The melting and crystallization behaviors of poly（e-caprolactone） （PCL） ultra-thin films with thickness from 15 ran to 8 nm were studied by AFM technique equipped with a hot-stage in real-time. It was found that m...The melting and crystallization behaviors of poly（e-caprolactone） （PCL） ultra-thin films with thickness from 15 ran to 8 nm were studied by AFM technique equipped with a hot-stage in real-time. It was found that melting can erase the spherulitic structure for polymer film with high thickness. However, annealing above the melting point can not completely erase the tree-like structure for the thinner polymer film. Generally, the structure formation of thin polymer films of PCL is controlled not only by melting and crystallization but also by dewetting during thermal annealing procedures, and dewetting predominates in the structure formation of ultra-thin films. However, the presence of tree-like morphology at 75 ℃ may be due to the strong interaction between PCL and mica surface, which may stick the PCL chains onto the mica surface during thermal annealing process. Moreover, the growth of the dendrites was investigated and it was found that crystallization is followed from a dewetted sample, and the branches did not grow with the stems. The crystallization of polymer in the ultra- thin films is a diffusion-controlled process. Both melting and crystallization behaviors of PCL in thin films are influenced by film thickness.展开更多
A kind of photosensitive ultra-thin film was fabricated from diazoresin (DR) and various calixarenes by using theself-assembly technique. Under UV irradiation both the ionic- and hydrogen bonds between the layers of t...A kind of photosensitive ultra-thin film was fabricated from diazoresin (DR) and various calixarenes by using theself-assembly technique. Under UV irradiation both the ionic- and hydrogen bonds between the layers of the film will convert into covalent bonds. As a result, the stability of the film toward polar solvents increases dramatically.展开更多
A kind of azo-containing resin(Azo-R)was synthesized by a simple way through the coupling reaction of 2-nitro-N-methyldiphenylamine-4-diazoresin(NDR)with phenol,and a new covalentely attached multilayer film from Azo-...A kind of azo-containing resin(Azo-R)was synthesized by a simple way through the coupling reaction of 2-nitro-N-methyldiphenylamine-4-diazoresin(NDR)with phenol,and a new covalentely attached multilayer film from Azo-R asH-donor and photosensitive diazoresin,diphenylamine-4-diazoresin(DR)as H-acceptor via H-bonding attraction by self-assembly technique has been fabricated.Following the decomposition of diazonium group of DR under exposure to UVlight,the H-bonds between the layers of the film convert to covalent bonds and the film becomes very stable toward polarsolvents or electrolyte aqueous solutions.Thus the UV-irradiated azo-containing films can be used to measure photocurrentin a conventional three-electrode photoelectrochemical cell using KCl as supporting electrolyte.It was confirmed that theazo-containing multilayer film is responsible for the photocurrent generation.展开更多
The instability of thin ferroelectric films is discussed based on the close similarity of dielectric properties between bulk Bi-layered perovskites and thin BaTiO<sub>3</sub> films. The dielectric properti...The instability of thin ferroelectric films is discussed based on the close similarity of dielectric properties between bulk Bi-layered perovskites and thin BaTiO<sub>3</sub> films. The dielectric properties of pseudo-two-dimensional layered perovskites suggest that the bulk layered ferroelectric is a good model of ultra-thin ferroelectric film with a few perovskite units, free from any misfit lattice strain. It seems plausible that the ferroelectric interaction is still prominent but shows a crossover from ferroelectric to antiferroelectric along the unique c-axis (perpendicular to the film plane);with decreasing thickness, the ferroelectricity appears within the plane, which results in so-called “canted ferroelectricity”. An extra relaxation mode induced by surface effect of thin films correlates with soft mode, which results in a new intermediate phase between the paraelectric and ferroelectric phases. These evidences may indicate no critical thickness even for ferroelectric ultra- thin films.展开更多
