Although multicrystalline Si photovoltaics have been extensively studied and applied in the collection of solar energy,the same systems suffer significant efficiency losses in indoor settings,where ambient light condi...Although multicrystalline Si photovoltaics have been extensively studied and applied in the collection of solar energy,the same systems suffer significant efficiency losses in indoor settings,where ambient light conditions are considerably smaller in intensity and possess greater components of non-normal incidence.Yet,indoor light-driven,stand-alone devices can offer sustainable advances in next-generation technologies such as the Internet of Things.Here,we present a non-invasive solution to aid in photovoltaic indoor light collection—radially distributed waveguide-encoded lattice(RDWEL)slim films(thickness 1.5 mm).Embedded with a monotonical radial array of cylindrical waveguides(±20°),the RDWEL demonstrates seamless light collection(FoV(fields of view)=74.5°)and imparts enhancements in JSC(short circuit current density)of 44%and 14%for indoor and outdoor lighting conditions,respectively,when coupled to a photovoltaic device and compared to an unstructured but otherwise identical slim film coating.展开更多
Based on the characteristics of laser-induced surface ignition,energetic photosensitive films show promising potential to meet the ignition requirements of various energetic materials(EMs).In this study,DATNBI/ferric ...Based on the characteristics of laser-induced surface ignition,energetic photosensitive films show promising potential to meet the ignition requirements of various energetic materials(EMs).In this study,DATNBI/ferric alginate(DI/FeA),DI/cobalt alginate(DI/CoA),and DI/nickel alginate(DI/Ni A)films are fabricated by employing sodium alginate(SA)with a three-dimensional network structure as the film matrix,via ionic cross-linking of SA with Fe^(3+),Co^(2+),and Ni^(2+)ions.The study demonstrates that the ionic cross-linking enhances the hydrophobic performance of the films,with the water contact angle increasing from 82.1° to 123.5°.Concurrently,the films'near-infrared(NIR)light absorption improved.Furthermore,transition metal ions facilitate accelerated electron transfer,thereby catalyzing the thermal decomposition of DATNBI.Under 1064 nm laser irradiation,the DI/Fe A film exhibits exceptional combustion performance,with an ignition delay time as low as 76 ms.It successfully acts as an NIR laser ignition medium to initiate the self-sustained combustion of CL-20.This study demonstrates the synergistic realization of enhanced hydrophobicity,improved photosensitivity,and promoted catalytic decomposition through microstructural design of the material,providing new insights for the design of additive-free EMs in laser ignition applications.展开更多
The development of sustainable materials has encouraged the use of biopolymers as alternatives to synthetic polymers.Polymeric films have stood out for their high potential in environmentally sustainable applications....The development of sustainable materials has encouraged the use of biopolymers as alternatives to synthetic polymers.Polymeric films have stood out for their high potential in environmentally sustainable applications.Conventional cellulose acetate(CA)-based films are attractive due to their biodegradability and film-forming ability.However,their functional performance often requires enhancement through the incorporation of additives.In this context,two bio-based additives were investigated:condensed tannin(0%,5%and 10%wt.),a natural polyphenol known for its antioxidant and antimicrobial properties,and nanocrystalline cellulose(CNC)(0%,0.5%and 1%wt.),which act as reinforcing agents to improve mechanical strength and barrier properties.The results showed that tannin generally enhanced mechanical strength and surface uniformity while imparting contact-based antimicrobial activity.CNC reduced water uptake and improved thermal stability,but when used alone,it tended to lower mechanical performance and increase surface roughness.The combination of CNC and tannin produced performance shifts that depended strongly on their relative concentrations,with no consistent synergistic effect across all properties.In certain balanced ratios,CNC benefited fromtannin’smatrix-stabilizing effect,leading to improved strength or reduced moisture absorption.Antimicrobial activity in acetic acid–based films was linked to residual acidity,whereas in acetonebased films,tannin alone was responsible for the antimicrobial effect by contact.These findings highlight that the physicochemical,mechanical,and functional performance of CA films(CAFs)is governed not only by additive type but also by the precise interplay between CNC and tannin,underscoring the need for formulation strategies tailored to the requirements of specific applications.展开更多
This review draws attention to the innovative use of arrowroot(Maranta arundinacea)fiber as a unique and underutilized biomass source for nanocrystalline cellulose(NCC)-based nanocomposites,presenting a noteworthy alt...This review draws attention to the innovative use of arrowroot(Maranta arundinacea)fiber as a unique and underutilized biomass source for nanocrystalline cellulose(NCC)-based nanocomposites,presenting a noteworthy alternative to extensively researched materials like wood pulp,bacterial cellulose,and chemically modified NCCs.In contrast to traditional sources,arrowroot possesses a naturally elevated cellulose and diminished lignin content,facilitating more effective NCC extraction requiring reduced chemical input and enabling environmentally friendly processing techniques.The review evaluates the performance of arrowroot-derived nanocomposites against systems documented in the literature,including NCC-based shape memory composites and nanoparticle-reinforced films,demonstrating enhanced tensile strength,improved moisture barrier properties,and thermal stability,as well as potential piezoelectric response.This study recognizes arrowroot as a viable option in the biomass-based nanocellulose sector,providing ecological and functional benefits while tackling significant issues such as process scalability and feedstock variability,thereby offering important insights for the advancement of sustainable materials.展开更多
Tin-lead(Sn-Pb)halide perovskite single crystals combine narrow bandgaps,long carrier diffusion lengths,and low trap densities,positioning them as ideal candidates for near-infrared(NIR)optoelectronics.However,convent...Tin-lead(Sn-Pb)halide perovskite single crystals combine narrow bandgaps,long carrier diffusion lengths,and low trap densities,positioning them as ideal candidates for near-infrared(NIR)optoelectronics.However,conventional growth strategies rely on bulk crystallization at elevated temperatures,leading to uncontrolled nucleation,Sn^(2+)oxidation,and poor compatibility with planar integration.Here,we develop a coordination-engineered crystallization strategy that enables direct,lowtemperature growth of micrometer-thick Sn-Pb single-crystal thin films on device-compatible substrates.By modulating metal-solvent coordination strength using a low-donor number cosolvent system,we delineate a narrow processing window that stabilizes precursor speciation,lowers the nucleation barrier,and guides directional crystal growth under mild thermal conditions(<40℃).The resulting crystal films exhibit smooth morphology,high crystallinity,compositional uniformity,and ultralow trap densities(~3.98×10^(12)cm^(-3)).When integrated into NIR photodetectors,these films deliver high responsivity(0.51 A W^(-1)at 900 nm),specific detectivity up to 3.6×10^(12)Jones,fast response(~188μs),and>25,000 cycles of ambient operational stability.This approach establishes a scalable platform for redox-stable,low-temperature growth of Sn-Pb perovskite crystal films and expands the processing-structure-function landscape for next-generation infrared optoelectronics.展开更多
This study investigates the effect of BaHfO_(3)(BHO)addition on the optical properties of YBa_2Cu_(3)O_(7-δ)(YBCO)superconducting thin films using spectroscopic ellipsometry.Through Raman spectroscopy and SEM analysi...This study investigates the effect of BaHfO_(3)(BHO)addition on the optical properties of YBa_2Cu_(3)O_(7-δ)(YBCO)superconducting thin films using spectroscopic ellipsometry.Through Raman spectroscopy and SEM analysis,optimal 10-min Ar ion etching effectively removes surface a-axis-oriented grains and Ba–Cu–O impurities,enhancing surface quality.Optical conductivity analysis reveals a doping-dependent evolution:10%BHO doping maximizes free carrier density and interband transition efficiency,attributed to optimized Cu–O bond contraction and reduced lattice distortions.Higher doping induces defect clustering,carrier scattering,and redshifted transitions due to lattice expansion.Dielectric function and loss function analyses confirm enhanced plasmonic behavior and flux pinning at 10%doping,while excessive doping degrades electronic transitions.These results highlight the critical role of controlled BHO addition and surface treatment in tailoring the optical and superconducting properties of YBCO,offering insights into the interplay among doping,carrier dynamics,and electronic structure in high-temperature superconductors(HTS).展开更多
