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The excitation of surface plasmons in metallic nanostructures provides an opportunity to localize light at the nanoscale, well below the scale of the wavelength of the light. The high local electromagnetic field intensities generated in the vicinity of the nanostructures through this nanofocusing effect are exploited in surface enhanced Raman spectroscopy (SERS). At narrow interparticle gaps, so-called hot-spots, the nanofocusing effect is particularly pronounced. Hence, the engineering of substrates with a consistently high density of hot-spots is a major challenge in the field of SERS. Here, a simple bottom-up approach is described for the fabrication of highly SERS-active gold core-satellite nanostructures, using electrostatic and DNA-directed self-assembly. It is demonstrated that well-defined core-satellite gold nanostructures can be fabricated without the need for expensive direct-write nanolithography tools such as electron-beam lithography (EBL). Self-assembly also provides excellent control over particle distances on the nanoscale. The as-fabricated core-satellite nanostructures exhibit SERS activities that are superior to commercial SERS substrates in signal intensity and reproducibility. This also highlights the potential of bottom-up self-assembly strategies for the fabrication of complex, well-defined functional nanostructures with future applications well beyond the field of sensing. [ABSTRACT FROM AUTHOR]

Preparation of shape-controlled metastable γ-MnS semiconductor nanocrystals has been achieved on a large scale through a simple solvothermal method in the presence of PVP. The key strategy is the use of sulfur powder as sulfur source in ethylene glycol (EG) solvent that also acted as a weak reducing agent. Reaction parameters such as reaction time and temperature are found to be important in controlling various hierarchical architectures, such as homogeneous semi-hollow core−shell, hollow nanospheres, and nanowires. Transmission electron microscopy observations indicate that these hierarchical architectures are formed mainly via Ostwald ripening. The optical absorption measurements reveal that these novel architectures exhibit remarkable shift of absorption peak during the course of structural compaction and grain growth. [ABSTRACT FROM AUTHOR]

Abstract: Pure α-MnO2 nanofibers with multiple branches were prepared through a simple refluxing method in the absence of catalysts or surfactants as templates. The synthetic procedure was based on the use of to oxidize under a weak acidic condition. A two-step epitaxial coalescence for the formation of this complex architecture was revealed by transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). First of all, the small nanofibers coalesced together through the (110) plane to form larger monocrystalline nanofibers, which then attached one by one through two of (110) and {211} planes, resulting in the final multiple branched architectures. [Copyright &y& Elsevier]

Abstract: The synthesis and shape evolution of α-Fe2O3 nanoparticles through oriented aggregation in solvothermal system were investigated. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) revealed that the three-dimensional (3D) flower-like α-Fe2O3 nanophase was formed by two-step crystallographically oriented aggregations, and then evolved to polyhedral nanoparticles by conventional Ostwald ripening. The organic solvent N, N-dimethylformamide (DMF) played an important role not only in chemical reaction, but also in oriented aggregation-based self-assembly. [Copyright &y& Elsevier]

Highlights: [•] Porous ZnO/Sn1−x Zn x O2−x nanocatalysts with high photocatalytic activity were synthesized by a two-step solvothermal method. [•] Zn doping in SnO2 shows an influence on particle size, specific surface area and band gap. [•] The formation of ZnO/Sn1−x Zn x O2−x heterostructure improves the separation of photogenerated electron–hole pairs. [•] The synergistic effects of metal ion doping and semiconductor/semiconductor heterostructure are reported. [ABSTRACT FROM AUTHOR]

During the past years, charge transport performance of solution-processed donor-acceptor (D-A) conjugated polymers has been explosively studied for successful instance of record-breaking carrier mobility. By contrast, corresponding spin dynamics was far-less probed except handful pioneering reports. Herein, we successfully observed room-temperature stable magnetoresistance (MR) response in organic spin valves using ambipolar naphthalenediimide-based D-A type conjugated polymers. Additionally, we found spin transport performance of these polymer-inserted junction was sensitive to chemical structures of polymer repeating units. Both alkyl-chain extension in the acceptor unit and cyano-group substitution in the donor unit can induce evident MR drop. Furthermore, we discovered spin dynamics inside these ambipolar materials exhibited disparate electrical dependence from classical unipolar small-molecule medium. Neither increased bias current size nor reversed polarity can downsize junction MR response in the spin valves based on these conjugated polymers hence verified underlying great potential of ambipolar media in spintronics devices. We would like to emphasize that no spinterface effect happened even when these solution-processed polymers contacted directly with ferromagnetic electrodes according to comprehensive magnetization study. This spin-related exploration opened a new avenue to understand spintronics from material level, and also unveiled inspiring potential of solution-processed D-A type conjugated polymers on future spin-memory devices. Image 1039672 • Organic spin valves using ambipolar naphthalenediimide-based conjugated polymers were fabricated. • Room-temperature stable magnetoresistance response was successfully observed. • The magnetoresistance data were sensitive to chemical structures of the conjugated polymer. [ABSTRACT FROM AUTHOR]

