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Electrochemical reduction of carbon dioxide (CO2) or carbon monoxide (CO) to valuable multi-carbon (C2+) products like acetate is a promising approach for a sustainable energy economy. However, it is still challenging to achieve high activity and selectivity for acetate production, especially in neutral electrolytes. Herein, a bioinspired hemin/Cu hybrid catalyst was developed to enhance the surface *CO coverage for highly efficient electroreduction of CO to acetate fuels. The hemin/Cu electrocatalyst exhibits a remarkable faradaic efficiency of 45.2% for CO-to-acetate electroreduction and a high acetate partial current density of 152.3 mA cm−2. Furthermore, the developed hybrid catalyst can operate stably at 200 mA cm−2 for 14.6 hours, producing concentrated acetate aqueous solutions (0.235 M, 2.1 wt%). The results of in situ Raman spectroscopy and theoretical calculations proved that the Fe–N4 structure of hemin could enhance the CO adsorption and enrich the local concentration of CO, thereby improving C–C coupling for acetate production. In addition, compared to the unmodified Cu catalysts, the Cu catalysts functionalized with cobalt phthalocyanine with a Co–N4 structure also exhibit improved acetate performance, proving the universality of this bioinspired molecule-enhanced strategy. This work paves a new way to designing bioinspired electrolysis systems for producing specific C2+ products from CO2 or CO electroreduction. [ABSTRACT FROM AUTHOR]

Chemical mechanism (CM)-related surface-enhanced Raman spectroscopy (SERS) has received tremendous interest due to its exceptional stability and excellent uniformity. Nevertheless, there remains a demand for ingenious methodologies for promoting effective charge transfer (CT) to improve SERS sensitivity further. Herein, a band structure engineered W18O49/g-C3N4 heterostructure (WCN) was first employed as a CM-based SERS substrate with remarkable enhancement and sensitivity. To investigate the Raman enhancement properties of the substrate, malachite green (MG) was employed as the Raman probe with the excitation of a 633 nm laser. The WCN substrate exhibits a Raman enhancement factor (EF) of 2.6 × 107, achieving a limit of detection (LOD) of 1.9 × 10−10 M for MG. The outstanding Raman amplification behavior can be attributed to the heterojunction-induced efficient CT process, energy band matching resonance due to minor doping with g-C3N4 serving as a band gap modifier, and improved photo-induced charge transfer (PICT) efficiency via the oxygen vacancies in the W18O49 units. Additionally, a flexible SERS substrate based on WCN was constructed using a vacuum filtration method and utilized to detect prohibited pharmaceutical residues on fish skin. The integration of this WCN and a nylon membrane not only preserves the Raman activity of the WCN for sensitive detection but also endows the Raman substrate with high flexibility and good mechanical durability, making it a potential candidate for in situ detection in particular environments. [ABSTRACT FROM AUTHOR]

High-performance SERS chips via self-assembled hollow Ag octahedra on PDMS were employed to achieve the sensitive identification and detection of antibiotic residues. The developed SERS chips were successfully applied in the detection of ciprofloxacin (CIP), amoxicillin (AMX) and cefazolin (CZL) in wastewater and tap water samples, as well as enrofloxacin (ENR) in milk, demonstrating the sensitive determination of antibiotics in the real environment. From this perspective, these SERS chips are expected to expand the on spot sensitive detection and identification field of antibiotic residues. [ABSTRACT FROM AUTHOR]

In2S3 has been regarded as a promising nontoxic alternative to CdS as an n-type electron transporting layer (ETL) for environmentally friendly antimony chalcogenide solar cells. However, the high-density of vacancy defects in In2S3 cause severe interfacial charge recombination in optoelectronic devices. To tackle this issue, herein we successfully incorporate a novel structurally two-dimensional wide-bandgap InOCl as an interfacial passivator between the In2S3 buffer layer and Sb2(S,Se)3 absorber through a simple InCl3 post-treatment strategy, which effectively improves the quality of the In2S3/Sb2(S,Se)3 heterointerface. Through careful experimental and computational studies, we believe that the wide bandgap InOCl passivator plays an important role in defect healing of In2S3 at the heterointerface by increasing the vacancy formation energy and thus reducing the density of defect states. Moreover, this interfacial layer contributes to the formation of a more favorable "spike"-like energy band alignment at the ETL/absorber interface and inhibits the transformation of In2S3 into In(OH)3 in moist air. As a result of significantly suppressed detrimental effects from interfacial recombination via positive defect healing, the In2S3/InOCl-based Sb2(S,Se)3 solar cell obtains a remarkable power conversion efficiency of 5.20%. To the best of our knowledge, this is the champion efficiency reported for In2S3-based antimony chalcogenide solar cells. [ABSTRACT FROM AUTHOR]