BiMeO_(3)–PbTiO_(3)(where Me represents transition metals)perovskite-type thin films have been widely studied due to their superior ferroelectric properties,including robust ferroelectric polarization and high Curie ...BiMeO_(3)–PbTiO_(3)(where Me represents transition metals)perovskite-type thin films have been widely studied due to their superior ferroelectric properties,including robust ferroelectric polarization and high Curie temperatures.In this study,PbTiO_(3)-based perovskite thin films of xBi(Cu_(1/2)Zr_(1/2))O_(3)–(1-x)PbTiO_(3)(xBCZ–(1-x)PT)were designed and prepared on Pt(111)/Ti/SiO_2/Si substrates using the conventional sol–gel method.The x BCZ–(1-x)PT thin films demonstrate remarkable crystallinity,characterized by a perovskite structure and a dense microstructure,which contribute to their highperformance ferroelectric and fatigue properties.Notably,the thin films exhibit large remnant polarization(2P_(r0))values,reaching 98μC·cm^(-2)and 74μC·cm^(-2)for the 0.05BCZ–0.95PT and 0.1BCZ–0.9PT compositions,respectively.Furthermore,the thin films also demonstrate a high Curie temperature(T_(C)=510℃),as well as favorable fatigue properties and low leakage current,suggesting their potential applicability in ferroelectric devices.展开更多
Ferroelectric materials are widely applied in the ferroelectronic devices,photovoltaics,and so on.Ultrathin ferroelectric thin films are highly desired for their applications,which still remain a challenge.In this wor...Ferroelectric materials are widely applied in the ferroelectronic devices,photovoltaics,and so on.Ultrathin ferroelectric thin films are highly desired for their applications,which still remain a challenge.In this work,the ultrathin barium titanate(BaTiO_(3),BTO)films are deposited directly on the fluorine-doped tin oxide glass(SnO_(2):F,FTO)substrates by radio frequency magnetron sputtering method at different temperatures.All BTO ultrathin films exhibit strong ferroelectric properties.Interestingly,BTO thin films deposited at room temperature(RT)also exhibit robust ferroelectricity.The polar domains are switched reversibly with a phase degree of~180°by piezoelectric force microscopy for the BTO thin films deposited at room temperature,attributing to the strain and ion migration.展开更多
BaFe_(12)O_(19)(BaM)thin films with thicknesses ranging from 15 nm–200 nm were deposited on Al_(2)O_(3)(0001)substrates by pulsed laser deposition(PLD).X-ray diffraction patterns show that a buffer layer with a thick...BaFe_(12)O_(19)(BaM)thin films with thicknesses ranging from 15 nm–200 nm were deposited on Al_(2)O_(3)(0001)substrates by pulsed laser deposition(PLD).X-ray diffraction patterns show that a buffer layer with a thickness of nearly 60 nm forms on the substrate,and then a c-axis perpendicularly oriented Ba M thin film grows on the buffer layer.Atomic force microscopy results indicate that the Ba M thin film exhibits a spiral island growth mode on the buffer layer.Magnetic hysteresis loop results confirm that the buffer layer exhibits no significant magnetic anisotropy,while the Ba M thin film exhibits perpendicular magnetic anisotropy.The out-of-plane coercivity decreases with increasing Ba M thin-film thickness due to the combined effect of grain size growth and lattice strain relaxation.The 200 nm thick film exhibits optimum magnetic properties with M_(s)=319 emu/cm^(3) and H_(c)=1546 Oe.展开更多
The dependence of interface structure and mechanical properties on the modulation layer thickness of VN/TiN−Ni nano-multilayered films deposited on Si substrates using a reactive magnetron sputtering technique was sys...The dependence of interface structure and mechanical properties on the modulation layer thickness of VN/TiN−Ni nano-multilayered films deposited on Si substrates using a reactive magnetron sputtering technique was systematically investigated. The films were characterized using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and nanoindentation. The results show that the TiN−Ni layer grows epitaxially on the VN layer, forming a coherent interface between the two sublayers. When the deposition time ratio of the two sublayers (TTiN−Ni꞉TVN) is 10꞉12, the films exhibit remarkable mechanical properties, with hardness, elastic modulus, and fracture toughness values of 25.9 GPa, 317 GPa, and 1.88 MPa·m^(1/2), respectively. Meanwhile, fracture toughness is improved by approximately 50% compared to the VN monolithic film. This enhancement is attributed to the coherent interface between the sublayers and the phase separation in the TiN−Ni layer.展开更多
Ising superconductivity has garnered much attention in recent years due to its extremely high in-plane upper critical field (B_(c2)).Here,we fabricated 14 multilayer Pb_(1-x)Bi_(x) (0%≤x≤40%) thin films on Si (111)-...Ising superconductivity has garnered much attention in recent years due to its extremely high in-plane upper critical field (B_(c2)).Here,we fabricated 14 multilayer Pb_(1-x)Bi_(x) (0%≤x≤40%) thin films on Si (111)-7×7 reconstructed surface by molecular beam epitaxy.Large B_(c2) beyond the Pauli limit is observed in all the Pb_(1-x)Bi_(x) films,indicating that they may exhibit characteristics of Ising superconductivity.Moreover,the introduction of Bi doping can significantly enhance and effectively tune the in-plane B_(c2) of Pb_(1-x)Bi_(x) films,which will help us better understand Ising superconductivity and provide a new platform for the development of tunable Ising superconductors.展开更多
Because of their low electrical conductivity,sluggish ion diffusion,and poor stability,conventional electrode materials are not able to meet the growing demands of energy storage and portable devices.Graphene assemble...Because of their low electrical conductivity,sluggish ion diffusion,and poor stability,conventional electrode materials are not able to meet the growing demands of energy storage and portable devices.Graphene assembled films(GAFs)formed from graphene nanosheets have an ultrahigh conductivity,a unique 2D network structure,and exceptional mechanical strength,which give them the potential to solve these problems.However,a systematic understanding of GAFs as an advanced electrode material is lacking.This review focuses on the use of GAFs in electrochemistry,providing a comprehensive analysis of their synthesis methods,surface/structural characteristics,and physical properties,and thus understand their structure-property relationships.Their advantages in batteries,supercapacitors,and electrochemical sensors are systematically evaluated,with an emphasis on their excellent electrical conductivity,ion transport kinetics,and interfacial stability.The existing problems in these devices,such as chemical inertness and mechanical brittleness,are discussed and potential solutions are proposed,including defect engineering and hybrid structures.This review should deepen our mechanistic understanding of the use of GAFs in electrochemical systems and provide actionable strategies for developing stable,high-performance electrode materials.展开更多