It is difficult to show microbial growth kinetics online when they grow in complex matrices. We presented a novel strategy to address this challenge by developing a high-performance microbial growth analyzer (HPMGA), which employed a unique 32-channel capacitively coupled contactless conductivity detector as a sensing element and fixed with a CellStatz software. It was capable of online showing accurate and repeatable growth curves of well-dispersed and bad-dispersed microbes, whether they grew in homogeneous simple culture broth or heterogeneous complex matrices. Moreover, it could automatically report key growth kinetics parameters. In comparison to optical density (OD), plate counting and broth microdilution (BMD) methods, we demonstrated its practicability in five scenarios: 1) the illustration of the growth, growth rate, and acceleration curves of Escherichia coli (E. coli); 2) the antimicrobial susceptibility testing (AST) of Oxacillin against Staphylococcus aureus (S. aureus); 3) the determination of Ag nanoparticle toxicity on Providencia rettgeri (P. rettgeri); 4) the characterization of milk fermentation; and 5) the enumeration of viable pathogenic Vibrio in shrimp body. Results highlighted that the HPMGA method had the advantages of universality and effectivity. This technology would significantly facilitate the routine analysis of microbial growth in many fields (biology, medicine, clinic, life, food, environment, and ecology), paving an avenue for microbiologists to achieve research goals that have been inhibited for years due to a lack of practical analytical methods. Based on a unique 32-channel capacitively coupled contactless conductivity detector and novel algorithms, the high-performance microbial growth analyzer (HPMGA) was capable of online showing the growth curves of well-dispersed and bad-dispersed microorganisms (e.g. E. coli , S. aureus , L. bulgaricus , P. rettgeri , and pathogenic Vibrio (flora)), whether they grew in homogeneous simple culture broth or heterogeneous complex matrices (e.g. blood, sewage sludge, milk, and shrimp bodies). Moreover, it could decompose the growth curves into growth rate and growth acceleration curves, and report key growth kinetics parameters. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A sufficient and tunable ohmic junction can be built in allochroic Pt/CN. • The ohmic contact is formed by the photoconversion of semiconducting CN to metalloid. • The reversible photoconversion of CN is accompanied with a color change. • The ohmic contact between Pt and CN significantly enhances the HER activity. • The deactivation and regeneration mechanisms of the allochroic Pt/CN are proposed. The direct hybridization of Pt and g-C 3 N 4 generally forms a Schottky barrier between the two components, which unavoidably hinders the migration of photogenerated electrons from g-C 3 N 4 to the Pt cocatalyst. Herein, we report the first efficient allochroic Pt/g-C 3 N 4 photocatalyst that can form an ohmic contact through photoconversion of semiconducting g-C 3 N 4 to metalloid, accompanied with the charge carrier storage and photocatalyst color change, which is proved experimentally and theoretically. Through intermittent exposure of Pt/g-C 3 N 4 photocatalyst to air for a few minutes during photocatalysis, the photocatalyst shows the highest hydrogen evolution performances. The ohmic contacts greatly promote the electron transfer from the semiconducting g-C 3 N 4 to the Pt cocatalyst driven by the built-in electric field. In addition, the mechanism for the photocatalyst deactivation and activation is presented. The compositional tuning of the allochroic g-C 3 N 4 through light irradiation and exposure to air can control over the photocatalytic activity and long-term stability for hydrogen evolution. This report for the first time unveils the deactivation and regeneration mechanisms of SCN. [ABSTRACT FROM AUTHOR]

Room temperature phosphorescence (RTP) materials have motivated massive attention due to their great advantages in anti-counterfeiting and optical encryption. However, the commonly used carbon-based RTP materials suffer from drawbacks of photobleaching, quenching and single phosphorescence color outputs, which obstruct their performance in high-level anti-counterfeiting techniques. Herein, we present a universal method for the fabrication of a carbon-dot@silica (CDs@SiO 2) composite that possesses ultralong lifetime, high phosphorescence quantum efficiency (PQE), excellent luminescence stability, and dual-color phosphorescence emission. Taking advantage of the restriction by rigid network of SiO 2 and stable covalent bonding between CDs and SiO 2 , the triplet excited states of CDs are stabilized. As a result, the CDs@SiO 2 exhibit ultralong lifetime of 1.33 s and 0.38 s under excitation at 254 nm and 365 nm, respectively. Furthermore, the phosphorescence color of CDs@SiO 2 can change from cyan to yellow when the exciting wavelength switches from 254 nm to 365 nm. The obtained CDs@SiO 2 also exhibit outstanding characteristics of anti-photobleaching and phosphorescence stability in an aqueous solution. Based on the unique phosphorescent properties of the CDs@SiO 2 , a stable and dual-color phosphorescence security label is designed for advanced information encryption. [Display omitted] • The CDs@SiO 2 powder possesses dual-color phosphorescence emission under different excitation. • The CDs@SiO 2 powder exhibits exceptionally long RTP lifetimes of 1.33 s and 0.38 s under 254 and 365 nm excitation, respectively. • These CDs@SiO 2 -based security labels show excitation-wavelength-dependent phosphorescence emissions, fantastic anti-photobleaching, and brilliant anti-quenching properties. [ABSTRACT FROM AUTHOR]

