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Graphdiyne (GDY) as an emerging carbon nanomaterial has attracted increasing attention because of its uniformly distributed pores, highly π-conjugated, and tunable electronic properties. These excellent characteristics have been widely explored in the fields of energy storage and catalysts, yet there is no report on the development of sensors based on the outstanding optical property of GDY. In this paper, a new sensing mechanism is reported built upon the synergistic effect between inner filter effect and photoinduced electron transfer. We constructed a novel nanosensor based upon the newly-synthesized nanomaterial and demonstrated a sensitive and selective detection for both Fe3+ ion and ascorbic acid, enabling the measurements in real clinical samples. For the first time fluorescent graphdiyne oxide quantum dots (GDYO-QDs) were prepared using a facile ultrasonic protocol and they were characterized with a range of techniques, showing a strong blue-green emission with 14.6% quantum yield. The emission is quenched efficiently by Fe3+ and recovered by ascorbic acid (AA). We have fabricated an off/on fluorescent nanosensors based on this unique property. The nanosensors are able to detect Fe3+ as low as 95 nmol L−1 with a promising dynamic range from 0.25 to 200 μmol L−1. The LOD of AA was 2.5 μmol L−1, with range of 10–500 μmol L−1. It showed a promising capability to detect Fe3+ and AA in serum samples. [ABSTRACT FROM AUTHOR]

2D transition metal carbides, nitrides, and carbonitrides called MXenes show outstanding performance in many applications due to their superior physical and chemical properties. Herein, a ZnO–MXene mixture with different contents of Ti3C2 is applied as electron transport layers (ETLs) and the influence of the Ti3C2 MXene in all‐inorganic metal halide perovskite nanocrystal light‐emitting diodes (perovskite NC LEDs) is explored. The addition of Ti3C2 makes more balanced charge carrier transport in LEDs by changing the energy level structure and electron mobility of ETL. Moreover, lower surface roughness is obtained for the ETL, thus guaranteeing uniform distribution of the perovskite NCs layer and further reducing leakage current. As a result, a 17.4% external quantum efficiency (EQE) with low efficiency roll‐off is achieved with 10% Ti3C2, which is a 22.5% improvement compared to LEDs without Ti3C2. [ABSTRACT FROM AUTHOR]

One‐dimensional semiconductor nanostructures have already been used for a variety of optoelectronic applications. Metal halide perovskites have emerged in recent years as promising high‐performance optoelectronic materials, but reports on 1D nanorods (NRs) of all‐inorganic halide perovskites are still scarce. This work demonstrates a synthetic strategy toward cesium‐based inorganic perovskite NRs by exploiting composition‐controlled crystal phase engineering. It is accomplished for Cd‐rich mixed‐cation CsPb1‐xCdxBr3 nanocrystals, where the initial 1D hexagonal perovskite phase drives the growth of the 1D NRs, as supported by first‐principles calculations. The band gaps of the resulting NRs are tunable by varying the Cd‐content, and the highly uniform CsPb0.08Cd0.92Br3 NRs (with an average length of 84 nm and width of 16 nm) exhibit a true blue‐color emission centered at 460 nm, with a high quantum yield of 48%. Moreover, this work also demonstrates the tunability of the Fermi levels in the films made of CsPb1‐xCdxBr3 alloyed nanocrystals, where samples with highest Cd content show an increase of the electron concentration and a related increase in the conductivity. [ABSTRACT FROM AUTHOR]

The development of sensitive, cheap, and portable methods for detecting nitroaromatics explosives has a profound significance and value for public health and environmental protection. For this purpose, a new D-π-A barbituric acid derivative CB-CYH with aggregation-induced emission (AIE) behavior was synthesized, which can interact with picric acid through photoinduced electron transfer (PET). Scanning electron microscopy (SEM) and dynamic light scattering (DLS) indicate that the enhanced emission of the compounds is related to the formation of nano-aggregates. It is well known that an important source of mechanochromic fluorescence (MCF) characteristic materials is the compound with AIE characteristics. The chemosensing test paper prepared by aggregated nanoparticles based on AIE properties is often subjected to external friction or squeeze during transportation or storage, resulting in changes of their optical properties, and destruction of test paper followed. Therefore, the development of compounds with AIE properties and stable optical properties in the presence of external stimuli is particularly important for chemosensing test paper. Molecular dynamics simulation (MDS) shows that the presence of hydrophobic cycloalkyl group in CB-CYH, which caused the molecules to be closely interspersed with each other; hence, it is difficult to change the microstructure and stacking mode of molecules by external stimulation simultaneously; the optical properties are not changed by external stimuli. Therefore, the test paper based on the AIE effect of CB-CYH was developed as chemosensing test paper for the detection of nitroaromatics. [ABSTRACT FROM AUTHOR]

The external quantum efficiencies (EQEs) of perovskite quantum dot light‐emitting diodes (QD‐LEDs) are close to the out‐coupling efficiency limitation. However, these high‐performance QD‐LEDs still suffer from a serious issue of efficiency roll‐off at high current density. More injected carriers produce photons less efficiently, strongly suggesting the variation of ratio between radiative and non‐radiative recombination. An approach is proposed to balance the carrier distribution and achieve high EQE at high current density. The average interdot distance between QDs is reduced and this facilitates carrier transport in QD films and thus electrons and holes have a balanced distribution in QD layers. Such encouraging results augment the proportion of radiative recombination, make devices with peak EQE of 12.7%, and present a great device performance at high current density with an EQE roll‐off of 11% at 500 mA cm−2 (the lowest roll‐off known so far) where the EQE is still over 11%. [ABSTRACT FROM AUTHOR]

