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A reliable 235U enrichment uniformity detection system based on a compact D-D neutron generator is developed to detect the 235U enrichment uniformity of different fuel elements in the same nuclear fuel rod. The high-yield compact D-D neutron generator provides 2.45 MeV D-D neutrons, decelerated by a moderator to thermal neutrons or epithermal neutrons, thereby inducing 235U fission to produce highly excited state fission fragments that undergo de-excitation via γ-ray emission. The system detects the 235U enrichment uniformity of a nuclear fuel rod by measuring γ-rays and establishing a relationship between the γ-ray count rate and 235U enrichment in nuclear fuel. The proposed system yields a confidence probability of 99.99% for a relative 235U enrichment deviation of 10% and a neutron yield of 5 × 108 n/s, and the detection accuracy increases with increasing neutron yield. Furthermore, the developed system can satisfy quality control requirements for nuclear fuel production to promote the safe development of nuclear power.

FV520B stainless steel is an important material for compression turbine impellers. Its corrosion resistance at high temperatures is critical for the manufacturing and service reliability management...

It is of great significance to investigate effect of multiple heat treatments on fracture property of centrifugal casting stainless steels Z3CN20.09M cut from pump casing with long-term thermal aging degradation for nuclear power plants to consider actual operation of nuclear power plants. Both multiple heat treatments and accelerated thermal aging experiment at the same temperature of 400 °C for different time were successively carried out on centrifugal casting stainless steels Z3CN20.09M in order to examine the metallographic modification and impact properties. Finally, an additional investigation on the related fracture properties was carried out, in which the critical initial fracture toughness Ji was determined by stretch zone width and 0.2 mm offset line methods. These results indicated that the multiple heat treatments led to the dispersed distribution of ferrite phases in austenite matrix and thus microhardness increased, but impact energy exhibited a decreasing tendency significantly. After long-term aging, the metallographic structure remained almost unchanged, but the size of ferrite phases showed a slight increasing trend because of spinodal decomposition in ferrite phases and G-phase precipitation. In addition, centrifugal casting stainless steels Z3CN20.09M with multiple heat treatments exhibited the higher microhardness, Charpy impact toughness, critical initial fracture toughness JIC (J-integral determined by 0.2 mm offset line method), and JSZW (J-integral determined by stretch zone width method) than those with primary heat treatment, while the specific number of the heat treatment had a low influence on fracture toughness.

Metal atoms were deposited on an Si (111)-7 × 7 surface, and they were adsorbed with alcohol gases (CH3OH/C2H5OH/C3H7OH). Initially, CnH2n+1OH adsorption was simply used as an intermediate layer to prevent the chemical reaction between metal and Si atoms. Through scanning tunneling microscopy (STM) and a mass spectrometer, the CnH2n+1OH dissociation process is further derived as the construction of a surface quasi-potential with horizontal and vertical directions. With the help of three typical metal depositions, the surface characteristics of CH3OH adsorption are more clearly presented in this paper. Adjusting the preheating temperature, the difference of thermal stability between CH3O– and H+ could be obviously derived in Au deposition. After a large amount of H+ was separated, the isolation characteristic of CH3O– was discussed in the case of Fe deposition. In the process of building a new metal-CH3O–-H+ model, the dual characteristics of CH3OH were synthetically verified in Sn deposition. CH3O– adsorption is prone to influencing the interaction between the metal deposition and substrate surface in the vertical direction, while H+ adsorption determines the horizontal behavior of metal atoms. These investigations lead one to believe that, to a certain extent, the formation of regular metal atomic structures on the Si (111)-7 × 7-CH3OH surface is promoted, especially according to the dual characteristics and adsorption models we explored.

Solution processed CsPbX3 films usually present a high content of Pb0 clusters, acting as significant defects on the perovskite surface. Conventional electron transport materials, including PC61BM, TiO2, ZnO, SnO2 and Nb2O5, can hardly passivate these defects. In this work, few-layered Eu2O3 nanoflakes (nano-Eu2O3) are prepared, which exhibit much higher redox activity towards Pb0/I0 than the commercial Eu2O3 powder. When nano-Eu2O3 is introduced as the buffer layer between the CsPbI2Br and PC61BM layers in inverted perovskite solar cells (PeSC), the devices deliver remarkably improved photovoltaic performance with an average power conversion efficiency (PCE) of 13.47% and a champion PCE of 14.09%, which is much superior to the control devices without nano-Eu2O3 (9.74/11.03%). A series of mechanism studies reveal that the addition of nano-Eu2O3 buffer layer enables not only more efficient hole-blocking but also remarkably enhanced defect passivation at the perovskite/PC61BM interface, both of which result in significantly reduced interfacial charge recombination. Besides, we show that the devices with nano-Eu2O3 exhibit obviously improved thermal stability with >90% PCE remaining after 400 h of thermal aging at 80 °C.

A highly efficient broadband terahertz absorber is designed. We present a broadband terahertz absorber based on heavily N-doped silicon metamaterials. The absorber can achieve over 90% abso...

All-inorganic cesium halide perovskite materials are intensively investigated due to their excellent photoelectric characteristics, but poor film coverage, unbalanced charge carrier transporting and insufficient exciton harvesting are remaining challenges to be overcome in order to achieve high electroluminescent (EL) performance in perovskite light-emitting diodes (PeLEDs). Here we show that these problems can be solved by introducing both a phosphorescent sensitizer (FIrpic) and an electron transporting material (TmPyPB) into all-inorganic cesium halide perovskite (CsPbBr3). And highly efficient green PeLEDs with full coverage CsPbBr3:TmPyPB:FIrpic film as the emissive layer have been achieved, exhibiting the maximum luminance of 37784 cd/m2, the maximum current efficiency of 22.6 cd/A and the corresponding maximum external quantum efficiency (EQE) of 5.85%, where the EQE is 48-fold to that of bare CsPbBr3 PeLEDs. The enhanced EL performance is attributed to less non-radiative current leakage, better film surface passivation effect, balanced charge carrier injection and transportation, as well as better exciton harvesting. It is believed that our work will provide an effective strategy to further improve EL performance of PeLEDs via better exciton harvesting.

