Search

Spintronics research has been of emerging interest in the inorganic and organic electronics field, and magnetic materials play an important role in spintronics. Here, the spin valve (SV) devices are reported based on few‐layered van der Waals semiconducting WSe2 or InSe sandwiched between room‐temperature ferromagnet Pt/Co/Ru and exfoliated layered ferromagnetic metal Fe3GeTe2 (FGT). The metallic interface rather than the Schottky barrier is formed despite the semiconducting nature of WSe2 and InSe, which may be originated from the interface hybridization with Pt/Co/Ru and FGT. The magnetoresistance of both devices persists up to the Curie temperature of FGT, and the magnitude of the magnetoresistance does not vary with the applied current, which indicates these devices have stable device performance. The work reveals that easily fabricated Pt/Co/Ru multilayers could be stable 3D perpendicular magnetocrystalline anisotropy (PMA) spin injection electrodes applied in SV devices, facilitated by combining 2D magnets, which is expected to be an attractive candidate for 2D applications. [ABSTRACT FROM AUTHOR]

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]

In this work, we study the enhancement of Raman signals and photocatalytic activity of Ag/ZnO heterojunctions with an Ag content of 1 at.%, which were synthesized by photochemical deposition of Ag nanoparticles onto pre-synthesized ZnO nanorods. A strong interaction between Ag and ZnO nanocrystals were evidenced by XPS and UV-vis spectroscopy. The binding energy of Ag nanoparticles shifts toward lower energy compared to that of pure Ag nanoparticles, revealing that electrons transfer from Ag to the ZnO nanocrystals. The red shift of the plasmon absorption peak of Ag nanoparticles in Ag/ZnO heterojunctions further confirms the strong interaction between the two components. This strong interaction, arising from the coupling between Ag and ZnO nanocrystals, is responsible for the enhancement of Raman signals and photocatalytic activity of the Ag/ZnO heterojunctions. [ABSTRACT FROM AUTHOR]

A nanocrystal catalyst Ag/ZnO was successfully synthesized using a simple solvothermal method in this study. This catalyst was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that this catalyst was composed of metallic Ag and ZnO. The photodegradation of methyl orange (MO) was investigated in aqueous suspension containing Ag/ZnO catalyst under UV irradiation. Liquid chromatography coupled with electrospray ionization ion-trap mass spectrometry was applied to the analysis of the samples coming from the photocatalytic degradation of MO. The experimental results showed that there were four intermediates existing in the photocatalytic reaction. MO could be mineralized in the Ag/ZnO suspension after 60 min illumination. [Copyright &y& Elsevier]

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]

Abstract: High yield of nickel ferrite nano-octahedra with size distribution from 40 to 90nm were synthesized through a simple hydrothermal method. The formation of faceted octahedra enclosed by {111} planes implies the much faster growth rate along 〈100〉 over 〈111〉 for face-centered cubic phase during hydrothermal process. Magnetic measurements indicated that the sample is soft-magnetic materials with much lower coercivity and much higher saturation magnetization compared to the nickel ferrite nano-crystals with similar size distribution but irregular shapes reported earlier. [Copyright &y& Elsevier]

Abstract: Anorthic SrHPO4 nanobelts and hexagonal Sr10O(PO4)6 nanorods were obtained by a simple hydrothermal method without adding any surfactant as template. The as-synthesized products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). TEM and HRTEM observations of the products revealed that the as-prepared SrHPO4 nanobelts and Sr10O(PO4)6 hexagonal nanorods are single crystals with their preferential growth direction along the normal of (100) and (001) planes, respectively. [Copyright &y& Elsevier]