PdFe ultrathin nanosheets (NSs) were prepared by one‐step hydrothermal route. PdFe NSs showed superior catalytic activity towards the oxidation of nitrite due to the large surface area of 2 dimensional (2D) nanostructure and the synergetic effect between Pd and Fe. A sensitive and selective electrochemical nitrite sensing platform was designed base on PdFe NSs and the amperometric technique. The limit of detection (LOD) was found to be 0.12 μM (S/N=3), with a linear relationship between nitrite concentration and response current in the range of 1–160 μM. The nitrite sensor was applied to analysis of nitrite in tap water and sausage successfully. [ABSTRACT FROM AUTHOR]

A facile method to prepare Pt-Cu nanowires (NWs) was introduced. Structural characterization such as high-resolution transmission electron microscope (HR-TEM), selected-area electron diffraction (SAED), EDS element mapping, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and inductively coupled plasma mass spectrometry (ICP-MS) showed the formation of Pt-Cu alloy, with a width of 4.5 nm on average. The formation process of Pt-Cu NWs was studied; it was found that bromine ion, who has preferential adsorption on Pt (100) face, served as a growth-directing agent; Brij58 not only served as a protector but also played an important role in forming Pt-Cu NWs; the mechanism was proposed. Their electrocatalytic activity towards methanol oxidation was investigated; we found that the current density of Pt-Cu NWs was 295 mA·mg-1 when the ratio of Pt/Cu is 1 : 1, which is 11.5 and 2.35 times higher than that of pure Pt (26 mA·mg-1) and commercial Pt/C (126 mA·mg-1). The high electrocatalytic activity is attributed to the presence of abundant structural defects and surface active sites on the synthesized Pt-Cu NWs. [ABSTRACT FROM AUTHOR]

Three new nonplanar barbituric derivatives, named as TTB, TTTB, and TOB, were synthesized. The D-π-A type conjugated compounds showed obvious intramolecular charge transfer (ICT) property, which was evidenced by theoretical calculations and spectral analyses. All of them exhibited aggregation induced emission (AIE) when formed nanoaggregates. These nanoaggregates also showed reversible mechanofluorochromism (MFC). Their red light emission became deep red after grinding and then recovered with dichloromethane fuming. Hence, a strategy to fabricate mechanofluorochromic nanoaggregate phosphors via nonplanar π-skeleton and steric effect was demonstrated, and these nanophosphors possess potentials for mechanosensors and anticounterfeiting technology. [ABSTRACT FROM AUTHOR]

• Harmonization of magnetic and physical structure of non-ideal magnetic nanoparticles (MNP). • Merging of single crystals in multicore-MNP (MCMNP). • Random/flux-closure magnetic structure within closely/loosely packed MCMNP, respectively. • Weak magnetism of nominal magnetite/maghemite MNP due to wustite. Using well-established measurement techniques like transmission electron microscopy (TEM), dynamic light scattering (DLS), small and wide angle X-ray scattering (SAXS, WAXS), susceptometry, and magnetorelaxometry, the distribution of the physical and magnetic size (magnetic moments) and magnetic anisotropy of a variety of structurally different magnetic nanoparticle samples (MNPs) is analyzed and compared. A term which accounts for the presence of weak magnetic areas (WMAs) within the MNPs was introduced to the widespread analysis model for M(H) data, enabling a consistent interpretation of the data in most of the systems. A comparison of the size distributions as obtained for the physical and the magnetic diameter suggests a multidomain structure for three single core systems under investigation, in all probability evoked by the presence of a wustite phase, as identified by WAXS. Analyzing the relationship d < d m < d c between the average single core diameter d , the effective magnetic (domain) size d m and the cluster diameter d c quantitatively, two qualitatively different magnetic structures in multicore MNP (MCMNP) systems were identified: (i) The magnetic moments of single cores within the MCMNP of fluidMAG tend to build flux closure structures, driven by dipole–dipole interaction. (ii) The magnetic behavior of Resovist® was attributed to the presence of domain sizes of about 12 nm within MCMNP, exceeding the single core diameters of 5 nm. Thereby, WAXS revealed a bimodal crystallite size distribution suggesting a crystallite merging process within the MCMNP. The value of the effective magnetic moment of these MCMNP could be explained within the presented "random moment cluster model" (RMCM). We conclude that the combination of physical and magnetic structure parameters obtained from complementary measurement methods allows a reliable assessment of the magnetic structure of single and multicore MNPs. [ABSTRACT FROM AUTHOR]

Abstract Au@AgPt yolk-shell nanoparticles (Y-SNPs) with Au core and porous Ag/Pt alloy shell were prepared via a double-template method. This synthesis employed Au@Ag core-shell nanoparticles as a hard-template to obtain Au@AgPt Y-SNPs by a galvanic replacement reaction between PtCl 6 2− and Ag. Brij-58 surfactant micelles served as a soft-template to prepare dendritic and porous shell. The thus-synthesized Au@AgPt Y-SNPs exhibited enhanced catalytic performance (889 mA mg Pt −1) and stability for methanol oxidation reaction (MOR) at room temperature, which is 5 times as high as the commercial Pt/C (20 wt% Pt). The enhanced electrocatalytic activity is attributed to following aspects: electronic effect between Pt and Au, synergism between Pt and Ag, and nanoreactor confinement effect in the cavity between the Au core and the shell. The present work provides a simple strategy for the formation of ternary metallic Y-SNPs, which exhibit promising applications in electrocatalysis, energy conversion and sensing. Graphical abstract Image 1 Highlights • Au@AgPt yolk-shell nanoparticles were prepared via a double-template method. • Au@AgPt exhibited enhanced catalytic performance and stability for methanol oxidation reaction. • Electronic effect, synergism and nanoreactor confinement effect paly important role in enhancing catalytic performance. [ABSTRACT FROM AUTHOR]