Design and fabrication of cost-effective (pre-)catalysts are important for water splitting and metal–air batteries. In this direction, various metal–organic frameworks (MOFs) have been investigated as pre-catalysts for oxygen evolution. However, the activation process and the complex reconstruction behaviour of these MOFs are not well understood. Herein, square-like MOF nanosheets in which carbon nanotubes were embedded were prepared by introducing an amine ligand to coordinate with Ni ions and then reacting with [Fe(CN)6]3−. The formed MOF nanosheets containing nickel and iron species were then activated by NaBH4, inducing the leaching of ligands and the formation of tiny active species in situ loaded on carbon nanotubes. The prepared catalyst shows superior oxygen evolution performance with an ultralow overpotential of 231 mV for 10 mA cm−2, a fast reaction kinetics with a small Tafel slope of 52.3 mV dec−1, and outstanding catalysis stability. The excellent electrocatalytic performance for oxygen evolution can be attributed to the structural advantage of in situ derived small sized active species and one-dimensional conductive networks. This work provides a new thought for the enhancement of the electrocatalytic performance of MOF materials. [ABSTRACT FROM AUTHOR]

As an essential smart material, stimuli-responsive chromic materials have received increasing research attention because of their visualization effects induced by external stimuli, including temperature, light, and mechanical stress. According to the types of stimuli, they can be categorized as thermochromic, photochromic, and mechanochromic materials, respectively. In recent studies, organic radical-based dynamic covalent chemistry (DCC) has demonstrated great potential to serve as a prototype for the preparation of stimuli-responsive chromic materials because the process is facilitated by simple radical–radical coupling reactions without the addition of catalysts or the generation of by-products and is usually accompanied by a distinct color change. This review aims to highlight carbon-centered radicals that can associate and dissociate reversibly with external stimuli and explore their potential as building blocks for the preparation of stimuli-responsive chromic materials. [ABSTRACT FROM AUTHOR]

Efficiently harvesting electroluminescent triplet excitons is of great importance for practical applications of organic light-emitting diodes (OLEDs). Hot exciton materials are regarded as the up-and-coming new generation luminogens and hold unique advantages for achieving high efficiency electroluminescent devices. Therefore, exploring a new molecular design strategy for developing new hot exciton materials remains a challenging yet fascinating task so far. In the current contribution, we present a novel design strategy for exploiting heterocycle aromaticity to fabricate new hot exciton materials from both theoretical and experimental perspectives. By virtue of heterocycle aromaticity and peripheral functionalization, molecular excited state energetics could be rationally modulated to achieve the desired energy gaps of singlet–triplet and triplet–triplet states and consequently facilitate a reverse intersystem crossing process from high-lying excited states and suppress possible energy loss pathways. On the strength of such a strategy, a series of new blue-emitting hot exciton materials based on non-aromatic pyrazoline derivatives was successfully fabricated and subsequently applied to OLED devices with EQEmax of 5.03%. These outcomes not only presented a series of new electroluminescent triplet-harvesting materials but also provided a practicable strategy for designing, screening and developing new generation luminogens for OLED applications. [ABSTRACT FROM AUTHOR]

An acid-driven separable nanodevice was designed for multilayer imaging of diverse biomarkers with different spatial distributions in living cells. The proposed nanodevice can simultaneously perform in situ imaging of the intracellular microRNAs and extracellular pH, affording a new approach to develop a precise imaging system for disease diagnosis. [ABSTRACT FROM AUTHOR]

Due to the ability to emit circularly polarised luminescence (CPL) for application in many areas, chiral luminescent materials have undergone rapid development in recent years. Herein, three chiral copper(I) chloro-bridged dimers R/S-(BINAP)2Cu(μ-X2) (X = Cl, Br and I) based on R/S-2,2′-bis(diphenylphosphino)-1,1′-binaphthalene (R/S-BINAP) ligands were synthesized conveniently at room temperature with high yields above 95%. Though emissions of the compounds in solution are weak, the dimers in the powder form and doped films displayed strong luminescence. Furthermore, the small singlet–triplet energy level gap and the calculated theoretical frontier molecular orbital distribution overlap suggested that these dimers have thermally activated delayed fluorescence characteristics. In addition, R/S-(BINAP)2Cu(μ-X2) doped films showed mirror symmetric circular dichroism and CPL spectra with a high dissymmetry factor (g) above 1 × 10−2. However, the corresponding circularly polarised organic light-emitting diodes (CP-OLEDs) fabricated by the evaporation method based on R/S-(BINAP)2Cu(μ-I2) exhibited a high maximum external quantum efficiency of 21.7%. Notably, the CP-OLEDs also displayed mirror imaged circularly polarised electroluminescence spectra with ‖gEL‖ factors of around 3.0 × 10−3. [ABSTRACT FROM AUTHOR]

