Latest ArticlesFolding of molecules is an essential process in nature, and various molecular machines achieve their chemical and mechanical function via controlled folding of molecular conformations. The electric field offers a unique strategy to drive the folding of molecular conformation and to control charge transport through single molecules but remains unexplored. The single-molecule break junction technique provides access to detect the conformational changes via the monitoring of single-molecule conductance, and the electric field between two metal electrodes with nanoscale spacing can provide an extremely strong to achieve in-situ control and detection of molecular folding at the single-molecule level. Here, we use the electric field to control the single-molecule folding using the scanning tunneling microscope break junction (STM-BJ) technique. The electric fields induced folding could lead to a ~1400% conductance change of the single-molecule junctions, and the folding/unfolding process can be in-situ switched at the scale of milliseconds. DFT calculations suggest the conformational control originates from the electric field-induced charge injection, and the formation of homoconjugated conformation with the overlapped orbitals. This work provides the first demonstration of electric field-driven molecular folding, which is essential for the understanding of molecular machines in nature and for the design of artificial molecular machines.
The 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.
As a new concept having emerged in last few years, the "deep eutectic solvents" (DESs) effect integrated into the imprinting technology inevitably exposes design limitations of stimuli-responsive molecularly imprinted polymers (MIPs), as well as inadequate analysis of the adsorption performance of MIPs. Herein, a simple yet defined N-isopropylacrylamide/(3-acrylamidopropyl) trimethylammonium chloride (NIPAM/APTMAC) binary DESs system was proposed to prepare intelligent MIPs with thermo-sensitivity. Accordingly, magnetic and thermo-responsive MIPs based on functional monomers-derived DESs (TM-DESs-MIPs1) were synthesized, revealing DESs effect-regulated affinity/kinetics for the enhanced adsorption capability, eco-friendly thermo-regulated elution for high release efficiency, and simple magnetic separation, along with superior selectivity to rhein (RH) and good regeneration ability. TM-DESs-MIPs1 were utilized to extract RH from Cassiae semen samples coupled with high performance liquid chromatography (HPLC), yielding satisfactory recoveries (79.47%−110.82%) and low limits of detection (LOD) (16.67 µg/L). Another two kinds of MIPs adopting the thermo-responsive moiety-derived DESs effect strategy further demonstrated great applicability of such intelligent MIPs for analyses of complicated samples.
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.
White light emitting systems of pure organic materials have attracted extensive research interest due to their better compatibility and functional scalability. The reported organic white light materials are mainly based on the multi-channel emission regulation of the compound itself or the mixing of multicolor luminescence materials, but studies on the dependence between multicolor luminescence and the external environment are lacking, which limits the application of these materials in areas such as identification and sensing. This paper reports that the 4- or 3‑hydroxyl-substituted naphthalimides NapH1 and NapH2 form intermolecular hydrogen bonds with adjacent molecules in the environment, and undergo excited-state intermolecular proton transfer under irradiation, resulting in blue-yellow or blue-red dual fluorescence emission, respectively. Since the two compounds have different two-color luminescence channels and the two-color intensity ratio is affected by the environment, and the intermolecular hydrogen bond is determined by the hydrogen bond receptor, polarity, and temperature in the environment, the full spectrum from blue to red light and white light emission can be obtained by adjusting the mixing ratio of the two dyes and the solvent polarity and the ambient temperature. This environmentally sensitive white emission is used to detect the alkalinity of different papers, and the dyed paper can be used as a test strip for acid-base vapor detection.