[Background and purposes]Proton exchange membrane fuel cells(PEMFCs),which convert hydrogen energy directly into electrical energy and water,have received overwhelming attention,owing to their potential to significant...[Background and purposes]Proton exchange membrane fuel cells(PEMFCs),which convert hydrogen energy directly into electrical energy and water,have received overwhelming attention,owing to their potential to significantly reduce energy consumption,pollution emissions and reliance on fossil fuels.Bipolar plates are the major part and key component of PEMFCs stack,which provide mechanical strength,collect and conduct current segregate oxidants and reduce agents.They contribute 70-80%weight and 20-30%cost of a whole stack,while significantly affecting the power density.There are three types plates,including metal bipolar plate,graphite bipolar plate and composite bipolar plate.Stainless steel bipolar plates,as one of metal bipolar plate,exhibit promising manufacturability,competitive cost and durability among various metal materials.However,stainless steel would be corroded in the harsh acid(pH 2-5)and humid PEMFCs environment,whereas the leached ions will contaminate the membrane.In addition,the passivated film formed on the surface will increase the interfacial contact resistance(ICR).In order to improve the corrosion resistance and electrical conductivity of steel bipolar plates,surface coatings are essential.Metal nitride coatings,metal carbide coatings,polymer coatings and carbon-based coatings have been introduced in recent years.Carbon-based coatings,mainly including a-C(amorphous Carbon),Ta-C(Tetrahedral amorphous carbon)and DLC(diamond-like carbon),have attracted considerable attention from both academia and industry,owing to their superior performance,such as chemical inertness,mechanical hardness and electrical conductivity.However,Ta-C films as protective coating of PEMFCs have been rarely reported,due to the difficulty in production for industrial application.In this paper,multi-layer Ta-C composite films were produced by using customized industrial-scale vacuum equipment to address those issues.[Methods]Multiple layered Ta-C coatings were prepared by using PIS624 equipment,which assembled filtered cathodic arc evaporation,ion beam and magnetron sputtering into one equipment,while SS304 and silicon specimens were used as substrate for testing and analysis.Adhesion layer and intermediate layer were deposited by using magnetron sputtering at deposition temperature of 150℃and pressure of 3×10^(−1) Pa,while the sputtering current was set to be 5 A and bias power to be 300 V.The Ta-C layer was coated at arc current of 80-100 A,bias voltage of 1500 V and gas flow of 75 sccm.A scanning electron microscope(CIQTEK SEM3200)was used to characterize surface morphology,coating structure and cross-section profile of the coatings.Raman spectrometer(LabRam HR Evolution,HORIBA JOBIN YVON)was used to identify the bonding valence states.Electrochemical tests were performed by using an electrochemical work station(CHI760,Shanghai Chenhua Instrument Co.,Ltd.),with the traditional three electrode system,where saturated Ag/AgCl and platinum mesh were used as the reference electrode and counter electrode,respectively.All samples were mounted in plastic tube and sealed with epoxy resin,with an exposure area of 2.25 cm^(2),serving as the working electrode.Electrochemical measurements were carried out in simulated PEMFCs cathode environment in 0.5 mol·L^(−1) H_(2)SO_(4)+5 ppm F−solution,at operating temperature of 70℃.As the cathode environment was harsher than the anode environment,all the samples are stabilized at the open-circuit potential(OCP)for approximately 30 min before the EIS measurements.ICR between bipolar plates and GDL was a key parameter affecting performance of the PEMFCs stack.The test sample sandwiched between 2 pieces of carbon paper(simulate gas diffusion layer,GDL)was placed between 2 gold-plated copper electrodes at a compaction pressure of 1.4 MPa,which was considered to be the conventional compaction pressure in the PEMFCs.Under the same conditions,the resistance of a single carbon paper was measured as well.The ICR was calculated according to the formula ICR=1/2(R2−R1)×S,where S was the contact area between GDL and coated stainless steel BPPs.All data of ICR were measured three times for averaging.[Results]The coatings deposited by filtered cathodic arc technology were compact and smooth,which reduced coating porosity and favorable to corrosion resistance.The coating thickness of adhesion and intermediate layers were 180 nm,while the protective Ta-C coating thickness was about 300 nm,forming multiple coating to provide stronger protection for metal bipolar plates.Cr,Ti,Nb and Ta coatings were selected as adhesion layers for comparison.According to electrochemical test,Ta and Nb coatings have higher corrosion resistance.However,Ta and Nb materials would be costly when they are used for mass production.Relatively,Cr and Ti materials were cost effective.Hence,a comprehensive assessment was indispensable to decide the materials to be selected as adhesion layer.Ta-TiN and Ti-TiN combined adhesion and intermediate layer exhibited stronger corrosion resistance,with the corrosion current to be less than 10^(−6) A·cm^(−2).Ta-C protective coating deposited by using filtered cathodic arc technology indicated displayed higher corrosion resistance,with the average corrosion density to be about 1.26×10^(−7) A·cm^(−2).Ta-C coating also shown larger contact angle,with the highest hydrophobicity,which was one of the important advantages for Ta-C,in terms of corrosion resistance.According to Raman spectroscopy,the I(D)/I(G)=549.8/1126.7=0.487,with the estimated fraction of sp^(3) bonding to be in the range of 5154%.The intermediate layer TiN has higher conductivity than the CrN layer.Considering cost,corrosion performance and ICR result,the Ti-TiN layer combination is recommended for industrial scale application.[Conclusions]Multiple layer coating structure of Ta-C film had stronger corrosion resistance;with more than 50%sp^(3) content,while it also had larger water contact angle and higher corrosion resistance than DLC film.The filtered arcing deposition technology was able to make the film to be more consistent and stable than normal arcing technology in terms of the preparation of Ta-C.The coating displayed corrosion density of 1.26×10^(−7) A·cm^(−2) and ICR of less than 5 mΩ·cm^(2),far beyond technical target of 2025 DOE(US Department of Energy).This indicated that the mass-production scale coating technology for PEMFC bipolar plates is highly possible.展开更多
The periodic [Ti/TiB2]n （n=l, 2, 3） multilayered films were prepared on the substrate of AISI 316L stainless steel by magnetron sputtering to enhance the adhesion of TiB2 films based on the remarkable mechanical per...The periodic [Ti/TiB2]n （n=l, 2, 3） multilayered films were prepared on the substrate of AISI 316L stainless steel by magnetron sputtering to enhance the adhesion of TiB2 films based on the remarkable mechanical performance of layered films. The influence of periods on microstructure, adhesion and hardness of [Ti/TiB2]n multilayered films was studied. X-ray diffraction （XRD） analysis shows that the monolayer TiB2 films exhibit （001） preferred orientation, and the preferred orientation of [Ti/TiB2], multilayered films transfers from （001） to （100） with the increase of periods. The cross-sectional morphology of each film displays homogeneity by field emission scanning electron microscopy （FESEM）. The hardness of the films measured via nanoindention changes from 20 to 26 GPa with the increase of periods. These values of hardness are a bit lower than that of the monolayer TiB2 films which is up to 33 GPa. However, the [Ti/TiB2]n multilayered films present a considerably good adhesion, which reaches a maximum of 24 N, in comparison with the monolayer TiB2 films according to the experimental results.展开更多
The discovery of high-temperature superconductivity in bilayer nickelate La_(3)Ni_(2)O_(7)under high-pressure conditions has spurred extensive efforts to stabilize superconductivity at ambient pressure.Recently,the re...The discovery of high-temperature superconductivity in bilayer nickelate La_(3)Ni_(2)O_(7)under high-pressure conditions has spurred extensive efforts to stabilize superconductivity at ambient pressure.Recently,the realization of superconductivity in compressively strained La_(3)Ni_(2)O_(7)thin films grown on the SrLaAlO_(4)substrates,with a T_(c)exceeding 40 K,represents a significant step toward this goal.Here,we investigate the influence of film thickness and carrier doping on the electronic structure of La_(3)Ni_(2)O_(7)thin films,ranging from 0.5 to 3 unit cells,using first-principles calculations.For a 2 unit-cell film with an optimal doping concentration of 0.3 hole per formula unit(0.15 hole/Ni),the Ni-d_(z^(2))interlayer bonding state crosses the Fermi level,resulting in the formation ofγpockets at the Fermi surface.These findings align with angle-resolved photoemission spectroscopy experimental data.Our results provide theoretical validation for the recent experimental discovery of ambient-pressure superconductivity in La_(3)Ni_(2)O_(7)thin films and underscore the significant impact of film thickness and carrier doping on electronic property modulation.展开更多