Abstract Two-dimensional layered transition metal dichalcogenides, such as tungsten disulfide (WS 2) and molybdenum disulfide (MoS 2), have been regarded as promising active materials for capacitive energy storage owing to their large specific surface area and multi-valence state of metals to pseudo-capacitive reactions. Here, WS 2 quantum dots (QDs) with uniform size were synthesized via a simple method and their pseudo-capacitance properties were investigated. The electrochemical performance was further improved by using surface treatment with 1,2-ethanedithiol. A specific capacitance (C F) of 457 F/g was thus achieved. Simultaneously, the outstanding cycling stability (8000 cycles) and coulombic efficiency of 81% were obtained. The results suggest that WS 2 QDs are an excellent candidate for high performance energy storage devices. Highlights • Modified WS 2 quantum dots with high active edge atoms and surface area. • Optimizing the contact between QDs and electrolyte. • Specific capacitance, cycling stability and coulombic efficiency were improved. • WS 2 quantum dots are an excellent candidate for energy storage. [ABSTRACT FROM AUTHOR]

Abstract A new carbazole-based naked-eye colorimetric and fluorescent sensor CPPB with aggregation induced emission (AIE) effect was successfully synthesized. The solid powder of CPPB emitted intense yellow fluorescence, and its emission wavelength and fluorescence intensity in DMSO/H 2 O solution varied with the percentage of water (f w). Nano-aggregates of CPPB molecules were prepared by increasing f w of DMSO/H 2 O solution, and the optimal aggregation state of CPPB was reached in 99% aqueous DMSO solution with the maximum fluorescence intensity. Moreover, CPPB displayed high selectivity and sensitivity toward cyanide anions (CN−) in 99% aqueous DMSO solution even in the presence of other competitive anions (CN−, F−, Cl−, AcO−, NO 3 −, I−, CO 3 2−, HCO 3 −, HSO 3 −, SO 4 2−, S2−, HS−, OH−, H 2 PO 4 − and HPO 4 2−) and the reactive oxygen species (H 2 O 2 , O 2 ·−, 1O 2 , t-BuOOH and ·OH). The sensing mechanism for CN− was confirmed by optical spectral studies, 1H NMR titration, HRMS spectra, Job's plot analyses and DFT calculations. Sensor CPPB for CN− detection revealed extremely low detection limit (67.4 nM), high anti–interference ability, wide pH response range (3.0–10.0) as well as the immediate response (15 s). Furthermore, the CPPB -based test strips were applied to detect CN− qualitatively and quantitatively in 100% aqueous solution. Graphical abstract We have successfully developed sensor CPPB, which exhibited distinct aggregation induced emission (AIE) effect, and detected CN− based on naked-eye colorimetric and fluorescent sensing with high selectivity and great sensitivity. Image 1 Highlights • Carbazole-based sensor CPPB was designed and synthesized, which exhibited obvious aggregation induced emission (AIE) effect. • Sensor CPPB detected CN− in 99% aqueous DMSO solution, and the test strips of CPPB recognized CN− in 100% aqueous solution. • The detection limit of CPPB for CN− were at nanomolar level in 99% aqueous DMSO solution. • Colorimetric responses of CPPB toward CN− were visible with the naked eyes under sunlight and UV lamp (365 nm). [ABSTRACT FROM AUTHOR]

Electrochemical deposition as a liquid phase epitaxial growth method is widely used to fabricate different kinds of hierarchical structures. As a typical heterostructure, TiO2/PbS is widely utilized in the areas of photovoltaics and photocatalysis. Oriented TiO2 nanorod (NR) arrays can provide direct pathways for the electron transport of photoanode. However, the lattice mismatch between TiO2 NR sides and PbS is very large; PbS nanoparticles (NPs) only formed on the top of TiO2 NRs. To solve this problem, TiO2/CdS core/shell nanocables were firstly prepared electrochemically because the lattice ratio between TiO2 and CdS was 0.916; and then, PbS NPs were successfully deposited over CdS shells (the lattice ratio between CdS and PbS was 0.697) to form TiO2/CdS/PbS hierarchical heterostructures. Experimental results demonstrated that the CdS interlayer could effectively promote the growth of PbS NPs on the surface and improve the fill factor and short current density of the photoanodes. [ABSTRACT FROM AUTHOR]

We report a facile and low-cost synthesis of WS2 quantum dots with bright broad-band emission, which are suitable for lighting applications. The thus fabricated WS2 light-emitting diodes (LEDs) exhibit voltage independent electroluminescence spectra, and the optimized white LEDs generate a high color rendering index of 93. [ABSTRACT FROM AUTHOR]

A hyperbranched porous polymer P based on adamantane and pyrene was synthesized through the Sonogashira coupling reaction. The three-dimensional rigid molecular skeleton of adamantane makes polymer P porous. Compound M, which acts as the block moiety between two adamantane groups in polymer P, was also synthesized for the control experiment. Compared with M, the characteristics of P changed remarkably with it exhibiting different emission behaviors and performances for the detection of DNT. In saturated DNT vapor, the quenching efficiency (ηEP) of film P (82%) was remarkably superior compared with that of film M (22%). In addition, a series of films with different thicknesses and different amounts of polymer P were prepared. Results showed that the quenching efficiencies did not change with an increase in the film thickness. [ABSTRACT FROM AUTHOR]

With the development of the display technology, there are higher requirements for color saturation and vividness. As a base unit, light-emitting diode (LED) has become a primary object of study. Perovskite quantum dots with high photoluminescence quantum yield, narrow emission, and wide color gamut have attracted special attention in recent years. Although LEDs based on perovskite exhibit excellent performance, there are few applications of perovskite LEDs in display. Herein, LEDs based on CsPbI3 perovskite were used as basic units for fabricating eight-segment LED displays. The LEDs exhibited a luminance of 780 cd/m2 and an external quantum efficiency of 6%. The current-density and luminance vs driving voltage confirms the uniformity of these LEDs in the eight segments, which will promote the application of perovskite nanocrystalline LEDs in the field of full color display. [ABSTRACT FROM AUTHOR]

