Neutral 1D Perovskite-Type ABX3 Phase Transition Material with a Narrowband Emission and Semiconductor Property

Cyclic organic amines are emerging as excellent building blocks to assemble organic–inorganic hybrid phase transition materials due to their flexible cyclic structure. Here, we have assembled a 1D organic-inorganic hybrid dielectric material C₅H₆NOPbBr₃ ( 1 ) by alloying the cyclic organic amine 3-hydroxypyridine. 1 displays a remarkable switchable dielectric response induced by an order-disorder transformation of the organic moiety, this transformation behaviour is confirmed by DSC and Hirshfeld surface measurements. More interestingly, 1 has a narrowband emission (FWHM=4.64 nm) at 590 nm; FWHM is a major quality figure for narrowband photodetectors. In addition, 1 exhibits semiconducting properties with an indirect bandgap of 2.78 eV by the analysis of the UV-Vis absorption results.     

A sensitive and selective HPLC–MS3 method for therapeutic drug monitoring of meropenem and its validation by comparison with HPLC–MS2 methods

Meropenem, a representative β-lactam antibiotic, is widely used to treat complicated and serious infections. Therefore, it is of great significance to monitor the plasma drug concentration for individualized antimicrobial therapy. This study first describes the development and validation of high-performance liquid chromatography–tandem mass spectrometry cubed method for monitoring meropenem in human plasma. Protein precipitation with methanol and a chromatographic analysis time of 7 min make this method simple and of high throughput. Meropenem was extracted from human plasma with recoveries >94.1%. Calibration curves were linear (R² > 0.995) in the concentration range of 0.5–50 μg/mL. Overall accuracy and precision did not exceed 8.0% as well as no significant matrix effect was observed. The novelty of this method is that the triple-stage mass spectrometry technology improves the selectivity and sensitivity. A comparison of the presented method and traditional liquid chromatography–tandem mass spectrometry method was assessed in 44 patients treated with meropenem and Passing–Bablok regression coefficients and Bland–Altman plots showed that no significant difference between the two methods. So the triple-stage mass spectrometry method developed in this study is appropriate and practical for the monitor of meropenem in the daily clinical laboratory practice.     

Phenylboronic acid-functionalized cross-linked chitosan magnetic adsorbents for the magnetic solid-phase extraction of benzoylurea pesticides

In this study, a 4-formylphenylboronic acid-modified cross-linked chitosan magnetic nanoparticle (FPBA@CCHS@Fe₃O₄) was fabricated. The synthesized material was utilized as the magnetic solid-phase extraction adsorbent for the enrichment of six benzoylurea pesticides. In addition to B-N coordination, FPBA@CCHS@Fe₃O₄ interacts with benzoylureas through hydrogen bonds and π-π stacking interaction on account of rich active groups (amino and hydroxyl) and aromatic rings in structure. Compared to traditional extraction methods, less adsorbent (20 mg) and reduced extraction time (3 min) were achieved. The adsorbent also exhibited good reusability (no less than 10 times). Coupled with a high-performance liquid chromatography–diode array detector, satisfactory recoveries (89.1–103.9%) and an acceptable limit of detection (0.2–0.7 μg/L) were obtained. Under optimized conditions, the established method was successfully applied to the tea infusion samples from six major tea categories with acceptable recoveries ranging from 76.8 to 110%, indicating its application potential for the quantitative detection of pesticides in complex matrices.     

Comparison of the separation of proteins of wide-ranging molecular weight via trilobal polypropylene capillary-channeled polymer fiber,commercial superficiously porous,and commercial size exclusion columns

Reversed phase and size-exclusion chromatography methods are commonly used for protein separations, although they are based on distinctly different principles. Reversed phase methods yield hydrophobicity-based (loosely-termed) separation of proteins on porous supports, but tend to be limited to proteins with modest molecular weights based on mass transfer limitations. Alternatively, size-exclusion provides complementary benefits in the separation of higher mass proteins based on entropic, not enthalpic, processes, but tend to yield limited peak capacities. In this study, microbore columns packed with a novel trilobal polypropylene capillary-channeled polymer fiber were used in a reversed phase modality for the separation of polypeptides and proteins of molecular weights ranging from 1.4 to 660 kDa. Chromatographic parameters including gradient times, flow rates, and trifluoroacetic acid concentrations in the mobile phase were optimized to maximize resolution and throughput. Following optimization, the performance of the trilobal fiber column was compared to two commercial-sourced columns, a superficially porous C4-derivatized silica and size exclusion, both of which are sold specifically for protein separations and operated according to the manufacturer-specified conditions. In comparison to the commercial columns, the fiber-based column yielded better separation performance across the entirety of the suite, at much lower cost and shorter separation times.     

