the binding force of GO nanosheets, the prepared PDA-GO membranes exhibit impressive long-term stability in cross-flow filtration, and maintain good nanofiltration performance at various feed pressures, tangential velocities, and even after external scratching. Moreover, because the deposited PDA layers obstruct the direct contact between GO and contaminants, the antifouling property of the PDA-GO membranes increases substantially, with recovery ratio about 98%.

As an emerging optical material, perovskite nanocrystals (NCs) exhibit excellent optoelectronic properties and show great potential for various optoelectronic applications. However, the inherent inferior stability against moisture, oxygen, light and heat limit their practical application. As well, the exploration and development of perovskite NCs with novel properties and functions are new challenges. To achieve these goals, the integration and encapsulation of perovskite NCs with multifunctional metal-organic frameworks (MOFs) to form perovskite NC@MOF composites, is a promising strategy for enhancing the stability and broadening the application scope. In this minireview, we summarize and discuss the synthesis strategies and functional mechanisms of perovskite NC@MOF composites, along with applications of light emitting diodes (LED), information security, photocatalysis, sensing, and detection. We further briefly point out the current challenges as well as the future opportunities for the emerged composite materials.

Graphene oxide (GO) nanosheets with atomic thickness and tunable physicochemical properties have been considered as promising nanobuilding blocks for fabrication of separation membranes with impressive performance. There are two kinds of molecular transport channels in laminar GO membranes, interlayer nanochannels formed by adjacent nanosheets and intrinsic defects/pores/edges of GO nanosheets. It has been demonstrated that precisely controlling the transport pathways at the angstrom level, through reduction, molecule/cation cross-linking, intercalation, physical confinement, electric field adjustment, pore creation, and defect sealing, can greatly improve the separation performance of GO membranes. Herein, we first briefly review the fabrication strategies of GO membranes and then comprehensively discuss the merits and mechanisms of controlling the transport pathways of GO membranes for liquid separation applications including static diffusion, pressure-driven filtration, and pervaporation.

Solvent-free chemical vapor crosslinking is reported for controlling the interlayer spacing of graphene oxide (GO) membranes by nucleophilic substitution and condensation reactions between GO and ethylenediamine (EDA) vapor. The prepared membranes display high rejections and good stability under various feed pressures and long-term cross-flow filtration.

Metal-organic frameworks (MOFs) show great potential for various applications. The functions of MOFs are closely related to their porous structures and lattice integrities. However, the generally existing guest solvent/linker molecules and crystalline defects will alter internal microstructures and microenvironments of MOFs. Meanwhile, although MOFs have tailorable pore structures within the range of microspores, the achievement of meso/macropores in MOFs is of scientific interest. Herein, a versatile air-thermal processing (ATP) strategy is reported to remove the residual molecules and incompletely coordinated linkers in MOFs. Through processing MOFs in confined space, the thermalized and pressurized air can assist the filling solvents and partially/totally uncoordinated linkers to overcome the energy barrier of escape, and then maximize MOF porosity. The obtained MOF materials with hierarchical micro/mesoporous structures display substantially improved adsorption capacities and selectivities. For example, CuBTC-A shows 36%, 72%, 22%, and 86% enhancements in surface area, pore volume, CO2 uptake, and CO2/N2 selectivity, respectively. Moreover, by adjusting processing temperature, the ATP strategy is available for fabricating MOF materials with hierarchically micro/meso/macroporous superstructures under modulator/template-free conditions.

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Molecular sieving membranes have great potential for energy-saving separations, but they suffer from permeability-selectivity trade-off limitation. In this report, simultaneous hetero-crystallization and hetero-linker coordination of metal-organic framework (MOF) hollow fiber membranes through one-pot synthesis for precise gas separation is reported. It is found that the hetero-polycrystalline membranes consist of 2D and 3D MOF phases and are defect-free and roughly orientated, hetero-linker exchange of 3D phase by larger geometric ones can narrow transport pathway, and framework rigidification occurs and thus fixes MOF channels. The prepared membranes are robust and reproducible, and exhibit substantially improved performance, with H

Membrane separation is regarded as efficient technology to alleviate global water crisis. Two-dimensional membranes are promising for contaminant removal from wastewaters, but their uncontrollable transport pathway and instability hinder the further development. In this study, the high-performance and stable two-dimensional framework membranes are self-assembled by graphene oxide (GO) nanosheets and amino-appended metal-organic polyhedrons (MOPs) for water purification and remediation. The MOP molecular cages are uniformly intercalated between GO nanosheets and enriched at defects/edges, and can crosslink membranes, to provide in-plane selective channels, refine vertical passageways, and fix out-of-plane interlayer spaces. The prepared GO/MOP framework membranes have improved stability and nanofiltration performance under cross-flow condition, can keep performance in water after 50 h filtration, and show high rejections over 92% for Na