Poly(3,4-ethenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) and graphene oxide (GO) as well as their hybrids have been widely used to prepare hole-transport layer (HTL) for inverted planar perovskite solar cells (PeSCs). However, their acidic nature is detrimental to the stability of PeSC. In this study, we report a simple and general strategy to prepare non-corrosive HTL by treating GO and PEDOT:PSS with ammonia or ammonium (i.e., (NH4)2HPO4), respectively. The PeSC based on ammonia-treated GO (a-GO) yields a power conversion efficiency (PCE) over 14%, remarkably outperforming those with pristine GO (∼12%) or PEDOT:PSS (∼13%). Similar improvement is also observed for the devices with ammonia or ammonium-treated PEDOT:PSS. The mechanism behind such improvement is thoroughly studied, demonstrating the significance of ammonia treatment on the HTL performance. More importantly, the devices based on ammonia-treated HTL exhibit significantly improved stability, as compared to those based on pristine PEDOT:PSS and GO.

This study proposed the new method of preparing Mg-based composite by mixed powder Ni and Ti onto the surface of pure Mg ingot. The prepared method caused that hydrogen absorbing phase Mg2Ni and catalytic phase NiTi generated and distributed regularly. The pure Mg ingot as the center and the powder Ni and Ti as cladding material on the surface were formed and sintered, in which the temperature range of generated alloy phase Mg2Ni and NiTi was confirmed at first; according to the temperature range, the size of Mg2Ni and NiTi crystal grains at 650°C and 850°C were analyzed and compared, respectively; The size of Mg2Ni alloy phase at the surface and center was calculated by comparing the atomic radius of Ni, Ti to confirm that Mg2Ni distributed on the surface due to the atom Ti replaced the atom Ni in Mg2Ni to generate the alloy phase NiTi; the capacity of the hydrogen desorption reached 4wt% within 5min. The disadvantages that easy to chalking and difficult to activate in the conventional method were avoided and achieved the application of the multilayer composite material in hydrogen storage field.

Mg-based alloys were prepared by rapid solidification of twin roll casting (TRC) which shows that the Mg-RE alloy expressed the quasi-amorphous phased and fine crystalline phase dual-phase material. Corrosion behavior of Mg-Based alloy in 3.5% NaCl solution after 48h immersion and mechanical properties were investigated. The result show that The Mg-RE alloy strip exhibited good corrosion resistance and higher ultimate tensile strength and elongation comparing to the AZ31 alloy strips. The elongation of Mg-RE alloy strip is also high than the AZ91 and ZK61 under powder metallurgy processing. These indicate that Mg-RE alloy produced by our method has a better ductility. This may due to the special microstructure of the Mg-RE alloy forms, i.e., quasi-amorphous phase plus fine crystalline phase dual phase state.

In this study, magnesium alloy AZ31 was successfully welded with aluminum alloy 6061 by diffusion bonding method. In addition, annealing process was applied to refine micro-structure and improve mechanical property. Microstructure and elemental distribution of interface were investigated with Scanning Electron Microscope (SEM) and Electron Probe Micro Analyzer (EPMA). Furthermore, experiments on diffusion bonded specimens with the usage of Transmission Electron Microscope (TEM) were carried out. At last, tensile strength was measured. It can be obtained that the width of diffusion layers increase with the increasing annealing temperatures. Elemental distribution of specimens with annealing were more uniform than that without annealing. The intermetallic compounds in diffusion layers are Al3Mg2 and Al12Mg17, their crystal structure are respectively face-centered cubic (fcc) and body-centered cubic (bcc). What’s more, tensile strength turns to be strongest after annealing at 250°C.

In this study, Mg-based alloys were prepared by rapid solidification of twin roll casting (TRC), then microstructure and element distribution were investigated respectively with Scanning Electron Microscope (SEM) and Electron Probe Micro Analyzer (EPMA). What’s more, in order to analyze microstructure and crystal structure of Mg-based alloys, experiments on specimens with the usage of X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) were also carried out. At last, the designed Mg-Re magnesium alloy with quasi-amorphous phase plus fine crystalline phase dual phase microstructure produced with our rapid solidification of TRC process. The rapid solidification process realized with a faster casting speed and a thinner roll gap that does not need any anther additional devices and vacuum environment. EPMA results and TEM analyses show that the quasi-amorphous phase has a high concentration in Al and RE element. There are quasi-amorphous phase in the middle of Mg-Re alloy cross section surrounded by dendrites phase and normal crystals. Acknowledgement. This work was supported by Cooperative Research and Development Center for Advanced Materials (CRDAM) funded by the Institute for Materials Research (IMR), Tohoku University (Project Number 18G0042).