Lead halide perovskite quantum dots (PeQDs) generally show slow hot carrier (HC) cooling because of the retarded relaxation of longitudinal optical (LO) phonons induced by hot phonon bottleneck effect. Although the feature is beneficial for designing photovoltaic devices beyond Schottky–Queisser limitation by manipulating HC excess energy, it would be hostile toward light‐emitting applications where fast HC cooling is preferred. Herein, a Ni2+ doping strategy is reported to effectively boost HC cooling in CsPbI3 PeQDs and inhibit Auger recombination, giving rise to near unity photoluminescent quantum yield (PLQY) for the Ni: CsPbI3 sample. Femtosecond transient (fs‐TA) absorption, temperature‐dependent PL spectra and theoretical calculations evidence that Ni2+ doping results in the enhancement of electron‐LO phonon coupling, the introduction of extra energy states at band edges, the increasement of effective carrier mass, and the modification of phonon dispersion spectra as well as density of states (DOS) of LO phonon modes. These synergistic roles ensure efficient Klemens decay within Ni: CsPbI3, which facilitates fast decay of hot phonons and break hot phonon bottleneck. These findings provide a valid route to tackle HC dynamics and pave a way for PeQDs‐based efficient light‐emitting applications. [ABSTRACT FROM AUTHOR]

Perovskite quantum dots (PeQDs) are seen as the credible alternative to traditional QDs ascolor converter in liquid crystal display (LCD). Unfortunately, PeQDs sufferfrom instability and color separation, and the prepared PeQDs enhanced films(PQDFs) need the protection of expensive barrier layers, which significantly increases price and limits their application. Herein, large‐area yellow monolithic PQDF is fabricated with both green CsPbBr3 and red CsPbBr1I2QDs encapsulated in the dual matrices of inorganic glass and polypropylene (PP) via an industrialized melt extruding & rolling method. The PQDF shows high photoluminescence quantum yield (PLQY) of 92% and narrow full width at half maximum (FWHM) of 19 nm (green) and 33 nm (red). Importantly, the bare PQDF without barrier layers can pass harsh aging test at 85 °C/85% RH and reach anoperating T90 lifetime over 1000 h. Finally, a white backlit unit is designed by coupling yellow monolithic PQDF with blue light guide panel, and the constructed prototype display shows superior color rendering performance forits narrow green/red emissions, reaching a color gamut of 110% National Television System Committee (NTSC). This work provides a novel and easy‐to‐industrialize route to prepare PQDFs to realize their commercial application in backlit display. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen production is considered as an ideal approach to solve global energy crisis and environmental pollution. Graphitic carbon nitride (g-C 3 N 4) has received extensive consideration due to its facile synthesis, stable physicochemical properties, and easy functionalization. However, the pristine g-C 3 N 4 usually shows unsatisfactory photocatalytic activity due to the limited separation efficiency of photogenerated charge carriers. Generally, introducing semiconductors or co-catalysts to construct g–C 3 N 4 –based heterojunction photocatalysts is recognized as an effective method to solve this bottleneck. In this review, the advantages and characteristics of various types of g–C 3 N 4 –based heterojunction are analyzed. Subsequently, the recent progress of highly efficient g–C 3 N 4 –based heterojunction photocatalysts in the field of photocatalytic water splitting is emphatically introduced. Finally, a vision of future perspectives and challenges of g–C 3 N 4 –based heterojunction photocatalysts in hydrogen production are presented. Predictably, this timely review will provide valuable reference for the design of efficient heterojunctions towards photocatalytic water splitting and other photoredox reactions. [Display omitted] • g–C 3 N 4 –based photocatalysts for solar hydrogen production are overviewed. • Heterojunction significantly improved the photocatalytic activity of g-C 3 N 4. • g-C 3 N 4 heterojunction/isotype junction can be synthesized by copolymerization. • The details for the design of g–C 3 N 4 –based heterojunctions are highlighted. • The challenges and prospects of g-C 3 N 4 photocatalysts are presented. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Laser‐driven projection display puts forward urgent demand for color converter materials to simultaneously achieve balanced‐spectrum properties and strong heat dissipation. Herein, this work develops a novel optofunctional composite by coupling Y3Al5O12:Ce3+ transparent ceramics (TC) with CaAlSiN3:Eu2+ phosphor‐in‐glass film (PiGF) for the first time. Remarkably, this new material architecture design enables a balance between the spectrum properties and heat dissipation ability, and can yield high‐quality white light with brightness of over 2500 lm, luminous efficacy (LE) of over 200 lm W−1, correlated color temperature (CCT) of 3700–4100 K, and improved color rendering index (CRI) of 60–70. Furthermore, the PiGF@TC‐converted laser projection system is also successfully designed, showing natural and real color restoration. Additionally, the combined action of thermal quenching and optical excitation intensity quenching is confirmed for the luminescence saturation upon high‐power blue laser driven. The main mechanism of optical quenching is identified to be energy upconversion dominated by second‐order nonlinear processes. The findings described here suggest a step toward developing the admirable laser‐driven color converters for next‐generation lighting sources. [ABSTRACT FROM AUTHOR]