Nitrogen doped graphene oxide (NG) modified WSe 2 nanorod composites (WSe 2 /NG) were prepared by a hydrothermal synthesis route. The synthesized samples were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectroscopy(DRS) and elemental analysis. Using methylene blue (MB) as a target organic dye, WSe 2 /NG nanocomposites exhibited significant enhancement in photocatalytic degradation of MB under visible light irradiation compared with WSe 2 . That was mainly attributed to the strong adsorption of MB, excellent electrical conductivity and charge separation features of the NG, leading to effectively restrained electron-hole pair recombination of WSe 2 nanorods. Among the hybrid photocatalysts, WSe 2 /50NG (50 wt% of NG) exhibited the highest photocatalytic activity with a rate constant of 0.0572 min −1 for the degradation of the MB in aqueous solution under visible light irradiation, and the removal efficiency reached 99.3% which was 2.4 times higher than that of WSe 2 . In addition, WSe 2 /NG also showed higher stability and good reusability. [ABSTRACT FROM AUTHOR]

Abstract: Lead‐halide perovskites are well known to decompose rapidly when exposed to polar solvents, such as water. Contrary to this common‐place observation, we have found that through introducing a suitable minor amount of water into the reaction mixture, we can synthesize stable CsPbBr3 nanocrystals. The size and the crystallinity, and as a result the band gap tunability of the strongly emitting CsPbBr3 nanocrystals correlate with the water content. Suitable amounts of water change the crystallization environment, inducing the formation of differently shaped perovskites, namely spherical NCs, rectangular nanoplatelets, or nanowires. Bright CsPbBr3 nanocrystals with the photoluminescence quantum yield reaching 90 % were employed for fabrication of inverted hybrid inorganic/organic light‐emitting devices, with the peak luminance of 4428 cd m−2 and external quantum yield of 1.7 %. [ABSTRACT FROM AUTHOR]

Abstract: Lead‐halide perovskites are well known to decompose rapidly when exposed to polar solvents, such as water. Contrary to this common‐place observation, we have found that through introducing a suitable minor amount of water into the reaction mixture, we can synthesize stable CsPbBr3 nanocrystals. The size and the crystallinity, and as a result the band gap tunability of the strongly emitting CsPbBr3 nanocrystals correlate with the water content. Suitable amounts of water change the crystallization environment, inducing the formation of differently shaped perovskites, namely spherical NCs, rectangular nanoplatelets, or nanowires. Bright CsPbBr3 nanocrystals with the photoluminescence quantum yield reaching 90 % were employed for fabrication of inverted hybrid inorganic/organic light‐emitting devices, with the peak luminance of 4428 cd m−2 and external quantum yield of 1.7 %. [ABSTRACT FROM AUTHOR]

From the viewpoint of intermediate-temperature solid oxide fuel cells (IT-SOFCs) application, except for excellent electrochemical performance, a satisfactory cathode must also meet excellent thermal expansion compatibility with other cell components. Therefore, in order to reduce the thermal expansion coefficient (TEC) value and improve catalytic activity of Sr(Co 0.9 Fe 0.1 )O 3−δ oxide, we report our effort on perovskite-type Ga 3+ doped SrCo 0.8 Fe 0.1 Ga 0.1 O 3-δ (SCFG) oxide as cathode material for IT-SOFCs. In this work, SCFG cathode was prepared using an improved sol–gel method and its properties were characterized by powder X-ray diffraction (XRD), X-ray Photoelectron Spectra (XPS), thermal expansion coefficient (TEC), electrical conductivity, and electrochemical impedance spectroscopy (EIS). The SCFG powder showed the expected orthorhombic crystal structure. XPS analysis disclosed multi-valence states of the transition-metal cations in SCFG, i.e., [Sr 2+ ][Co 3+ /Co 4+ ] 0.8 [Fe 3+ /Fe 4+ ] 0.1 [Ga 3+ ] 0.1 O 3−δ . The maximum conductivity of SCFG was 122 S cm −1 at 800 °C. The average TEC value of the SCFG sample was 12.6 × 10 −6 K −1 between room temperature and 1023 K, which is lower than the TEC of Sr(Co 0.9 Fe 0.1 )O 3−δ cathode and is very similar to the value of the electrolyte. The R p values of SCFG cathode on Ce 0.8 Sm 0.2 O 1.9 (SDC) and La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3-δ (LSGM) electrolytes were 0.047 and 0.053 Ω cm 2 at 800°C, respectively. The maximum power densities of a single-cell with SCFG cathode on 300 μm thick SDC electrolyte were 504, 335 and 193 mW cm −2 at 800, 750 and 700 °C, respectively. These results indicate that SCFG oxide is a promising cathode material for IT-SOFCs duo to its good thermal expansion match with electrolyte and adequate electrochemical performance. [ABSTRACT FROM AUTHOR]

Hollow dendritic Ag/Pt alloy nanoparticles were synthesized by a double template method: Ag nanoparticles as the hard template to obtain hollow spheres by a galvanic replacement reaction between PtCl62− and metallic Ag and surfactant micelles (Brij58) as the soft template to generate porous dendrites. The formation of a Ag/Pt alloy phase was confirmed by XRD and HRTEM. Elemental mapping and line scanning revealed the formation of the hollow architecture. We studied the effects of the Ag/Pt ratio, surfactant and reaction temperature on the morphology. In addition, we explored the formation process of hollow dendritic Ag/Pt nanoparticles by tracking the morphologies of the nanostructures formed at different stages. In order to improve the electrocatalytic property, we controlled the size of the nanoparticles and the thickness of the shell by adjusting the amount of the precursor. We found that these Ag/Pt alloy nanoparticles exhibited high activity (440 mA mg−1) and stability as an electrocatalyst for catalyzing methanol oxidation. [ABSTRACT FROM AUTHOR]