A detailed investigation about the dependence of microstructure and electrical properties on annealing temperature was carried out for cerium oxide(CeO2) ultra-thin films(18 nm to 110 nm) on n-type Si(100) substrates ...A detailed investigation about the dependence of microstructure and electrical properties on annealing temperature was carried out for cerium oxide(CeO2) ultra-thin films(18 nm to 110 nm) on n-type Si(100) substrates by RF magnetron sputtering. Substrate temperature was kept constant at 400 ℃ for all samples. The as-deposited films were subsequently annealed in air ambient at 700,800 and 900 ℃ for 1 h respectively. The crystallinity and surface morphology of the CeO2 films were analyzed with X-ray diffractometer(XRD),scanning electron microscope(SEM),atomic force microscope(AFM) and Raman scattering measurement. Electrical properties of the Au/CeO2/Si/Au structure were examined by high frequency capacitance-voltage(C-V) characteristics at 1 MHz and leakage current density-electric field(J-E) characteristics. A Raman peak of the CeO2 thin films was seen at 463 cm-1. From C-V data,these films exhibit dielectric constants ranging from 18 to 23,the hysteresis width(-VFB) ranging from 0.015 V to 0.12 V and the density of trapped charges ranging from 1.45×1011 to 3.01×1011 cm-2. A leakage current of 4.75×10-8 -9.0×10-7 A/cm2 at 2 MV/cm was observed. The experimental results show that the CeO2 buffer layers are suitable for non-volatile metal-ferroelectric-insulator-semiconductor(MFIS) structure field-effect-transistors(FETs) memory applications.展开更多
This study systematically investigated the influence of deposition rate on the structure,broadband opti⁃cal properties(1.0-13.0μm),and stress characteristics of Germanium(Ge)films.Additionally,a method for enhancing ...This study systematically investigated the influence of deposition rate on the structure,broadband opti⁃cal properties(1.0-13.0μm),and stress characteristics of Germanium(Ge)films.Additionally,a method for enhancing the performance of infrared filters based on rate-modulated deposition of Ge films was proposed.The optical absorption of Ge films in the short-wave infrared(SWIR)and long-wave infrared(LWIR)bands can be effectively reduced by modulating the deposition rate.As the deposition rate increases,the Ge films maintain an amorphous structure.The optical constants of the films in the 1.0-2.5μm and 2.5-13.0μm bands were precisely determined using the Cody-Lorentz model and the classical Lorentz oscillator model,respectively.Notably,high⁃er deposition rates result in a gradual increase in the refractive index.The extinction coefficient increases with the deposition rate in the SWIR region,attributed to the widening of the Urbach tail,while it decreases in the LWIR region due to the reduced absorption caused by the Ge-O stretching mode.Additionally,the films exhibit a tensile stress that decreases with increasing deposition rate.Finally,the effectiveness of the proposed fabrication method for an infrared filter with Ge films deposited at an optimized rate was demonstrated through practical examples.This work provides theoretical and technical support for the application of Ge films in high-performance infrared filters.展开更多
The scalable fabrication of stretchable conjugated polymer films via solution printing is essential for their practical application in largearea wearable electronics.However,the printed conjugated polymer films typica...The scalable fabrication of stretchable conjugated polymer films via solution printing is essential for their practical application in largearea wearable electronics.However,the printed conjugated polymer films typically exhibit high crystallinity,limiting their mechanical deformability.Herein,we propose a plasticizer-assisted printing strategy to simultaneously enhance the stretchability and electrical performance of films based on the conjugated polymer poly(3-(5-(5-methylselenophen-2-yl)thiophen-2-yl)-6-(5-methylthiophen-2-yl)-2,5-bis(4-octyltetradecyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione)(P(TDPP-Se)).The incorporation of a plasticizer trioctyl trimellitate(TOTM)promotes P(TDPP-Se)aggregation in initial solution,facilitates chain alignment under flow field,and shorten solidification process,thereby restricting randomly polymer crystallization.Consequently,a low-crystallinity film with favorable edge-on orientation,strong chain alignment and improved chain dynamics is realized,which effectively alleviates crystallites fragmentation and crack propagation under large strain.The TOTM-plasticized film exhibits approximately 2-fold improvements in fracture strain and charge mobility,along with superior mobility retention under 100%strain in comparison to the neat film.This study provides a feasible approach for microstructure control in printed stretchable conjugated polymer film.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
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
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
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
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
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