A new non-interpenetrated three-dimensional (3D) pillared-layered TPP-based LMOF [Zn3(TPyTPP)0.5(BDC)3]·8DMF (denoted as Zn-MOF 1) was successfully prepared (TPyTPP = tetrakis(4-(pyridin-4-yl)phenyl)pyrazine and H2BDC = 1,4-benzenedicarboxylic acid). Zn-MOF 1 was characterized by single-crystal X-ray diffraction, PXRD, IR, N2 adsorption, thermogravimetric analysis, and luminescent spectrum. Impressively, luminescent sensing studies reveal that activated Zn-MOF 1 not only displays excellent luminescence-quenching efficiency with the values of high Ksv and low LODs toward 5-hydroxytryptamine (5-HT) and 5-hydroxyindole-3-acetic acid (5-HIAA), respectively, but also possesses outstanding sensing characteristics in terms of fast response, high sensitivity, and specific selectivity. Zn-MOF 1 performs as efficient sensing of carcinoid biomarkers to provide a fresh detection platform for the diagnosis of carcinoids. In addition, the sensing mechanism was also explored on the basis of ultraviolet-visible (UV-vis) absorption, DFT calculations, and structural analysis.

Scanning tunneling microscope results showed that Au and Fe atoms were steamed on the Si (111)-(7 × 7) substrate surface, with or without the step region. The experimental comparison proved that the induced effect of the step region is a controllable process, which CH3OH can adjust. In this paper, the latest progress on the dynamic phenomenon on the step region is discussed, including three deposition types: strong deposition, weak deposition, and the new quasi deposition. With a relatively weak interaction between Au and Si atoms, the linearity of the weak deposition is present in the step region. In contrast, Fe atoms tend to form a strong deposition along the boundary line between the flat and step regions. Different depositions correspond to different surface potential energy: a newly formed surface is stabilized by a quasi-potential made by breaking, and a metal atomic structure can be stabilized by forming several quasi depositions. After discussing the good adsorption properties, CH3OH can be used as an intermediate layer on the step region. As an important result of quasi deposition, a regular linear Fe cluster structure is created, which is perpendicular to the boundary line.

Purpose: In this study, pore size and porosity distribution of porous Ti-6Al-4V scaffolds (pTi) were controlled by 3D printing. The effects of pore size distribution at a constant porosity, or porosity distribution at a constant pore size pertaining to functions of adhesion, proliferation, and differentiation of the mouse embryonic osteoblast precursor (MC3T3-E1) cells were researched separately. Methods: 3D printing was used to design five groups of pTi, designated as PS300/HP, PS300/LP, PS500/HP, PS500/LP, and PS800/HP based on pore size and porosity distribution. MC3T3-E1 cells were cultured on pTi, and non-porous Ti-6Al-4V samples (npTi) were prepared as control. The pTi was characterized with the scanning electron microscopy (SEM). MC3T3-E1 cells were stained via AlamarBlue assay and viability and proliferation analyzed. The mRNA levels of alkaline phosphatase (ALP), osteocalcin (OCN), collagentype-1 (Col-1), and runt-related transcription factor 2 (Runx2) in MC3T3-E1 cells were analyzed by real-time PCR analysis. Results: The average pore size and porosity of pTi were recorded as (301 ± 9 μm, 58.8 ± 1.8%), (300 ± 9 μm, 43.4 ± 1.3%), (501 ± 11 μm, 58.3 ± 1.2%), (499 ± 12 μm, 42.7 ± 1.1%), and (804 ± 10 μm, 58.9 ± 1.3%), respectively. SEM images confirmed active attachment of cells and oriented with the direction of metal rod after pTi/MC3T3-E1 co-culture for 3 and 7 days. In addition, MC3T3-E1 cells grown on the PS800/HP displayed significantly higher proliferation compared with each group after 3 days incubation ( p < 0.05). Moreover, cells showed some degree of proliferation in all groups, with the highest value recorded for PS800/HP after culture for 7 days ( p < 0.05). The gene expression pattern of ALP, OCN, Col-1, and Runx2 confirmed that these were down-regulated when pore size increased or porosity decreased of pTi ( p < 0.05). Conclusion: The pTi facilitated the adhesion and differentiation of osteoblast when pore size decreased or porosity increased. The scaffold model resembles physical modification with porous structures, which has potential application in the surface modifications of Ti implant.

Accuracy of extracting ultra-low contact resistivity by the end-resistance method is evaluated. As the contact length becomes smaller than the transfer length, the end-resistance approaches the contact resistance, and the error decreases with the reduction of contact length and contact resistivity. The contact resistivity lower than $10^{-9}\Omega-\mathrm{c}\mathrm{m}^{2}$ can be extracted with accuracy lower than $3\times 10^{-10}\Omega-\mathrm{c}\mathrm{m}^{2}$. This end-resistance method is verified by self-aligned transmission line model test structure. Statistic analysis of the distribution of contact resistance and the uniformity of the contact interface are also demonstrated.

Perovskite light-emitting diodes (PeLEDs) are promising next-generation light sources due to the excellent optical and electronic properties of the materials as well as their process simplicity and low cost. To boost their electroluminescence (EL) efficiency, a plethora of approaches are proposed and demonstrated. Here, another possibility by introducing an exciton retrieving layer (ERL) into the devices is reported. A composite layer, formed by vacuum co-evaporating an electron transporting material (1,3,5-tri(m-pyrid-3-yl-phenyl)benzene, TmPyPB) and a blue phosphorescent material (bis(2-(4,6-difluorophenyl)-pyridinato-N,C2′)picolinate, FIrpic), is inserted into PeLEDs as an ERL in between the emitting layer and the electron transporting layer. Both 3D and quasi-2D PeLEDs with an ERL exhibit strongly enhanced EL performance without changing the emission spectra. 3D PeLEDs show a low turn-on voltage of ∼3.6 V, a maximum luminance of 14 363 cd m−2, and a maximum external quantum efficiency (EQE) of 1.26%, which correspond to 2.5-fold luminance and 3.8-fold EQE enhancements compared with the control device. Quasi-2D PeLEDs exhibit a low turn-on voltage of ∼3.6 V, a maximum luminance of 9481 cd m−2, and a maximum EQE of 4.24%, corresponding to a 2.7-fold EQE enhancement compared with the control device. The physical mechanism is further discussed theoretically and validated experimentally. The blue phosphorescent FIrpic can act as a sensitizer such that energy can be transferred from both the singlet and triplet excitons of TmPyPB to the excited states of CsPbBr3via Forster and Dexter energy transfer processes.