In this work, gold nanoparticles were synthesized, the introduction of Hg 2+ led to the formation of Au-Hg amalgam, which was found to possess an enhanced peroxidase-mimicking activity towards H 2 O 2 -mediated oxidation of 3, 3′, 5, 5′-Tetramethylbenzidine (colorless) to produce a blue product. This color reaction was exploited as a sensitive and selective method for colorimetric detection of Hg 2+ and H 2 O 2 , the linear ranges were 0.1–5 nM and 0.5–100 μ M, respectively. Furthermore, a test strip was successfully designed, it exhibited high sensitive, rapid and low cost for Hg 2+ and H 2 O 2 detection. More importantly, the colorimetric method could be successfully applied to real sample application in solution and in a test strip. [ABSTRACT FROM AUTHOR]

We report a sensitive sensing strategy based on metal-enhanced fluorescence (MEF) and hybridization chain reaction (HCR). Hg 2+ aptamers were immobilized on magnetic nanoparticles (NPs) and HCR process happened without Hg 2+ , forming long DNA chains and allowing fluorescent indicator (SYBR Green) intercalated in the double helix. After magnetic separation from test solution, positively charged Ag@SiO 2 NPs were added, they were electrostatically absorbed on negatively charged DNA chains, acting as “smart dust” to enhance fluorescence signal. This design was used for Hg 2+ detection and it showed high sensitivity with a limit of detection down to 25 pM. This method also exhibited good selectivity over other metal ions and was successfully applied in real water sample analyses. [ABSTRACT FROM AUTHOR]

Over the last two decades, intensive research efforts have been devoted to the suppressions of photoluminescence (PL) blinking and Auger recombination in metal-chalcogenide nanocrystals (NCs), with significant progresses being made only very recently in few specific NC structures. Here we show that nonblinking PL is readily available in the newly synthesized perovskite CsPbI3 NCs and that their Auger recombination of charged excitons is greatly slowed down, as signified by a PL lifetime about twice shorter than that of neutral excitons. Moreover, spectral diffusion is completely absent in single CsPbI3 NCs at the cryogenic temperature, leading to a resolution-limited PL line width of ∼200 μeV. [ABSTRACT FROM AUTHOR]

High-Performance Biomechanical Energy Harvester Enabled by Switching Interfacial Adhesion via Hydrogen Bonding and Phase Separation (Adv. Funct. Hydrogen bonds, interfacial engineering, phase separation, surface charges, triboelectric nanogenerators Keywords: hydrogen bonds; interfacial engineering; phase separation; surface charges; triboelectric nanogenerators EN hydrogen bonds interfacial engineering phase separation surface charges triboelectric nanogenerators 1 1 1 09/21/22 20220919 NES 220919 B Biomechanical Energy Harvesters b In article number 2204304, William W. Yu, Wen Jung Li, Walid A. Daoud, and co-workers demonstrate a high-performance flexible biomechanical energy harvester by switching its interfacial adhesion via hydrogen bonding interactions and solvent evaporation induced phase separation. [Extracted from the article]

Two-photon-pumped lasers have been regarded as a promising strategy to achieve frequency up-conversion for situations where the condition of phase matching required by conventional approaches cannot be fulfilled. However, their practical applications have been hindered by the lack of materials holding both efficient two-photon absorption and ease of achieving population inversion. Here, we show that this challenge can be tackled by employing colloidal nanocrystals of perovskite semiconductors. We observe highly efficient two-photon absorption (with a cross section of 2.7 × 106 GM) in toluene solutions of CsPbBr3 nanocrystals that can excite large optical gain (>500 cm-1) in thin films. We have succeeded in demonstrating stable two-photon-pumped lasing at a remarkable low threshold by coupling CsPbBr3 nanocrystals with microtubule resonators. Our findings suggest perovskite nanocrystals can be used as excellent gain medium for high-performance frequency-up-conversion lasers toward practical applications. [ABSTRACT FROM AUTHOR]

Quantum dot white light-emitting diodes (QD-WLEDs) were fabricated from green- and red-emitting AgInS2/ZnS core/shell QDs coated on GaN LEDs. Their electroluminescence (EL) spectra were measured at different currents, ranging from 50 mA to 400 mA, and showed good color stability. The modulation bandwidth of previously prepared QD-WLEDs was confirmed to be much wider than that of YAG:Ce phosphor-based WLEDs. These results indicate that the AgInS2/ZnS core/shell QDs are good color-converting materials for WLEDs and they are capable in visible light communication (VLC). [ABSTRACT FROM AUTHOR]

The enhanced photoluminescence (PL) for In-rich copper indium sulfide quantum dots (CIS QDs) was observed. The conduction electron-Cu vacancy recombination and the donor–acceptor pair (DAP) defect recombination were considered to exist in CIS QDs at the same time. The temperature-dependent PL study showed that the emission of these QDs might be mainly originated from the recombination between electrons in the quantized conduction band and holes in the copper vacancy acceptor when x was 0.500 (Cu x In 1− x S). However, the temperature coefficient of PL peak position decreased when x was 0.237. That meant the DAP recombination increased in the In-rich CIS QDs. [ABSTRACT FROM AUTHOR]

Vertically aligned TiO 2 /CdS and TiO 2 /CdS/CdSe nanocable arrays on fluorine-doped tin oxide (FTO) were fabricated by electrochemical deposition of CdS and CdS/CdSe shells over TiO 2 nanorod arrays. The morphology, composition, structure and optical absorbance of CdS and CdS/CdSe shells sensitized TiO 2 nanorod arrays were characterized by different analytical methods. The CdS shell with a hexagonal structure and the CdSe shell with a face-centered structure were densely and uniformly coated on the tetragonal TiO 2 nanorod cores both radially and longitudinally. The photovoltaic measurement showed that the photocurrent density obtained under AM1.5G illumination with a zero bias potential (Ag/AgCl electrode) largely increased from 2.17 to 6.57 mA/cm 2 , when the TiO 2 /CdS nanocables were further covered by the CdSe shell. [ABSTRACT FROM AUTHOR]

