Latest ArticlesDefects at the grain boundaries (GBs) of perovskite film highly restrict both the efficiency and stability of perovskite solar cells (PSCs). Herein, organic small molecules of butanedioic acid (BA) and acetylenedicarboxylic acid (AA), containing two carbonyl (C=O) groups and different core-units, were incorporated into perovskite as additives for PSCs application. Thanks to the strong coordination interaction between CO group and under-coordinated Pb2+, the additives can effectively passivate film defects and regulate the perovskite crystallization, yielding high-quality perovskite films with lower defect densities. More importantly, the additives can efficiently regulate the charge transport behaviors in PSCs. Benefiting from the defects passivation and the regulation of charge carrier dynamics, the BA and AA-treaded PSCs show the power conversion efficiencies of 21.52% and 20.50%, which are higher than that of the control device (19.41%). Besides, the optimal devices exhibit a remarkable enhanced long-term stability and moisture tolerance compared to the pristine devices. Furthermore, the transient absorption spectrum reveals the mechanism of enhanced photovoltaic performances, attributing to the improvement of charge transport capability at the perovskite/Spiro-OMeTAD interfaces. This work affords a promising strategy to improve the efficiency and stability of PSCs through regulating the charge-carrier dynamic process in perovskite film.
Gold-catalyzed amination reactions based on azides via α-imino gold carbene intermediates have attracted extensive attention in the past decades because this methodology leads to the facile and efficient construction of synthetically useful N-containing molecules, especially valuable N-heterocycles. However, successful examples of intermolecular generation of α-imino gold carbenes by using azides as amination reagents are rarely explored probably due to the weak nucleophilicity of azides. Herein, we disclose an efficient gold-catalyzed intermolecular aminative cyclopropanation of ynamides with the allyl azides, enabling flexible synthesis of a wide range of valuable 3-azabicyclo[3.1.0]hex-2-ene derivatives in good to excellent yields with excellent diastereoselectivities. Importantly, this protocol represents the first use of allyl azide as an efficient amination reagent in gold-catalyzed alkyne amination reactions.
Cholelithiasis affects approximately 10%-20% of the adult population globally. And cholesterol accumulation and nucleation of cholesterol crystals are commonly recognized as the primary process in the initiation and progression of gallstones. Hydroxypropyl-β-cyclodextrin (HPCD) is a supramolecular host compound that can solubilize cholesterol, potentially serving as a preventative or therapeutic agent for cholelithiasis. However, we found that the administration of HPCD treatment did not impede the formation of gallstones in mice, mainly attributed to the pre-complexation of its cavity during the transition process. Here we synthesized a prodrug of HPCD and prepared a HPCD nanoparticle (HPCD-NP), which can be transported efficiently to the gallbladder through the hepatobiliary system following an intravenous injection. In the bile, the HPCD-NP degraded into free HPCD, bound to cholesterol crystals and gallstones within the gallbladder and effectively increased cholesterol solubilization, leading to gallstones regression. Given the established safety of both HPCD and cyclodextrin-based nanoparticles in numerous animal and human studies, HPCD-NP shows considerable promise for the prevention and treatment of human cholelithiasis.
A pseudocapacitance dominated anode material assembled from Li3VO4 nanocrystals encapsulated in the interlayers of N-doped graphene has been developed via a facile 2D nanospace confined strategy for lithium ion capacitors (LICs). In this contribution, the N-doped graphene synthesized by a faicle solid state reaction using C3N4 nanosheets as template and glucose as carbon source provides sufficient 2D nanospace for the confined and homogeneous growth of Li3VO4 at the nanoscale, and simultaneously efficiently anchors each nanobuilding block inside the interlayers, thus realizing the utilizaiton of full potential of active components. The so-formed 3D hybrids not only ensure intimate electronic coupling between active materials and N-doped graphene, but also realize robust structure integrity. Owing to these unique advantages, the resulting hybrids show pseudocapacitance dominated lithium storage behaviors with capacitive contributions of over 90% at both low and high current rates. The LVO@C@NG delivers reversible capacities of 206 mAh/g at 10 A/g, capacity retention of 92.7% after 1000 cycles at 2 A/g, and a high energy density of 113.6 Wh/kg at 231.8 W/kg for LICs.