The hot deformation behavior, microstructure evolution and fracture characteristics of bimodal microstructured Ti−6Al−2Zr−1Mo−1V alloy were investigated by isothermal tensile tests. Results reveal that flow softening is caused by dynamic globularization of the bimodal microstructure, which also results in a relatively high stress exponent and thermal activation energy. The corresponding SEM, EBSD and TEM observations indicate that the dynamic globularization at 750 and 800 °C is accomplished by the formation of α/α sub-grain boundary and penetration of the β phase. However, dynamic recrystallization (DRX) is the main globularization mechanism at 850 °C, which was proved by the generation of fine grains with a necklace-like character due to the transformation of low-angle boundaries (LABs) into high-angle boundaries (HABs). With an increase in the deformation temperature or a decrease in the strain rate, the fracture mechanism changes from microvoid coalescence to intergranular fracture.

This work adopts one- and two-step modified Hummers' method to chemically exfoliate graphene nanosheets (GNs) from graphite flake powders and carbon nanotubes (CNTs). The protocol for making the GN products involves one- and two-step exfoliation using KMnO4 oxidation agent. Experimental results reveal that the two-step exfoliation induce high efficiency of chemical oxidation, especially for the synthesis of GNs from CNT precursor. The thermal reduction enables the removal of surface functionalities, thus narrowing the band gap of GN-based electrodes, e.g., from ∼2.12 eV to ∼1.60 eV. The two series of graphene samples, prepared from graphite flake and CNTs, are chemically cut into nanoscale and serve as graphene quantum dots (GQDs). The photoluminescence (PL) excitation behavior is strongly affected by oxidation level and band gap of GQD products. After the thermal reduction, the PL peak shifts to lower wavelength region (i.e., 427–451 nm), offering a blue-shift behavior. The blue-shift behavior primarily originated from surface functionalization, particle size and shape of GQDs. Without any thermal reduction, the GQD suspensions exhibit an improved PL intensity, attributed to fast carrier‒carrier scattering dominates over the electron‒phonon scattering onto the basal plane of graphene sheets due to their high oxidation level and large band gap. As a result, this study offers an efficient way to tune the band gap of GQDs, favoring the development of optoelectronic and biological applications using graphene-based materials in the future.

Fe atoms were deposited on Si(1 1 1)-7 × 7 restructured surface, which had been covered by CH3OH molecules. A newly formed surface is stabilized by a quasi-potential made by breaking, and adsorbed atoms or molecules can be stabilized by forming “quasi-compounds”. Then, aim to greatly enhance the magnetic properties of the memory units, nitriding experiments were implemented on the existing Fe compounds. With the in-situ observation of STM, a series of Fe3N structures make up the newly emerged iron-nitride compounds, showing good linear characteristics. By adjusting the concentration, this study further explored its formation process and compounds models.

A simple alcohol-soluble perylene derivative (i.e., tetramethylammonium salt of perylene-3,4,9,10-tetracarboxylic acid; TMA-PTC) was prepared and applied as a cathode interlayer (CIL) to modify the PC61BM/Ag interface in planar p–i–n perovskite solar cells (PeSCs). As a result, the power conversion efficiency (PCE) of the TMA-PTC-based PeSCs is ca. 30% higher than that of the devices without CIL. It was revealed that the enhancement in PCE might be attributed to the improved electron-transporting and hole-blocking properties of the PC61BM/TMA-PTC/Ag interfaces. Moreover, the TMA-PTC devices show remarkably higher stability than those without CIL probably due to the suppressed corrosion of perovskite on Ag cathode. Our findings thus demonstrate a multifunctional and solution-processable CIL that may be a promising block for the fabrication of low-cost, high-efficiency and stable planar p–i–n PeSCs.

PEDOT-coated WOx nanorodes (NRs) were prepared for the first time by simply stirring WOx nanowires (NWs) with 3,4-ethylenedioxythiophene (EDOT) in aqueous solution. A series of spectroscopic characterizations indicate that the polymerization of EDOT occurrs not only on the surface but also along the [010] planes of WOx NW, resulting in the truncation of long WOx NW to produce WOx@PEDOT NRs with abundant oxygen vacancies. Furthermore, WOx@PEDOT NRs were used to prepare a hole transport layer (HTL) in planar p–i–n perovskite solar cells (PeSCs). The WOx@PEDOT-based devices yielded a comparable average power conversion efficiency (PCE) of 12.89% with improved open-circuit voltage (VOC) and fill factor (FF) but lower short-circuit current density (JSC), as compared to the devices with conventional PEDOT:PSS (12.88%). The observed device performance is mainly attributed to the better perovskite texture on the WOx@PEDOT HTL, improved energy alignment, and suppressed charge recombination at the WOx@PEDOT/perovsk...