Metalloporphyrins possess promising prospect in the oxidative electron-transfer systems. We report here the controllable synthesis of magnetically separable metalloporphyrin via a covalent bonding between Fe(III) meso-Tetra (4-carboxyphenyl) porphine chloride and magnetic nanoparticles. The as-synthesized magnetically separable metalloporphyrin showed 69.02% decoloration efficiency for Acid orange 7. It could be readily recovered from the reaction solution by using a permanent magnetic bar and its decoloration activity remained 95.64% after three cycles of repetitive uses. The stable recycle performance was ascribed to the covalent bond linkage between the metalloporphyrin molecules and the small sized, non-aggregation, and freely dispersed nanoparticles. [ABSTRACT FROM AUTHOR]

Magnetic Fe 3 O 4 nanoparticles decorated with native carboxyl groups (Fe 3 O 4 COOH) were prepared and used as magnetic carriers. These carriers were different from traditional solid supports, because they were free-standing and no aggregation in solution. Lipases were covalently bonded to these Fe 3 O 4 nanoparticles through 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (Sulfo-NHS) activated coupling to synthesize magnetically responsive lipases (MRLs). The analyses of transmission electron microscope (TEM) showed no significant change on the size and shape of Fe 3 O 4 nanoparticles after being conjugated with lipases. The conjugation of Fe 3 O 4 nanoparticles and lipases was confirmed by electrophoresis and zeta potential analyses. Furthermore, the factors that affected the enzyme activity and specific activity of the MRLs were discussed. The optimized conjugation conditions were found to be that the dosages of the lipase solution and the EDC solution were 200 μL and 10 μL for 1 mL Fe 3 O 4 respectively, the molar ratio of EDC and Sulfo-NHS was 1:2.5, and the conjugation time was 2 h. The prepared MRLs exhibited higher thermal stability and reusability. [ABSTRACT FROM AUTHOR]

Multigas sensing is highly demanded in the fields of environmental monitoring, industrial production, and coal mine security. Three near-infrared emission wavelengths from PbSe quantum dots (QDs) were used to analyze the concentration of three gases simultaneously through direct absorption spectroscopy, including acetylene (C2H2), methane (CH4), and ammonia (NH3). The corresponding lower detection limits for the three gases were 20, 100, and 20 ppm, respectively, with an accuracy of 2%. This study demonstrates that QDs with tunable emissions have great potential for simultaneous and uninterfered multiplex gas analysis and detection due to the advantages of the easy tunability of multiplex emitting wavelengths from QDs. [ABSTRACT FROM AUTHOR]

A biosensing platform using Ag@SiO2-DNA-fluorophore nanostructure was designed for metal ions and small organic molecules detection. DNA hybridization occurred in the presence of the targets through the formation of base-target-base complex; accordingly, the fluorophore (Cy3) was brought to the surface of Ag@SiO2 core/shell nanostructures. Through controlling the thickness of the silica shell on the Ag nanoparticle, the fluorescence of Cy3 could be enhanced by the surface plasmon resonance of Ag nanoparticle for up to 2.5 folds. This metal-enhanced fluorescence (MEF) sensor provided high sensitivity and selectivity for the detection of Hg2+, Ag+, and coralyne. It may be developed as a new class of MEF biosensors for other metal ions and organic molecules analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phase transformation was achieved via an insertion reaction with additive ZnBr 2. • Nonlumi nescent Cs 4 PbBr 6 were transformed to green Zn-doped CsPbBr 3 /Cs 4 PbBr 6 NCs. • The transformed Zn-doped CsPbBr 3 /Cs 4 PbBr 6 NCs exhibited high PL QY of 77.5%. • The transformed NCs based EL LED was fabricated with a record EQE of 3.2%. Zero-dimensional (0D) perovskites have attracted a great deal of attention over the last few years due to their fascinating properties. However, their application in electroluminescent (EL) Light-emitting diodes (LEDs) is limited and suffering from extremely low device performance. Herein, the nonluminescent Cs 4 PbBr 6 nanocrystals (NCs) were successfully transformed to highly luminescent Zn-doped CsPbBr 3 /Cs 4 PbBr 6 NCs via an insertion reaction with ZnBr 2 , which changed the atomic molar ratios of NCs and promoted the formation of CsPbBr 3. In this reaction, the Zn2+ ions provided by ZnBr 2 together with the Pb2+ ions can occupy the B-site due to the similar ion radius. The extra Br- ions not only can facilitate the transformation process, but also can passivate the surface defects of the NCs, resulting in high photoluminescence quantum yield (PL QY) of 77.5%. Furthermore, as-synthesized Zn-doped CsPbBr 3 /Cs 4 PbBr 6 NCs were used as emitters to fabricate EL LEDs. The device achieved the maximum current efficiency of 9.8 cd/A and a peak external quantum efficiency of 3.2%, which is the best performance of the CsPbBr 3 /Cs 4 PbBr 6 based LEDs. This reveals the great application potential of CsPbBr 3 /Cs 4 PbBr 6 NCs as EL emitters in LEDs. [ABSTRACT FROM AUTHOR]

Graphdiyne (GDY) with the characteristic delocalized sp and sp2 electronic structure is an excellent carbon carrier for metal-based catalysts. However, the semiconductor properties limited its electrocatalytic activity. Herein, a two-dimensional (2D) few-layered graphdiyne/graphene (GDY/G) heterostructure was employed to anchor NiFe layered double hydroxides (NiFe-LDH) for enhanced oxygen evolution reaction (OER). This heterostructure not only exhibits excellent conductivity for charge transfer due to the graphene layer, but also significantly regulates the electronic structure of NiFe-LDH for enhanced intrinsic activity on account of the strong covalent bond between the Ni/Fe active site and GDY. Remarkably, the NiFe-LDH/GDY/G catalyst achieved a competitive low overpotential of 215 mV @ 10 mA cm−2 as well as a small Tafel slope of 22 mV dec−1. The improved OER kinetics could be attributed to the unique few-layered GDY/G heterostructure with a larger electrochemical active surface area, faster charge transfer kinetics, and higher intrinsic activity. [Display omitted] • Graphdiyne/graphene (GDY/G) heterostructure was synthesized as conductive carbon support. • NiFe layered double hydroxides were anchored on GDY/G as an OER catalyst. • A superior OER performance was obtained which is attributed to the unique 2D/2D support. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including the characterization of nanocrystals, the mechanisms and growth of zinc oxide nanostructure arrays, and the rheological modeling of flow serration behavior in metallic glasses.

