Asymmetric Plasmonic Moth-Eye Nanoarrays with Side Opening for Broadband Incident-Angle-Insensitive Antireflection and Absorption.

Plasmonic absorbers with broadband angle-insensitive antireflection have attracted intense interests because of its wide applications in optical devices. Hybrid surfaces with multiple different sub-wavelength array units can provide broadened antireflection, while many of these antireflective surfaces only work for specific angles and require high complexity of nanofabrication. Here, a plasmonic asymmetric nanostructure composed of the moth-eye dielectric nanoarray partially modified with the top Ag nanoshell providing a side opening for broadband incident-angle-insensitive antireflection and absorption, is rationally designed by nanoimprinting lithography and oblique angle deposition. This study illustrates that the plasmonic asymmetric nanostructure not only excites strong plasmonic resonance, but also induces more light entry into the dielectric nanocavity and then enhances the internal scattering, leading to optimized light localization. Hence, the asymmetric nanostructure can effectively enhance light confinement at different incident angles and exhibit better antireflection and the corresponding absorption performance than that of symmetric nanostructure over the visible wavelengths, especially suppressing at least 16.4% lower reflectance in the range of 645-800 nm at normal incidence.Moreover, the reflectance variance of asymmetric nanostructure with the incident angle changing from 5° to 60° is much smaller than that of symmetric nanostructure, making our approach relevant for various applications in photocatalysis, photothermal conversion, and so on.

Spontaneous Transport Mechanics of Water Droplets under a Synergistic Action of Designed Pattern and Non-Wetting Gradient.

The controllable spontaneous transport of water droplets on solid surfaces has a broad application background in daily life. Herein, a patterned surface with two different non-wetting characteristics was developed to control the droplet transport behavior. Consequently, the patterned surface exhibited great water-repellant properties in the superhydrophobic region, and the water contact angle reached 160° ± 0.2°. Meanwhile, the water contact angle on the wedge-shaped hydrophilic region dropped to 22° after UV irradiation treatment. On this basis, the maximum transport distance of water droplets could be observed on the sample surface with a small wedge angle of 5° (10.62 mm), and the maximum average transport velocity of droplets was obtained on the sample surface with a large wedge angle of 10° (218.01 mm/s). In terms of spontaneous droplet transport on an inclined surface (4°), both the 8 µL droplet and 50 µL droplet could move upward against gravity, which showed that the sample surface possessed an obvious driving force for droplet transport. Surface non-wetting gradient and the wedge-shaped pattern provided unbalanced surface tension to produce the driving forces in the process of droplet transport, and the Laplace pressure as well is produced inside the water droplet during this process. This work provides a new strategy to develop a patterned superhydrophobic surface for droplet transport.

Mechanically Switchable Multifunctional Device for Regulating Passive Radiative Cooling and Solar Heating.

Energy consumption during cooling and heating poses a great threat to the development of society. Thermal regulation, as switchable cooling and heating in a single platform, is therefore urgently demanded. Herein, a switchable multifunctional device integrating heating, cooling, and latent energy storage was proposed for temperature regulation and window energy saving for buildings. A radiative cooling (RC) emitter, a phase-change (PC) membrane, and a solar-heating (SH) film were connected layer by layer to form a sandwich structure. The RC emitter exhibited selective infrared emission (emissivity in the atmospheric window: 0.81, emissivity outside the atmospheric window: 0.39) and a high solar reflectance (0.92). Meanwhile, the SH film had a high solar absorptivity (0.90). More importantly, both the RC emitter and the SH film displayed excellent wear resistance and UV resistance. The PC layer can control the temperature at a steady state under dynamic weather conditions, which could be verified by indoor and outdoor measurements. The thermal regulation performance of the multifunctional device was also verified by outdoor measurements. The temperature difference between the RC and SH models of the multifunctional device could reach up to 25 °C. The as-constructed switchable multifunctional device is a promising candidate for alleviating the cooling and heating energy consumption and realizing energy saving for windows.

Low-Energy Photons Dual Harvest for Photocatalytic Hydrogen Evolution: Bimodal Surface Plasma Resonance Related Synergism of Upconversion and Pyroelectricity.