To study the effect of annealing temperature on the joints between magnesium and aluminum alloys, and improve the properties of bonding layers, composite plates of magnesium alloy (AZ31B) and aluminum alloy (6061) were welded using the vacuum diffusion bonding method. The composite specimens were continuously annealed in an electrical furnace under the protection of argon gas. The microstructures were then observed using scanning electron microscopy. X-ray diffractometry was used to investigate the residual stresses in the specimens. The elemental distribution was analyzed with an electron probe micro analyzer. The tensile strength and hardness were also measured. Results show that the diffusion layers become wide as the heat treatment temperature increases, and the residual stress of the specimen is at a minimum and tensile strength is the largest when being annealed at 250 °C. Therefore, 250 °C is the most appropriate annealing temperature.

Aim to greatly enhance the magnetic performance, room temperature nitriding experiments were implemented on the existing linear Fe clusters. Firstly, the dissociation of CH3OH adsorption process was deducted in detail, which laid a good foundation for the better use of surface quasi-potential. Further to solve the coming problems like weak linearity and low nitriding effect, atomic layers of Fe deposition are confirmed as the key to NH3 dissociation process (at room temperature). Specifically, the higher Fe atomic layer contacted by NH3, the weaker influence of surface quasi-potential. With the introduction of Ar, Fe cluster structure could be precisely controlled at single atomic layer, result in good NH3 dissociation and nitriding efficiency. Combining with magnetic performance result, the density of residual magnetization is improved from 1.5E−0.5 emu to 7.0E−0.5 emu, forming an obvious linear structure.

Poly(methyl methacrylate)/expanded graphite (PMMA/EG) composites are prepared using water-assisted mixing extrusion (WAME) technique. Scanning and transmission electron microscopy micrographs show that the EG exhibits better exfoliation and dispersion in the composite samples prepared with water injection than that in those without water injection. More EG layer networks and stronger PMMA-EG interfacial interaction are formed in the composite samples prepared with water injection, which are confirmed by the results of the FTIR and rheological measurements and the linear fits of experimentally obtained tensile yield stresses. The composite samples with well exfoliated and dispersed EG layers exhibit higher thermal conductivity and mechanical properties, which are ascribed to lower interfacial thermal resistance and stronger interfacial interaction, respectively. Finally, a mechanism for promoted EG exfoliation and dispersion in the PMMA matrix during the WAME is interpreted by analyzing the combined effect of injected high-pressure water with the shear force provided by the extruder screw.

Critical cooling rates for producing metallic glasses were evaluated based on a calculated continuous cooling transformation (CCT) diagram. Temperature distributions of the melt in molten pool in the vertical type twin-roll casting (VTRC) process of metallic glasses were simulated, and cooling rates under different casting conditions were calculated with the simulated results. By comparing the results obtained by CCT diagrams and simulation, the possibility of producing metallic glasses by the VTRC method and influences of casting conditions on cooling rate were discussed. The results reveal that cooling rate with 3 or 4 orders of magnitude by the VTRC process can be attained in producing Mg-based metallic glasses, which is faster than the critical cooling rate calculated by the CCT diagram. One side pouring mode can improve the temperature distributions of casting pool. VTRC process has a good ability in continuous casting metallic glassy thin strips.

We demonstrate a facile and green approach to preparing a vanadium oxide hydrate (VOx·nH2O) layer to serve as the hole-transport layer (HTL) in high-performance polymer solar cells (PSCs). The VOx·nH2O layer was in situ prepared by a combined H2O2 and ultraviolet-ozone (UVO) processing on a VOx layer. The as-prepared VOx·nH2O layer featured a work function of 5.0 ± 0.1 eV, high transmittance, and better interface properties compared to those of the generally prepared VOx (UVO or thermal annealing) layers. PSCs based on poly[(ethylhexyl-thiophenyl)-benzodithiophene-(ethylhexyl)-thienothiophene]/[6,6]-phenyl-C71-butyric acid methyl ester using the VOx·nH2O layer as the HTL yielded high power conversion efficiencies (PCEs) up to 8.11%, outperforming the devices with VOx layers (PCE of 6.79% for the UVO-processed VOx layer and 6.10% for the thermally annealed VOx layer) and conventional polyethylenedioxythiophene–polystyrenesulfonate (PEDOT:PSS) layers (PCE of 7.67%). The improved PCE was attributed to the en...

Effective hole transport layers (HTLs) are still critical and desirable for the fabrication of high-performance, high-stability and cost-effective polymer solar cells (PSCs). In this work, we report that the graphene oxide (GO) simply modified with CuCl2-doping (GO:CuCl2) can be used as an effective HTL to produce high-performance PSC based on poly[(ethylhexyl-thiophenyl)-benzodithiophene-(ethylhexyl)-thienothiophene]:[6,6]-phenyl C71 butyric acid methyl ester (PTB7-Th: PC71BM). As a result, the average power conversion efficiency (PCE) reaches 7.68%, remarkably higher than that of the device using pristine GO as HTL (7.10%) and comparable to that of the device with conventional HTL of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) (7.69%). UPS measurements suggest that the work function of GO:CuCl2 is slightly increased relative to that of undoped GO. AFM characterizations also reveal a more continuous film morphology for the deposited GO:CuCl2 layer on indium tin oxide (ITO). Such improvements render an ohmic contact as well as a better interfacial contact between the electrode and active layer, yielding improved open-current voltage (Voc), fill factor (FF) and thus enhanced PCE.

This study examines the thermal properties of ZnO-coated carbon fiber (CF) filaments for high-performance infrared (IR) heaters. An efficient pulse microwave (PM) method is applied to deposit different morphologies of ZnO crystals at various pH values of Zn 2+ solutions, i.e., fragments (pH = 9), thin films (pH = 10), bulky islands (pH = 11), and nanoparticles (pH = 12). Under the applied voltage of 25 V, the CF composite filament, prepared by the PM route at pH = 10, offers the highest thermal radiation power and superior heat-storage capability among these IR heaters. Its saturation temperature and heating rate of ZnO-coated CF heater can reach to 184 °C and 28 °C/min, respectively. The enhanced thermal performance can be ascribed to the facts (i) the ZnO crystals create more emissive surface area and (ii) the composite filament illuminate more homogeneous spectral IR rays, showing the synergetic effect.

