Counting statistics of tunneling through a single molecule: effect of distortion and displacement of vibrational potential surface

We analyze the effects of a distortion of the nuclear potential of a molecular quantum dot (QD), as well as a shift of its equilibrium position, on nonequilibrium-vibration-assisted tunneling through the QD with a single level ($\epsilon_d$) coupled to the vibrational mode. For this purpose, we derive an explicit analytical expression for the Franck-Condon (FC) factor for a displaced-distorted oscillator surface of the molecule and establish rate equations in the joint electron-phonon representation to examine the current-voltage characteristics and zero-frequency shot noise, and skewness as well. Our numerical analyses shows that the distortion has two important effects. The first one is that it breaks the symmetry between the excitation spectra of the charge states, leading to asymmetric tunneling properties with respect to $\epsilon_d>0$ and $\epsilon_d<0$. Secondly, distortion (frequency change of the oscillator) significantly changes the voltage-activated cascaded transition mechanism, and consequently gives rise to a different nonequilibrium vibrational distribution from that of the case without distortion. Taken in conjunction with strongly modified FC factors due to distortion, this results in some new transport features: the appearance of strong NDC even for a single-level QD with symmetric tunnel couplings; a giant Fano factor even for a molecule with an extremely weak electron-phonon interaction; and enhanced skewness that can have a large negative value under certain conditions.Comment: 29 pages, 11 figures, published versio

MoS₂ nanosheets with expanded interlayer spacing for enhanced sodium storage

Sodium-ion battery technology is a promising alternative to lithium-ion batteries for low-cost and large-scale energy storage applications. The larger size of the Na-ion relative to the Li-ion imposes kinetic limitations and often results in sluggish Na-ion diffusion. It is a great necessity to explore prominent structural features of materials to overcome the limitations and improve the diffusion. Layered MoS2 has an ideal two-dimensional diffusion pathway because of the weak van der Waals interaction between the layers. However, the limited gallery height of 0.3 nm is insufficient to achieve fast Na-ion diffusion. A facile hydrothermal route at medium-ranged temperatures is reported in this work to obtain interlayer expanded MoS2 nanosheets. The interlayer spacing is greatly expanded to 1 nm and facilitates Na-ion insertion and extraction in the van der Waals gaps. The nanosheet morphology shortens the Na-ion diffusion distance from the lateral side. The interlayer expanded MoS2 nanosheets are used as sodium-ion battery anodes in the voltage window of 0.5–2.8 V, where intercalation reaction contributes to Na storage and the layered structure can be preserved. The nanosheets exhibit a high cycling stability by retaining 92% of the initial charge capacity after 100 cycles and a great rate capability of 43 mA h g−1 at 2 A g−1. Kinetics study reveals a significant alleviation of diffusional limitation, verifying the improved Na-ion diffusion and enhanced Na storage. The presented work explores the utilization of the van der Waals gaps to store ions and sheds light on designing two-dimensional materials in other energy systems

Polyimide@Ketjenblack Composite: A Porous Organic Cathode for Fast Rechargeable Potassium-Ion Batteries

Potassium‐ion batteries (PIBs) configurated by organic electrodes have been identified as a promising alternative to lithium‐ion batteries. Here, a porous organic Polyimide@Ketjenblack is demonstrated in PIBs as a cathode, which exhibits excellent performance with a large reversible capacity (143 mAh g^{-1} at 100 mA g^{-1}), high rate capability (125 and 105 mAh g^{-1} at 1000 and 5000 mA g^{-1}), and long cycling stability (76% capacity retention at 2000 mA g^{-1} over 1000 cycles). The domination of fast capacitive‐like reaction kinetics is verified, which benefits from the porous structure synthesized using in situ polymerization. Moreover, a renewable and low‐cost full cell is demonstrated with superior rate behavior (106 mAh g^{-1} at 3200 mA g^{-1}). This work proposes a strategy to design polymer electrodes for high‐performance organic PIBs

Performance enhancement of permeable asphalt mixtures with recycled aggregate for concrete pavement application