Lead zirconate titanate(PbZr_(x)Ti_(1-x)O_(3),PZT)ferroelectric films possess remarkable characteristics such as high residual polarization,high dielectric constant,and high piezoelectric coefficient and have great ap...Lead zirconate titanate(PbZr_(x)Ti_(1-x)O_(3),PZT)ferroelectric films possess remarkable characteristics such as high residual polarization,high dielectric constant,and high piezoelectric coefficient and have great application prospects in modern electronics,communications,medical care,and military fields.At present,the microstructure changes of PZT ferroelectric thin films have a significant impact on their electrical properties.Therefore,this work summarizes the influences of geometric structure(thickness,porosity),composition structure(Zr/Ti ratio,doping),and grain structure(grain size,grain boundaries,orientation)on the electrical properties of PZT ferroelectric thin films.The results show that the changes in thickness and porosity have a significant impact on the electrical properties of PZT ferroelectric films.Especially,the actual application scenarios and preparation processes determine the required geometric dimensions and structures of PZT ferroelectric films.The Zr/Ti ratio and doping mainly affect the electrical properties by influencing the phase composition of PZT ferroelectric films.The changes in grain size,boundary structure,and orientation dependence mainly have a certain degree of influence on the domain response and domain switching behavior of PZT ferroelectric thin films.In conclusion,different structures have different influence effects on the dielectric,ferroelectric,and piezoelectric properties of PZT ferroelectric films.The way the tiny structure affects how PZT thin films work was shown,helping to guide the design of ferroelectric thin film devices.In order to further study and apply piezoelectric ceramic devices,it is crucial to have an in-depth understanding of the relationship between the structure and performance of piezoelectric ceramic devices.展开更多
Polymer adsorption at solid interfaces plays an important role in the dynamics of nanoscale polymer films.We investigated the influence of the interfacial chain adsorption on the glass transition temperature(Tg)and de...Polymer adsorption at solid interfaces plays an important role in the dynamics of nanoscale polymer films.We investigated the influence of the interfacial chain adsorption on the glass transition temperature(Tg)and dewetting of polystyrene(PS)thin films on a graphene substrate that has strong interaction with PS.We found that the Tgs of PS films show a non-monotonic trend with increasing amount of polymer adsorption at the interface—first increasing and then decreasing,and this change in Tg is accompanied by a wetting-dewetting transition of the PS films.Film morphological analysis showed that the PS films dewet from the interfacially adsorbed layers rather than from the substrate,i.e.,autophobic dewetting,indicating the presence of an unfavorable interaction between the adsorbed and free PS chains.We ascribed the repulsive interaction to the formation of a dense adsorbed layer on graphene due to the π-π interaction between PS and graphene,which prevents the nonadsorbed PS chain from penetrating into the adsorbed layer.This may lead to drops in Tg at high adsorption extent.展开更多
FeCoCrMnNiN_(x)high entropy nitride ceramics thin films were prepared using the magnetron sputtering method,and the effects of nitrogen content on the thin films’properties were later examined.The addition of N_(2)af...FeCoCrMnNiN_(x)high entropy nitride ceramics thin films were prepared using the magnetron sputtering method,and the effects of nitrogen content on the thin films’properties were later examined.The addition of N_(2)affected the microstructures of the thin films and their mechanical and corrosion properties.Compared with the FeCoCrMnNi thin films with 1-sccm N_(2),the addition of 2 and 3 sccm of N_(2)by as much as 5.45at%and 6.34at%changed the solid solution’s crystalline structure into an amorphous structure.The addition of nitro-gen caused drastic changes to the surface morphology,creating a smoother and more uniform surface without cauliflower units.The atomic force microscopy image analysis indicated that the addition of nitrogen reduced the surface roughness from 5.58 to 1.82 nm.Adding N_(2)to the CoCrFeMnNi thin film helped increase its mechanical properties,such as hardness and strength,while the Young’s modulus decreased.The hardness of(8.75±0.5)GPa and the reduced Young’s modulus of(257.37±11.4)GPa of the FeCoCrMnNi thin film reached(12.67±1.2)and(194.39±12.4)GPa,respectively,with 1 sccm N_(2).The applied coating of the CoCrFeMnNi thin film on 304SUS increased the corrosion resistance,whereas the addition of nitrogen to the CoCrFeMnNi thin film also improved its corrosion res-istance compared with that of the CoCrFeMnNi thin film without nitrogen.展开更多
SrRuO_(3)is a canonical itinerant ferromagnet,yet its properties in the extreme two-dimensional limit on a(111)crystal plane remain largely unexplored.Here,we demonstrate a complete transformation of its ground state ...SrRuO_(3)is a canonical itinerant ferromagnet,yet its properties in the extreme two-dimensional limit on a(111)crystal plane remain largely unexplored.Here,we demonstrate a complete transformation of its ground state driven by dimensional reduction.As the thickness of(111)-oriented SrRuO_(3)films is reduced to a few unit cells,the system transitions from a metallic ferromagnet to a semiconducting antiferromagnet.This emergent antiferromagnetism is evidenced by a vanishing magnetic remanence and most strikingly,by the appearance of an unconventional twelve-fold anisotropic magnetoresistance.First-principles calculations confirm that an A-type antiferromagnetic order is the stable ground state in the ultrathin limit.Our findings establish(111)dimensional engineering as a powerful route to manipulate correlated electron states and uncover novel functionalities for antiferromagnetic spintronics.展开更多
Polymeric materials,known for their lightweight and strength,are widely used today.However,their non-biodegradable nature poses significant environmental challenges.This research aimed to develop biodegradable films f...Polymeric materials,known for their lightweight and strength,are widely used today.However,their non-biodegradable nature poses significant environmental challenges.This research aimed to develop biodegradable films from fruits and vegetables,using alginate as a binding agent.Using a completely randomized design,seven experimental sets were prepared with carrots,Kimju guava,and Namwa banana peel fibers as the primary materials and alginate as the secondary material at three levels:1.2,1.8,and 2.4 by weight.The solution technique was employed to create the samples.Upon testing mechanical and physical properties,experimental set 3,consisting of 60%guava and 1.8%alginate,emerged as the optimal ratio.This combination exhibited favorable physical properties,including a thickness of 0.26±0.02 mm,meeting the standards for food packaging films.Additionally,the tensile strength was 0.50±0.01 N/m²,and the elongation at break was 55.60±0.44%.Regarding chemical properties,the moisture content of 5.64±0.03%fell within the acceptable range for dried food.Furthermore,a 30-day soil burial test revealed that the sample from experimental set 3 exhibited the highest degradation rate.In conclusion,these findings suggest that guava can be a promising raw material for producing biodegradable plastics suitable for packaging applications.展开更多
基金supported by the European Research Council(ERC)under the European Union's Horizon 2020 Research and Innovation Programme(Grant Agreement No.818762)the Engineering and Physical Sciences Research Council(Grant No.EP/V048953/1)and the Isaac Newton Trust(grant 22.39(m))。
文摘Although multicrystalline Si photovoltaics have been extensively studied and applied in the collection of solar energy,the same systems suffer significant efficiency losses in indoor settings,where ambient light conditions are considerably smaller in intensity and possess greater components of non-normal incidence.Yet,indoor light-driven,stand-alone devices can offer sustainable advances in next-generation technologies such as the Internet of Things.Here,we present a non-invasive solution to aid in photovoltaic indoor light collection—radially distributed waveguide-encoded lattice(RDWEL)slim films(thickness 1.5 mm).Embedded with a monotonical radial array of cylindrical waveguides(±20°),the RDWEL demonstrates seamless light collection(FoV(fields of view)=74.5°)and imparts enhancements in JSC(short circuit current density)of 44%and 14%for indoor and outdoor lighting conditions,respectively,when coupled to a photovoltaic device and compared to an unstructured but otherwise identical slim film coating.
