Advances of Electrochemical and Electrochemiluminescent Sensors Based on Covalent Organic Frameworks

Covalent organic frameworks(COFs),a rapidly developing category of crystalline conjugated organic polymers,possess highly ordered structures,large specific surface areas,stable chemical properties,and tunable pore microenvironments.Since the first report of boroxine/boronate ester-linked COFs in 2005,COFs have rapidly gained popularity,showing important application prospects in various fields,such as sensing,catalysis,separation,and energy storage.Among them,COFs-based electrochemical(EC)sensors with upgraded analytical performance are arousing extensive interest.In this review,therefore,we summarize the basic properties and the general synthesis methods of COFs used in the field of electroanalytical chemistry,with special emphasis on their usages in the fabrication of chemical sensors,ions sensors,immunosensors,and aptasensors.Notably,the emerged COFs in the electrochemiluminescence(ECL)realm are thoroughly covered along with their preliminary applications.Additionally,final conclusions on state-of-the-art COFs are provided in terms of EC and ECL sensors,as well as challenges and prospects for extending and improving the research and applications of COFs in electroanalytical chemistry.

The growth and expansive applications of amorphous Ga_(2)O_(3)

As a promising ultra-wide bandgap semiconductor material,gallium oxide(Ga_(2)O_(3))is attracting extensive attention of researchers due to its feasible growth process,appropriate bandgap of 4.4 e V-5.3 e V allowing for deep-ultraviolet(deepUV)detection,good physical and chemical stability,high breakdown field strength and electron mobility,etc.Different from the strict processes for controllable crystalline Ga_(2)O_(3)(usually refer to as stable monoclinicβ-Ga_(2)O_(3)),amorphous Ga_(2)O_(3)(a-Ga_(2)O_(3))film can be prepared uniformly at low temperature on a large-area deposition substrate,suggesting great advantages such as low manufacturing cost and excellent flexibility,dispensing with high-temperature and high vacuum techniques.Thus,a-Ga_(2)O_(3)extremely facilitates important applications in various applied fields.Therefore,in this concise review,we summarize several major deposition methods for a-Ga_(2)O_(3)films,of which the characteristics are discussed.Additionally,potential methods to optimize the film properties are proposed by right of the inspiration from some recent studies.Subsequently,the applications of a-Ga_(2)O_(3)thin films,e.g.,in photodetectors,resistive random access memories(RRAMs)and gas sensors,are represented with a fruitful discussion of their structures and operating mechanisms.

Nitrogen and fluorine co-doped graphene for ultra-stable lithium metal anodes

The heteroatom doping strategies have been utilized to effectively improve the performance of the carbon-based hosts,such as graphene,for lithium(Li)metal in high energy density lithium metal batteries.However,solely doped graphene hosts often need the assistance of other materials with either better lithiophilicity or electronic conductance to achieve smooth and efficient deposition of Li,which adds extra weight or volume.Herein,graphene co-doped by nitrogen and fluorine(NFG)is employed as a stable host for Li,where the N-doping provides lithiophilicity and electronic conductivity lacked by F-doping and the F-doping facilitates fast formation of solid electrolyte interphase(SEI)retarded by N-doping.The well regulation of Li plating/stripping and SEI formation is verified by quickly stabilized and small-magnitude voltage hysteresis,which stands out in Li hosts based on doped graphene and leads to excellent long-term cycling performance of NFG based electrodes.A voltage hysteresis of 20 mV is observed for more than 850 h in the symmetrical cell.The remarkable efficiency of lithium usage is confirmed by the highcapacity retention of a full cell paired with LiFePO_(4)(LFP),which exceeds 70%after 500 cycles.This work presents an innovative perspective on the control of Li plating/stripping by simultaneously introducing two kinds of dopants into graphene and paving the way for exploring practical Li metal batteries.

Enhancing lead-free photovoltaic performance:Minimizing buried surface voids in tin perovskite films through weakly polar solvent pre-treatment strategy

Buried interfacial voids have always been a notorious phenomenon observed in the fabrication of lead perovskite films. The existence of interfacial voids at the buried interface will capture the carrier, suppress carrier transport efficiencies, and affect the stability of photovoltaic devices. However, the impact of these buried interfacial voids on tin perovskites, a promising avenue for advancing lead-free photovoltaics, has been largely overlooked. Here, we utilize an innovative weakly polar solvent pretreatment strategy(WPSPS) to mitigate buried interfacial voids of tin perovskites. Our investigation reveals the presence of numerous voids in tin perovskites during annealing, attributed to trapped dimethyl sulfoxide(DMSO) used in film formation. The WPSPS method facilitates accelerated DMSO evaporation, effectively reducing residual DMSO. Interestingly, the WPSPS shifts the energy level of PEDOT:PSS downward, making it more aligned with the perovskite. This alignment enhances the efficiency of charge carrier transport. As the result, tin perovskite film quality is significantly improved,achieving a maximum power conversion efficiency approaching 12% with only an 8.3% efficiency loss after 1700 h of stability tests, which compares well with the state-of-the-art stability of tin-based perovskite solar cells.