Utilization of low-energy photons for efficient photocatalysis remains a challenging pursuit. Herein, a strategy is reported to boost the photocatalytic performance, by promoting low-energy photons dual harvest through bimodal surface plasmon resonance (SPR)-enhanced synergistically upconversion and pyroelectricity. It is achieved by introducing triplet-triplet annihilation upconversion (TTA-UC) materials and plasmonic material (Au nanorods, AuNRs) into composite fibers composed of pyroelectric substrate (poly(vinylidene fluoride)) and photocatalyst Cd0.5 Zn0.5 S. Interestingly, the dual combination of TTA-UC and AuNRs SPR in the presence of polyvinylidene fluoride substrate with pyroelectric property promotes the photocatalytic hydrogen evolution performance by 2.88 folds with the highest average apparent quantum yield of 7.0% under the low-energy light (λ > 475 nm), which far outweighs the role of separate application of TTA-UC (34%) and AuNRs SPR (76%). The presence of pyroelectricity plays an important role in the built-in electric field as well as the accordingly photogenerated carrier behavior in the composite photocatalytic materials, and the pyroelectricity can be affected by AuNRs with different morphologies, which is proved by the Kelvin probe force microscopy and photocurrent data. This work provides a new avenue for fully utilizing low-energy photons in the solar spectrum for improving photocatalytic performance.

Crystallinity and ß Phase Fraction of PVDF in Biaxially Stretched PVDF/PMMA Films.

Polyvinylidene fluoride (PVDF) and poly(methyl methacrylate) (PMMA) blend films were prepared using biaxial stretching. The effects of PMMA content and stretching ratio on the crystallinity and ß phase fraction of PVDF in blend films were investigated. The distributions of crystallinity and ß phase fraction on variable locations were also studied. The results of FTIR and XRD showed that ß phase appeared in PVDF/PMMA blends after extrusion and casting procedures. Although ß phase fraction decreased after preheating, there was still an increasing trend during following biaxial stretching. More importantly, the increase in PMMA content improved ß phase fraction, and the highest ß phase fraction of 93% was achieved at PMMA content of 30 wt% and stretching ratio of 2×2. Besides, the reduction in PMMA content and the increase in stretching ratio improved the crystallinity of PVDF. The mechanical properties of the stretched films were significantly improved by increasing the stretching ratio as well. The uniform stress distribution on different regions of biaxial stretching films contributed to the uniform distribution of ß phase fraction and crystallinity of PVDF with the aid of simulation. This work confirmed that biaxial stretching can be a candidate method to prepare PVDF/PMMA blend films with uniform distributions of comparable ß phase and crystallinity of PVDF.

Strain-tuned magnetism and half-metal to metal transition in defective BCN monolayer.

Recently, two-dimensional (2D) BCN, an in-plane heterostructure formed by graphene and hexagonal boron nitride, has been successfully synthesized experimentally and exhibits diverse electronic properties. Unfortunately, it has been slow on the application of 2D BCN for spintronics due to the lack of the magnetic ordering. Here, using density functional theory calculations, we explored the effect of vacancy defect and biaxial strain on the electronic and magnetic properties of BCN monolayer. It is demonstrated that BCN monolayer can be converted from nonmagnetic semiconductor to magnetic half-metal/metal by introducing C or B vacancies. The half-metal/metal behavior can be remained under the different vacancy concentrations in defective BCN monolayer. In addition, BCN monolayer with C and B vacancies can be converted between half-metal and metal by applying biaxial strain. Moreover, the magnetic properties of defective BCN monolayer can also be efficiently modulated under the biaxial strain by regulating the spin polarization of the C/N/B 2porbitals. Our findings not only provide an effective way to achieve half-metal/metal transition, but also can induce and manipulate the magnetism of BCN monolayer, which may be utilized for the development of 2D BCN spintronic nanodevices.

Near-Infrared Light-Induced Sequential Shape Recovery and Separation of Assembled Temperature Memory Polymer Microparticles.