基金supported by Research Fund of SWUST for PhD(Grant No.22zx7175)Sichuan Science and Technology Program(Grant No.2024NSFSC1097)。
文摘Based on the characteristics of laser-induced surface ignition,energetic photosensitive films show promising potential to meet the ignition requirements of various energetic materials(EMs).In this study,DATNBI/ferric alginate(DI/FeA),DI/cobalt alginate(DI/CoA),and DI/nickel alginate(DI/Ni A)films are fabricated by employing sodium alginate(SA)with a three-dimensional network structure as the film matrix,via ionic cross-linking of SA with Fe^(3+),Co^(2+),and Ni^(2+)ions.The study demonstrates that the ionic cross-linking enhances the hydrophobic performance of the films,with the water contact angle increasing from 82.1° to 123.5°.Concurrently,the films'near-infrared(NIR)light absorption improved.Furthermore,transition metal ions facilitate accelerated electron transfer,thereby catalyzing the thermal decomposition of DATNBI.Under 1064 nm laser irradiation,the DI/Fe A film exhibits exceptional combustion performance,with an ignition delay time as low as 76 ms.It successfully acts as an NIR laser ignition medium to initiate the self-sustained combustion of CL-20.This study demonstrates the synergistic realization of enhanced hydrophobicity,improved photosensitivity,and promoted catalytic decomposition through microstructural design of the material,providing new insights for the design of additive-free EMs in laser ignition applications.
基金funded by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior(CAPES,https://www.gov.br/capes)and by Mitacs(https://www.mitacs.ca),under grant number IT42277Letícia Vitorazi acknowledges support from FAPERJ(https://www.faperj.br)under grant number E-26/200.129/2023—Bolsa JCNE/FAPERJ+1 种基金Flavia Braghiroli acknowledges the Natural Sciences and Engineering Research Council of Canada(NSERC),Alliance project ALLRP 585984-23the Fonds de recherche duQuébec—Nature et technologies(FRQNT)(https://doi.org/10.69777/355295),grant number 202250.
文摘The development of sustainable materials has encouraged the use of biopolymers as alternatives to synthetic polymers.Polymeric films have stood out for their high potential in environmentally sustainable applications.Conventional cellulose acetate(CA)-based films are attractive due to their biodegradability and film-forming ability.However,their functional performance often requires enhancement through the incorporation of additives.In this context,two bio-based additives were investigated:condensed tannin(0%,5%and 10%wt.),a natural polyphenol known for its antioxidant and antimicrobial properties,and nanocrystalline cellulose(CNC)(0%,0.5%and 1%wt.),which act as reinforcing agents to improve mechanical strength and barrier properties.The results showed that tannin generally enhanced mechanical strength and surface uniformity while imparting contact-based antimicrobial activity.CNC reduced water uptake and improved thermal stability,but when used alone,it tended to lower mechanical performance and increase surface roughness.The combination of CNC and tannin produced performance shifts that depended strongly on their relative concentrations,with no consistent synergistic effect across all properties.In certain balanced ratios,CNC benefited fromtannin’smatrix-stabilizing effect,leading to improved strength or reduced moisture absorption.Antimicrobial activity in acetic acid–based films was linked to residual acidity,whereas in acetonebased films,tannin alone was responsible for the antimicrobial effect by contact.These findings highlight that the physicochemical,mechanical,and functional performance of CA films(CAFs)is governed not only by additive type but also by the precise interplay between CNC and tannin,underscoring the need for formulation strategies tailored to the requirements of specific applications.
基金the financial support provided by Universiti Putra Malaysiasupported by the Matching Grant(9300489).
文摘This review draws attention to the innovative use of arrowroot(Maranta arundinacea)fiber as a unique and underutilized biomass source for nanocrystalline cellulose(NCC)-based nanocomposites,presenting a noteworthy alternative to extensively researched materials like wood pulp,bacterial cellulose,and chemically modified NCCs.In contrast to traditional sources,arrowroot possesses a naturally elevated cellulose and diminished lignin content,facilitating more effective NCC extraction requiring reduced chemical input and enabling environmentally friendly processing techniques.The review evaluates the performance of arrowroot-derived nanocomposites against systems documented in the literature,including NCC-based shape memory composites and nanoparticle-reinforced films,demonstrating enhanced tensile strength,improved moisture barrier properties,and thermal stability,as well as potential piezoelectric response.This study recognizes arrowroot as a viable option in the biomass-based nanocellulose sector,providing ecological and functional benefits while tackling significant issues such as process scalability and feedstock variability,thereby offering important insights for the advancement of sustainable materials.
基金support received from the National Research Foundation of Korea(NRF)through the Ministry of Science,ICT(Information and Communication Technology),under grant numbers RS-2023-00302646 and RS-2025-02316700.
文摘Tin-lead(Sn-Pb)halide perovskite single crystals combine narrow bandgaps,long carrier diffusion lengths,and low trap densities,positioning them as ideal candidates for near-infrared(NIR)optoelectronics.However,conventional growth strategies rely on bulk crystallization at elevated temperatures,leading to uncontrolled nucleation,Sn^(2+)oxidation,and poor compatibility with planar integration.Here,we develop a coordination-engineered crystallization strategy that enables direct,lowtemperature growth of micrometer-thick Sn-Pb single-crystal thin films on device-compatible substrates.By modulating metal-solvent coordination strength using a low-donor number cosolvent system,we delineate a narrow processing window that stabilizes precursor speciation,lowers the nucleation barrier,and guides directional crystal growth under mild thermal conditions(<40℃).The resulting crystal films exhibit smooth morphology,high crystallinity,compositional uniformity,and ultralow trap densities(~3.98×10^(12)cm^(-3)).When integrated into NIR photodetectors,these films deliver high responsivity(0.51 A W^(-1)at 900 nm),specific detectivity up to 3.6×10^(12)Jones,fast response(~188μs),and>25,000 cycles of ambient operational stability.This approach establishes a scalable platform for redox-stable,low-temperature growth of Sn-Pb perovskite crystal films and expands the processing-structure-function landscape for next-generation infrared optoelectronics.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52172271,12374378,52307026,and 52477022)the National Key Research and Development Program of China(Grant No.2022YFE03150200)Shanghai Science and Technology Innovation Program(Grant No.23511101600)。
文摘This study investigates the effect of BaHfO_(3)(BHO)addition on the optical properties of YBa_2Cu_(3)O_(7-δ)(YBCO)superconducting thin films using spectroscopic ellipsometry.Through Raman spectroscopy and SEM analysis,optimal 10-min Ar ion etching effectively removes surface a-axis-oriented grains and Ba–Cu–O impurities,enhancing surface quality.Optical conductivity analysis reveals a doping-dependent evolution:10%BHO doping maximizes free carrier density and interband transition efficiency,attributed to optimized Cu–O bond contraction and reduced lattice distortions.Higher doping induces defect clustering,carrier scattering,and redshifted transitions due to lattice expansion.Dielectric function and loss function analyses confirm enhanced plasmonic behavior and flux pinning at 10%doping,while excessive doping degrades electronic transitions.These results highlight the critical role of controlled BHO addition and surface treatment in tailoring the optical and superconducting properties of YBCO,offering insights into the interplay among doping,carrier dynamics,and electronic structure in high-temperature superconductors(HTS).
