Heterogeneous engineering of MnSe@NC@ReS_(2) core-shell nanowires for advanced sodium-/potassium-ion batteries

Sodium-ion batteries(SIBs) and potassium-ion batteries(PIBs) have been attracting great attentions and widely been exploited due to the abundant sodium/potassium resources.Hence,the preparation of high-powered anode materials for SIBs/PIBs plays a decisive role for the commercial applications of SIBs/PIBs in the future.Manganese selenides are a class of potential anode materials for SIBs/PIBs because of their small band gap and high electrical conductivity.In this work,MnSe and ReS_(2) core-shell nanowires connecting by polydopamine derived carbon nanotube(MnSe@NC@ReS_(2)) have been successfully synthesized from growing ReS_(2) nanosheets array on the surface of MnSe@NC nano wires,which present excellent Na^(+)/K^(+) storage performance.While applied as SIBs anode,the specific capacity of 300 mAh·g^(-1) was maintwined after 400 cycles at the current density of 1.0 A·g^(-1).Besides,it could also keep 120 mAh·g^(-1) specific capacity after 900 cycles at 1.0 A·g^(-1) for the anode of PIBs.These heterogeneous engineering and one-dimensional-two-dimensional(1D-2D) hybrid strategies could provide an ideal strategy for the synthesis of new hetero-structured anode materials with outstanding battery performance for SIBs and PIBs.

Schiff base flexible organic crystals toward multifunctional applications

The emergence offlexible organic crystals changed the perception of molecu-lar crystals that were regarded as brittle entities over a long period of time,and sparked a great interest in exploring mechanically compliant organic crystalline materials toward next-generation smart materials during the past decade.Schiff base compounds are considered to be one of the most promising candidates forflexible organic crystals owing to their easy synthesis,high yield,stimuli respon-siveness and good mechanical properties.This paper gives an overview of the recent development of Schiff baseflexible organic crystals(including elastic organic crystals,plastic organic crystals,andflexible organic crystals integrating elastic-ity and plasticity)from serendipitous discovery to design strategies and versatile applications such as stimuli responses,optical waveguides,optoelectronic devices,biomimetic soft robots,and organic photonic integrated circuits.Notably,atomic force microscopy-micromanipulation technique has been utilized to bring the mul-tifunctional applications offlexible organic crystals from the macroscopic level to the microscopic world.Since understanding mechanicalflexibility at the molec-ular level through crystal engineering can assist us to trace down the structural origin of mechanical properties,we focus on the packing structures of various Schiff baseflexible organic crystals driven by non-covalent intermolecular inter-actions and their close correlation with mechanical behaviors.We hope that the information given here will help in the design of novelflexible organic crys-tals combined with other unique properties,and promote further research into the area of mechanically compliant organic crystalline materials toward multifunctional applications.

Progress in Fluorene-based Wide-bandgap Steric Semiconductors

Molecular bulks are favorable for the thermal and morphological stability in organic wide-bandgap semiconducting polymers with potential applications in both information and energy electronics. In this review, we present our progress in the design of fluorene-based bulky semiconductors with a fractal four-element pattern. Firstly, we established one-pot methods to spirofluorenes, especially spiro[fluorene-9,9＇-xanthene] （SFX） serving as the next-generation spiro-based semiconductors. Secondly, we observed the supramolecular forces at the bulky groups and discovered the supramolecular steric hindrance （SSH） effect on polymorphisms, nanocrystals as well as device performance. Thus, a synergistically molecular attractor-repulsor theory （SMART） was proposed for the control of nanocrystal morphology, thin film phase and morphology. Thirdly, the third possible type of defects has been identified to generate green band （g-band） emission in wide- bandgap semiconductors by the introduction of molecular strain design of cyclofluorene. Finally, the first bulky polydiarylfluorene with highly crystalline and β conformation was achieved by an attractor-repulsor design of tadpole-shape monomer, which offered an effective platform to fabricate stable wide-bandgap semiconducting devices. All the discoveries offer the solid basis to break through bottlenecks of organic/polymer wide-bandgap semiconductors by the improvements of overall performances.

Molecular mechanisms of autophagy and implications in liver diseases

Autophagy is a highly conserved process in which cytosolic contents are degraded by the lysosome,which plays an important role in energy and nutrient balance,and protein or organelle quality control.The liver is the most important organ for metabolism.Studies to date have revealed a significant role of autophagy in the maintenance of liver homeostasis under basal and stressed conditions,and the impairment of autophagy has been closely linked to various liver diseases.Therefore,a comprehensive understanding of the roles of autophagy in liver diseases may help in the development of therapeutic strategies via targeting autophagy.In this review,we will summarize the latest understanding of the molecular mechanisms of autophagy and systematically discuss its implications in various liver diseases,including alcohol-related liver disease,non-alcoholic fatty liver disease,viral hepatitis,hepatocellular carcinoma,and acetaminophen-induced liver injury.