An efficient microwave-assisted synthesis (MS) method to synthesize highly crystalline Cu nanocrystals onto reduced graphene oxide (rGO) sheets for glucose oxidation reaction (GOR) has been investigated. The mass density of Cu nanocrystals onto rGO sheets, ranged from 22.6 to 42.8 wt%, is selected as a controlling factor in determining the catalytic activity toward GOR in alkali electrolyte. The cyclic voltammetry measurement reveals an obvious signature of GOR on the Cu(III)/Cu(II) active surface. Through an appropriate loading of Cu crystals, the Cu-rGO catalysts exhibits an improved performance toward the GOR, including excellent sensitivity, wide detection range, fast response, and superior selectivity. The enhanced performance can be ascribed to a synergetic effect that consists of small crystalline size, uniform dispersion, and two-dimensional conductive support, imparting high accessibility to non-enzymatic catalysis of glucose. Herein the rGO sheets works as a two-dimensional conductive scaffold, capable of rapidly conducting electron and well dispersing Cu nanocrystals. The injection amperometric investigation confirms the highest selectivity of 284 mA g − 1 μM −1 is attained, according to a linear regression plot of current response versus glucose concentration, i.e. , 0‒1 mM. Accordingly, the robust design of Cu-rGO catalyst electrode can serve as a feasible candidate for non-enzymatic glucose biosensor.

It is known that polychromatic carbon quantum dots (CQDs) can be obtained by doping and surface modification. The layer-wise synthesis of blue and green emitting CQDs (with typical sizes between 3 and 6 nm) is described here by adding oxalic acid and by introducing polycarboxy groups. By changing the external environment, the emission of CQDs can be adjusted in the blue-green spectral region (469-527 nm) under photoexcitation at 405 nm. The findings presented here provide new directions for the reversible regulatory transformation of polychromatic CQDs. The luminescence also is affected by a variety of conditions such as surface defects, degree of polymerization, polarity of external solutions, and hydrogen bonding which is studied in some detail. Graphical abstract Schematic presentation of the blue-green fluorescent transformation of the green carbon quantum dots(G-CQDs) to blue carbon quantum dots(B-CQDs).

Inorganic perovskite CsPbI2 Br has advantages of excellent thermal stability and reasonable bandgap, which make it suitable for top layer of tandem solar cells. Nevertheless, solution-processed all-inorganic perovskites generally suffer from high-density defects as well as significant tensile strain near underlayer/perovskite interface, both leading to compromised device efficiency and stability. In this work, the defect density as well as interfacial tensile strain in inverted CsPbI2 Br perovskite solar cells (PeSCs) is remarkably reduced by using a bilayer underlayer composed of dopant-free 2,2',7,7'-tetrakis(N,N-dip-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMeTAD) and copper phthalocyanine 3,4',4″,4'″-tetrasulfonated acid tetrasodium salt (TS-CuPc) nanoparticles. As compared to control devices with pristine Spiro-OMeTAD, devices based on Spiro-OMeTAD/TS-CuPc exhibit remarkably improved photovoltaic performance and enhanced thermal/humidity stability due to the better perovskite crystallization, improved interfacial passivation, and hole-collection as well as efficient interfacial strain release. As a result, a champion efficiency of 14.85% can be achieved, which is approaching to the best reported for dopant-free and inverted all-inorganic PeSCs. The work thus provides an efficient strategy to simultaneously regulate the defects density and strain issue related to inorganic perovskites.

A new type of Mg-rare earth (Ce, La) and the AZ31 alloy sheets were prepared by vertical twin-roll casting (TRC) technology under identical casting conditions, and their microstructural features, degradation behaviours and bone responses were investigated. The microstructural characterization showed that the Mg-RE (rare earth) exhibited a higher amorphous forming ability than the AZ31. Moreover, the results of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization indicated that the Mg-RE sheets displayed a higher corrosion resistance compared with the AZ31 sheets. Additionally, the Ti, Mg-RE and AZ31 sheet implants were immobilized and implanted in a rat femur model to observe degradation behavior during 16 weeks. in vivo tests showed that no significant change in the femur surrounding the Ti group, which excluded the external factor that the new bone formation resulting from bone remodeling. Furthermore, the Mg-RE group induced more newly formed bones, which met the necessary conditions for the prevention of pathological fractures. Therefore, the novel Mg-RE alloy appear to hold a healing candidate as the biodegradable implant material.

A molecular dynamics (MD) simulation was used to investigate the adsorption of graphene oxide (GO) and graphene (G) onto an Fe3O4(111) surface. The MD simulation results indicated that the direction of the GO/G sheets introduced onto the Fe3O4(111) surface affected the morphologies of the GO/G sheets and the interface interaction energies. When the GO/G sheets were introduced onto the Fe3O4(111) surface from the parallel direction, a smooth, single-layered structure of the GO/G sheets formed, and the interface interaction energies were low. The interface interaction energy of GO-Fe3O4 interface was lower than that between G and Fe3O4(111) surfaces because of the strong interactions between the carboxyl groups on the GO edges and the iron atoms on the surface. The ideal distribution and lower interface interaction energies of the polymers (PEG and PEI) with GO/G indicated that the GO/G coated layer on the Fe3O4 surface could be further modified. According to results, GO, under specific stirring spe...

