Latest ArticlesThe past few years have witnessed power conversion efficiency (PCE) of organic solar cells (OSCs) skyrocketing to the value of 20% due to the outstanding advantages of organic photoactive materials. The latter, which consist of donor and acceptor materials, indeed play important roles in OSCs, and particularly one building block has attracted considerable research attention, namely benzothiadiazole (BT). The diversity of OSCs based on the BT structure have indeed sprung up, and the progressive increase in PCE values is more than just eye-catching since it heralds a renewal and bright future of OSCs. This review analyzes significant studies that have led to these remarkable progresses and focuses on the most effective BT small-molecules and BT polymers for OSC reported in the last decades. The pivotal structure–property relationships, donor–acceptor matching criteria, and morphology control approaches are gathered and discussed in this paper. Lastly, we summarize the remaining challenges and offer a personal perspective on the future advance and improvement of OSCs.
Development of new metal-free heterogeneous catalysts has long been the focus of intense research interest. The integration of multifunctional monomers into the skeletons of porous organic polymers (POPs) provides an efficient pathway to achieve this goal. Herein, we rationally designed and successfully prepared a new Tröger's base (TB)-derived POPs by insertion of pillar[5]arene macrocycle as a positively auxiliary group. Combined the both merits of pillar[5]arene macrocycle and TB moiety, the as-prepared polymer was further explored as an effective metal-free heterogeneous catalyst and exhibited promoted catalytic performance in Knoevenagel condensation and CO2 conversion. This work provides a new strategy to fabricate metal-free heterogeneous catalysts based on macrocyclic POPs.
Polystyrene resins (PS) have been practical ion exchangers for radionuclides removal from water. However, nonspecific effects of ion exchange groups continue to be a major obstacle for emergency treatment with coexisting ions of high concentrations. The selectivity for Cs+ enables zirconium phosphate (ZrP) to be the most promising inorganic sorbent for radioactive cesium extraction, despite being difficult to synthesize and causing excessive pressure loss in fixed-bed reactors due to fine powder. Herein, through facile confined crystallization in host macropores, we prepared PS confined α-ZrP nanocrystalline (ZrP-PS). Size-screen sorption of layered α-ZrP and sulfonic acid group preconcentration of PS synergistically enable a considerably higher Cs+ affinity of ZrP-PS than PS, as confirmed by X-ray photoelectron spectroscopy (XPS) analysis. ZrP-PS demonstrated remarkable cesium sequestration performance in both batch and continuous experiments, with a high adsorption capacity of 269.58 mg/g, a rapid equilibrium within 80 min, and a continuous effluent volume of 2300 L/kg sorbents. Given the excellent selectivity for Cs+ and flexibility to separate from treated water, ZrP-PS holds great promise as purification packages for the emergency treatment of radioactively contaminated water.
Metal-organic frameworks (MOFs) with inherent porosity and suspended acidic groups are promising proton conducting materials in water or aqua-ammonia media. Herein we report a new lanthanide phosphonate, namely, Dy2(amp2H2)2(mal)(H2O)2·5H2O (MDAF-6). It possesses a 3D open-framework structure, and shows a high NH3 adsorption capacity of 142.4 cm3/g at P/P0 = 0.98 at 298 K due to acid-base interaction. Interestingly, the proton conductivity of MDAF-6-NH3 is enhanced by five orders of magnitude compared to MDAF-6 after 8.5 h exposure in saturated NH3-H2O vapor, indicating the importance of coexistent conjugate acid-base pairs of H3O+-H2O and NH4+-NH3 in promoting proton conduction. Magnetic studies of MDAF-6 revealed slow magnetization relaxation under zero dc field, characteristic of single-molecule magnet behavior. This work provides not only a new multifunctional MOF material, but also a new strategy to improve proton conduction in aqua-ammonia medium.
As an emerging star in the family of two-dimensional (2D) materials, 2D transition metal carbides, carbonitrides and nitrides, collectively referred to as MXenes, have large specific surface area, rich active sites, metallic conductivity and adjustable surface chemical properties. These features make MXenes promising candidates for gas-sensing materials. For the past few years, MXene-based sensors have drawn increasing attention due to their enhanced sensor performance. Based on this, this review systematically represents the structure, synthesis methods and properties of MXenes, and summarizes their applications in gas sensors. Firstly, the types, structure, main synthesis methods and properties of MXenes are introduced in a comprehensive way. Next, the corresponding design principle and working mechanism of MXene-based gas sensor are clarified. Subsequently, the sensing performances of pristine MXenes and the MXene-based nanocomposite are discussed. Finally, some future opportunities and challenges of MXene-based sensors are pointed out.
While nickel(Ⅱ) complexes have been widely used as catalysts for carbon-carbon coupling reactions, the exploration of their photophysical and photochemical properties is still in the infancy. Here, a series of square-planar Ni(Ⅱ) complexes [(diNHC)NiX2] bearing chelating benzimidazole-based bis(N-heterocyclic carbene) ligands and varying anionic coligands (1, X = Cl; 2, X = Br; 3, X = I) are synthesized and structurally characterized. In solid state, both 1 and 2 exhibit orange-red photoluminescence under ambient conditions. The photophysical and electrochemical measurements along with density functional theory (DFT) calculations reveal that the low-energy emissions can be attributed to singlet excited states with ligand-to-ligand charge-transfer (LLCT) character. This work suggests that strong-field N-heterocyclic carbene ligands play a crucial role to achieve the luminescence of Ni(Ⅱ) complexes.