Robust amorphous glass protected CsPbBr3 (CsPbBr3@glass) perovskite quantum dots (PeQDs) with ultra‐pure green emission and superior long‐term stability are highly desirable for developing wide‐color‐gamut liquid crystal displays. However, most of the reported CsPbBr3@glass nanocomposites are subject to low external quantum efficiency (EQE). This work demonstrates that ZrO2 additive has an "accumulation" effect on the borosilicate glass network structure to promote in situ nucleation/growth of PeQDs inside glass rather than self‐crystallization. This effect is beneficial in reducing surface defects, improving the quality of PeQDs, and thus boosting radiative recombination of excitons. As a consequence, the as‐prepared CsPbBr3@glass shows a record EQE of up to 75% and can pass the accelerated aging tests at 85 °C/85% RH for 1000 h and blue light irradiation over 2000 h. Finally, a prototype display using CsPbBr3@glass‐based straight‐down backlit unit is designed and gains more favorable responses in blind selection tests for its high brightness of 2647 cd m−2 and high color purity of 88%. The findings will pave the way for realizing the commercial application of CsPbBr3@glass nanocomposite in PeQDs‐converted backlit display. [ABSTRACT FROM AUTHOR]

Currently, lanthanide (Ln3+) doped Pb‐free double perovskites (DPs) suffer from competitive emissions of the self‐trapped exciton (STE) and Ln3+. Herein, a new type of Nd3+‐doped Cs2AgInCl6 DPs with Na+/Bi3+ co‐alloying is developed. Benefiting from Na+/Bi3+‐induced local structural modification, both STE broadband visible luminescence and Nd3+ near‐infrared (NIR) emissions are boosted via free exciton sensitization. Specifically, a total 648‐fold enhancement in emitting intensities compared to the Na+/Bi3+‐free counterpart is realized, with a significantly improved NIR photoluminescence quantum yield (PLQY) from 0.16% to 30.3%. First‐principles density functional theory calculations, Raman spectra, and steady/transient‐state PL spectra verify the modification of local site symmetry, breakdown of parity‐forbidden absorption, and reduction of electron‐phonon coupling via Na+/Bi3+ doping. Finally, a compact vis–NIR broadband light‐emitting diode (LED) is designed by coupling the Na/Bi/Nd: Cs2AgInCl6 DP with a commercial ultraviolet LED chip, which shows promising applications in spectroscopic analyses and multifunctional lighting. [ABSTRACT FROM AUTHOR]

Laser‐driven projector puts forward urgent demand for light‐conversion materials to achieve high‐quality image display. Herein, a composite structure phosphor‐in‐glass film (PiGF) is fabricated via screen‐printing YAG:Ce and low‐melting glass on the alumina substrate. Benefited from well‐retained optical properties of YAG:Ce in amorphous glass and high thermal conductivity of substrate, PiGF can produce desirable luminous flux of 7169 lm and luminous efficiency of 192 lm W−1 at saturation threshold of 13.25 W mm−2. Furthermore, it is demonstrated that thermal management by using a cool fan with aluminum heat sink is essential to reduce heat aggregation and improve white‐light stability of PiGF‐based laser lighting source operated in a reflective mode. Accordingly, a PiGF‐converted laser projection system is successfully designed for the first time, showing more vivid and brighter display feature benefited from high laser‐driven luminance of LCD screen (2180 cd m−2). This work highlights the practical application of PiGF@alumina‐substrate composite as an efficient laser‐driven color converter in high‐brightness projection display. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