We successfully synthesized a novel anionic luminescent metal–organic framework (MOF) (NENU-524) with a lonsdaleite topology. NENU-524 contains a trigonal prismatic unit {Zn8(btca)6(2-NH2-bdc)3} that can be regarded as a double secondary building unit with an unusual triply bound triangular frustum geometry. The prepared NENU-524 had a permanent porosity and excellent stability in air. NENU-524 was used as a platform to encapsulate yellow-emitting [Ir(ppy)2(bpy)]+ cations in the nanotube channels of the blue-emitting MOF via an ion-exchange process. The [Ir(ppy)2(bpy)]+@NENU-524 MOF ([Ir(ppy)2(bpy)]+ concentration 3.86 wt%) emitted a pure white light with CIE coordinates of (0.300, 0.336) and a high quantum yield of up to 15.2%. The white light-emitting diodes assembled using [Ir(ppy)2(bpy)]+@NENU-524 as a white phosphor emitted a bright white light, suggesting that the composite is a promising material for use in lighting. The assembled white light-emitting diodes continued to emit a bright white light for up to one month. This simple and feasible approach could be used to develop luminescent luminophor@MOFs composites for practical applications.

Magnesium alloy is honored as green engineering material for its low density, high specific strength, high specific rigidity, well cutting processing property, well electromagnetic shielding property, heat conduction and easy to recycle. In this paper, AZ31 Magnesium alloy sheet at difference thickness were prepared by symmetric and asymmetric rolling employed with six-roller mill. Microstructure of the two kinds of rolling magnesium alloy thin sheets at 0.5mm thickness were investigated. The grain distribution of AZ31magnesium alloy sheets made by asymmetry rolling at room temperature are more uniform than those made by symmetry process. The grains made by asymmetry are more tiny and the tensile strength and elongation increased obviously and the mechanical properties got better. At room temperature, value of n increased. Large value of n benefit to stamping forming. At room temperature, the value of LDR of asymmetry rolling sheets is 1.26, which was higher than symmetry rolling. So asymmetry rolling benefits to stamping forming.

In this work, a facile preparation of Cu-Au bimetallic nanoparticles (NPs) with core-shell nanostructures is reported. Importantly, as-prepared Cu-Au NPs are highly stable, solution-processable and exhibit a broad localized surface plasmon resonance (LSPR) band at long wavelengths of 550–850 nm. Highly efficient plasmonic organic solar cells (OSCs) were fabricated by embedding Cu-Au NPs in an anodic poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer. The average power conversion efficiency (PCE) was enhanced from 3.21% to 3.63% for poly(3-hexylthiophene) (P3HT):phenyl-C 61 -butyric acid methyl ester (PC 61 BM) based devices, from 6.51% to 7.13% for poly[(ethylhexyl-thiophenyl)-benzodithiophene -(ethylhexyl)-thienothiophene](PTB7-th):PC 61 BM based devices and from 7.53% to 8.48% for PTB7-th:PC 71 BM based devices, corresponding to 9.5–13.4% PCE improvement. Such an improvement is very comparable to that (12.5%) obtained in those with plasmonic Au NPs but achieved at lower cost. This study thus demonstrates a novel and cost-effective approach to enhance the photovoltaic performance of OSCs, in combination with the broad-band plasmonic Cu-Au bimetallic nanostructures.

The polymer solar cell (PSC) with Ca/Al electrode always suffers from low stability mainly due to the incorporation of oxygen and moisture-sensitive Ca electron-transport interlayer (ETL). To alleviate this problem, air-stable alternatives to Ca ETL are highly desired. Herein, we report two solution-processable, air-stable, effective and inexpensive ETLs based on potassium-neutralized perylene tetracarboxylic derivative (K 4 PTC) and its rGO composite (rGO-K 4 PTC), respectively. These ETL materials were facilely prepared and characterized by means of UV-vis, FL, FTIR, XPS and UPS. Importantly, both ETLs exhibited a low work function (WF) of 4.0 eV, which well matches the LUMO level of fullerene acceptors and allows their use as ETL in PSCs. As a result, the P3HT and PTB7-th-based devices with respective ETL remarkably outperformed those without ETL yielding increases of ∼35% in power conversion efficiencies (PCEs), which indicates good electron-transporting capabilities of K 4 PTC and rGO-K 4 PTC interlayers. The high-performance PSCs with the ETL gave average PCEs of 6.17–6.18% (for PTB7-th:PC 61 BM-based devices) and 7.26% (for PTB7-th:PC 71 BM-based devices), respectively, fairly comparable to those of Ca/Al devices (6.50% and 7.50%). Furthermore, the rGO-K 4 PTC device exhibited stability higher than that of the K 4 PTC device probably due to the fact that the rGO-K 4 PTC layer can provide more efficient protection for the active layer against degradation. Thus, rGO-K 4 PTC layer might be more suitable for real applications as compared to the K 4 PTC layer.

Hierarchical carbon nanotubes (CNTs) and graphene nanosheets (GNs) supported MnO 2 nanoneedles have been synthesized through a facile chemical-wet route without any further thermal treatment. The electrochemical capacitive performances of MnO 2 -based composite electrodes are analyzed using cyclic voltammetry, galvanostatic charge–discharge cycling, and impedance spectroscopy. It is found that the electrochemical utilization of MnO 2 nanoneedles is effectively enhanced by the synergistic effect that combines the MnO 2 crystals and the carbon supports, raising more active sites available for formation of charge transfer and electric double-layer in the hybrid architecture. The maximal specific capacitance of capacitors attains as high as 440 F g −1 . The specific energy of MnO 2 /GN capacitor can reach as high as ∼40 Wh kg −1 at a specific power of 20,000 W kg −1 , analyzed by the Ragone plot. The improved performance can described to the fact that the robust design of hybrid structure is capable of (i) maximizing the utilization of MnO 2 nanoneedles and (ii) leading to fast chemical reaction kinetics including ionic electro-sorption and charge transfer. This method provides a straightforward approach to deposit MnO 2 onto GNs as electrode materials for various energy-storage devices.