The practical applications of lithium sulfur batteries have been greatly restricted by the polysulfide shuttle effect and non-conductivity of sulfur. Here, we report a nickel-catalyzed carbonization method to synthesize three-dimensional (3D) nickel@N-doped carbon-nanotube (CNT) foams for lithium-sulfur batteries. The corresponding carbon/sulfur cathode with a high sulfur loading of 3.71 mg cm−2 possesses a high initial capacity of 855.6 mAh g−1 at 135 mA g−1 and good cyclic stability with a low fading rate of 0.153% per cycle for 100 cycles at 270 mA g−1. The growth of carbon thin layers on the nickel nanoparticles results in the encapsulation of the nanoparticles in the CNTs, which makes the carbon forms highly conductive and prevents the metal nanoparticles from being oxidized by polysulfides. The high conductivity is favorable for the electron transfer between polysulfides and carbon electrode. Moreover, the doped nitrogen atoms on the CNTs have strong chemical adsorption ability for polysulfides, accelerating redox reaction of polysulfides on the carbon electrode (i.e., suppressing the shuttle effect). These unique structural characteristics well explain the excellent electrochemical performance of the assembled batteries. It is believed that the fabricated carbon foam is a promising material for high sulfur-loading lithium-sulfur battery. [Display omitted] • Encapsulates carbon-coated Ni metal nanoparticles in N-doped carbon nanotube. • 3D highly conductive network and strongly chemisorptionto polysulfides. • Stable cycle performance of lithium-sulfur battery under high sulfur loading. [ABSTRACT FROM AUTHOR]

Perovskite quantum dots are considered an ideal alternative to traditional phosphor color converters because of their excellent optical properties. However, the bottleneck problem of instability has tremendously limited their practical applications. In the present work, we fabricate green-emitting CsPbBr 3 @glass and red-emitting CsPbBr 1.5 I 1.5 @glass nanocomposites via an in-situ nucleation/growth method. Importantly, the CsPbX 3 @glass (X 3 = Br 3 , Br 1.5 I 1.5) samples exhibit striking thermal reversibility in the heating/cooling cycle experiments. Furthermore, CsPbX 3 monolithic films with high photoluminescence quantum yields (PLQYs) of 80–95% and narrow full-width at half-maximum (FWHM) down to 16 nm are achieved by dispersing ground CsPbX 3 @glass particles in polydimethylsiloxane (PDMS) matrix. Benefiting from dual encapsulation of inorganic glass matrix and organic polymer matrix, the film can endure harsh accelerated aging tests (at 85 °C/85%RH for 500 h). Finally, combining the as-prepared yellow monolithic film with blue chips as the backlight endows the liquid crystal display (LCD) with a wide color gamut (a color gamut of 146% of commercial LCD, 101% of NTSC after passing the color filters), demonstrating great prospects in the display industry. • CsPbX 3 (X 3 = Br 3 , Br 1.5 I 1.5) QDs were in-situ precipitated inside glass matrix via controlling nucleation/growth process. • CsPbX 3 monolithic films exhibited high PLQY of 80–95% and FWHM down to 16 nm. • The CsPbX 3 @glass@PDMS composite films possessed extremely excellent moisture and heat resistance. • A white LED backlit unit was simply achieved by coupling a yellow composite film with blue chips. • The color gamut of screen reached 101% NTSC 1953 standard and 146% commercial LCD after passing the color filters. [ABSTRACT FROM AUTHOR]

Abstract: Water–gas shift reaction was carried out over a series of CuO/CeO2 catalysts doped with trivalent rare earth oxide (RE2O3, RE=Y, La, Nd and Sm), prepared via co-precipitation method. The effect of the dopants on the structure and catalytic properties of CuO/CeO2 catalysts was investigated with the aid of X-ray diffraction (XRD), Raman spectra, N2 physisorption, H2-TPR and selective N2O chemisorption characterizations. The results reveal the beneficial role of La2O3 and Nd2O3 doping in increasing the WGS catalytic activities and stabilities of CuO/CeO2 catalysts, while the addition of Y2O3 and Sm2O3 leads to the negative effect. Correlating to the characteristic results, it is found that the performance of CuO/CeO2–RE2O3 catalysts strongly depends on their surface copper dispersion, microstrain value and the amount of oxygen vacancies generated in ceria lattice. Besides, enough evidences suggest that, the most effective active site for WGS reaction is the moderate copper oxide (crystalline) interacted with surface oxygen vacancies of ceria in the CuO–CeO2 system. [Copyright &y& Elsevier]