Light-induced, shape-changing polymeric microparticles have many applications. Here, the near-infrared (NIR)-light-triggered sequential recovery and separation of assembled large and small polymer microparticles using cross-linked blends of poly(ethylene-vinyl acetate) and trans-polyisoprene as temperature memory polymers as well as two NaYF4 based up-conversion nanoparticles (UCPs) to provide luminescent and photothermal effects are reported. Under irradiation of NIR light with a low light power density, small particles assembled onto the compressed large one recover first due to the low switching temperature (Tsw ) arising from the temperature-memory effect. The small particles can separate from the underlying large particle in flowing aqueous media. The recovery of the large particle occurs at a high power density. Two UCPs of NaYF4 : 20Yb, 0.2Tm, 5Gd and NaYF4 : 18Yb, 2Er, 5Gd facilitate the detection of small and large microparticles via providing blue and green light emissions, respectively. This work can expand the applications of light-induced shape-changing polymer microparticles in the biomedical field, controlled catalysis, microfluidic devices, and so on.

Efficient Photocatalysis of Composite Films Based on Plasmon-Enhanced Triplet-Triplet Annihilation.

To avoid secondary environmental pollution caused by photocatalysts in their applications, our work offers a new strategy for fabricating photocatalytic films based on plasmon-enhanced triplet-triplet annihilation upconversion (TTA-UC). Polydimethylsiloxane (PDMS) films containing platinum (II)-octaethylporphyrin and 9,10-diphenylanthracene (PtDPAP), and gold nanoparticles (AuNPs) were prepared. While graphene (G) was used as an adhesive and conductive layer, CdS nanoparticles were deposited onto the films (AuNPs-PtDPAP/G/CdS) by plasma glow discharge pretreatment. The AuNPs-PtDPAP film had an enhancement in the green-to-blue upconversion compared with the pristine PtDPAP film. CdS can utilize the AuNPs plasmon-enhanced TTA-UC photons to realize efficient photocatalytic reactions. The pseudo-first-order rate constant (kpfo) of the optimized active and stable photocatalytic film, 0.3 AuNPs-PtDPAP/G/CdS, reached 0.294 h-1 for tetracycline degradation under green light irradiation. Its kpfo in decomposing tetracycline under visible light is 2.62 times higher than that of the PtDPAP/G/CdS. The reported composite films provide a strategy to improve the photocatalytic activity and promote the practical applications of nanosize photocatalysts.

A Pragmatic Bilayer Selective Emitter for Efficient Radiative Cooling under Direct Sunlight.

Radiative cooling can make the selective emitter cool below ambient temperature without any external energy. Recent advances in photonic crystal and metamaterial technology made a high-efficiency selective emitter achievable by precisely controlling the emitter's Infrared emission spectrum. However, the high cost of the photonic crystals and meta-materials limit their application. Herein, an efficient bilayer selective emitter is prepared based on the molecular vibrations of functional nanoparticles. By optimizing the volume fraction of the functional nanoparticles, the bilayer selective emitter can theoretically cool 36.7 °C and 25.5 °C below the ambient temperature in the nighttime and daytime, respectively. Such an efficient cooling performance is comparable with the published photonic crystal and metamaterial selective emitters. The rooftop measurements show that the bilayer selective emitter is effective in the ambient air even under direct sunlight. The relatively low cost and excellent cooling performance enable the bilayer selective emitter to have great potential for a practical purpose.

Comparison of interleukin-6, interleukin-10, procalcitonin and C-reactive protein in identifying high-risk febrile illness in pediatric cancer patients: A prospective observational study.

The aim of this study is to systematically compare the performance of C-reactive protein (CRP), procalcitonin (PCT) and serum cytokines in identifying pediatric cancer patients with high-risk infection. A prospective observational study was performed from January 2014 through December 2016. Consecutive pediatric cancer patients who experienced febrile illness during hospitalization were enrolled. The CRP, PCT, interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α and interferon (IFN)-γ were determined within 6 h of fever onset. A total of 3118 episodes of febrile illness were included, with 13.1% episodes documented as bloodstream infection (BSI) and 3.5% diagnosed as septic shock. Patients with BSI presented much higher levels of PCT, IL-6, IL-10 and TNF-α than patients with other types of fever and have much higher incidence of septic shock (11.2% vs. 2.3%, P < 0.001). IL-6 and IL-10 showed better performance in identifying patients with gram-negative bacteremia (GNB) and septic shock than CRP and PCT, respectively. The area under the curve (AUCs) of receiver operating characteristic (ROC) curve for septic shock prediction were 0.65, 0.78, 0.89 and 0.87 for CRP, PCT, IL-6 and IL-10, respectively. Furthermore, elevation of IL-6 and IL-10 were strongly associated with the development of GNB and septic shock. Our results indicate that BSI, especially GNB, is a high-risk form of infection which results in high incidence of septic shock. IL-6 and IL-10 performance better than CRP and PCT in identifying patients with high-risk febrile illness.