Lithiophilic hyperbranched Cu nanostructure for stable Li metal anodes

Porous copper(Cu)current collectors are regarded as a promising host for stabilizing lithium(Li)metal anodes but suffer from uncontrollable Li metal deposition due to the intrinsic lithiophobic nature of Cu.This study proposes a vertically aligned Cu host with hyperbranched CuxO nanostructure to provide lithiophilic nucleation sites for homogeneous Li metal deposition.Specifically,the vertically aligned Cu nanostructure dramatically reduces the local current density and brings homogeneous Li‐ion flux.The lithiophilic hyperbranched CuxO nanostructure with a low nucleation barrier could induce homogeneous Li nucleation and growth.As a result,the Cu@CuxO nanostructured host exhibits a low nucleation overpotential of 44.3 mV and achieves highly electrochemical reversibility with high Coulombic efficiency of 98.33%in a half‐cell.The Cu@CuxO nanostructured electrode is capable of working under different current densities varying from 0.5 to 5 mA/cm2 in a symmetric cell.The assembled full cell coupling of the Li/Cu@CuxO composite anode with the LiFePO4 cathode manifests stable long‐term cycling life at 1 C.This study elaborates on the synergistic effect of electrode structure design and interfacial chemistry modification to regulate the Li deposition/dissolution behavior,thus exhibiting remarkable electrochemical performances for next‐generation Li‐metal batteries.

DNA origami-templated assembly of plasmonic nanostructures with enhanced Raman scattering

DNA origami have been established as versatile templates to fabricate plasmonic nanostructures in predefined shapes and multiple dimensions. Limited to the size of DNA origami, which are approximate to 100 nm, it is hard to assemble more intricate plasmonic nanostructures in large scale. Herein, we used rectangular DNA origami as the template to anchor two 30-nm gold nanoparticles(Au NPs) which induced dimers nanostructures. Transmission electron microscopy(TEM) images showed the assembly of Au NPs with high yields. Using the linkers to organize the DNA origami templates into nanoribbons,chains of Au NPs were obtained, which was validated bythe TEM images. Furthermore, we observed a significant Raman signal enhancement from molecules covalently attached to the Au NP-dimers and Au NP-chains. Our method opens up the prospects of high-ordered plasmonic nanostructures with tailored optical properties.

Suppression of deep‑level traps via semicarbazide hydrochloride additives for high‑performance tin‑based perovskite solar cells

Tin perovskites with exemplary optoelectronic properties ofer potential application in lead-free perovskite solar cells.However,Sn vacancies and undercoordinated Sn ions on the tin perovskite surfaces can create deep-level traps,leading to nonradiative recombination and absorption of nucleophilic O_(2)molecules,impeding further device efciency and stability.Here,in this study,a new additive of semicarbazide hydrochloride(SEM-HCl)with a N–C=O functional group was introduced into the perovskite precursor to fabricate high-quality flms with a low concentration of deep-level trap densities.This,in turn,serves to prevent undesirable interaction between photogenerated carriers and adsorbed oxygen molecules in the device’s operational environment,ultimately reducing the proliferation of superoxide entities.As the result,the SEM-HCl-derived devices show a peak efciency of 10.9%with improved device stability.These unencapsulated devices maintain almost 100%of their initial efciencies after working for 100 h under continuous AM1.5 illumination conditions.

Polarization-dispersive imaging spectrometer for scattering circular dichroism spectroscopy of single chiral nanostructures

Circular dichroism spectroscopy is one of the most important tools in nanoscopic chiroptics.However,there is lack of simple,fast and reliable method for measuring the circular dichroism responses of single nanostructures.To tackle this issue,we report a polarization-dispersive imaging spectrometer which is capable of measuring the scattering circular dichroism response of a single chiral nanostructure with a single shot.Using this technique,we studied the scattering circular dichroism spectra of a model system,the vertically coupled plasmonic nanorod pair.Both experimental and theoretical results indicate that the polarization-dispersive spectrometer measures the imaginary part of nonlocal susceptibility of the structure.We further applied the technique to 3-dimensional Au nanorod structures assembled on DNA origami templates together with correlated scanning electron microscopic measurements.Rich chiroptical phenomena were unveiled at the single nanostructure level.