基金Project supported by the National Key Research and Development Program of China(Grant No.2021YFA1400300)the National Natural Science Foundation of China(Grant Nos.22271309,12304268,12261131499,and 11921004)the China Postdoctoral Science Foundation(Grant No.2023M743741)。
文摘BiMeO_(3)–PbTiO_(3)(where Me represents transition metals)perovskite-type thin films have been widely studied due to their superior ferroelectric properties,including robust ferroelectric polarization and high Curie temperatures.In this study,PbTiO_(3)-based perovskite thin films of xBi(Cu_(1/2)Zr_(1/2))O_(3)–(1-x)PbTiO_(3)(xBCZ–(1-x)PT)were designed and prepared on Pt(111)/Ti/SiO_2/Si substrates using the conventional sol–gel method.The x BCZ–(1-x)PT thin films demonstrate remarkable crystallinity,characterized by a perovskite structure and a dense microstructure,which contribute to their highperformance ferroelectric and fatigue properties.Notably,the thin films exhibit large remnant polarization(2P_(r0))values,reaching 98μC·cm^(-2)and 74μC·cm^(-2)for the 0.05BCZ–0.95PT and 0.1BCZ–0.9PT compositions,respectively.Furthermore,the thin films also demonstrate a high Curie temperature(T_(C)=510℃),as well as favorable fatigue properties and low leakage current,suggesting their potential applicability in ferroelectric devices.
基金financially supported by the National Key Research and Development Program of China(No.2019YFB1503500)
文摘Ferroelectric materials are widely applied in the ferroelectronic devices,photovoltaics,and so on.Ultrathin ferroelectric thin films are highly desired for their applications,which still remain a challenge.In this work,the ultrathin barium titanate(BaTiO_(3),BTO)films are deposited directly on the fluorine-doped tin oxide glass(SnO_(2):F,FTO)substrates by radio frequency magnetron sputtering method at different temperatures.All BTO ultrathin films exhibit strong ferroelectric properties.Interestingly,BTO thin films deposited at room temperature(RT)also exhibit robust ferroelectricity.The polar domains are switched reversibly with a phase degree of~180°by piezoelectric force microscopy for the BTO thin films deposited at room temperature,attributing to the strain and ion migration.
文摘BaFe_(12)O_(19)(BaM)thin films with thicknesses ranging from 15 nm–200 nm were deposited on Al_(2)O_(3)(0001)substrates by pulsed laser deposition(PLD).X-ray diffraction patterns show that a buffer layer with a thickness of nearly 60 nm forms on the substrate,and then a c-axis perpendicularly oriented Ba M thin film grows on the buffer layer.Atomic force microscopy results indicate that the Ba M thin film exhibits a spiral island growth mode on the buffer layer.Magnetic hysteresis loop results confirm that the buffer layer exhibits no significant magnetic anisotropy,while the Ba M thin film exhibits perpendicular magnetic anisotropy.The out-of-plane coercivity decreases with increasing Ba M thin-film thickness due to the combined effect of grain size growth and lattice strain relaxation.The 200 nm thick film exhibits optimum magnetic properties with M_(s)=319 emu/cm^(3) and H_(c)=1546 Oe.
基金financially supported by the National Natural Science Foundation of China(No.51971148)the Key Project Foundation of Hanjiang Normal University,China(No.XJ2024A09)+1 种基金the Excellent Young and Middle-aged Science and Technology Innovation Team Project in Higher Education Institutions of Hubei Province,China(No.T2020024)the Shanghai Engineering Research Center of High-Performance Medical Device Materials,China(No.20DZ2255500)。
文摘The dependence of interface structure and mechanical properties on the modulation layer thickness of VN/TiN−Ni nano-multilayered films deposited on Si substrates using a reactive magnetron sputtering technique was systematically investigated. The films were characterized using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and nanoindentation. The results show that the TiN−Ni layer grows epitaxially on the VN layer, forming a coherent interface between the two sublayers. When the deposition time ratio of the two sublayers (TTiN−Ni꞉TVN) is 10꞉12, the films exhibit remarkable mechanical properties, with hardness, elastic modulus, and fracture toughness values of 25.9 GPa, 317 GPa, and 1.88 MPa·m^(1/2), respectively. Meanwhile, fracture toughness is improved by approximately 50% compared to the VN monolithic film. This enhancement is attributed to the coherent interface between the sublayers and the phase separation in the TiN−Ni layer.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12374196, 92165201, and 11634011)the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0302800)+2 种基金the Chinese Academy of Sciences Project for Young Scientists in Basic Research (Grant No. YSBR-046)the Fundamental Research Funds for the Central Universities (Grant Nos. WK3510000006 and WK3430000003)Anhui Initiative in Quantum Information Technologies (Grant No. AHY170000)。
文摘Ising superconductivity has garnered much attention in recent years due to its extremely high in-plane upper critical field (B_(c2)).Here,we fabricated 14 multilayer Pb_(1-x)Bi_(x) (0%≤x≤40%) thin films on Si (111)-7×7 reconstructed surface by molecular beam epitaxy.Large B_(c2) beyond the Pauli limit is observed in all the Pb_(1-x)Bi_(x) films,indicating that they may exhibit characteristics of Ising superconductivity.Moreover,the introduction of Bi doping can significantly enhance and effectively tune the in-plane B_(c2) of Pb_(1-x)Bi_(x) films,which will help us better understand Ising superconductivity and provide a new platform for the development of tunable Ising superconductors.
基金the National Natural Science Foundation of China(22279097)the Key R&D Program of Hubei Province(2023BAB103)the PhD Scientific Research and Innovation Foundation of The Education Department of Hainan Province Joint Project of Sanya Yazhou Bay Science and Technology City(HSPHDSRF-2024-03-022)。
文摘Because of their low electrical conductivity,sluggish ion diffusion,and poor stability,conventional electrode materials are not able to meet the growing demands of energy storage and portable devices.Graphene assembled films(GAFs)formed from graphene nanosheets have an ultrahigh conductivity,a unique 2D network structure,and exceptional mechanical strength,which give them the potential to solve these problems.However,a systematic understanding of GAFs as an advanced electrode material is lacking.This review focuses on the use of GAFs in electrochemistry,providing a comprehensive analysis of their synthesis methods,surface/structural characteristics,and physical properties,and thus understand their structure-property relationships.Their advantages in batteries,supercapacitors,and electrochemical sensors are systematically evaluated,with an emphasis on their excellent electrical conductivity,ion transport kinetics,and interfacial stability.The existing problems in these devices,such as chemical inertness and mechanical brittleness,are discussed and potential solutions are proposed,including defect engineering and hybrid structures.This review should deepen our mechanistic understanding of the use of GAFs in electrochemical systems and provide actionable strategies for developing stable,high-performance electrode materials.