Enhancement of fluorescent emission in photonic crystal film and application in photocatalysis.

Fluorescent photonic crystal films composed of monodisperse NaYF4:15Yb,0.5Tm@SiO2 (where 15 and 0.5 represent the mole percentage of reactants) core-shell spheres were successfully fabricated and applied in photocatalysis. The core-shell spheres were prepared using a modified Stober method, and fluorescent photonic crystal films were fabricated via a simple self-assembly method. The morphologies, structures and upconversion fluorescent properties of the fluorescent photonic crystal films with different photonic band gaps were characterized. Moreover, their photocatalytic capability in decomposing rhodamine B using near-infrared light was studied. Results indicate that the band edge effect plays a critical role in the enhancement of short wave emission intensity of fluorescent photonic crystal films. Specifically, in comparison to the reference sample without a band edge effect, the 363 nm emission intensity was enhanced by 5.97 times, while the percentage of UV upconversion emission was improved by 6.23%. In addition, the 451 nm emission intensity was enhanced by 5.81 times, and the percentage of visible upconversion emission was improved by 8.88%. Furthermore, fluorescent photonic crystal films with enhanced short wave emission exhibited great photocatalytic performance in the degradation of rhodamine B aqueous solutions under near-infrared light.

[Progress in clinical studies of chimeric antigen receptor engineered T cells for treatment of childhood cancer].

Nowadays, the 5-year survival rate of childhood cancer patients can be more than 80%, but some patients with relapse and refractory cancers have shown no good response to traditional strategies. Chimeric antigen receptor engineered T (CAR-T) cell therapy is promising for these patients. CAR-T cells recognize the tumor-associated antigens in a non-major histocompatibility complex-restricted manner, so their anti-tumor ability is enhanced. There are four generations of CAR-T cells now. The complete remission rate of pediatric patients with relapse and refractory acute lymphoblastic leukemia can be as high as 90% when treated with CD19-targeting CAR-T cells. Furthermore, CAR-T cell therapy can also be used to bridge to transplantation and donor CAR-T cell infusion can be a strategy to prevent relapse after hematopoietic stem cell transplantation. As to solid tumors, only patients with neuroblastoma present good response to the GD2-targeting CAR-T cell therapy. The toxic or side effects of CAR-T cell therapy include cytokine release syndrome, off-tumor effect, tumor lysis syndrome, and insertion mutation. Although the CD19-targeting CAR-T cell therapy for childhood cancer can result in a high remission rate, the relapse rate is high, including CD19+ and CD19- relapse. The mechanisms for relapse merit further investigatio.

Oriented Built-in Electric Field Introduced by Surface Gradient Diffusion Doping for Enhanced Photocatalytic H2 Evolution in CdS Nanorods.

Element doping has been extensively attempted to develop visible-light-driven photocatalysts, which introduces impurity levels and enhances light absorption. However, the dopants can also become recombination centers for photogenerated electrons and holes. To address the recombination challenge, we report a gradient phosphorus-doped CdS (CdS-P) homojunction nanostructure, creating an oriented built-in electric-field for efficient extraction of carriers from inside to surface of the photocatalyst. The apparent quantum efficiency (AQY) based on the cocatalyst-free photocatalyst is up to 8.2% at 420 nm while the H2 evolution rate boosts to 194.3 µmol·h-1·mg-1, which is 58.3 times higher than that of pristine CdS. This concept of oriented built-in electric field introduced by surface gradient diffusion doping should provide a new approach to design other types of semiconductor photocatalysts for efficient solar-to-chemical conversion.