Enhanced Crystal Quality of Perovskite via Protonated Graphitic Carbon Nitride Added in Carbon-Based Perovskite Solar Cells

The quality of perovskite layers has a great impact on the performance of perovskite solar cells (PSCs). However, defects and related trap sites are generated inevitably in the solution-processed polycrystalline perovskite films. It is meaningful to reduce and passivate the defect states by incorporating additive into the perovskite layer to improve perovskite crystallization. Here an environmental friendly 2D nanomaterial protonated graphitic carbon nitride (p-g-C\begin{document}$_3$\end{document}N\begin{document}$_4$\end{document}) was successfully synthesized and doped into perovskite layer of carbon-based PSCs. The addition of p-g-C\begin{document}$_3$\end{document}N\begin{document}$_4$\end{document} into perovskite precursor solution not only adjusts nucleation and growth rate of methylammonium lead tri-iodide (MAPbI\begin{document}$_3$\end{document}) crystal for obtaining flat perovskite surface with larger grain size, but also reduces intrinsic defects of perovskite layer. It is found that the p-g-C\begin{document}$_3$\end{document}N\begin{document}$_4$\end{document} locates at the perovskite core, and the active groups -NH\begin{document}$_2$\end{document}/NH\begin{document}$_3$\end{document} and NH have a hydrogen bond strengthening, which effectively passivates electron traps and enhances the crystal quality of perovskite. As a result, a higher power conversion efficiency of 6.61% is achieved, compared with that doped with g-C\begin{document}$_3$\end{document}N\begin{document}$_4$\end{document} (5.93%) and undoped one (4.48%). This work demonstrates a simple method to modify the perovskite film by doping new modified additives and develops a low-cost preparation for carbon-based PSCs.     

基于“透过表面接枝”方式制备低分散性和高接枝密度聚合物刷的研究

"透过表面接枝"(grafting-through)是一种聚合物表面改性的新方法,可以显著改善传统grafting-from和grafting-to方法接枝工艺的缺陷,获得兼具高接枝密度和低分散性的聚合物刷产物.本文采用布朗动力学模拟方法,模拟研究了grafting-through方法接枝聚合物刷过程中的主控因素,从微观动力学角度阐明其特有的链增长趋同化效应是保持产物聚合物刷较低分散性的主因.引发效率在grafting-through中可显著提高,且产物聚合物刷的分子量呈现泊松分布.此外,反应中保持高的单体通量,可以同时实现产物聚合物较长的平均链长和较低的分散性,有利于制备性能优异的改性材料.该研究对深入理解grafting-through接枝过程的动力学主控因素,促进grafting-through技术的推广和工艺的改进具有一定的理论指导意义.     

Vapor deposition of ultrathin hydrophilic polymer coatings enabling candle soot composite for highly sensitive humidity sensors

Candle soot (CS) is a desirable carbon nanomaterial for sensors owing to its highly porous nanostructure and large specific surface area. CS is advantageous in its low-cost and facile preparation compared to graphene and carbon nanotubes, but its pristine nanostructure is susceptible to collapse, hampering its application in electronic devices. This article reports conformal coating of nanoscale crosslinked hydrophilic polymer on CS film using initiated chemical vapor deposition, which well preserved the CS nanostructure and obtained nanoporous CS@polymer composites. Tuning coating thickness enabled composites with different morphologies and specific surface areas. Surprisingly, the humidity sensor made from composite with the lowest filling degree, thus largest specific surface area, showed relatively low sensitivity, which is likely due to its discontinuous structure, thus insufficient conductive channels. Composite sensor with optimum filling degree shows excellent sensing response of more than 10³ with the linearity of R² = 0.9400 within a broad relative humidity range from 11% to 96%. The composite sensor also exhibits outstanding sensing performance compared to literature with low hysteresis (3.00%), a satisfactory response time (28.69 s), and a fast recovery time (0.19 s). The composite sensor is fairly stable and durable even after 24 h soaking in water. Furthermore, embedding a humidity sensor into a face mask realizes real-time monitoring of human breath and cough, suggesting promising applications in respiratory monitoring.     