Visible light responsive titanium dioxide/graphene oxide composites (TGO) were synthesized via electrostatic attraction at a low temperature of 80 °C. A superior visible light driven photocatalytic degradation of quinoline for TGO was achieved (75.56%), which was 6.17 times as high as that of P25 under the same reaction condition. The recycling experiment showed that 93.32% photocatalytic activity was remained after four cycles of repetitive uses. The excellent visible light driven photocatalytic activity and recycle stability could be attributed to the extending optical absorption edge and easy photogenerated electron-hole separation by trapping the electrons generated from titanium dioxide in the presence of graphene oxide. A tentative mechanism was postulated for the photodegradation of quinoline over TGO. [ABSTRACT FROM AUTHOR]

In a line with most recent trends in developing non-toxic fluorescent nanomaterials, we combined blue emissive carbon dots with green and red emissive zinc copper indium sulfide (ZCIS) core/shell quantum dots (QDs) to achieve white light-emitting diodes (WLEDs) with a high color rendering index of 93. This indicates that ZCIS QDs, with their broad emission bands, can be employed to effectively make up the emission of carbon dots in the yellow and red regions to produce WLEDs in the wide region of color temperature by tuning the volume ratio of these constituting luminophores. Their electroluminescence characteristics including color rendering index, Commission Internationale de l'Eclairage (CIE) color coordinates, and color temperatures were evaluated as a function of forward current. The CIE-1931 chromaticity coordinates of the as-prepared WLEDs, exhibiting good stability, were slightly shifted from (0.321, 0.312) at 10mA to (0.351, 0.322) at 30 mA, which was mainly caused by the different thermal quenching coefficients of carbon dots and ZCIS QDs. [ABSTRACT FROM AUTHOR]

We have studied the optical properties of PbSe colloidal quantum dot-solution filled hollow core multimode silica waveguides as a function of quantum dot-solution concentration, waveguide length, optical pump power and choice of organic solvent in order to establish the conditions to maximize near infrared spontaneous emission intensities. The optical performance was compared and showed good agreement with a simple three level system model for the quantum dots confined in an optical waveguide. Near infrared absorption-free solvent of tetrachlorethylene was confirmed to be a good candidate for the waveguide medium due to the enhancement of output intensity from the liquid-core fiber compared to the performance in toluene-based fiber. This approach demonstrates a useful method for early characterization of quantum dot materials in a waveguide test-bed with minimal material processing on the colloidal nanoparticles. [ABSTRACT FROM AUTHOR]

Highlights: [•] Reactive Red 120 was modified on the surface of magnetic chitosan microspheres. [•] A fivefold adsorption quantity for lysozyme was obtained. [•] A high desorption ratio was achieved by using NaCl phosphate buffer. [•] The modified magnetic chitosan microspheres were stable adsorbents for lysozyme. [•] High purity and high yield of lysozyme from egg white solution were achieved. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pre-formed Pt–Ru colloidal nanoparticles were used to prepare nearly monodisperse Pt–Ru/SnO2 supported catalysts. [•] The hydrogenation rate of o-CNB to o-CAN was as high as 2600h−1 without using any solvent. [•] 99.5% Selectivity to o-CAN at 100% conversion of o-CNB was achieved. [ABSTRACT FROM AUTHOR]

[Display omitted] • The PLQYs of CsCdBr 3 NRs are improved from ~0 to 57% by PbBr 2 doping. • The optimized perovskite NRs show pure-blue emission located at 459 nm. • The optimized NRs based LEDs achieved the maximum brightness of 225 cd m−2. One-dimensional (1D) semiconductor nanorods (NRs) are very promising materials for light-emitting diodes (LEDs) due to their unique optoelectronic properties, while the research on 1D perovskite NRs is relatively rare. Herein, the 1D CsCdBr 3 perovskite NRs were synthesized by simple thermal injection method, in which the [CdX 6 ]4- octahedra sharing opposite faces can form infinite linear chains along the c axis. But their low photoluminescence quantum yields (PL QYs) limit their application in LEDs. To improve the optoelectronic properties of CsCdBr 3 NRs, the PbBr 2 is chosen as the dopant to synthesize the Pb2+ doped CsCdBr 3 perovskite NRs. When the molar ratio of PbBr 2 :CdBr 2 is 0.25, the perovskite NRs with the PL QYs of 48% and pure-blue emission centered at 459 nm were obtained. Furthermore, the optimized NRs were used as the emissive layer to fabricate a perovskite LED that is the only one blue perovskite LED based on 1D NRs. This device shows bright pure-blue emission with good spectral stability, suggesting that the 1D perovskite NRs are good choice to achieve next-generation lighting and display. [ABSTRACT FROM AUTHOR]