Controllable self-assembly of NaREF4 upconversion nanoparticles and their distinctive fluorescence properties.

The paper presents the growth of hexagonal NaYF4:Yb(3+), Tm(3+) nanocrystals with tunable sizes induced by different contents of doped Yb(3+) ions (10%-99.5%) using the thermal decomposition method. These nanoparticles, which have different sizes, are then self-assembled at the interface of cyclohexane and ethylene and transferred onto a normal glass slide. It is found that the size of nanoparticles directs their self-assembly. Due to the appropriate size of 40.5 nm, 15% Yb(3+) ions doped nanoparticles are able to be self-assembled into an ordered inorganic monolayer membrane with a large area of about 10 × 10 µm(2). More importantly, the obvious short-wave (300-500 nm) fluorescence improvement of the ordered 2D self-assembly structure is observed to be relative to disordered nanoparticles, which is because intrinsic absorption and scattering of upconversion nanoparticles leads to the self-loss of fluorescence, especially the short-wave fluorescence inside the disordered structure, and the relative emission of short-wave fluorescence is reduced. The construction of a 2D self-assembly structure can effectively avoid this and improve the radiated short-wave fluorescence, especially UV photons, and is able to direct the design of new types of solid-state optical materials in many fields.

Simultaneous morphology manipulation and upconversion luminescence enhancement of ß-NaYF4:Yb3+/Er3+ microcrystals by simply tuning the KF dosage.

A strategy has been adopted for simultaneous morphology manipulation and upconversion luminescence enhancement of ß-NaYF4:Yb(3+)/Er(3+) microcrystals by simply tuning the KF dosage. X-ray power diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and photoluminescence spectra (PL) were used to characterize the samples. The influence of molar ratio of KF to Y(3+) on the crystal phase and morphology has been systematically investigated and discussed. It is found that the molar ratio of KF to Y(3+) can strongly control the morphology of the as-synthesized ß-NaYF4 samples because of the different capping effect of F(-) ions on the different crystal faces. The possible formation mechanism has been proposed on the basis of a series of time-dependent experiments. More importantly, the upconversion luminescence of ß-NaYF4:Yb(3+)/Er(3+) was greatly enhanced by increasing the molar ratio of KF to RE(3+) (RE = Y, Yb, Er), which is attributed to the distortion of local crystal field symmetry around lanthanide ions through K(+) ions doping. This synthetic methodology is expected to provide a new strategy for simultaneous morphology control and remarkable upconversion luminescence enhancement of yttrium fluorides, which may be applicable for other rare earth fluorides.

Graphene strongly wrapped TiO2 for high-reactive photocatalyst: a new sight for significant application of graphene.

A new idea was employed to simultaneously reduce graphene oxide (GO) and wrap it on the surface of high-reactive anatase TiO2 for fabricating novel TiO2-graphene (GP) hybrid materials. The process was based on the surface negatively charged property of GO. With the introduction of strong chemical interaction between TiO2 and GP, the GP wrapped TiO2 gives a strong red-shift of the light absorption edge and a further narrowed bandgap compared to that of GP randomly supported TiO2. This structure can also significantly enhance the separation efficiency of photogenerated electrons and holes. Furthermore, in contrast to the normal anatase TiO2, as-prepared TiO2 is dominated with the high-reactive {001} facet. The superiority of the formed "core-shell" structure is confirmed by photocatalytic degradation of methylene blue (MB) under the xenon lamp and visible light irradiation. New photocatalytic mechanisms are also proposed based on the obtained results. This work may open a new doorway for new significant application of GP to prepare more GP-based high-reactive photocatalysts for environmental protection.

A bio-inspired inner-motile photocatalyst film: a magnetically actuated artificial cilia photocatalyst.