This study adopts an efficient microwave-assisted (MA) route to deposit Al2O3 layer onto microscaled carbon fabrics (CFs) as a filament for infrared (IR) heater. The MA deposition is able to coat different densities of alumina on the surface of CFs by adjusting ionic concentration of Al3+. The highly-crystalline Al2O3 layers can be formed under microwave irradiation of 720 W. It has shown that both the heating rate and maximal temperature are increasing functions of the surface density of alumina. This improved thermal efficiency originates from the decoration of Al2O3 onto the CFs, liberating the IR-light illumination with different wavelengths and increasing the emissive surface area of CF filaments. Under the operating condition at 25 V, the heating rate and the maximal temperature of composite filaments can reach 36.6° C/min and 213° C, respectively. The composite heater displays the highest irradiation power of 49.2 W, approximately 2.6 times higher as compared to the original CF heater. This satisfactory result expresses that a robust design that combines with CF heaters and decoration of alumina deposits exhibits a potential feasibility for commercializing IR illuminators with high thermal irradiation performance.

A diffusion/transformation coupled model has been developed which combines finite difference (FD) model with a phenomenological model. The composition of the different iron-nitrogen(Fe-N) hardening phase can be regard as a function of nitriding time and nitrogen concentration. The diffusion model and transformation model are linked by the limiting nitrogen solubilities and the effective diffusion coefficients. The effect of alloy elements (Cr, Mo, Mn, V, Ni etc.) is considered by introducing an alloy coefficient for limiting nitrogen solubilities and diffusion coefficient. The diffusion/transformation model can predict nitrogen concentration, phase composition and hardness distribution. The model is employed to simulate the nitriding process of SCr420H low-alloy steels. The simulated nitrogen concentration and hardness profiles are consistent with the measured ones. In addition, the predicted depth distributions of iron-nitrogen phase agree well with the available experimental results. Therefore, the comparison shows the reliability of the coupled model. It can be applied to improve the nitriding process parameters.

Understanding the chemical evolution at the interface of organic light-emitting diodes (OLEDs) under working conditions is critical for addressing device failure and further improving performance. In this work, an in-operando approach was developed employing synchrotron-based X-ray absorption spectroscopy (XAS) to investigate the electronic structures and chemical degradation mechanisms of a model tris(8-hydroxyquinoline) aluminum (Alq3)-based OLED device under working condition. The results identify that Mg atoms from the electrode migrate into the Alq3 organic layer under a potential bias and replace Al atom sites, forming the unstable Mgq3 species which lead to device degradation. The findings from the classic and simple model device elucidate the degradation mechanisms occurred at the interface of OLED devices, which may facilitate the development of more efficient and stable OLED devices with complex structures.

High entropy oxide (HEO) is a new-type inorganic material composed of multiple principle metal elements with a single-phase structure and is proved to display many potential unexpected properties such as high structural stability and superionic conductivity. Herein, a novel spinel-structured high entropy oxide (FeCoNiCrMn)3O4 is prepared by high-temperature solid state reaction and evaluated as anode for lithium-ion batteries (LIBs). In-situ high-temperature X-ray diffraction (HT-XRD) is used to reveal structure evolution of mixed oxides with the calcination temperature increase and a single-phase spinel-structured (FeCoNiCrMn)3O4 is obtained at 900 °C. The effect of temperature on structure and electrochemical performance of HEO were investigated, and the HEO-900 anode with commercial mass loading exerts higher capacity (discharge/charge, 1034/680 mAh g−1) and better rate capability (182 mAh g−1 at 2 Ag-1) than HEO-950 and HEO-1000 for its moderate particle size, and all the three samples show excellent cycling stability. Ex-situ XRD and transmission electron microscope are applied to unravel the lithium-storage mechanism of (FeCoNiCrMn)3O4, an amorphization reaction process occurs during the initial discharging and the amorphous structure is maintained in subsequent cycles. The synergetic effect of multiple metal cations with different radius, valence states and reaction potentials and entropy stabilization effect make the HEO display a superior electrochemical performance in LIBs. This work provides a new concept to design multi-element transition metal oxide anode materials by high entropy strategy.

To date, doped 2,2,7,7-Tetrakis(N,N-dip-methoxyphenylamine)-9,9-spirobifluorene (Spiro-OMeTAD) is still state-of-the-art hole transport material (HTM) for inverted perovskite solar cells (PeSCs). Nevertheless, hydroscopic dopants usually lead to accelerated degradation of perovskite and hence reduce the device durability especially those based on all-inorganic perovskite. In this work, we report a series of dopant-free mixtures (SpiPA) of hydrophilic Spiro-OMeTAD and hydrophobic poly(triarylamine) (PTAA), which exhibit tunable surface wettability due to the dominant lateral phase separation. When applying them as HTM for inverted CsPbI2Br PeSCs, SpiPA-II based devices yield enhanced efficiency up to 12.52% with significantly reduced hysteresis, as compared to the devices with other mixed HTLs (SpiPA-I, SpiPA-III, SpiPA-IV) and conventional HTLs including pristine Spiro-OMeTAD (10.26%), PTAA (9.05%) and NiOx (10.75%). Additionally, the corresponding mechanism has been studied in detail.