Viruses are ubiquitous in human life. Some viruses can be used as vectors of genetic engineering and specific pesticides. Other viruses trigger a variety of diseases in humans, animals and plants, resulting in high infection rates and mortality. Therefore, convenient, accurate and rapid detection of viruses is of great significance for the diagnosis and treatment of subsequent diseases. In contrast to traditional methods of detection, which rely on time-consuming and complex techniques such as polymerase chain reaction (PCR), fluorescent probes and imaging methods generate real-time results, with high specificity, and have been widely used in viral detection. In this review, the application of viral fluorescent probes in analyzing the molecular structure, detection and biological imaging is discussed. In particular, we categorized the probes based on their specificity for human and plant viruses, reviewing the latest findings and analyzing their limitations. The potential of fluorescent molecular probes in the treatment of viral disease and environmental analysis, and their possible combinations with protein and immune technology are discussed.
Due to the limitations of conventional chemotherapy including side effects, poor prognosis, and drug resistance, there is an urgent need for the development of a novel multi-functional combined therapy strategy. Dopamine-modified oxaliplatin prodrug (OXA-DA) was successfully synthesized in this study to ameliorate the organ distribution of oxaliplatin for improving the drug efficacy and reducing toxic side effects, and OXA-DA was applied to develop a porous oxaliplatin cross-linked polydopamine nanoparticle for loading siPD-L1 to construct multifunctional nanoplatform. The multifunctional nanoplatform was modified with poly(2-ethyl-2-oxazoline) (PEOz), which occurred charge reversal in the tumor microenvironment, and exerted the lysosomal escape effect in tumor cells to improve the bioavailability of small interfering RNA targeting programmed cell death-ligand 1 (siPD-L1). The pH-responsive charge reversal, photothermal, biodegradation, lysosomal escape ability, PD-L1 protein degradation, toxicity properties and multiple antitumor effects were comprehensively evaluated in vitro and in vivo experiments. The findings indicated that OXA-DA-siPD-L1@PDA-PEOz excellently induced tumor cell necrosis and apoptosis as a result of the synergistic effect of chemo-photothermal therapy, and upregulated CD8+ T cells produced interferon-γ (IFN-γ) to further attack the tumor cells. In conclusion, the novel nanoplatform-mediated chemo/photothermal/immunotherapy has promising clinical applications in the treatment of malignant tumors.
Graphite tailings produced by natural graphite is usually regarded as garbage to be buried underground, which would result in a certain waste of resources. Here, in order to explore the utilization of natural graphite tailings (NGT), a liquid-polyacrylonitrile (LPAN) is used to modify the NGT fragments and aggregate them together to form secondary graphite particles with low surface area and high tap density. Moreover, the modified NGT show much better electrochemical performances than those of original one. When tested in full cells coupled with NMC532 cathode, the material achieves a high rate capability and cycle stability at the cutoff voltage of 4.25 V as well as 4.45 V, which maintains 84.32% capacity retention after 500 cycles at 1 C rate (4.25 V), higher than that of the pristine one (73.65%). The enhanced performances can be attributed to the use of LPAN to create a unique carbon layer upon graphite tailings to reconstruct surface and repair defects, and also to granulate an isotropic structure of secondary graphite particles, which can help to weaken the anisotropy of Li+ diffusion pathway and form a uniform, complete and stable solid-electrolyte-interface (SEI) on the surface of primary NGT fragments to promote a fast Li+ diffusion and suppress lithium metal dendrites upon charge and discharge.
Polycyclic aromatic hydrocarbons (PAHs) play an important role in the industry, and the development of new materials for the selective separation of PAHs is of great significance. In this work, we report a hexahedral metal-organic cage with low symmetry by subcomponent self-assembly. In this cage, the eight ZnⅡ centers adopt an interesting ΛΛ/ΔΔΔΔΔΔ or ΛΛΛΛΛΛ/ΔΔ configuration. This cage with a cavity volume of 520 Å3 can bind anthracene, phenanthrene, and pyrene to form 1:1 host-guest complexes, while the bigger triphenylene, chrysene, perylene, and coronene cannot be encapsulated. The binding constant Ka of pyrene is about 1.110 × 103 (mol/L)−1, which is more than an order of magnitude larger than that of anthracene and phenanthrene (111 (mol/L)−1, 277 (mol/L)−1, respectively). X-ray structure studies reveal that the pyrene is located in the cavity and stabilized by multiple CH⋅⋅⋅π interactions. After separation from a mixture of PAHs, pyrene with > 96.1% purity can be obtained. This work provides a useful method for the first time for the selective separation of pyrene from PAHs mixture by utilizing a metal-organic cage as the material, making it a useful tool for purifying and separating specific compounds from complex mixtures.