A new type of inner-motile photocatalyst film is explored to enhance photocatalytic performance using magnetically actuated artificial cilia. The inner-motile photocatalyst film is capable of generating flow and mixing on the microscale because it produces a motion similar to that of natural cilia when it is subjected to a rotational magnetic field. Compared with traditional photocatalyst films, the inner-motile photocatalyst film exhibits the unique ability of microfluidic manipulation. It uses an impactful and self-contained design to accelerate interior mass transfer and desorption of degradation species. Moreover, the special cilia-like structures increase the surface area and light absorption. Consequently, the photocatalytic activity of the inner-motile photocatalyst film is dramatically improved to approximately 3.0 times that of the traditional planar film. The inner-motile photocatalyst film also exhibits high photocatalytic durability and can be reused several times with ease. Furthermore, this feasible yet versatile platform can be extended to other photocatalyst systems, such as TiO2, P25, ZnO, and Co3O4 systems, to improve their photocatalytic performance.

Different upconversion properties of ß-NaYF4:Yb3+,Tm3+/Er3+ in affecting the near-infrared-driven photocatalytic activity of high-reactive TiO2.

Double-shell-structured ß-NaYF4:Yb(3+),Tm(3+)/Er(3+)@SiO2@TiO2 upconversion photocatalysts have been successfully synthesized by a simple hydrothermal method. It is found that the double-shell-structured photocatalyst consists of uniform ß-NaYF4:Yb(3+),Tm(3+)/Er(3+) nanocrystals, SiO2 as the media shell, and anatase TiO2 nanocrystals exposed with the high-reactive {001} facets as the outer shell. The TiO2 shell is modified to absorb both the UV and visible light in order to make sufficient use of the upconverted light from ß-NaYF4:Yb(3+),Tm(3+)/Er(3+) for photocatalysis. Effective energy transfer from ß-NaYF4:Yb(3+),Tm(3+)/Er(3+) to TiO2 and its importance are confirmed. The photocatalytic activity in the degradation of Rhodamine B (RhB) under the near-infrared (NIR) (980 nm laser) irradiation suggests that the NIR-driven photocatalytic activity of the double-shell-structured photocatalyst is significantly dependent on the properties of the upconversion materials and the irradiated NIR power density. Moreover, the NIR-driven photocatalyst shows stable photocatalytic degradation of RhB in the recycled tests. This study suggests a promising system and a new insight to understand the application of appropriate upconversion materials to effectively utilize the NIR for photocatalytic applications of TiO2-based photocatalysts, which may advance the application of solar energy in the future.

Controlled synthesis of NaYF4 nanoparticles and upconversion properties of NaYF4:Yb, Er (Tm)/FC transparent nanocomposite thin films.

Monodisperse oleic acid stabilized pure NaYF(4) nanoparticles with controlled size and shape have been successfully synthesized by changing the initial reaction temperature. Transparent nanocomposite thin films consisting of NaYF(4):Yb, Er (Tm) upconverting nanoparticles (UCNPs) and fluorocarbon resin (FC) are deposited on the slide glass by dip-coating method. The results show that these nanocomposite thin films exhibit intense green and blue upconversion photoluminescence under 980 nm laser excitation and higher transparency than blank substrate. The NaYF(4):Yb,Er (Tm) nanoparticles and NaYF(4):Yb,Er (Tm)/FC nanocomposite thin films have been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), SEM/back-scattered electron (BSE), atomic force microscopy (AFM), UV-Vis spectrophotometer (UVPC), and photoluminescence (PL) spectra. These nanocomposite thin films can be potentially used in solar cells field.

The reactivity of nano silica with calcium hydroxide.

The reactivity of nano silica (SiO2) with calcium hydroxide (Ca(OH)2) was evaluated and characterized in this study. Ca(OH)2 activated nano SiO2 takes place through an exothermic process, which is mainly attributed to the breakdown of Si-O-Si bonds. Ca(2+) offsets the charge imbalance and bonds to Si-OH and Si-O(-) giving rise to calcium silicate hydrate (CSH) gel. Care has to be taken that the reactivity of nano SiO2 with Ca(OH) 2significantly depends on the Q³ percentage in nano SiO 2. Q³ percentages significantly influence the reaction kinetic of nano SiO2 . The higher Q³ percentage results in a higher reaction degree of nano SiO2 with Ca(OH)2 and shorter setting times of the pastes. The higher Q³ percentage results in a lower total reaction heat of nano SiO2 with Ca(OH)2. It is suggested that the Q³ percentages of nano SiO2 should be in excess of 30% to keep the satisfactory setting properties of the pastes for the application requirements of bone cement.