Lead halide perovskite film exhibits excellent optoelectronic properties. The currently most common preparation method usually needs a conductive-annealing process, which inevitably leads to residual strain and defects, hindering the performance of the resulting perovskite solar cells (PSCs). In this work, we develop a residual strain regulation (RSR) strategy in which an appropriate amount of ligand-capped CsPbI3 quantum dot (QD) solution is used as the antisolvent during the preparation process of (CH(NH2)2)0.95Cs0.05PbI3 perovskite films. In this strategy, not only do the lattice-matching CsPbI3 QDs act as heterogeneous nucleation centers, but also the ligands attach to the perovskite film's surface, which significantly regulates the crystallization kinetics and releases the residual strain during the annealing process. The strategy successfully delivers multiple effects: an enlarged grain size, fewer defects, reduced nonradiative recombination and higher charge transfer efficiency. Therefore, the device shows a PCE of 23.32%, higher than that of a control device of 21.61%. First-principles calculations are performed to study the electronic structure of the perovskite films under strained conditions. We believe that this facile approach provides a novel strain engineering strategy for PSC technology. [ABSTRACT FROM AUTHOR]

The development of hydrogen–oxygen fuel cells with an alkaline electrolyte was highly limited by the sluggish kinetics of the hydrogen oxidation reaction (HOR). Here, with a pyrolysis-reduction route, a new RuNi-based electrocatalyst was prepared, which presents an ultrathin nanowire-like structure. In alkaline media, this catalyst shows an excellent catalytic performance with an exchange current density of 1.10 mA cm−2disk for hydrogen oxidation. The exchange current density and mass activity of this catalyst are much higher than those of its single-metal counterparts and even the commercial Pt/C catalyst containing 20% Pt. Such a remarkable catalytic activity can be explained by the interaction between Ru and Ni; the incorporation of Ni may induce an electronic effect on the optimization of the Ru–Had strength and provide a functional surface that can absorb OH species, thus boosting the catalytic activity. These findings may cast a new light on the exploration of low-cost but high-efficiency catalysts for fuel cells. [ABSTRACT FROM AUTHOR]

Although perovskite solar cells have been widely investigated to improve the photovoltaic conversion efficiency so far, perovskite light absorbers have a severe disadvantage for commercialization due to their facile degradation when exposed to humidity and oxygen. Herein, we suggest a synergic anti-solvent dripping strategy to improve the performance and stability of a photovoltaic device using a mixture of PMMA/sodium borate salt (borax) and perovskite materials. We characterized its unique features, i.e., the enhanced hydrogen bond formation between the PMMA/sodium borate mixture and the perovskite light absorber, which induced the lateral grain growth of perovskite films and efficient passivation of the surface and grain boundaries. Consequently, the PMMA/borax-treated devices exhibited significantly improved efficiency from 20.93% to 22.05% and retained 80% of the initial device performance over 1084 h at 22 °C and 50% RH. We believe that this technology will be useful for commercializing various optoelectronic devices. [ABSTRACT FROM AUTHOR]

Electrochemiluminescence (ECL) is produced by chemiluminescence reactions initiated by electrochemical methods. On this basis, ECL microscopy (ECLM) is an emerging visualization tool to directly study local electrochemical features with good spatial and temporal resolution. Recent progress in ECLM demonstrates that it is particularly important in single-cell studies on the morphological structures and functional characteristics of cells due to the unique heterogeneity of cells. Compared with other single-cell imaging methods, ECLM possesses advantages such as a low optical background, high sensitivity, simple instrumentation and surface-confined mode. In this mini-review, we discuss the recent development of single-cell ECLM and classify these works according to different ECL routes. Because ECL routes significantly influence the features of ECLM, such as the thickness of the emitting layer and the brightness of emitters, it is necessary to provide a new insight to revisit these works and discuss what ECL routes can be chosen to study single-cell processes from different perspectives. Considering the gradual growth in single-cell ECLM, we show the developmental trajectory and how these works connect with one another. In addition, the coexisting challenges as well as opportunities inspire us to design more ECLM methods to investigate local electrochemical phenomena. [ABSTRACT FROM AUTHOR]