In this study, Zr-MOF material (UiO-66) was modified with different metal oxides (CeO2, Ga2O3, and CoO) and employed in the conversion of cellulose to levulinic acid (LA) in aqueous medium. The research results showed that the introduction of the metal oxides increased the acid content of the catalysts, especially in medium-strong acid. The selectivity of LA was related to the type of metal oxide and the content of medium-strong acid. Due to the activity of Ga2O3 and more medium-strong acid, the yield of LA reaches a maximum yield of 32.0 mol% at 513 K for 360 min when Ga2O3-UiO-66 was employed as the catalysts. The combination of metal oxide and UiO-66 enables the reaction to proceed, providing a new direction for the conversion of cellulose to LA in the aqueous phase. In this study, Zr-MOFs material (UiO-66) was modified with different metal oxides (CeO2, Ga2O3, and CoO) and employed in the conversion of cellulose to levulinic acid in aqueous medium. The results indicated that the addition of metal oxides changes the acidity of UiO-66, which improves the catalytic activity. The selectivity of LA was related to the type of metal oxide and the content of medium-strong acid.

In this work, a versatile postmodification strategy based polydopamine (PDA) grafting is reported for improving CO2 separation performance of MOF membranes. Owning to the strong bioadhesion, PDA can be deposited on the UiO-66 membrane through a simple and mild process. Since PDA impregnation in invalid nanometer-sized pinholes and grain boundaries of the MOF membrane suppress nonselective gas transports, the modified PDA/UiO-66 membrane exhibits significantly enhanced CO2/N2 and CO2/CH4 selectivities of 51.6 and 28.9, respectively, which are 2–3 times higher than the reported MOF membranes with similar permeance. Meanwhile, because PDA modification do not change UiO-66 intrinsic pores and membrane thickness is submicrometer-sized, the CO2 permeance is 2–3 orders of magnitude larger than those membranes with similar selectivity, up to 3.7 × 10–7 mol m–2 s–1 Pa–1 (1115 GPU). Moreover, the PDA/UiO-66 membrane with good reproducibility has excellent long-term stability for CO2 capture under moist condition in...

Spectral tuning is important for the development of persistent phosphors. Here we introduce a color conversion concept to obtain abundant persistent luminescence spectra in addition to existing methods of exploring new matrix and/or dopants. In this study, CaAl2O4:Eu,Nd was chosen as a blue persistent donor phosphor, while Lu3Al5O12:Ce and other four commercial phosphors were explored as conversion phosphors to obtain colorful persistent luminescence spectra. Both the persistent donor phosphor and conversion phosphors were embedded into resin, forming ternary composite chips to ensure efficient energy transfer. Continuous color tuning were realized by simply changing the mass ratio of the persistent donor phosphor vs. conversion phosphor. Our work will be significant in indicating other persistent/conversion composite materials or nanostructures with abundant spectral properties.

In addition to the innovation of nonfullerene acceptors, the development of highly efficient nonfullerene organic solar cells requires the design of new polymer donors and fundamental understanding...

Great developments in the field of metal–organic framework (MOF) membranes have been achieved recently, especially in production with a large membrane area, modification for better performance, and application with additional functions. However, their significance has not been fully recognized and understood. This review summarizes production methodologies, including direct crystallization, interfacial/contra-diffusion synthesis, layer-by-layer assembly, confinement conversion, microfluidic processing, and vapor deposition. The mechanisms and merits of these synthesis methods are analyzed. Modification strategies for the combination of MOFs and introduced components are discussed, and classified into coating, heteroepitaxial growth, embedding, occupation, grafting, and substitution. Modification improves the performance distinctly by changing the construction, microstructure, affinity, and pore size of MOF membranes. The application of MOF membranes in gas separation, nanofiltration, ionic sieving, stimuli responsiveness, and catalysis are reviewed, and the separation mechanisms are analyzed. Moreover, some possible opportunities and challenges for further development of MOF membranes are pointed out.