[Display omitted] • The KPF 6 as a bifunctional additive is introduced into the perovskite layer. • The function of KPF 6 on crystal growth and device performance is investigated. • The KPF 6 can promote crystallization and heal ionic defects of perovskite films. • The optimized device shows a champion PCE of 22.04% and remarkable stability. High crystallization quality and low defect state density of perovskite films are essential for high-performance devices. Herein, we develop a facile and effective method using potassium hexafluorophosphate (KPF 6) to fabricate perovskite solar cells (PSCs) with highly improved power conversion efficiency (PCE) and outstanding stability. The corresponding mechanisms of the improved crystallization process, grain boundaries (GBs) passivation, and internal ionic defect passivation of the perovskite films are systematically studied. The results indicate that the introduced PF 6 − can promote crystallization by increasing fully coordinated intermediate groups in the perovskite solution and compensate for halide vacancies, which can modify ionic point defects in the perovskite films, resulting in reduced non-radiative recombination. Meanwhile, K+ ions are predominantly distributed at the GBs, which not only benefits the device efficiency but also significantly reduces the hysteresis due to the passivation effect. The champion passivated device presents a PCE of 22.04%, with a significantly improved PCE of around 16% compared with that of the control device (18.99%), retaining 80% of its initial PCE after 1000 h of light soaking without any encapsulation. Our work provides a defect passivation method for further improving both the PCE and stability of PSCs and can also be extended to other devices. [ABSTRACT FROM AUTHOR]

Since the aggregation induced emission (AIE) phenomenon was reported, many research groups have used this unique AIE effect to develop chemo- or bio-sensors for detecting ions, gases, explosives, proteins, and enzymes. Most of these sensors work in their aggregate state, therefore, fluorescence stability has become one of the important problem, and unfortunately, as far as we know, there is no paper to discuss what factors can improve the fluorescence stability of AIE compounds in the aggregate state, if the fluorescence stability of the sensors are poor, there will seriously affect the detection result. In this article, we found that compounds with hydrophobic long alkyl substituents can maintain stable fluorescence intensity for a long time in the aggregate state. In addition, cyclohexane is introduced as a hydrophobic substituent. Therefore, the fluorescence stability of the aggregates also increased by 90% within 1800s. The aggregation solutions of CB-3 and CSB-2 were left for two weeks, and no significant changes were found in the fluorescence intensity. Molecular dynamics simulation (MDS) shows that the presence of hydrophobic substituents in compounds cause the molecules to be closely interspersed with each other, hence, making it difficult to change the optical properties, microstructure and stacking mode of the AIE aggregates by external stimulations. The introduction of hydrophobic substituents improves the fluorescence stability of AIE compounds, and makes the AIE phenomenon more valuable in the fields of biological/chemical sensing and imaging. [Display omitted] • Visualization of AIE process was illustrated by molecular dynamics simulation. • Long alkyl and cyclohexane substituents are introduced into the AIE molecule as hydrophobic groups. • Hydrophobic groups enhances the AIE fluorescence stability in the aggregate state in water. • The CSB-2 still exhibited a superior performance in detecting TNT in aqueous media after placed for a week. [ABSTRACT FROM AUTHOR]

Abstract: Water-dispersible anatase TiO2 nanoparticles were synthesized at a low temperature (80°C) without using surfactants via the mechanism of electrostatic stabilization. The water-dispersible TiO2 nanoparticles solution was stable and no precipitation occurred after 3months. Photocatalytic evaluation demonstrated that the as-synthesized TiO2 nanoparticles possess excellent quinoline degradation performance (a 2.33×10−2 min−1 apparent reaction rate constant comparing to 1.22×10−2 min−1 for P25) and recycle stability (the photocatalytic activity remained 96.6% of the initial activity after four cycles of repetitive uses). These could be attributed to the small size and good water-dispersibility of the as-synthesized TiO2 nanoparticles that led to large specific surface area and easy photogenerated electron–hole transportation. [Copyright &y& Elsevier]

This paper presents a new approach to nanosphere lithography, which overcomes undesirable manufacturing issues such as complex tilted-rotary evaporation and ion beam milling. A key innovation in this process is the use of non-conductive edge strips placed on top of the samples prior to metal removal. Such elements help to direct the flow of reactive ions during plasma etching and produce well-ordered arrays of metallic nanorings and nanocrescents over large areas of ~1 cm². The obtained highly uniform nanocrescent array exhibits an electric resonance of 1.7 μm and a magnetic resonance of 3 μm. The absorption resonances of the fabricated nanorings depend on their diameters and shift toward shorter wavelengths (λ = 1:7 μm for do = 308 nm) as compared to larger rings (λ = 2:2 μm do D 351 nm). FDTD-based simulations match well with the experimental results. This 'shaped nanosphere lithography' approach creates opportunities to generate nanorings and nanocrescents that promise potential applications in chemical and biological sensing, for surface enhanced spectroscopy and in the field of infrared metamaterials. [ABSTRACT FROM AUTHOR]

Abstract: Magnetically recoverable Fe3O4/TiO2 composites were prepared via a modified sol–gel method at a low temperature of 80°C. Photocatalytic evaluation showed the relative quantity of Fe3O4 to TiO2 played an overwhelming role in the photocatalytic activity of Fe3O4/TiO2 composite. Superior photocatalytic activity was achieved, which was 25.6% higher than that of P25. The Fe3O4/TiO2 composites could be readily recovered from the reaction solution by using a permanent magnetic bar and their photocatalytic activity remained 95.6% after three cycles of repetitive use. [Copyright &y& Elsevier]

Anatase TiO2 nanoparticles with an average size of 16 nm were synthesized via a modified sol–gel method and were employed to degrade quinoline under UV irradiation (λ = 365 nm). The influence of reaction parameters such as TiO2 dosage, initial quinoline concentration and pH was investigated. Under the optimized reaction condition, 91.5% photodegradation efficiency of quinoline was achieved. When the TiO2 nanoparticles were reused for four times, the photodegradation efficiency was still as high as 90.6%. The analysis of the organic intermediates suggested that superoxide radical (ꔷO2) predominantly attacked the pyridine ring of quinoline leading to the formation of 2-aminobenzaldehyde, 2-quinolinone, 4-quinolinone; while the hydroxyl radical (ꔷOH) contributed much less by attacking benzene rings resulting in the formation of 5-hydroxyquinoline. The photocatalytic performance of the as-synthesized TiO2 nanoparticles was comparable to the commercial P25. A tentative mechanism was postulated for the photodegradation of quinoline over TiO2 nanoparticles. [Copyright &y& Elsevier]