Metal nanoclusters (MeNCs), composed of a few to hundreds of metal atoms and appropriate surface ligands, have attracted extensive interest in the electrochemiluminescence (ECL) realm owing to their molecule-like optical, electronic, and physicochemical attributes and are strongly anticipated for discrete energy levels, fascinating electrocatalytic activity, and good biocompatibility. Over the past decade, huge efforts have been devoted to the synthesis, properties, and application research of ECL-related MeNCs, and this field is still a subject of heightened concern. Therefore, this perspective aims to provide a comprehensive overview of the recent advances of MeNCs in the ECL domain, mainly covering the emerged ECL available MeNCs, unique chemical and optical properties, and the general ECL mechanisms. Synthesis strategies for desirable ECL performance are further highlighted, and the resulting ECL sensing applications utilizing MeNCs as luminophores, quenchers, and substrates are discussed systematically. Finally, we anticipate the future prospects and challenges in the development of this area. [ABSTRACT FROM AUTHOR]

The activation of thermodynamically stable and kinetically inert dinitrogen (N2) has been a great challenge due to the significant strength of the triple bond. Recently, in an experimental study on N2 activation by boron species, a highly reactive two-coordinated borylene broke through the limitations of traditional strategies of N2 activation by metal species. Still, studies on metal-free N2 activation remain underdeveloped. Here, we systematically investigate a frustrated Lewis pair (FLP) combining carbene and borenium (or borinium) cations to screen potential candidates for N2 activation via density functional theory calculations. As a result, we found that two FLPs (closed form FLP, borenium and open form FLP, borinium) are able to activate N2 in a thermodynamically and kinetically favorable manner, with a low energy barrier of 9.6 and 7.3 kcal mol−1, respectively. Furthermore, aromaticity was found to play an important role in the stabilization of the products, supported by nucleus-independent chemical shift (NICS), anisotropy of the current-induced density (ACID) and electron density of delocalized bonds (EDDB) analysis. Our findings provide an alternative approach for metal-free N2 activation, highlighting the importance of FLP chemistry and aromaticity in N2 activation. [ABSTRACT FROM AUTHOR]

We report a DNA origami cipher disk (DOCD) allowing random, continuous and reversible switchover between six visibly different patterns in response to the input DNA strands. A DOCD-enabled tandem-in-time cryptographic protocol was thereby established by using a string of DNA strands as a carrier for accurate information encoding and transmission. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid lead halide perovskite photodetectors have attracted worldwide attention in the field of optoelectronics. This study reports on a solution processable UV photodetector with a vertical-structure which contains a homogenous and dense layer of wide-bandgap methylammonium lead chlorine (CH3NH3PbCl3) semiconductor as a photon-response absorber. The resultant CH3NH3PbCl3-based UV photodetector achieves a fast response time of 7.76 μs and a high on/off ratio of over 5 × 103. In addition, the photodetector exhibits an impressive light detecting ability with a specific detectivity (D*) of 7.08 × 1011 Jones at an illumination intensity of 0.6 μW cm−2 at 375 nm. Moreover, CH3NH3PbCl3-based UV photodetectors without encapsulation show long-term stability (1200 h with 5% attenuation) under simulated operational conditions (25 °C, and 80% relative humidity in air). In addition, the CH3NH3PbCl3-based photodetectors are proven to adapt to flexible substrates such as polyethylene naphthalate. This work reveals great potential of photodetectors with wide bandgap perovskites in the applications of UV light detection. [ABSTRACT FROM AUTHOR]

Optimizing the composition, structure, and carrier of non-noble-metal-based metal–organic framework (MOF) materials effectively improves their electrocatalytic performance. Recently, CoNi bimetallic MOFs have attracted attention for hydrogen production in alkaline water electrolysis devices. Unfortunately, the most common studies have focused on the control of the morphology and structure of the MOF itself, while ignoring the effects of the synergy between the MOF and the carrier or other conductive agents. In this work, a multi-walled carbon nanotube-coupled CoNi MOF composite (CoNi MOFs-mCNTs) was synthesized via a solvothermal method using multi-walled carbon nanotubes (mCNTs) as a shape-directing agent and its application was explored for the oxygen evolution reaction (OER) in alkaline solution. The electrochemical test results demonstrate that, compared with commercial RuO2 (CM-RuO2) and a CoNi MOF without mCNTs, the CoNi MOFs-mCNTs with optimal mCNTs content show improved OER activity and durability. Physical characterization indicates that the structure and electronic properties of the CoNi MOFs-mCNTs are primarily influenced by the mCNTs, which conveys that CoNi MOFs-mCNTs with a high specific surface area exhibit improved OER activity in alkaline solution. [ABSTRACT FROM AUTHOR]