基金Major Science and technology projects of Anhui Province (202103a05020003)。
文摘[Background and purposes]Proton exchange membrane fuel cells(PEMFCs),which convert hydrogen energy directly into electrical energy and water,have received overwhelming attention,owing to their potential to significantly reduce energy consumption,pollution emissions and reliance on fossil fuels.Bipolar plates are the major part and key component of PEMFCs stack,which provide mechanical strength,collect and conduct current segregate oxidants and reduce agents.They contribute 70-80%weight and 20-30%cost of a whole stack,while significantly affecting the power density.There are three types plates,including metal bipolar plate,graphite bipolar plate and composite bipolar plate.Stainless steel bipolar plates,as one of metal bipolar plate,exhibit promising manufacturability,competitive cost and durability among various metal materials.However,stainless steel would be corroded in the harsh acid(pH 2-5)and humid PEMFCs environment,whereas the leached ions will contaminate the membrane.In addition,the passivated film formed on the surface will increase the interfacial contact resistance(ICR).In order to improve the corrosion resistance and electrical conductivity of steel bipolar plates,surface coatings are essential.Metal nitride coatings,metal carbide coatings,polymer coatings and carbon-based coatings have been introduced in recent years.Carbon-based coatings,mainly including a-C(amorphous Carbon),Ta-C(Tetrahedral amorphous carbon)and DLC(diamond-like carbon),have attracted considerable attention from both academia and industry,owing to their superior performance,such as chemical inertness,mechanical hardness and electrical conductivity.However,Ta-C films as protective coating of PEMFCs have been rarely reported,due to the difficulty in production for industrial application.In this paper,multi-layer Ta-C composite films were produced by using customized industrial-scale vacuum equipment to address those issues.[Methods]Multiple layered Ta-C coatings were prepared by using PIS624 equipment,which assembled filtered cathodic arc evaporation,ion beam and magnetron sputtering into one equipment,while SS304 and silicon specimens were used as substrate for testing and analysis.Adhesion layer and intermediate layer were deposited by using magnetron sputtering at deposition temperature of 150℃and pressure of 3×10^(−1) Pa,while the sputtering current was set to be 5 A and bias power to be 300 V.The Ta-C layer was coated at arc current of 80-100 A,bias voltage of 1500 V and gas flow of 75 sccm.A scanning electron microscope(CIQTEK SEM3200)was used to characterize surface morphology,coating structure and cross-section profile of the coatings.Raman spectrometer(LabRam HR Evolution,HORIBA JOBIN YVON)was used to identify the bonding valence states.Electrochemical tests were performed by using an electrochemical work station(CHI760,Shanghai Chenhua Instrument Co.,Ltd.),with the traditional three electrode system,where saturated Ag/AgCl and platinum mesh were used as the reference electrode and counter electrode,respectively.All samples were mounted in plastic tube and sealed with epoxy resin,with an exposure area of 2.25 cm^(2),serving as the working electrode.Electrochemical measurements were carried out in simulated PEMFCs cathode environment in 0.5 mol·L^(−1) H_(2)SO_(4)+5 ppm F−solution,at operating temperature of 70℃.As the cathode environment was harsher than the anode environment,all the samples are stabilized at the open-circuit potential(OCP)for approximately 30 min before the EIS measurements.ICR between bipolar plates and GDL was a key parameter affecting performance of the PEMFCs stack.The test sample sandwiched between 2 pieces of carbon paper(simulate gas diffusion layer,GDL)was placed between 2 gold-plated copper electrodes at a compaction pressure of 1.4 MPa,which was considered to be the conventional compaction pressure in the PEMFCs.Under the same conditions,the resistance of a single carbon paper was measured as well.The ICR was calculated according to the formula ICR=1/2(R2−R1)×S,where S was the contact area between GDL and coated stainless steel BPPs.All data of ICR were measured three times for averaging.[Results]The coatings deposited by filtered cathodic arc technology were compact and smooth,which reduced coating porosity and favorable to corrosion resistance.The coating thickness of adhesion and intermediate layers were 180 nm,while the protective Ta-C coating thickness was about 300 nm,forming multiple coating to provide stronger protection for metal bipolar plates.Cr,Ti,Nb and Ta coatings were selected as adhesion layers for comparison.According to electrochemical test,Ta and Nb coatings have higher corrosion resistance.However,Ta and Nb materials would be costly when they are used for mass production.Relatively,Cr and Ti materials were cost effective.Hence,a comprehensive assessment was indispensable to decide the materials to be selected as adhesion layer.Ta-TiN and Ti-TiN combined adhesion and intermediate layer exhibited stronger corrosion resistance,with the corrosion current to be less than 10^(−6) A·cm^(−2).Ta-C protective coating deposited by using filtered cathodic arc technology indicated displayed higher corrosion resistance,with the average corrosion density to be about 1.26×10^(−7) A·cm^(−2).Ta-C coating also shown larger contact angle,with the highest hydrophobicity,which was one of the important advantages for Ta-C,in terms of corrosion resistance.According to Raman spectroscopy,the I(D)/I(G)=549.8/1126.7=0.487,with the estimated fraction of sp^(3) bonding to be in the range of 5154%.The intermediate layer TiN has higher conductivity than the CrN layer.Considering cost,corrosion performance and ICR result,the Ti-TiN layer combination is recommended for industrial scale application.[Conclusions]Multiple layer coating structure of Ta-C film had stronger corrosion resistance;with more than 50%sp^(3) content,while it also had larger water contact angle and higher corrosion resistance than DLC film.The filtered arcing deposition technology was able to make the film to be more consistent and stable than normal arcing technology in terms of the preparation of Ta-C.The coating displayed corrosion density of 1.26×10^(−7) A·cm^(−2) and ICR of less than 5 mΩ·cm^(2),far beyond technical target of 2025 DOE(US Department of Energy).This indicated that the mass-production scale coating technology for PEMFC bipolar plates is highly possible.
基金Project(51175212)supported by the National Natural Science Foundation of China
文摘The periodic [Ti/TiB2]n （n=l, 2, 3） multilayered films were prepared on the substrate of AISI 316L stainless steel by magnetron sputtering to enhance the adhesion of TiB2 films based on the remarkable mechanical performance of layered films. The influence of periods on microstructure, adhesion and hardness of [Ti/TiB2]n multilayered films was studied. X-ray diffraction （XRD） analysis shows that the monolayer TiB2 films exhibit （001） preferred orientation, and the preferred orientation of [Ti/TiB2], multilayered films transfers from （001） to （100） with the increase of periods. The cross-sectional morphology of each film displays homogeneity by field emission scanning electron microscopy （FESEM）. The hardness of the films measured via nanoindention changes from 20 to 26 GPa with the increase of periods. These values of hardness are a bit lower than that of the monolayer TiB2 films which is up to 33 GPa. However, the [Ti/TiB2]n multilayered films present a considerably good adhesion, which reaches a maximum of 24 N, in comparison with the monolayer TiB2 films according to the experimental results.