Abstract: Er3+ doped SrF2–SiO2 transparent glass ceramics were prepared by sol–gel method and heat treatment. The decomposition of Sr2+–CF3COO− and the formation of SrF2 nano-crystals were found to proceed synchronously in the xerogel. After crystallization of the xerogel, SrF2 nano-crystals with 8–10nm in size distributed homogenously among the glassy matrix, and the microstructure of the glass ceramic was stable under and at the temperature of 800°C probably due to interfacial interaction between nano-crystals and glassy matrix. When heat-treated at 800°C, the chemically bonded water in the sample was eliminated, resulting in the appearance of the visible luminescence bands of 2H11/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions. [Copyright &y& Elsevier]

Abstract: NdF3 nanoparticles were formed in neutral solution by hydrothermal process, which self-assembled into plate-built chains through oriented aggregations at the absence of any organic additive. The self-assembly consisted of two steps: firstly, nanoparticles sequentially aggregated together by coalescence mainly through (100) and (010) planes to form larger mono-crystalline plates, followed by Ostwald ripening to smooth their surfaces; secondly, the surface-smoothened plates stacked face to face with each other along (001) direction to construct the long chains. The oriented aggregation of nanocrystals in large scale proceeding in the absence of any organic component provides an attractive approach for fabricating novel architectures. [Copyright &y& Elsevier]

[Display omitted] • A strategy to fabricate conductive SiO 2 @Ga core–shell microparticles is developed. • Maximizing catalytically active surface gallium for electrocatalysis of Li 2 S x. • The addition of microparticles promote the ion transfer kinetics of the electrodes. • A mechanism of conductive electron-given-surface and fast Li+ transport is proposed. • Li-S batteries with high sulfur loading and high specific capacity are achieved. A novel silica@gallium core–shell structure is designed to maximize catalytically active surface gallium for highly efficient electrocatalysis of lithium polysulfides in lithium-sulfur batteries. The fabricated SiO 2 @Ga/S cathode battery exhibits a high reversible capacity of 927.1 mAh g−1 at 0.75C and excellent cycling stability with a capacity retention rate of 85.97% for 600 cycles. When the sulfur mass loading is up to 6.5 mg cm−2, the battery displays a high discharge capacity of ~ 4.145 mAh cm−2 with high Coulombic efficiency of 85.04% after 200 cycles. Finally, a mechanism that the highly conductive electron-given-surface of liquid metal Ga shell on the surface of SiO 2 in the thick electrodes for reversible electrocatalysis of lithium polysulfides in lithium-sulfur batteries is proposed. [ABSTRACT FROM AUTHOR]

The lack of analytical strategies to directly determine the bacteriostatic activity of nanomaterials in complex aqueous media (e.g., environmentally relevant scenarios) seriously hampers the harvest of reliable data for nanomaterial risk assessment. Here, we created an automated phenotypic method based on a developed multi-channel contactless conductometric sensor. Bacterial growth kinetics of E. coli and S. aureus were determined via on-line monitoring of conductivity changes in simple media (e.g., liquid LB broth) and complex media (e.g., relevant river water and seawater samples with diverse pH, salinity, conductivity, turbidity, chemical oxygen demand and total suspended solids). The high temporal resolution growth curves provide detailed information on the bacteria inhibition of the model nanomaterial - Au nanospheres, Au nanorods, Ag nanospheres and Ag nanocubes - at each growth stage, thus enabling users to directly obtain minimum inhibitory concentrations. The method highlights the advantages of universality, simplicity and affordability. It opens up possibilities for the development of a powerful analytical platform for researches in the field of nanoscience, e.g. to assess ecotoxicity of nanomaterials. [Display omitted] ● The developed multi-channel contactless conductometric sensor has wide working window. ● High temporal resolution growth curves of E. coli and S. aureus are generated with the contactless conductometric sensor. ● Growth curves provide detailed information on the bacteria inhibition of diverse nanomaterials. ● Automated determination of accurate bacteriostatic activity is realized in both simple and complex aqueous media. [ABSTRACT FROM AUTHOR]