An Iridium Complex as an AIE-active Photosensitizer for Image-guided Photodynamic Therapy

Image-guided photodynamic therapy (PDT) has received growing attention due to its non-invasiveness and precise controllability. However, the PDT efficiency of most photosensitizers are decreased in living system due to the aggregation-caused singlet oxygen (¹O₂) generation decreasing. Herein, we present an Iridium (III) pyridylpyrrole complex (Ir-1) featuring of aggregation-induced emission (AIE) and ¹O₂ generation characteristics for image-guided PDT of cancer. Ir-1 aqueous solution exhibits bright red phosphorescence peaked at 630 nm, large Stokes shift of 227 nm, and good ¹O₂ generation ability. The ¹O₂ generating rate of Ir-1 in EtOH/water mixture solution is 2.3 times higher than that of Rose Bengal. In vitro experimental results revealed that Ir-1 has better biocompatibility and higher phototoxicity compared with clinically used photosensitizers (Rose Bengal and Ce6), suggesting that Ir-1 can serve as a photosensitizer for image-guided PDT of cancer.     

Low percolation conductive graphite flakes-filled poly(urethane-imide) composites with high thermal stability via imidization self-foaming structure

In the study, the conductive graphite flakes filled poly(urethane-imide) composites (PUI/GFs) with high performance were constructed by the thermal imidization self-foaming reaction. It was found that the foaming action could promote the redistribution of GFs during curing process and the formation of stable linear conductive pathways. The percolation threshold of PUI/GFs composites was lowered from 1.26 wt% (2000 mesh GFs) or 0.86 wt% (1000 mesh GFs) to 0.79 wt% (500 mesh GFs), which were relatively low percolation thresholds for polymer/GFs composites so far. When the content of 500 mesh GFs was 4.0 wt%, the electrical conductivity of the composite was as high as 3.96 × 10^?1 S/m. Also, a poly(urethane-imide) (PUI) matrix with excellent thermal stability (T_d10%: 334.97 °C) and mechanical properties (elongation at break: 324.52%, tensile strength: 15.88 MPa) was obtained by introducing the rigid aromatic heterocycle into the polyurethane (PU) hard segments. Moreover, the zero temperature coefficient of resistivity for the composites was observed at the temperature range from 30 °C to 200 °C. Consequently, PUI/GFs composites may provide the novel strategy for considerable conductive materials with high thermal stability in electrical conductivity.     

Localized surface plasmon resonance properties and biomedical applications of copper selenide nanomaterials

Nanomaterials with localized surface plasmon resonance (LSPR) locating in the near-infrared region have broad application prospects in the field of biomedicine. However, the biggest problem that limits the biomedical application of such nanomaterials lies in two aspects: First, the potential long-term in vivo toxicity caused by the metabolism of many nanomaterials with LSPR effect; Second, most of current nanomaterials with LSPR effect are difficult to achieve LSPR wavelength tunability in the near-infrared region to adapt to different biomedical applications. Copper selenide nanomaterials are composed of selenium and copper, which are necessary nutrient elements for human life. Because of the active and flexible chemical properties of selenium and copper, copper selenide nanomaterials can not only be effectively degraded and utilized in human body, but also be endowed with various physicochemical properties by chemical modification or doping. Recently, copper selenide nanomaterials have shown unique properties such as LSPR in the near-infrared region, making them attractive for near-infrared thermal ablation, photoacoustic imaging, disease marker detection, multimode imaging, and so on. Currently, to the best of our knowledge, there is no review on the LSPR properties of copper selenide nanomaterials and its biomedical applications. This review first discusses the relationship between the physicochemical properties and the LSPR of copper selenide nanomaterials and then summarizes the latest progress in the application of copper selenide nanomaterials in biological detection, diagnosis, and treatment of diseases. In addition, the advantages, and prospects of copper selenide nanomaterials in biomedicine are also highlighted.