Electrosynthesis of hydrogen peroxide (H2O2) is an on-site method that enables independent distribution applications in many fields due to its small-scale and sustainable features. The crucial point remains developing highly active, selective and cost-effective electrocatalysts. The electrosynthesis of H2O2 in acidic media is more practical owing to its stability and no need for further purification. We herein report a phosphorus and selenium tuning Co-based non-precious catalyst (CoPSe) toward two-electron oxygen reduction reaction (2e– ORR) to produce H2O2 in acidic media. The starting point of using both P and Se is finding a balance between strong ORR activity of CoSe and weak activity of CoP. The results demonstrated that the CoPSe catalyst exhibited the optimized 2e– ORR activity compared with CoP and CoSe. It disclosed an onset potential of 0.68 V and the H2O2 selectivity 76%-85% in a wide potential range (0–0.5 V). Notably, the CoPSe catalyst overcomes a significant challenge of a narrow-range selectivity for transition-metal based 2e– ORR catalysts. Finally, combining with electro-Fenton reaction, an on-site system was constructed for efficient degradation of organic pollutants. This work provides a promising non-precious Co-based electrocatalyst for the electrosynthesis of H2O2 in acidic media.
In this work, semirigid linkers of the alkyl-thiophene-alkyl structure are developed to construct double-cable polymers. Three alkyl units, propyl (C3H6), hexyl (C6H12), and dodecyl (C12H24), are applied as semirigid linkers, yielding three double-cable polymers: PBC6-T, PBC12-T, and PBC24-T, respectively. PBC12-T which uses C6H12-thiophene-C6H12 linkers is found to exhibit the best device efficiency of 5.56%, while PBC6-T and PBC24-T with shorter or longer linkers yield device efficiencies of only 2.65% and 1.09% in single-component organic solar cells (SCOSCs). Further studies reveal that PBC12-T exhibits higher crystallinity and improved charge transport, resulting in better efficiencies. Our work provides an approach to construct double-cable conjugated polymers with long alkyl linkers, and it shows the importance of the linker length for the photovoltaic performance of SCOSCs.
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.
In this study, magnesium and coconut shell carbon (CSC) were prepared by a ball milled process and used for water disinfection with adsorbing tiny amounts of copper(Ⅱ). Dissolved oxygen (DO) was reduced to hydrogen peroxide (H2O2) via a two-electron pathway by Mg corrosion. Cu(Ⅱ) in the wastewater will be enriched on the CSC surface and efficiently catalyzes H2O2 for inactivating E. coli. The results show that E. coli with an initial concentration of approximately 106 CFU/mL was under the detection limit (< 4 CFU/mL) within 15 min. All of the Cu(Ⅱ) could be adsorbed by the composite and catalyzed H2O2 to different active species. The quenching experiments, electron spin resonance (ESR) capture measurements and the UV-vis spectroscopy detection confirmed the present of the hydroxyl radicals (•OH), superoxide radicals (•O2−) and Cu(Ⅲ). Different with tradition Fenton like process, Cu(Ⅲ), rather than radicals, played the major role during the Mg-CSC/Cu(Ⅱ) process. In addition to the cellular membrane damage, most of the bacterial genomic DNA was also be degraded and the bacterial reactivation was avoided. The Mg-CSC/Cu(Ⅱ) process also showed a satisfied disinfection performance in real wastewater treatment. Overall, this study provides a new strategy for water disinfection.
Carbon dots (CDs) with superior fluorescence properties have attracted a growing number of research interests in anti-counterfeiting. However, the preparation of CDs with thermally turn-on fluorescence and full-color-emitting in visible spectrum is still a big challenge due to the complicated reaction mechanism in the formation of CDs. Here, a simple precursor-oriented strategy for the preparation of multicolor CDs with heat-stimuli turn-on fluorescence is reported. Comprehensive experimental characterizations and theoretical calculations revealed that the emission wavelength of CDs can be readily tuned from 460 nm to 654 nm with selected precursors, which was ascribed to the extent of conjugated sp2-domains (core states) and the amount of oxygen- and nitrogen-containing groups bound to sp2-domains (surface states). After simply mixing two or three kinds of CDs, a full-color range of fluorescence emission was realized, and the CDs-based fluorescence inks were successfully fabricated. Particularly, all the printed patterns from the inkjet exhibited a thermal-induced enhancement in fluorescence. On this basis, combining CDs with heating-induced "turn-off" fluorescence materials can lead to multidimensional and multistage encryption. These results demonstrate that the thermochromic and photochromic CDs with much more enhanced security exhibit promising application in data storage and encryption.
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