• A new method to fabricate 3D porous sulfur/gallium hybrid materials is developed. • The 3D porous sulfur/gallium hybrid materials increase the electrical and ion conductivity of the cathode. • The 3D porous sulfur/gallium hybrid materials promote the activation of the electrodes. • The surface of liquid metal Ga promote the redox reaction of lithium polysulfides due to its strong electrocatalytic effect. • Li-S batteries with high sulfur loading, long cycling and high specific capacity are achieved. Lithium–sulfur battery has long been considered as the best choice for the next generation secondary battery. However, the intrinsic insulativity of sulfur and the polysulfide shuttle effect have been the key problems that hinder the commercialization of lithium sulfur batteries. Here, using a facile shearing implement assists thermal synthesis process, in which liquid metal gallium and sulfur (mass ratio1:10) are the only reactants, we create a 3D porous sulfur/gallium hybrid materials (S/Ga). Micro/nanometer liquid metal gallium particles embed in the porous sulfur. The S/Ga cathode lithium cell exhibits a high Coulombic efficiencies of 98.7%, and high specific capacities of 1044 mAh g−1 after 100 cycles at 1.0 mA cm−2, and good cyclic stability. During first cycle discharge process of the S/Ga cathode, the sulfur reduces to Li 2 S 8 and dissolves in the electrolyte, then the liquid metal Ga has an intimate electrical contact with conductive carbon substrates. Electrons are easily transferred to high conductive liquid metal Ga. Due to the electron abundance on Ga surface, it shows an electrocatalytic effect for the conversion of soluble lithium polysulfides (Li 2 S 4-8) to Li 2 S 2 /Li 2 S, thus improving S utilization and cyclic stability. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• The S + K-codoped g-C 3 N 4 presents excellent H 2 production (8.78 mmol g−1 h−1) under visible light. • The S + K-codoped g-C 3 N 4 inhibits the recombination of photogenerated carriers. • The S + K-codoped g-C 3 N 4 photocatalyst shows apparent quantum efficiency of 70 % at 420 nm for H 2 production. Modifying the structure of a photocatalyst to tailor its electronic and physicochemical properties is an effective approach for efficient photocatalysis. Herein, we demonstrate that co-doping non-metal (S) and metal (K) atoms into graphitic carbon nitride (g-C 3 N 4) provides excellent visible-light photocatalytic hydrogen production activity of 8.78 mmol g−1 h−1, which is 98 times higher than that of pristine g-C 3 N 4 (0.09 mmol g−1 h−1). The apparent quantum efficiency of the S+K-co-doped g-C 3 N 4 reaches 70 % at 420 nm. This outstanding photocatalytic performance attributed to an increased specific surface area from 6.78 to 74.23 cm3 g−1, which reduced the recombination of photogenerated charge carriers and enhanced conductivity. Various characterizations are undertaken to elucidate the S+K-co-doped g-C 3 N 4 photocatalytic mechanism. Our work not only demonstrates a facile, eco-friendly and scalable strategy for the synthesis of S+K-co-doped g-C 3 N 4 photocatalysts, but also opens a new avenue for the design of co-doped photocatalysts. [ABSTRACT FROM AUTHOR]

A double-side solar H 2 evolution nanopaper has been fabricated by electrostatic self-assembly assisted vacuum filtration method. The nanopaper is found to be highly porous, crystalline, flexible and chemical stable. It shows excellent mechanical property with tensile strength of 18.5 MPa and Young's modulus of 414 MPa, a high hydrogen evolution rate of 3.9 mmol g−1 h−1 (i.e. 6.5 μmol cm-2 h−1), and remarkable long-term photostability. • A g-C 3 N 4 /nanocellulose nanopaper that is highly porous, crystalline, flexible and chemically stable has been fabricated. • The hybrid nanopaper has an excellent mechanical property and hydrogen production activity. • The hybrid nanopaper is able to produce H 2 from both sides. • This work leads the way to a plethora of free-standing nanopapers. Carbon nitride, regarded as a promising, environmentally friendly and sustainable photocatalyst for solar hydrogen generation, has shown a gradual improvement of photocatalytic activity with an apparent quantum yield up to 60%. However, it is still challenging to achieve flexible, efficient and scalable carbon nitride solar hydrogen evolution devices, limiting its practical application. Herein we report a visible-light-driven double-side hydrogen evolution nanopaper that is highly porous, crystalline and chemically stable. The nanopaper was fabricated via vacuum filtration of electrostatically self-assembled carbon nitride and nanocellulose. This nanopaper shows excellent mechanical properties with tensile strength of 18.5 MPa and Young's modulus of 414 MPa, a high hydrogen evolution rate of 3.9 mmol g−1 h−1 (corresponding to 6.5 μmol cm−2 h−1), and remarkable photostability over 32-h photocatalytic tests. [ABSTRACT FROM AUTHOR]

Halogenated methane serves as a universal platform molecule for building high-value chemicals. Utilizing sodium chloride solution for photocatalytic methane chlorination presents an environmentally friendly method for methane conversion. However, competing reactions in gas-solid-liquid systems leads to low efficiency and selectivity in photocatalytic methane chlorination. Here, an in situ method is employed to fabricate a hydrophobic layer of TaO x species on the surface of NaTaO 3 . Through in-situ XPS and XANES spectra analysis, it is determined that TaO x is a coordination unsaturated species. The TaO x species transforms the surface properties from the inherent hydrophilicity of NaTaO 3 to the hydrophobicity of TaO x /NaTaO 3 , which enhances the accessibility of CH 4 for adsorption and activation, and thus promotes the methane chlorination reaction within the gas-liquid-solid three-phase system. The optimized TaO x /NaTaO 3 photocatalyst has a good durability for multiple cycles of methane chlorination reactions, yielding CH 3 Cl at a rate of 233 µmol g -1 h -1 with a selectivity of 83%. In contrast, pure NaTaO 3 exhibits almost no activity toward CH 3 Cl formation, instead catalyzing the over-oxidation of CH 4 into CO 2 . Notably, the activity of the optimized TaO x /NaTaO 3 photocatalyst surpasses that of reported noble metal photocatalysts. This research offers an effective strategy for enhancing the selectivity of photocatalytic methane chlorination using inorganic chlorine ions., (© 2024 Wiley‐VCH GmbH.)

