We demonstrate the aggregation-induced electrochemiluminescence (AIECL) generated by 1,1,2,2-tetrakis­(4-bromophenyl)­ethane (TBPE)-based conjugated microporous polymers (TBPE-CMPs) and its biosensing application. We synthesized three TBPE-CMPs (i.e., TBPE-CMP-1, -2, -3) using three different molecules including tris­(4-ethynylphenyl)­amine (TEPA), 4,4′-diethynylbiphenyl (DEP), and 2,4,6-tris­(4-ethynylphenyl)-1,3,5-triazine (TEPT). The TBPE-CMPs can act as electrochemiluminescence (ECL) emitters to generate AIECL. Among them, TBPE-CMP-1 exhibits the highest ECL efficiency (1.72%) due to the improved electron–hole recombination efficiency and efficient suppression of nonradiative transition. Moreover, the ECL properties of TBPE-CMPs can be tuned by the introduction of different conjugated molecules that can decrease the energy gap to facilitate the injection of an electron into the conjugated polymer backbone. Importantly, TBPE-CMP-1 can be used to construct an ECL sensor for the detection of dopamine, whose electro-oxidation products (e.g., leucodopaminechrome (LDC), dopaminechrome (DC), 5,6-dihydroxyindole (DHI), and 5,6-indolequinone (IDQ)) may function as energy acceptors to quench the ECL emission of TBPE-CMP-1. This ECL sensor exhibits high sensitivity and good anti-interference capability against ascorbic acid and uric acid.

Suppressing the recombination of photogenerated charges is one of the most important routes for enhancing the catalytic performance of semiconductor photocatalysts. In addition to the built‐in field produced by semiconductor heterostructures and the photo‐electrocatalysis realized by applying an external electrical potential to photocatalysts assembled on electrodes, other strategies are waiting to be scientifically explored and understood. In this work, a Lorentz force–assisted charge carrier separation enhancement strategy is reported to improve the photocatalytic efficiency by applying a magnetic field to a photocatalytic system. The photocatalytic efficiency can be improved by 26% just by placing a permanent magnet beneath the normal photocatalytic system without any additional power supply. The mechanism by which the Lorentz force acts oppositely on the photogenerated electrons and holes is introduced, resulting in the suppression of the photoinduced charge recombination. This work provides insights into the specific role of the Lorentz force in suppressing the recombination of electron–hole pairs in their initial photogenerated states. This suppression would increase the population of charge carriers that would subsequently be transported in the semiconductor. It is believed that this strategy based on magnetic effects will initiate a new way of thinking about photoinduced charge separation.

Covalent organic frameworks (COFs) can exhibit high specific surface area and catalytic activity, but traditional solution-based synthesis methods often lead to insoluble and infusible powders or fragile films on solution surface. Herein we report large-area –C=N– linked two-dimensional (2D) COF films with controllable thicknesses via vapor induced conversion in a chemical vapor deposition (CVD) system. The assembly process is achieved by reversible Schiff base polycondensation between PyTTA film and TPA vapor, which results in a uniform organic framework film directly on growth substrate, and is driven by π‐π stacking interactions with the aid of water and acetic acid. Wafer-scale 2D COF films with different structures have been successfully synthesized by adjusting their building blocks, suggesting its generic applicability. The carrier mobility of PyTTA-TPA COF films can reach 1.89 × 10−3 cm2 V−1 s−1. When employed as catalysts in hydrogen evolution reaction (HER), they show high electrocatalytic activity compared with metal-free COFs or even some metallic catalysts. Our results represent a versatile route for the direct construction of large-area uniform 2D COF films on substrates towards multi-functional applications of 2D π‐conjugated systems.

The preparation of large‐area 2D conductive metal–organic framework (MOF) films remains highly desirable but challenging. Here, inspired by the capillary phenomenon, a face‐to‐face confinement growth method to grow conductive 2D Cu2(TCPP) (TCPP = meso‐tetra(4‐carboxyphenyl)porphine) MOF films on dielectric substrates is developed. Trace amounts of solutions containing low‐concentration Cu2+ and TCPP are pumped cyclically into a micropore interface to produce this growth. The crystal structures are confirmed with various characterization techniques, which include high‐resolution atomic force microscopy and cryogenic transmission electron microscopy (Cryo‐TEM). The Cu2(TCPP) MOF film exhibit an electrical conductivity of ≈0.007 S cm−1, which is approximately four orders of magnitude higher than other carboxylic‐acid‐based MOF materials (10−6 S cm−1). Other wafer‐scale conductive MOF films such as M3(HHTP)2 (M = Cu, Co, and Ni; HHTP = 2,3,6,7,10,11‐triphenylenehexol) can be produced utilizing this strategy and suggests this method has widescale applicability potential.

No abstract

By mimicking the layered structure of nacre, we successfully fabricated a nano-laminar coating on high-voltage insulators. The coating is demonstrated to achieve a higher flashover strength by effectively dissipating surface charge under dc stress.

Knowledge of latitudinal patterns in plant defense and herbivory is crucial for understanding the mechanisms that govern ecosystem functioning and for predicting their responses to climate change. Using a widely distributed species in East Asia, Quercus variabilis, we aim to reveal defense patterns of trees with respect to ontogeny along latitudinal gradients. Six leaf chemical (total phenolics and total condensed tannin concentrations) and physical (cellulose, hemicellulose, lignin and dry mass concentration) defensive traits as well as leaf herbivory (% leaf area loss) were investigated in natural Chinese cork oak (Q. variabilis) forests across two ontogenetic stages (juvenile and mature trees) along a ~14°-latitudinal gradient. Our results showed that juveniles had higher herbivory values and a higher concentration of leaf chemical defense substances compared with mature trees across the latitudinal gradient. In addition, chemical defense and herbivory in both ontogenetic stages decreased with increasing latitude, which supports the latitudinal herbivory-defense hypothesis and optimal defense theory. The identified trade-offs between chemical and physical defense were primarily determined by environmental variation associated with the latitudinal gradient, with the climatic factors (annual precipitation, minimum temperature of the coldest month) largely contributing to the latitudinal defense pattern in both juvenile and mature oak trees.

2D metal-organic framework (MOF) film as the active layer show promising application prospects in various fields including sensors, catalysis, and electronic devices. However, exploring the application of 2D MOF film in the field of artificial synapses has not been implemented yet. In this work, we fabricated a novel 2D MOF film (Cu-THPP, THPP = 5,10,15,20-Tetrakis(4-hydroxyphenyl)-21H,23H-porphine), and further used it as an active layer to explore the application in the simulation of human brain synapses. It shows excellent light-stimulated synaptic plasticity properties, and exhibits the foundation function of synapses such as longterm plasticity (LTP), short-term plasticity (STP), and the conversion of STP to LTP. Most critically, the MOF based artificial synaptic device exhibits an excellent stability in atmosphere. This work opens the door for the application of 2D MOF film in the simulation of human brain synapses.