High‐quality backlit display puts forward urgent demand for color‐converting materials. Recently, metal halide perovskites (MHPs) with full spectral tunability, high photoluminescence quantum yields (PLQYs), and high color purity have found potential application in wide‐color‐gamut display. Regrettably, naked MHPs suffer from long‐term instable issue and cannot pass harsh stability tests. Herein, amorphous‐glass‐protected green/red CsPbX3 quantum dots (QDs) are prepared by elaborately optimizing glass structure, perovskite concentration, and in situ crystallization. PLQYs of green CsPbBr3@glass and red CsPbBr1.5I1.5@glass reach 94% and 78%, respectively, which are the highest ones of CsPbX3@glass composites reported so far and comparable to colloidal counterparts. Benefited from complete isolation of QDs from external environment by glass network, CsPbX3@glass can endure harsh commercial standard aging tests of 85 °C/85%RH and blue‐light‐irradiation, which are applied to construct white light‐emitting diodes (wLEDs) with high external quantum efficiency of 13.8% and ultra‐high luminance of 500 000 cd m−2. Accordingly, the perovskite wLED arrays‐based backlit unit and a prototype display device are designed for the first time, showing more vivid and wide‐color‐gamut feature benefited from narrowband emissions of CsPbX3 QDs. This work highlights practical application of CsPbX3@glass composite as an efficient and stable light color converter in backlit display. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Laser‐driven projection display puts forward urgent demand for color converter materials to achieve wide‐color‐gamut and high‐quality image presentation. In this study, a hierarchical structure quantum dots‐in‐glass film (QiGF) is fabricated via co‐sintering stable green/red‐emitting CsPbX3@glass (X3 = Br3, Br1.5I1.5) and commercial low‐melting glass on the sapphire substrate. Benefiting from the well‐retained optical properties of CsPbX3 quantum dots in amorphous glass and high thermal conductivity, QiGF succeeded in inhibiting luminescence saturation after 20 W mm−2 blue laser irradiation. A brand‐new white‐lighting source designed by coupling a blue laser with a pattern "QiGF wheel" produced ultra‐narrow blue/green/red tri‐color emissions and total luminous flux of 146 lm. Accordingly, a QiGF‐converted laser projection system is successfully designed for the first time, showing more natural and real color restoration for its wide color gamut display feature (157% of conventional light‐emitting diode projection and 107% of NTSC standard). The present study highlights the practical application of CsPbX3 quantum dots composite as an efficient laser‐driven color converter in projection display. [ABSTRACT FROM AUTHOR]

Currently, advanced optical security techniques are imminent in response to the increasingly rampant counterfeit and pirated goods on a global scale. Herein, hexagonal Na(NdxY1−x)F4 (x = 0–1) solid‐solution nanocrystals (NCs) embedded glasses are successfully fabricated via in situ glass crystallization. Benefited from the protection of inorganic glass, Na(NdxY1−x)F4 NCs exhibit superior long‐term stability and can endure high‐power 808 nm laser irradiation. Importantly, opposite variations between near‐infrared (NIR) luminescence and laser‐induced temperature can be detected for the nanocomposites, which are sensitive to Nd3+ doping concentration. As a proof‐of‐concept experiment, Nd3+ concentration dependent anti‐counterfeiting patterns with high‐concealment and high‐precision are designed and show bright emission and dimmish thermal images in Nd3+‐tenuous composites under the irradiation of 808 nm laser, while opposite displays can be achieved in Nd3+‐enriched one. This kind of information encryption triggered by a commercial single light source to achieve dual opposing displays in one material can effectively improve security in anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Merging cryptographic primitive technologies and physical unclonable functions (PUFs) have become a new paradigm of one‐way encryption. Herein, the authors report a dynamic PUF cryptographic primitive based on plasmonic fluorescence blinking from single or a few dye molecules embedded within the nanogaps of plasmonic patch nanoantennas. This cryptographic primitive carries two sets of high‐capacity optical codes: the fluorescence blinking of the embedded dye molecules and multi‐color light scattering enabled by the plasmonic nanoantennas. The former allows the generation of temporal binary codes from a large number of individual plasmonic patch nanoantennas by holding either "1" (bright state) or "0" (dark state), while the latter provides a permanent color‐based novenary code that acts as a decryption channel for authentication. Benefiting from the high electromagnetic field localized within the nanogaps and the large Purcell enhancement of the plasmonic nanoantennas, the fluorescence blinking is readily detectable by a common fluorescence microscope with a mercury arc lamp as a low‐power excitation source. The developed dynamic PUF codes are robustly and accurately authenticated by a self‐programmed computer vision algorithm. This study revolutionizes the conventional static PUF encryption to nanophotonics‐based dynamic encryption, opening a new avenue for next‐generation advanced anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