High fluoride water is one of the major problems against drinking water and are affecting millions of people all over the world. Refined adsorbents and water treatment plants aim at massive water supply but can’t meet scattered household requirements, especially in the developing areas. Here, we developed a facile defluoridation method in which F− can be removed by boiling eggs or shell assisted by phosphate. 0.4 L of high fluoride water (10 mg/L) can be transformed to safe drinking water with F− concentration lower than 1.5 mg/L by boiling one egg at 80 °C for 10 min with the addition of 0.3 g/L of NaH2PO4 and 0.05 v% acetic acid. The mechanism study shows that F− is adsorbed onto the egg shell outer surface forming nanorod arrays of fluorapatite and/or F− substituted hydroxyapatite. Higher F− adsorption capacity can be obtained (Langmuir adsorption capacity, 47.9 mg/g) if using egg shell powder instead of whole eggs. Pilot scale defluoridation (2.5 L, 10 times) was successfully realized by boiling egg shell in the presence of phosphate and acetic acid. The boiling shell defluoridation technology has potential household applications by common people with little professional backgrounds.

Gas-liquid interfaces with unique physicochemical properties have great potential for the self-assembly of many materials. Herein, a concept of the autonomous self-crystallization of MOF films at air-water interfaces is reported. The free-standing ZIF-8 films with a large area of about 20 cm2 can be preferentially assembled only at the water surface. Under the influence of the atomically well-defined and amphiphilic interface on anisotropically polar linkers, the thus-prepared ZIF-8 films exhibit highly out-of-plane orientation and smooth-rough Janus crystalline facets.

Graphene oxide (GO) membranes are extremely suitable for ultrafast molecular separation. However, the expansion of the GO interlayer spacing in aqueous solution causes poor rejection of small solutes and the risk of membrane dissociation. We reported a concept of constructing three-dimensional sandwich hollow fibers for confining the interlayer spacing and restraining swelling of GO membranes. Through coating the porous polymer via simple immersion-precipitation phase inversion, GO membranes are sandwiched between the porous coats and hollow fiber substrates. The out-of-plane swelling and interlayer-spacing expansion are suppressed bilaterally by the coats and substrates. Benefiting from the confined interlayer spacing of 0.86 nm, the sandwich GO membranes exhibit large permeance and impressive rejections over 97% and 98% for mono and multivalent salts, which are much higher than those of conventional GO membranes, usually less than 40%. Moreover, the sandwich GO membranes display substantially improved water stability and can maintain the high performance even under ultrasonic treatment.

Polymer solar cells (PSCs) based on narrow bandgap (NBG) photovoltaic materials have attracted significant attention due to their unique applications in semitransparent devices and organic tandem solar cells. In this work, we design and synthesize a new NBG polymer PBTT based on 2-(2-ethylhexyl)-thienyl substituted benzodithiophene (BDT-T) and n-octyl-3-fluorothieno[3,4-b]thiophene-2-carboxylate (TT) as donor material for the applications in non-fullerene PSCs. Compared with the widely used NBG polymer PTB7-Th, PBTT exhibited higher film extinction coefficient of 9.27 × 10 4 cm−1, higher-lying energy levels, more ordered molecule packing and higher hole mobility of 2.13 × 10 −3 cm2 V−1 s −1. The PSCs based on PBTT: IEICO obtained a power conversion efficiency (PCE) of 9.5% with a Voc of 0.86 V, a Jsc of 17.9 mA cm−2 and a FF of 61.3%, which is significantly enhanced over that (7.3%) of the corresponding devices with PTB7-Th as donor. The significantly improved PCE could be attributed to the higher charge mobility and the improved morphology of the PBTT: IEICO blend film. These results demonstrate that PBTT is a very promising NBG polymer donor material for the applications in non-fullerene PSCs.

Incorporation of nanoparticles has been considered as an efficient method for enhancing the adsorption performance of metal–organic frameworks (MOFs). Alkali metal compounds possess outstanding affinity to acidic CO2. In this study, a robust self-conversion strategy is reported for improving the carbon capture performance of MOFs, through directly transforming partial metal centers to basic carbonate (BC) nanoparticles. Based on the hydrolysis of coordination bonds induced by water impurity in solvents and the decarboxylation of linkers under thermal and alkaline conditions, the self-loading of BC in MOFs can be realized by solvent vapor-assisted thermal treatment. Since water impurity causes limited self-conversion and excess organic solvent can purify MOFs, the BC-MOF materials maintain good crystallinity and even show superior porosity. Owing to the increased specific surface areas, open metal sites, and alkalinity of BC, the prepared MOF composites exhibit substantially improved CO2 capture performance with good balance between capacity and selectivity. For example, after self-conversion with ethanol solvent, the CO2 adsorption capacity and CO2/N2 (15 : 85) selectivity at 298 K and 100 kPa increase from 3.7 mmol g−1 and 11.4 to 5.8 mmol g−1 and 29.2, respectively.