Fluorinated p-n Type Copolyfluorene as Polymer Electret for Stable Nonvolatile Organic Transistor Memory Device

Abstract In this study, a kind of fluorinated copolyfluorene, named poly[（4-（octyloxy）-9,9-diphenylfluorene-2,7-diyl）-alt- （2,3,5,6-tetrafluoro-1,4-phenylene）] （PODPF-TFP）, is synthesized by facile palladium-based direct aromatization. Compared to the non-fluorinated counterpart, poly[（4-（octyloxy）-9,9-diphenylfluorene-2,7-diyl）-alt-（p-phenylene）] （PODPF-P）, deeper HOMO/LUMO energy level combined with steric hindrance effect endow PODPF-TFP with excellent spectra and morphology stability. Finally, organic field-effect transistor （OFET） memory devices are fabricated with PODPF-P/PODPF- TFP as the dielectric layers, and they both exhibit flash type storage characteristic. Owing to the electronegativity of fluorine atom, the device based on PODPF-TFP exhibits larger memory window and more stable Ion/Ioff ratio during a retention time of 10^4 s as well as a better aging stability. The present study suggests that fluorinated p-n copolyfluorene electrets could enhance the capabilities of charge trapping and storage, which are promising for OFET memory devices.

Electrospun Supramolecular Hybrid Microfibers from Conjugated Polymers:Color Transformation and Conductivity Evolution

A type of novel electrospun supramolecular hybrid microfibers comprising poly(9-(4-(octyloxy)-phenyl)-2,7-fluoren-9-ol)(PPFOH)and poly(A/-vinylcarbazole)(PVK)are successfully prepared for intriguing multi-color emission properties.The supramolecular tunable PPFOH aggregation in PVK matrix endows the complex with a smart energy transfer behavior to obtain the multi-color emissions.In stark contrast to PVK fibers,the emission color of PPFOH/PVK fibers with an efficient dispersion of PPFOH fluorophores at a proper dope ratio can be tuned in a wide spectrum of blue(0.1%),sky blue(0.5%),nearly white(1%),cyan(2%),green(5%)and yellow(10%).Besides,conductive behaviors of the microfiber were demonstrated in accompany with the increment of the doping ratio of PPFOH to PVK.Successful fabrication of polymer light-emitting diode(PLED)based on the blended electrospun fiber provided a further evidence of its excellent electrical property for potential applications in optoelectronic devices.

Matrix Effect on Polydiarylfluorenes Electrospun Hybrid Microfibers: From Morphology Tuning to High Explosive Detection Efficiency

Precisely optimizing the morphology of functional hybrid polymeric systems is crucial to improve its photophysical property and further extend their optoelectronic applications. The physic-chemical property of polymeric matrix in electrospinning (ES) processing is a key factor to dominate the condensed structure of these hybrid microstructures and further improve its functionality. Herein, we set a flexible poly(ethylene oxide) (PEO) as the matrix to obtain a series of polydiarylfluorenes (including PHDPF, PODPF and PNDPF) electrospun hybrid microfibers with a robust deep-blue emission. Significantly different from the rough morphology of their poly(N-vinylcarbazole) (PVK) ES hybrid fibers, polydiarylfluorenes/PEO ES fibers showed a smooth morphology and small size with a diameter of 1∼2 µm. Besides, there is a relatively weak phase separation under rapid solvent evaporation during the ES processing, associated with the hydrogen-bonded-assisted network of PEO in ES fibers. These relative “homogeneous” ES fibers present efficient deep-blue emission (PLQY>50%), due to weak interchain aggregation. More interestingly, low fraction of planar (β) conformation appears in the uniform PODPF/PEO ES fibers, induced by the external traction force in ES processing. Meanwhile, PNDPF/PEO ES fibers present a highest sensitivity than those of other ES fibers, associated with the smallest diameter and large surface area. Finally, compared to PODPF/PVK fibers and PODPF/PEO amorphous ES fibers, PODPF/PEO ES fibers obtained from DCE solution exhibit an excellent quenching behavior toward a saturated DNT vapor, mainly due to the synergistic effect of small size, weak separation, β-conformation formation and high deep-blue emission efficiency.