The incorporation of recycled concrete aggregate (RCA) in permeable asphalt mixtures (PAMs) is an efficient method of utilizing construction demolished waste. It not only conforms to the trend of building sponge cities, but also alleviates the problem of overexploitation of natural aggregate resources. As the performance of PAM containing recycled aggregate is not comparable to natural aggregate, modification treatments and the addition of hybrid fibers are adopted as two enhancement methods to improve the performance of PAM with RAC in this study. It is found that replacing natural aggregate with recycled aggregate increases the optimum asphalt content (OAC) but decreases the residual stability. The OAC is increased by 45% when the RCA ratio is 100%, whereas applying silicone resin can give a 16.2% decrease in the OAC. Enhancing RCA with silicone resin can increase the water stability to be comparable with natural aggregate. Moreover, with modification treatment using calcium hydroxide solution, the mechanical strength of PAM is enhanced to even higher than that of natural coarse aggregate mixture alone. Improvements in both mechanical strength and water stability are also achieved by strengthening recycled aggregate with cement slurry, although the performance is less effective than using silicone resin. With the increase in the content of RCA, the permeability coefficients of PAM first decrease and then exhibit an increasing trend. The results indicate that the PAM with RCA and modification treatments can perform satisfactorily as a pavement material in practice. Applying probable modification, PAM incorporating RCA meets the criteria for use in concrete pavement applications

Green Synthesis of Carbon Nanospheres for Enhanced Electrochemical Sensing of Dopamine

Data Availability Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.Supporting Information is available online at: https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/celc.202201129#support-information-section .The detection of dopamine (DA) has received enormous attention since it is widely recognized as an important neurotransmitter associated with nerve signaling and some diseases. In this work, glucose-derived carbon nanospheres (CNs) are synthesized by the green hydrothermal approach and are served to modify electrodes for the detection of DA. The CNs were successfully synthesized and were investigated in detail by various characterization technologies. The CNs modified glassy carbon electrode (CNs/GCE) exhibits better electrochemical sensing performance with a wide linear range of 0.05–1600 μM and a low limit of 8.3 nM for determination of DA, as compared with the modified electrodes reported previously. The CNs/GCE was successfully applied to detect DA in human serum samples, which makes it promising for a variety of biomedical applications. More importantly, this work shows a novel green and simple strategy for the development of cost-effective and high-performance sensing materials, which provides more opportunities for design of electrochemical sensors with future capabilities of mass production in practical applications.National Natural Science Foundation of China. Grant Numbers: 21874087, 22274090; Shanxi Scholarship Council of China. Grant Number: 2021-012; James Cook University

Facile synthesis of hierarchical fern leaf-like Sb and its application as an additive-free anode for fast reversible Na-ion storage

Hierarchical Sb was successfully fabricated via a very simple and cost-effective electrochemical deposition method. Morphological and structural characterizations show that the as-prepared Sb has a uniform fern leaf-like structure which is composed of well-crystallized Sb nanoparticles. The formation mechanism of the fern leaf-like Sb was also investigated. The hierarchical Sb exhibits desirable properties for sodium storage, such as high electrical conductivity and large surface area. When used as an additive-free anode for Na-ion batteries, the as-obtained fern leaf-like Sb reveals excellent cycling stability and rate capability. It can afford a high reversible capacity of 589 mA h g−1 over 150 cycles at 0.5 A g−1 and retain a capacity of 498 mA h g−1 at a high rate of 10 A g−1. Furthermore, a full cell constructed using P2-Na2/3Ni1/3Mn2/3O2//fern leaf-like Sb also displays remarkably stable and robust Na-storage performance, which includes a high capacity retention of 70% after 100 cycles at 0.5 A g−1 and a large capacity of 370 mA h g−1 at 10 A g−1. The excellent electrochemical performance of fern leaf-like Sb can be attributed to its morphological and structural features that ensure fast ion and electron transport and a stable electrode structure

Leverage of nuclease-deficient CasX for preventing pathological angiogenesis

Gene editing with a CRISPR/Cas system is a novel potential strategy for treating human diseases. Pharmacological inhibition of phosphoinositide 3-kinase (PI3K) δ suppresses retinal angiogenesis in a mouse model of oxygen-induced retinopathy. Here we show that an innovative system of adeno-associated virus (AAV)-mediated CRISPR/nuclease-deficient (d)CasX fused with the Krueppel-associated box (KRAB) domain is leveraged to block (81.2% ± 6.5%) in vitro expression of p110δ, the catalytic subunit of PI3Kδ, encoded by Pik3cd. This CRISPR/dCasX-KRAB (4, 269 bp) system is small enough to be fit into a single AAV vector. We then document that recombinant AAV serotype (rAAV)1 efficiently transduces vascular endothelial cells from pathologic retinal vessels, which show high expression of p110δ; furthermore, we demonstrate that blockade of retinal p110δ expression by intravitreally injected rAAV1-CRISPR/dCasX-KRAB targeting the Pik3cd promoter prevents (32.1% ± 5.3%) retinal p110δ expression as well as pathological retinal angiogenesis in a mouse model of oxygen-induced retinopathy. These data establish a strong foundation for treating pathological angiogenesis by AAV-mediated CRISPR interference with p110δ expression