A lithium–sulfur battery, a potential next-generation secondary battery, is affected by poor conductivity of sulfur and the dissolution of intermediate polysulfides. Here we report a lithium–sulfur battery with ultrahigh sulfur loading and excellent cycling stability using porous graphitic carbon (PGC) as a high-conductivity carrier of sulfur and carbon fiber with crisscross conductive framework as an electric attachment site of sulfur. PGC is fabricated through a simple and environmentally friendly synthesis process involving high-temperature graphitization in a N2 atmosphere followed by an annealing process in air. Due to the presence of porous graphitic structure, with C–O termination groups, PGC endows the lithium–sulfur battery system with excellent cycling performance. The lithium–sulfur battery cathode constructed by PGC with a sulfur loading of 2.5 mg cm−2 still retains a high specific capacity of 734.4 mA h g−1 after 200 cycles. Meanwhile, an ultrahigh sulfur loading of 12.8 mg cm−2 for a CR2025 coin cell is achieved, which is the highest sulfur loading reported in the literature for the coin cell. The ultrahigh sulfur loading cell also shows good electrochemical properties, profiting from the mesopores terminated with C–O groups, high specific surface area of 1129.9 m2 g−1 and high-conductivity graphitic structure. [ABSTRACT FROM AUTHOR]

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]

[Display omitted] • The AgBr/HCCN photocatalyst was fabricated using an electric self-assembly approach. • The hybrid photocatalyst features an all-solid-state direct Z-scheme heterojunction. • The Z-scheme heterojunction improves the photogenerated charge carriers' separation. • The contact level of the heterojunction affects the performance of the photocatalyst. • The AgBr/HCCN photocatalyst exhibits a 5.4-fold enhancement in hydrogen evolution. Constructing a Z-scheme heterojunction with enhanced photocatalytic hydrogen evolution for graphitic carbon nitride-based (g-C 3 N 4) composites is challenging because integrating g-C 3 N 4 with other semiconductors, without specific band structure design, typically results in type I or type II heterojunctions. These heterojunctions have lower redox ability and limited enhancement in photocatalysis. Herein, we select highly crystalline carbon nitride (HCCN) as a proof-of-concept substrate. For the first time, we develop a AgBr nanosphere/HCCN composite photocatalyst that features an all-solid-state direct Z-scheme heterojunction for visible-light photocatalytic hydrogen evolution. The electron transfer mechanism is initially studied from the band structures and Fermi levels of HCCN and AgBr. It is subsequently confirmed by X-ray photoelectron spectroscopy (XPS), and electron microscopy. The close heterojunction contact and the built-in electron field of the Z-scheme heterojunction promote the migration and separation of photogenerated electrons and holes in the composite photocatalyst. Due to the redistribution of charge carriers, the photocatalyst shows superior redox capability and a markedly enhanced hydrogen evolution performance compared to its individual components. Combining all the advantages, AgBr nanosphere/HCCN reached an apparent quantum efficiency (AQE) of 6 % under the illumination of 410 nm, which is 4 times higher than that of the single HCCN component. [ABSTRACT FROM AUTHOR]

Crystalline graphitic carbon nitride is an excellent photocatalyst for hydrogen production due to its non-toxicity, stability, elemental abundance, and visible-light response. Herein, we present a new type of composite photocatalysts, eco-friendly bamboo-charcoal-loaded graphitic carbon nitrides to accelerate the separation of electron-hole pairs. The suitable loading of bamboo charcoal on graphitic carbon nitrides shows an increased specific surface area from 85 to 120 m2 g−1, and excellent visible-light photocatalytic hydrogen production activity of 4.1 mmol g−1 h−1, which is 2.3 times higher than that of pristine carbon nitride (1.8 mmol g−1 h−1). Under irradiation, the photogenerated electrons fast migrate from graphitic carbon nitride to bamboo charcoal through an ohmic contact between them, reducing the recombination of electron-hole pairs. This study highlights the effect of carbonaceous material loading on photocatalytic activity of carbon nitrides and opens an avenue to design efficient loaded photocatalysts with natural abundant materials. • BC is loaded on g-C 3 N 4 via a simple method for visible-light driven H 2 production. • The modification of g-C 3 N 4 with nature-abundant materials is demonstrated. • An ohmic junction between BC and g-C 3 N 4 accelerates the transfer of electrons. [ABSTRACT FROM AUTHOR]