Lithium metal is one of the most promising anodes for lithium batteries because of their high theoretical specific capacity and the low electrochemical potential. However, the commercialization of lithium metal anodes (LMAs) is facing significant obstacles, such as uncontrolled lithium dendrite growth and unstable solid electrolyte interface, leading to inferior Coulombic efficiency, unsatisfactory cycling stability and even serious safety issues. Introducing low-cost natural clay-based materials (NCBMs) in LMAs is deemed as one of the most effective methods to solve aforementioned issues. These NCBMs have received considerable attention for stabilizing LMAs due to their unique structure, large specific surface areas, abundant surface groups, high mechanical strength, excellent thermal stability, and environmental friendliness. Considering the rapidly growing research enthusiasm for this topic in the last several years, here, we review the recent progress on the application of NCBMs in stable and dendrite-free LMAs. The different structures and modification methods of natural clays are first summarized. In addition, the relationship between their modification methods and nano/microstructures, as well as their impact on the electrochemical properties of LMAs are systematically discussed. Finally, the current challenges and opportunities for application of NCBMs in stable LMAs are also proposed to facilitate their further development.
Colorectal cancer (CRC) is one of the most prevalent malignant tumors worldwide, exhibiting high morbidity and mortality. Lack of efficient tools for early diagnosis and surgical resection guidance of CRC have been a serious threat to the long-term survival rate of the CRC patients. Recent studies have shown that relative higher viscosity was presented in tumor cells compared to that in normal cells, leading to viscosity as a potential biomarker for CRC. Herein, we reported the development of a series of novel viscosity-sensitive and mitochondria-specific fluorescent probes (HTB, HTI, and HTP) for CRC detection. Among them, HTB showed high sensitivity, minimal background interference, low cytotoxicity, and significant viscous response capability, making it an ideal tool for distinguishing colorectal tumor cells from normal cells. Importantly, we have successfully utilized HTB to visualize in a CRC-cells-derived xenograft (CDX) model, enriching its medical imaging capacity, which laid a foundation for further clinical translational application.
Na3V2(PO4)3 (NVP) is regarded as alternative cathode material for sodium-ion batteries (SIBs) due to its potential high-rate performance and pronounced long-term cycle stability. However, electronic conductivity and tap density are difficult to be balanced. Herein, we report that high-temperature shock (HTS) can prepare "single crystalline like" NVP which combines high-rate capability with high tap density together into one with the assistance of carbon framework and large particle. Thus, high reversible capacity of 110 mAh/g at 0.1 C with 89.9% capacity retention after 1600 cycles at 1 C and specific capacity of 83.5 mAh/g at 50 C rate has been exhibited. This study provides a novel strategy to guide the production of high tap density, and rate performance polyanionic cathode materials.
Optimizing the interfacial quality of halide perovskites heterojunction to promote the photogenerated charge separation is of great significance in photocatalytic reactions. However, the delicately regulation of interfacial structure and properties of halide perovskites hybrid is still a big challenge owing to the growth uncontrollability and incompatibility between different constituents. Here we use BiOBr nanosheets as the start-template to in situ epitaxially grow Cs3Bi2Br9 nanosheets by “cosharing” Bi and Br atoms strategy for designing a 2D/2D Cs3Bi2Br9/BiOBr heterojunction. Systematic studies show that the epitaxial heterojunction can optimize the synergistic effect of BiOBr and Cs3Bi2Br9 via the formation of tight-contact interfaces, strong interfacial electronic coupling and charge redistribution, which can not only drive the Z-scheme charge transfer mechanism to greatly promote the spatial separation of electron-hole pairs, but also modulate the interfacial electronic structure to facilitate the adsorption and activation of toluene molecules. The heterojunction exhibited 62.3 and 2.4-fold photoactivity improvement for toluene oxidation to benzaldehyde than parental BiOBr and Cs3Bi2Br9, respectively. This study not only proposed a novel dual atom-bridge protocol to engineer high-quality perovskite heterojunctions, but also uncovered the potential of heterojunction in promoting electron-hole separation as well as the application in photocatalytic organic synthesis.