基金supported by the National Key R&D Program of China(Gran Nos.2022YFA1402304 and 2022YFA1402802)the National Natural Science Foundation of China(Grant Nos.12494591,12122405,12274169,and 92165204)+4 种基金Program for Science and Technology Innovation Team in Zhejiang(Grant No.2021R01004)Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices(Grant No.2022B1212010008)Guangdong Fundamental Research Center for Magnetoelectric Physics(2024B0303390001)Guangdong Provincial Quantum Science Strategic Initiative(Grant No.GDZX2401010)the Fundamental Research Funds for the Central Universities。
文摘The discovery of high-temperature superconductivity in bilayer nickelate La_(3)Ni_(2)O_(7)under high-pressure conditions has spurred extensive efforts to stabilize superconductivity at ambient pressure.Recently,the realization of superconductivity in compressively strained La_(3)Ni_(2)O_(7)thin films grown on the SrLaAlO_(4)substrates,with a T_(c)exceeding 40 K,represents a significant step toward this goal.Here,we investigate the influence of film thickness and carrier doping on the electronic structure of La_(3)Ni_(2)O_(7)thin films,ranging from 0.5 to 3 unit cells,using first-principles calculations.For a 2 unit-cell film with an optimal doping concentration of 0.3 hole per formula unit(0.15 hole/Ni),the Ni-d_(z^(2))interlayer bonding state crosses the Fermi level,resulting in the formation ofγpockets at the Fermi surface.These findings align with angle-resolved photoemission spectroscopy experimental data.Our results provide theoretical validation for the recent experimental discovery of ambient-pressure superconductivity in La_(3)Ni_(2)O_(7)thin films and underscore the significant impact of film thickness and carrier doping on electronic property modulation.
基金Supported by National Natural Science Foundation of China(Grant No.55275227)。
文摘Lead zirconate titanate(PbZr_(x)Ti_(1-x)O_(3),PZT)ferroelectric films possess remarkable characteristics such as high residual polarization,high dielectric constant,and high piezoelectric coefficient and have great application prospects in modern electronics,communications,medical care,and military fields.At present,the microstructure changes of PZT ferroelectric thin films have a significant impact on their electrical properties.Therefore,this work summarizes the influences of geometric structure(thickness,porosity),composition structure(Zr/Ti ratio,doping),and grain structure(grain size,grain boundaries,orientation)on the electrical properties of PZT ferroelectric thin films.The results show that the changes in thickness and porosity have a significant impact on the electrical properties of PZT ferroelectric films.Especially,the actual application scenarios and preparation processes determine the required geometric dimensions and structures of PZT ferroelectric films.The Zr/Ti ratio and doping mainly affect the electrical properties by influencing the phase composition of PZT ferroelectric films.The changes in grain size,boundary structure,and orientation dependence mainly have a certain degree of influence on the domain response and domain switching behavior of PZT ferroelectric thin films.In conclusion,different structures have different influence effects on the dielectric,ferroelectric,and piezoelectric properties of PZT ferroelectric films.The way the tiny structure affects how PZT thin films work was shown,helping to guide the design of ferroelectric thin film devices.In order to further study and apply piezoelectric ceramic devices,it is crucial to have an in-depth understanding of the relationship between the structure and performance of piezoelectric ceramic devices.
基金supported by the National Natural Science Foundation of China(Nos.22122306,22303084 and 52373025)。
文摘Polymer adsorption at solid interfaces plays an important role in the dynamics of nanoscale polymer films.We investigated the influence of the interfacial chain adsorption on the glass transition temperature(Tg)and dewetting of polystyrene(PS)thin films on a graphene substrate that has strong interaction with PS.We found that the Tgs of PS films show a non-monotonic trend with increasing amount of polymer adsorption at the interface—first increasing and then decreasing,and this change in Tg is accompanied by a wetting-dewetting transition of the PS films.Film morphological analysis showed that the PS films dewet from the interfacially adsorbed layers rather than from the substrate,i.e.,autophobic dewetting,indicating the presence of an unfavorable interaction between the adsorbed and free PS chains.We ascribed the repulsive interaction to the formation of a dense adsorbed layer on graphene due to the π-π interaction between PS and graphene,which prevents the nonadsorbed PS chain from penetrating into the adsorbed layer.This may lead to drops in Tg at high adsorption extent.
基金the Ahvaz Branch, Islamic Azad University for the financial support
文摘FeCoCrMnNiN_(x)high entropy nitride ceramics thin films were prepared using the magnetron sputtering method,and the effects of nitrogen content on the thin films’properties were later examined.The addition of N_(2)affected the microstructures of the thin films and their mechanical and corrosion properties.Compared with the FeCoCrMnNi thin films with 1-sccm N_(2),the addition of 2 and 3 sccm of N_(2)by as much as 5.45at%and 6.34at%changed the solid solution’s crystalline structure into an amorphous structure.The addition of nitro-gen caused drastic changes to the surface morphology,creating a smoother and more uniform surface without cauliflower units.The atomic force microscopy image analysis indicated that the addition of nitrogen reduced the surface roughness from 5.58 to 1.82 nm.Adding N_(2)to the CoCrFeMnNi thin film helped increase its mechanical properties,such as hardness and strength,while the Young’s modulus decreased.The hardness of(8.75±0.5)GPa and the reduced Young’s modulus of(257.37±11.4)GPa of the FeCoCrMnNi thin film reached(12.67±1.2)and(194.39±12.4)GPa,respectively,with 1 sccm N_(2).The applied coating of the CoCrFeMnNi thin film on 304SUS increased the corrosion resistance,whereas the addition of nitrogen to the CoCrFeMnNi thin film also improved its corrosion res-istance compared with that of the CoCrFeMnNi thin film without nitrogen.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204521,12250710675,and 12504198)the National Key R&D Program of China(Grant No.2022YFA1403000)。
文摘SrRuO_(3)is a canonical itinerant ferromagnet,yet its properties in the extreme two-dimensional limit on a(111)crystal plane remain largely unexplored.Here,we demonstrate a complete transformation of its ground state driven by dimensional reduction.As the thickness of(111)-oriented SrRuO_(3)films is reduced to a few unit cells,the system transitions from a metallic ferromagnet to a semiconducting antiferromagnet.This emergent antiferromagnetism is evidenced by a vanishing magnetic remanence and most strikingly,by the appearance of an unconventional twelve-fold anisotropic magnetoresistance.First-principles calculations confirm that an A-type antiferromagnetic order is the stable ground state in the ultrathin limit.Our findings establish(111)dimensional engineering as a powerful route to manipulate correlated electron states and uncover novel functionalities for antiferromagnetic spintronics.
基金funding from the Environmental Science Program for Academic Excellence and Community Research for Fiscal Year 2024,a financial resource of the Environmental Science and Technology Program,Faculty of Science,Buriram Rajabhat University.Additionally,Buriram Rajabhat University provided a publication budget.
文摘Polymeric materials,known for their lightweight and strength,are widely used today.However,their non-biodegradable nature poses significant environmental challenges.This research aimed to develop biodegradable films from fruits and vegetables,using alginate as a binding agent.Using a completely randomized design,seven experimental sets were prepared with carrots,Kimju guava,and Namwa banana peel fibers as the primary materials and alginate as the secondary material at three levels:1.2,1.8,and 2.4 by weight.The solution technique was employed to create the samples.Upon testing mechanical and physical properties,experimental set 3,consisting of 60%guava and 1.8%alginate,emerged as the optimal ratio.This combination exhibited favorable physical properties,including a thickness of 0.26±0.02 mm,meeting the standards for food packaging films.Additionally,the tensile strength was 0.50±0.01 N/m²,and the elongation at break was 55.60±0.44%.Regarding chemical properties,the moisture content of 5.64±0.03%fell within the acceptable range for dried food.Furthermore,a 30-day soil burial test revealed that the sample from experimental set 3 exhibited the highest degradation rate.In conclusion,these findings suggest that guava can be a promising raw material for producing biodegradable plastics suitable for packaging applications.