Lead-free double perovskites (DPs) are emerging highly stable emitters with efficient broadband self-trapped exciton (STE) photoluminescence (PL), but their low electroluminescent (EL) efficiency is a critical shortcoming. This work promotes the external quantum efficiency (EQE) and luminance of DP-based white light-emitting diode (wLED) with a normal device structure to 0.76% and 2793 cd m -2 via two modifications: This work prevents the formation of adverse metallic silver, spatially confined STE, and lowers local site symmetry in Cs 2 Na 0.4 Ag 0.6 In 0.97 Bi 0.03 Cl 6 DP by terbium doping; and this work develops a guest-host strategy to improve film morphology, reduce defect density, and increase carrier mobility. These alterations cause substantial increase in STE radiative recombination and charge injection efficiency of perovskite layer. Finally, pure white EL with ideal color coordinates of (0.328, 0.329) and a record-breaking optoelectronic performance is achieved by introducing additional green carbon dots in LED to fill the deficient green component., (© 2023 Wiley-VCH GmbH.)

Deep-red light-emitting diodes (DR-LEDs, >660 nm) with high color-purity and narrow-bandwidth emission are promising for full-color displays and solid-state lighting applications. Currently, the DR-LEDs are mainly based on conventional emitters such as organic materials and heavy-metal based quantum dots (QDs) and perovskites. However, the organic materials always suffer from the complicated synthesis, inferior color purity with full-width at half-maximum (FWHM) more than 40 nm, and the QDs and perovskites still suffer from serious problems related to toxicity. Herein, this work reports the synthesis of efficient and high color-purity deep-red carbon dots (CDs) with a record narrow FWHM of 21 nm and a high quantum yield of more than 50% from readily available green plants. Moreover, an exciplex host is further established using a polymer and small molecular blend, which has been shown to be an efficient strategy for producing high color-purity monochrome emission from deep-red CDs via Förster energy transfer (FET). The deep-red CD-LEDs display high color-purity with Commission Internationale de l'Eclairage (CIE) coordinates of (0.692, 0.307). To the best of the knowledge, this is the first report of high color-purity CD-LEDs in the deep-red region, opening the door for the application of CDs in the development of high-resolution light-emitting display technologies., (© 2023 Wiley-VCH GmbH.)

Nonlinear multi-phonon (2-7) absorption in the Na + /Bi 3+ -alloyed Cs 2 AgInCl 6 lead-free double perovskites with ∼100% photoluminescence quantum yield and superior stability is observed for the first time, which can be pumped by a femtosecond laser in a wide spectral range (800-2600 nm). First-principles calculations verify that the parity-forbidden transition from the valence band maximum and conduction band minimum (at the Γ point) is not broken by Na + /Bi 3+ doping, and strong optical band-to-band absorption occurs at the L & X points. Time-resolved emission spectra evidence that single-photon and multi-photon pumping leads to the same self-trapped exciton transition and high-order nonlinear absorption will not induce a remarkable thermal effect. Finally, we demonstrate that the Cs 2 Na 0.4 Ag 0.6 In 0.99 Bi 0.01 Cl 6 DP shows great potential for next-generation wavelength-selective and highly sensitive multiphoton imaging applications.

Impurity doping is an effective approach to tuning the optoelectronic performance of host materials by imparting extrinsic electronic channels. Herein, a family of lanthanide (Ln 3+ ) ions was successfully incorporated into a Bi:Cs 2 AgInCl 6 lead-free double-perovskite (DP) semiconductor, expanding the spectral range from visible (Vis) to near-infrared (NIR) and improving the photoluminescence quantum yield (PLQY). After multidoping with Nd, Yb, Er and Tm, Bi/Ln:Cs 2 AgInCl 6 yielded an ultrabroadband continuous emission spectrum with a full width at half-maximum of ~365 nm originating from intrinsic self-trapped exciton recombination and abundant 4f-4f transitions of the Ln 3+ dopants. Steady-state and transient-state spectra were used to ascertain the energy transfer and emissive processes. To avoid adverse energy interactions between the various Ln 3+ ions in a single DP host, a heterogeneous architecture was designed to spatially confine different Ln 3+ dopants via a "DP-in-glass composite" (DiG) structure. This bottom-up strategy endowed the prepared Ln 3+ -doped DIG with a high PLQY of 40% (nearly three times as high as that of the multidoped DP) and superior long-term stability. Finally, a compact Vis-NIR ultrabroadband (400~2000 nm) light source was easily fabricated by coupling the DiG with a commercial UV LED chip, and this light source has promising applications in nondestructive spectroscopic analyses and multifunctional lighting., (© 2022. The Author(s).)