Introducing excellent capacitive materials and tailoring their combination modes with bacterial cells are promising steps to improve the integration degree and performance of supercapacitive paper-based microbial fuel cells (SC-PMFCs). Herein, through a layer-by-layer (LBL) strategy, in situ formed polypyrrole and bacterial cells were alternately constructed on carbon cloth for the anode of a SC-PMFC. The capacitive bioanode fabricated by three modifications of the polypyrrole/bacteria bilayer achieved the best performance due to the combined effects of bacterial loading amount, conductivity and metabolic activity loss during the whole LBL fabrication process. Benefiting from the functions of polypyrrole as both a capacitive material and a conductive intercalator between the bacterial layers, this bioanode exhibited improved electron transfer efficiency, enhanced power density and increased capacitance. Meanwhile, the polypyrrole layers in this capacitive bioanode can provide a protective effect to the bacterial layers, leading to superior performance-retention capacity during the storage period. This work creates an effective way to improve the integration level between MFC and supercapacitor technologies, which would push the development of SC-PMFCs and provide guidance to other biofuel cell-involved combination technologies. [ABSTRACT FROM AUTHOR]

All-inorganic tin halide perovskite compounds, such as CsSnI3, have attracted attention in the field of solar cells due to their eco-friendly properties. It is quite a challenge to fabricate high-quality CsSnI3 perovskite films with low defect density due to the low defect tolerance and overquick crystallization growth rate. Herein, we propose a simple yet effective method to modulate the dynamic balance between the growth and nucleation of perovskite crystals for black orthorhombic phase CsSnI3. We found that well-crystallized CsSnI3 thin films can be easily obtained through two-step thermal annealing at low temperatures of 40 °C and 70 °C. We further introduced 1-(4-carboxyphenyl)-2-thiourea to coordinate with surface undercoordinated Sn2+ cations of CsSnI3 thin films through C＝S and C＝O functional groups, significantly decreasing the defect density. The CsSnI3 perovskite solar cells based on a printable c-TiO2/m-TiO2/Al2O3/NiO/carbon mesoporous framework achieved a power conversion efficiency of 8.03% with high reproducibility, which is the best efficiency among those reported for all-inorganic CsSnI3 mesoporous perovskite solar cells to date. Furthermore, the corresponding devices retained 90% of the initial efficiency after 3000 hours of storage in a N2-filled glovebox. [ABSTRACT FROM AUTHOR]

Hydrazone compounds could be highly emissive in the solid state. However, most hydrazone-linking COFs are poorly luminescent. Here we report the enhancement of fluorescence in a 2D hydrazone-linking COF by side chain engineering. Stacking of the bulky and semi-rigid crown ether side chains restricts intramolecular rotation of the backbone around the hydrazone linkers, reducing the thermal dissipation and achieving 20-fold improved emission. [ABSTRACT FROM AUTHOR]

A fluorogenic RNA aptamer nanodevice integrating an entropy-driven RNA amplifier with near-infrared (NIR) light control was developed, affording high contrast and sensitivity for imaging low-abundance mRNA in living cells. The design principle offers a new approach for developing low-background imaging systems for live-cell studies and manipulation. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) capture has attracted considerable attention from both experimental and theoretical chemists. In comparison, carbon disulfide (CS2) activation is less developed. Here, we carry out a thorough comparative density functional theory study to examine the reaction mechanisms of CS2 activation by five-membered heterocycle-bridged P/N frustrated Lewis pairs (FLPs). Calculations suggest that despite a weaker carbon–sulfur bond, all the CS2 activations have higher reaction barriers than the CO2 capture, which could be attributed to electrostatic repulsion between FLPs and CS2 caused by the reversed polarity of C＝S in CS2 rather than the electrostatic attraction in CO2 capture. In addition, aromaticity is found to play an important role in CS2 capture as it stabilizes both the transition states and products in heterocycle-bridged FLPs. All these findings could be useful for experimentalists to realize small molecule activations by FLPs. [ABSTRACT FROM AUTHOR]