Latest ArticlesRed emissive carbon dots (CDs) powder was synthesized on a large scale from phloroglucinol and boric acid by a novel solid state reaction with yield up to 75%. This method is safe and convenient, for it needs neither high pressure reactors nor complicated post-treatment procedures. The as-prepared carbon dots powder exhibited strong red fluorescence with excitation-independent behavior. XPS measurement and PL spectra suggest that such red fluorescence arise from boron-doped structures in CDs, which increases along with the boron concentration on CDs surface but decreases when the concentration quenching effect takes place. To overcome the aggregation induced fluorescence quenching of the solid CDs powder, the conventional methods are dispersing CDs into a large amount of inert substrates. But our present work provides a new strategy to realize strong red fluorescence of CDs in solid state. As a result, such carbon dots powder works well for latent fingerprint identification on various material surfaces.
A novel diselenide-containing crown ether (BC7Se2) was fabricated, which can polymerize to form cyclic oligomers through intermolecular dynamic covalent reaction by irradiation of visible light. The size and distribution of oligomers are related to the monomer concentration. The decomposition reaction of oligomers is controlled by topology and solvents. Furthermore, potassium cation can inhibit the polymerization of BC7Se2 and accelerate the decomposition of oligomers.
The rapid development of internet and internet of things brings new opportunities for the expansion of intelligent sensors, and acetone as a major disease detection indicator (i.e., diabetes) making it become extremely important clinical indicator. Herein, uniform mesoporous ZnO spheres were successfully synthesized via novel formaldehyde-assisted metal-ligand crosslinking strategy. In order to adjust the pore structure of mesoporous ZnO, various mesoporous ZnO spheres were synthesized by changing weight percentage of Zn(NO3)2·6H2O to tannic acid (TA). Moreover, highly active heterojunction mesoporous ZnO/Co3O4 has been fabricated based on as-prepared ultra-small Co3O4 nanocrystals (ca. 3 nm) and mesoporous ZnO spheres by flexible impregnation technique. Profit from nano-size effect and synergistic effect of p-n heterojunction, mesoporous ZnO/Co3O4 exhibited excellent acetone sensing performance with high selectivity, superior sensitivity and responsiveness. Typically, 5 wt% Co3O4 embedded mesoporous ZnO sphere showed prominent acetone response (ca. 46 for 50 ppm), which was about 11.5 times higher than that in pure ZnO sensing device, and it was also endowed high cyclic stability. The nanocrystals embedded hybrid material is expected to be used as promising efficient material in the field of catalysis and gas sensing.
An efficient and eco-friendly protocol for synthesizing difluoromethylated oxindoles through a visible-light induced one-pot tandem reaction of N-arylacrylamides, difluoroacetic acid and PhI(OAc)2 was developed. This reaction proceeded in the absence of any additive, base, metal-catalyst and external photosensitizer, using cheap and easily available CHF2CO2H as the difluoromethylation reagent and bulk biomass-derived 2-MeTHF as the sole solvent. 26 Examples of N-arylacrylamide substrates were investigated, and all of them successfully underwent difluoromethylation to deliver the target products in good to excellent yields.
The high specific capacitance along with good cycling stability are crucial for practical applications of supercapacitors, which always demands high-performance and stable electrode materials. In this work, we report a series of ternary composites of CoO-ZnO with different fractions of reduced graphene oxide (rGO) synthesized by in-situ growth on nickel foam, named as CZG-1, 2 and 3, respectively. This sort of binder-free electrodes presents excellent electrochemical properties as well as large capacitance due to their low electrical resistance and high oxygen vacancies. Particularly, the sample of CZG-2 (CoO-ZnO/rGO 20 mg) in a nanoreticular structure shows the best electrochemical performance with a maximum specific capacitance of 1951.8 F/g (216.9 mAh/g) at a current intensity of 1 A/g. The CZG-2-based hybrid supercapacitor delivers a high energy density up to 45.9 Wh/kg at a high power density of 800 W/kg, and kept the capacitance retention of 90.1% over 5000 charge-discharge cycles.
The construction of nanostructured ion-transport channels is highly desirable in the design of advanced electrolyte materials, as it can enhance ion conductivity by offering short ion-transport pathways. In this work, we present a supramolecular strategy to fabricate a nanocomposite electrolyte containing highly ordered lamellar proton-conducting nanochannels, by the electrostatic self-assembly of a polyoxometalate H3PW12O40 (PW) and a comb copolymer poly(4-methlstyrene)-graft-poly(N-vinyl pyrrolidone). PW can effectively regulate the self-assembling order of polymer moieties to form a large-range lamellar structure, meanwhile, introducing protons into the nanoscale lamellar domains to build proton transport channels. Moreover, the rigid PW clusters contribute a remarkable mechanical reinforcement to the nanocomposites. The lamellar nanocomposite exhibits a conductivity of 4.3×10-4 S/cm and a storage modulus of 1.1×107 Pa at room temperature. This study provides a new strategy to construct nanostructured ion-conductive pathways in electrolyte materials.