The unipolar n‐type polymeric semiconductors are crucial for the development of complementary inverters and complementary logic circuits. To achieve this target, the polymer skeleton should be electron‐deficient, which guarantees the energy‐level alignment between the lowest unoccupied molecular orbital energy level of polymeric materials and the work function of electrode, further permitting effective electron injection. Different from the introduction of the sp2‐hybridized nitrogen atoms and fluorine atoms, cyano‐substituted aromatic blocks are synthesized and further copolymerized with naphthalene diimide (NDI) unit, affording a series of copolymers of PNDI‐BTCN, PNDI‐TVTCN, and PNDI‐SVSCN. The photophysical, electrochemical, and thermal properties of all the copolymers are systematically investigated, and their semiconducting performance is studied by fabricating field‐effect transistors and tested under atmosphere. All the polymers exhibit unipolar n‐type semiconducting performance because of the synergetic effect of strong electron‐withdrawing NDI units and cyano‐substituted aromatic blocks. The highest mobility of 0.20 cm2 V−1 s−1 is obtained. Moreover, theoretical simulation and thin‐film characterization are conducted to reveal the difference in semiconducting performance among the three polymeric materials. [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]

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. [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]

[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]

A new seedless method is reported for synthesizing monodispersed gold nanorods (AuNRs) with a remarkably high yield (≈100%) and highly tunable longitudinal surface plasmon resonance (LSPR). The soft‐template modification and well‐controlled growth kinetics synergistically influence the nanorod growth, providing an effective strategy for synthesizing monodispersed AuNRs with different dimensions. For more detail, see the Full Paper by H. Wang and co‐workers on page 3291 ff. [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]

Porous CuxO/TiO2 architectures with enhanced dispersion of the active phase are synthesized by a facile MOF-templated method. Such a unique composite would furnish excellent catalytic activity for CO oxidation under relatively mild conditions. [ABSTRACT FROM AUTHOR]

• Carbon coated and Fe-F co-doped NaTi 2 (PO 4) 3 materials are synthesized for Aqueous Li-ion Battery. • The addition of F restrains the dissolution of Fe3+ and enhances the structure stability in aqueous solution. • Na 0.9 Ti 1.9 Fe 0.1 (PO 4) 2.9 F 0.1 /C shows ultra-long cycling stability especially at high rate. The developed strategy of combination of coating and lattice doping is put forward to improve the structural stability and electrical conductivity of NaTi 2 (PO 4) 3 -based anode materials and further enhance the cycling performance. [Display omitted] NASICON-type NaTi 2 (PO 4) 3 (NTP) with stable 3D framework exhibits great application prospect as anode materials for aqueous lithium ion battery (ALIB). However, the low electrical conductivity of NTP adversely affects its rate and cycling performance. Surface coating and lattice doping are considered to be effective means to improve the performance of the material. Herein, carbon coated and Fe-F co-doped NTP anode materials were synthesized for ALIBs. It is found that the LiMn 2 O 4 ||NTP-Fe 0.1 -F 0.1 /C full cell delivers a high discharge specific capacity of 112.8, 103.2 and 96.2 mAh g−1 at 0.5, 5 and 10 C, respectively, in the voltage range of 0.5–1.9 V when Ni foam is used as gasket for the cell assembly. The performances of the cell especially the cycling lifetime at high charge-discharge rates are further improved using electrochemically stable stainless steel as gasket. A high coulombic efficiency of 100% and a low capacity decay of only 0.8% at 5 C and 14.9% at 10 C are achieved even after 2000 cycles of charge-discharge test. This is the most stable NTP-based ALIBs reported in the literature. The outstanding electrochemical property and the long cycling lifetime of the NTP-Fe 0.1 -F 0.1 /C material is due to the enhanced structural stability and electron/Li+ ion transfer kinetics. [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]

[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]

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]

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]