The development of advanced luminescent materials is highly desirable for addressing the rising threat of forgery. However, it is challenging to achieve stable full-color upconversion (UC) tuning in the same matrix upon a single-beam light excitation so as to ensure that authentic items are irreproducible. Herein, hexagonal Er/Tm:CsYb 2 F 7 nanocrystals (NCs) embedded inorganic glass via an in situ crystallization strategy is fabricated, which can emit blue, cyan, green, yellow, orange, red and near-infrared (NIR) UC emissions by simply modifying an incident 980 nm laser power. This UC tuning is attributed to the combination roles of the highly efficient laser-induced photothermal effect of the CsYb 2 F 7 host and simultaneous emissions of Er and Tm activators. Importantly, the robust inorganic glass matrix endows Er/Tm:CsYb 2 F 7 NCs with excellent water resistance and the ability to withstand high-power laser irradiation. Based on these unique characteristics, a proof-of-concept anti-counterfeiting experiment is designed. The results indicate that dynamic full-color UC luminescence patterns can be easily tuned by simply changing the power of the incident 980 nm laser. The present work not only confirms that the designed photothermal material can increase information security, but also provides a new idea for practical applications in the field of anti-counterfeiting.

Among the numerous two-dimensional van der Waals (vdW) magnetic materials, Fe 3 GeTe 2 (FGT), due to its outstanding properties such as metallicity, high Curie temperature and strong perpendicular magnetic anisotropy, has quickly emerged as a candidate with the most potential for the fabrication of all-vdW spintronic devices. Here, we fabricated a simple vertical homojunction based on two few-layer exfoliated FGT flakes. Under a certain range of external magnetic fields, the magnetization reversal can be achieved by applying a negative or positive pulse current, which can reduce the coercivity through the spin orbit torque of FGT itself in addition to the Joule heat. Moreover, the asymmetrical switching current is caused by the spin transfer torque in the homojunction. As the temperature increases, the magnetization reversal can be observed at a smaller external magnetic field. Our demonstrations of the current-assisted magnetization reversal under a magnetic field in all-vdW structures may provide support for the potential application of vdW magnetism.

2D layered chalcogenide semiconductors have been proposed as a promising class of materials for low-dimensional electronic, optoelectronic, and spintronic devices. Here, all-2D van der Waals vertical spin-valve devices, that combine the 2D layered semiconductor InSe as a spacer with the 2D layered ferromagnetic metal Fe 3 GeTe 2 as spin injection and detection electrodes, are reported. Two distinct transport behaviors are observed: tunneling and metallic, which are assigned to the formation of a pinhole-free tunnel barrier at the Fe 3 GeTe 2 /InSe interface and pinholes in the InSe spacer layer, respectively. For the tunneling device, a large magnetoresistance (MR) of 41% is obtained under an applied bias current of 0.1 µA at 10 K, which is about three times larger than that of the metallic device. Moreover, the tunneling device exhibits a lower operating bias current but a more sensitive bias current dependence than the metallic device. The MR and spin polarization of both the metallic and tunneling devices decrease with increasing temperature, which can be fitted well by Bloch's law. These findings reveal the critical role of pinholes in the MR of all-2D van der Waals ferromagnet/semiconductor heterojunction devices., (© 2021 Wiley-VCH GmbH.)

Here we report a supercapacitor with high energy density and high cycling stability using low-cost and environmentally friendly CoMoO4/bamboo charcoal (BC) hybrid materials as the cathode. The hybrid materials were fabricated via a one-pot solvothermal reaction followed by an annealing process. The optimized CoMoO4/BC hybrid material has a specific surface area of 74.4 m2 g-1, being 1.7-fold higher than that of the CoMoO4 precursor. The hybrid electrode shows a high specific capacitance of 422.3 F g-1 at 0.5 A g-1 and 304.8 F g-1 at 50 A g-1. The as-assembled CoMoO4/BC||activated carbon supercapacitor exhibits a high energy density of 56.7 W h kg-1 and 18.3 W h kg-1 at a power density of 785 W kg-1 and 40 000 W kg-1, respectively. Furthermore, it also shows excellent long-term cycling stability. Subjected to 40 000 cycles of charge-discharge test at a current density of 50 A g-1, there is only about 10% capacitance loss (occurring only during the first 5000 cycles). This excellent electrochemical performance is ascribed to the covalent C-Mo and C-O bonds formed between CoMoO4 and BC as well as the porous feature of the hybrid material, which provide highways for electron transfer and ion transportation within the electrodes and at the electrode-electrolyte interface.