Inkjet printed large-area flexible circuits:a simple methodology for optimizing the printing quality

In this work, a simple methodology was developed to enhance the patterning resolution of inkjet printing, involving process optimization as well as substrate modification and treatment. The line width of the inkjetprinted silver lines was successfully reduced to 1/3 of the original value using this methodology. Large-area flexible circuits with delicate patterns and good morphology were thus fabricated. The resultant flexible circuits showed excellent electrical conductivity as low as 4.5 Ω/□ and strong tolerance to mechanical bending. The simple methodology is also applicable to substrates with various wettability, which suggests a general strategy to enhance the printing quality of inkjet printing for manufacturing high-performance large-area flexible electronics.

Single-Step Organization of Plasmonic Gold Metamaterials with Self-Assembled DNA Nanostructures

Self-assembled DNA nanostructures hold great promise as nanoscale templates for organizing nanoparticles(NPs)with nearatomistic resolution.However,large-scale organization of NPs with high yield is highly desirable for nanoelectronics and nanophotonic applications.Here,we design fve-strand DNA tiles that can readily self-assemble into well-organized micrometerscale DNA nanostructures.By organizing gold nanoparticles(AuNPs)on these self-assembled DNA nanostructures,we realize the fabrication of one-and two-dimensional Au nanostructures in single steps.We further demonstrate the one-pot synthesis of Au metamaterials for highly amplifed surface-enhanced Raman Scattering(SERS).Tis single-step and high-yield strategy thus holds great potential for fabricating plasmonic metamaterials.

The Strategies of Pathogen-Oriented Therapy on Circumventing Antimicrobial Resistance

The emerging antimicrobial resistance(AMR)poses serious threats to the global public health.Conventional antibiotics have been eclipsed in combating with drug-resistant bacteria.Moreover,the developing and deploying of novel antimicrobial drugs have trudged,as few new antibiotics are being developed over time and even fewer of them can hit the market.Alternative therapeutic strategies to resolve the AMR crisis are urgently required.Pathogen-oriented therapy(POT)springs up as a promising approach in circumventing antibiotic resistance.The tactic underling POT is applying antibacterial compounds or materials directly to infected regions to treat specific bacteria species or strains with goals of improving the drug efficacy and reducing nontargeting and the development of drug resistance.This review exemplifies recent trends in the development of POTs for circumventing AMR,including the adoption of antibiotic-antibiotic conjugates,antimicrobial peptides,therapeutic monoclonal antibodies,nanotechnologies,CRISPR-Cas systems,and microbiota modulations.Employing these alternative approaches alone or in combination shows promising advantages for addressing the growing clinical embarrassment of antibiotics in fighting drug-resistant bacteria.

Paper-based all-solid-state flexible asymmetric micro-supercapacitors fabricated by a simple pencil drawing methodology

Flexible micro-scale energy storage devices as the key component to power the flexible miniaturized electronic devices are attracting extensive attention. In this study, interdigitated asymmetric all-solidstate flexible micro-supercapacitors（MSCs） were fabricated by a simple pencil drawing process followed by electrodepositing MnO_2 on one of the as-drawn graphite electrode as anode and the other as cathode.The as-prepared electrodes showed high areal specific capacitance of 220 μF/cm^2 at 2.5 μA/cm^2. The energy density and the corresponding power density of the resultant asymmetrical flexible MSCs were up to 110 μWh/cm^2 and 1.2 μW/cm^2, respectively. Furthermore, excellent cycling performance（91% retention of capacity after 1000 cycles） was achieved. The resultant devices also exhibited good electrochemical stability under bending conditions, demonstrating superior flexibility. This study provides a simple yet efficient methodology for designing and fabricating flexible supercapacitors applicable for portable and wearable electronics.

DNA Nanotechnology-based Biocomputing

With silicon-based microelectronic technology pushed to its limit,scientists hunt to exploit biomolecules to power the bio-computer as substitutes.As a typical biomolecule,DNA now has been employed as a tool to create computing systems because of its superior parallel computing ability and outstanding data storage capability.However,the key challenges in this area lie in the human intervention during the computation process and the lack of platforms for central processor.DNA nanotechnology has created hundreds of complex and hierarchical DNA nanostructures with highly controllable motions by exploiting the unparalleled self-recognition properties of DNA molecule.These DNA nanostructures can provide platforms for central processor and reduce the human intervention during the computation process,which can offer unprecedented opportunities for biocomputing.In this review,recent advances in DNA nanotechnology are briefly summarized and the newly emerging concept of biocomputing with DNA nanostructures is introduced.