Photocatalytic water splitting utilizing solar energy is considered as one of the most ideal strategies for solving the energy and environmental issues. Recently, two-dimensional (2D) materials with an intrinsic dipole show great chance to achieve excellent photocatalytic performance. In this work, blue-phase monolayer carbon monochalcogenides (CX, X = S, Se) are constructed and systematically studied as photocatalysts for water splitting by performing first-principles calculations based on density functional theory. After confirming the great dynamical, thermal, and mechanical stability of CX monolayers, we observe that they possess moderate band gaps (2.41 eV for CS and 2.46 eV for CSe) and high carrier mobility (3.23 × 104 cm2 V-1 s-1 for CS and 4.27 × 103 cm2 V-1 s-1 for CSe), comparable to those of many recently reported 2D photocatalysts. Moreover, these two monolayer materials are found to have large intrinsic dipole (0.43 D for CS and 0.51 D for CSe), thus the build-in internal electric field can be selfintroduced, which can effectively drive the separation of photongenerated carriers. More importantly, the well-aligned band edge as well as rather pronounced optical absorption in the visible-light and ultraviolet regions further ensure that our proposed CX monolayers can be used as high efficient photocatalysts for water splitting. Additionally, the effects of external strain on the electronic, optical and photocatalytic properties of CX monolayers are also evaluated. These theoretical predictions will stimulate further work to open up the energy-related applications of CX monolayers.
The flourishing development in flexible electronics has provoked intensive research in flexible strain sensors to realize accurate perception acquisition under different external stimuli. However, building hydrogel-based strain sensors with high stretchability and sensitivity remains a great challenge. Herein, MXene nanosheets were composited into polyacrylamide-sodium alginate matrix to construct mechanical robust and sensitive double networked hydrogel strain sensor. The hydrophilic MXene nanosheets formed strong interactions with the polymer matrix and endowed the hydrogel with excellent tensile properties (3150%), compliant mechanical strength (2.03 kPa−1 in Young's Module) and long-lasting stability and fatigue resistance (1000 dynamic cycles under 1, 600% strain). Due to the highly oriented MXene-based three dimensional conductive networks, the hydrogel sensor achieved extremely high tensile sensitivity (18.15 in gauge factor) and compression sensitivity (0.38 kPa−1 below 3 kPa). MXene hydrogel-based strain sensors also displayed negligible hysteresis in electromechanical performance, typical frequent-independent feature and rapid response time to external stimuli. Moreover, the sensor exhibited accurate response to different scales of human movements, providing potential application in speech recognition, expression recognition and handwriting verification.
The emergence of fluorescent light-up molecular probe, which can specifically turn on their fluorescent in the presence of stimulation factors, has open up a new opportunity to advance biosensing and bioimaging. In this work, we designed and synthesized a peptide-AIE conjugate probe for cell imaging with controlled in situ assembled nanostructures. The modular designed probe is consisted of a self-assembled peptide-tetraphenylethene (TPE) motif, a fibroblast activation protein alpha (FAP-α) responsive motif, a hydrophilic motif and a targeting motif. The probe exhibits typically turn-on fluorescence property specifically triggered by FAP-α, which is a significant overexpressed membrane protein on pancreatic tumor cells. Interestingly, the peptide modified the TPE dramatically impacts the assembled nanostructure, which can be modulated by peptide sequences. As a result, the peptide FF(Phe-Phe) modification of TPE as the self-assembled motif provides a suitable balance of the probe with light-up property and nanofiber assembled structure in situ. Finally, our probe could effectively detect the FAP-α on tumor cells with high specificity. Meantime, the nanofibers in situ assembled on the surface of CAFs enhanced the probe accumulation and prolonged the retention for cell imaging. We envision that this study may inspire new insights into the design of nanostructure controlled AIE light-up bio-probe.
To better understand the spatial distribution of brain functions, we need to monitor and analyze neuronal activities. Electrophysiological technique has provided an important method for the exploration of some neural circuits. However, this method cannot simultaneously detect the activities of nerve cell groups. Therefore, methods that can monitor the spatial distribution of neuronal population activity are demanded to explore brain functions. Voltage-sensitive dyes (VSDs) shift their absorption or emission optical signals in response to different membrane potentials, allowing assessing the global electrical state of neurons. Optical recording technique coupled with VSDs is a promising method to monitor the brain functions by detecting optical signal changes. This review focuses on the fast and slow responses of VSDs to membrane potential changes and optical recordings utilized in the central nervous system. In this review, we attempt to show how VSDs and optical recordings can be used to obtain brain functional monitoring at high spatial and temporal resolution. Understanding of brain functions will not only greatly improve the cognition of information transmission of complex neural network, but also provide new methods of treating brain diseases such as Parkinson's and Alzheimer's diseases.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