An ideal anti-counterfeiting technique has to be inexpensive, mass-producible, nondestructive, unclonable and convenient for authentication. Although many anti-counterfeiting technologies have been developed, very few of them fulfill all the above requirements. Here we report a non-destructive, inkjet-printable, artificial intelligence (AI)-decodable and unclonable security label. The stochastic pinning points at the three-phase contact line of the ink droplets is crucial for the successful inkjet printing of the unclonable security labels. Upon the solvent evaporation, the three-phase contact lines are pinned around the pinning points, where the quantum dots in the ink droplets deposited on, forming physically unclonable flower-like patterns. By utilizing the RGB emission quantum dots, full-color fluorescence security labels can be produced. A convenient and reliable AI-based authentication strategy is developed, allowing for the fast authentication of the covert, unclonable flower-like dot patterns with different sharpness, brightness, rotations, amplifications and the mixture of these parameters.

Surface-enhanced Raman spectroscopy (SERS) has attracted increasing interest for chemical and biochemical sensing. Several studies have shown that SERS intensities are significantly increased when an optical interference substrate composed of a dielectric spacer and a reflector is used as a supporting substrate. However, the origin of this additional enhancement has not been systematically studied. In this paper, high sensitivity SERS substrates composed of self-assembled core-satellite nanostructures and silica-coated silicon interference layers have been developed. Their SERS enhancement is shown to be a function of the thickness of silica spacer on a more reflective silicon substrate. Finite difference time domain modeling is presented to show that the SERS enhancement is due to a spacer contribution via a sign change of the reflection coefficients at the interfaces. The magnitude of the local-field enhancement is defined by the interference of light reflected from the silica-air and silica-silicon interfaces, which constructively added at the hot spots providing a possibility to maximize intensity in the nanogaps between the self-assembled nanoparticles by changing the thickness of silica layer. The core-satellite assemblies on a 135 nm silica-coated silicon substrate exhibit a SERS activity of approximately 13 times higher than the glass substrate.

The majority of visible-light photocatalysts show very low hydrogen evolution activity in the absence of noble metal co-catalysts due to their fast carrier recombination rate. Metallic interstitial nitrides have been recognized as excellent hydrogen evolution electrocatalysts and therefore are promising alternative co-catalysts for photocatalytic hydrogen production. Herein we report a low-cost, efficient, noble-metal-free visible-light-driven hydrogen evolution photocatalyst composed of Ni3N/g-C3N4 heterostructures. The as-prepared photocatalyst with a Ni3N loading content of 3 wt% shows a high hydrogen evolution rate of 169 μmol g-1 h-1, which is slightly higher than that of 3 wt% Pt modified g-C3N4 (152.0 μmol g-1 h-1). The Ni3N/g-C3N4 photocatalysts also exhibit remarkable photostability for four consecutive cycles of photocatalytic activity tests with a total reaction time of 12 hours. The excellent performance of the Ni3N/g-C3N4 photocatalyst is ascribed to the formation of an optimal number of Ni3N/g-C3N4 heterojunctions that improve photogenerated carrier separation and offer abundant photocatalytically active sites for surface reactions.

Gold nanorods (AuNRs) are versatile materials due to their broadly tunable optical properties associated with their anisotropic feature. Conventional seed-mediated synthesis is, however, not only limited by the operational complexity and over-sensitivity towards subtle changes of experimental conditions but also suffers from low yield (≈15 %). A facile seedless method is reported to overcome these challenges. Monodispersed AuNRs with high yield (≈100 %) and highly adjustable longitudinal surface plasmon resonance (LSPR) are reproducibly synthesized. The parameters that influence the AuNRs growth were thoroughly investigated in terms of growth kinetics and soft-template regulation, offering a better understanding of the template-based mechanism. The facile synthesis, broad tunability of LSRP, high reproducibility, high yield, and ease of scale-up make this method promising for the future mass production of monodispersed AuNRs for applications in catalysis, sensing, and biomedicine., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Uniform quasicubic alpha-Fe(2)O(3) nanoparticles enclosed by six identical {110} planes were synthesized by a simple solvothermal method. TEM investigations revealed that they were formed through oriented attachment of primary nanocrystals assisted by Ostwald ripening, and PVP surfactant played an important role in control over the final morphology of the products. These quasicubic nanoparticles could catalyze oxidation of almost 100% CO at a temperature of 230 degrees C, much lower than those of nanophases with flowerlike, hollow, or other forms of irregular external morphologies having various crystal planes exposed to the gas, indicating that the external morphology and especially the exposure crystal planes of alpha-Fe(2)O(3) nanocatalyst affect the catalytic activity more significantly than the traditionally accepted factors (such as high BET surface area, hollow structure, etc.) do for CO catalytic oxidation.