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 work explores the potential of La_(1-x)Pr_(x)NiO_(4+δ)thin films fabricated by Pulsed Injection Metal-Organic Chemical Vapor Deposition as oxygen electrodes for low-temperature solid oxide cells.La_(1-x)Pr_(x)Ni...This work explores the potential of La_(1-x)Pr_(x)NiO_(4+δ)thin films fabricated by Pulsed Injection Metal-Organic Chemical Vapor Deposition as oxygen electrodes for low-temperature solid oxide cells.La_(1-x)Pr_(x)NiO_(4+δ)materials offer promising mixed ionic and electronic conductivity and high oxygen reduction reaction kinetics.In this study,we focus on the microstructural and electrochemical properties of LaPrNiO_(4+δ)thin films deposited at various temperatures(600-650℃),revealing that a two-temperature deposition process yields nano-architectured films with a dense bottom film and a porous nano-columnar top layer of the same material.Electrochemical impedance spectroscopy and electrical conductivity relaxation experiments demonstrate enhanced surface exchange coefficients compared to bulk LaPrNiO_(4+δ)and La_(2)NiO_(4+δ)and high performance,with polarization resistances as low as 0.10Ωcm^(2) at 600℃ and 1.00 at 500℃.To better understand the electrochemical behavior of these electrodes,we investigated the limiting mechanisms of oxygen reduction by analyzing the kinetic response to varying oxygen partial pressures and performing detailed impedance analyses.These nano-columnar LaPrNiO_(4+δ)oxygen electrodes were also deposited on commercial half-cells,enabling the resulting full cells to operate successfully in both reversible solid oxide fuel cell and electrolysis cell modes,reaching a performance of 0.34 W cm^(-2) at 600℃ in reversible solid oxide fuel cell mode.This work underscores the promise of LaPrNiO_(4+δ)thin films for efficient low-temperature-solid oxide cells while addressing challenges in durability and stability.展开更多
Chiral magnets have attracted considerable attention due to their intricate magnetic properties,among which B20compounds constitute a quintessential class that has gained significant focus,particularly in the study of...Chiral magnets have attracted considerable attention due to their intricate magnetic properties,among which B20compounds constitute a quintessential class that has gained significant focus,particularly in the study of skyrmions.MnGe,as a member of the B20 family,exhibits a more complex magnetic structure compared with other materials with similar crystal structures.In this work,we successfully synthesized high-quality MnGe thin films and characterized their magnetoresistance,M-H curves,magneto-Seebeck effect,and magnetic force microscopy(MFM)images,all of which demonstrate pronounced magnetic anisotropy.Notably,the Seebeck coefficient exhibits a plateau at low magnetic fields when the magnetic field is applied in the film plane,indicating a field region in which the magnetic structure remains stable.MFM imaging further reveals magnetic transitions within the MnGe films when the magnetic field is oriented along the film plane.These findings are crucial for advancing our understanding of the magnetic ground state of MnGe and the evolution of its magnetic structure under an applied external magnetic field.展开更多
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
This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi_(2)MoO_(6)/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodep...This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi_(2)MoO_(6)/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodeposition of noble metal silver(Ag)onto the composite structure.The catalytic efficiency of semiconductor photocatalysts is greatly improved by utilizing the localized surface plasmon resonance(LSPR)effect observed in Ag nanoparticles(NPs).Furthermore,the noble metal Ag serves as an intermediary bridge facilitating charge transfer between Bi_(2)MoO_(6)and BiOBr,while the formation of a Schottky barrier effectively inhibits the recombination of photo-generated electron-hole pairs.As a result,the Ag-deposited Bi_(2)MoO_(6)/BiOBr film exhibits superior photocatalytic performance in the reduction of CO_(2)compared to its unmodified counterpart.Our experimental results indicate a non-linear relationship between Ag deposition and the efficiency of photocatalytic CO_(2)reduction to CO,characterized by an initial increase in efficiency followed by a decline.The optimized 1.5%-Ag/Bi_(2)MoO_(6)/BiOBr film demonstrates exceptional photocatalytic activity,attaining a CO production rate of 13.65μmol/(g·h).This research explores the fundamental mechanisms that lead to improved photocatalytic CO_(2)reduction capabilities of the Ag/Bi_(2)MoO_(6)/BiOBr film.Our research offers important perspectives for the thoughtful design and production of highly efficient photocatalysts,which are essential for advancing sustainable energy solutions.展开更多
基金supported by the National Natural Science Foundation of China for General (Nos. 50303017,50373044),Major (Nos. 20490220, 50390090)the Special Funds for Major State Basic Research Projects(No. 2003CB615600)
文摘The melting and crystallization behaviors of poly（e-caprolactone） （PCL） ultra-thin films with thickness from 15 ran to 8 nm were studied by AFM technique equipped with a hot-stage in real-time. It was found that melting can erase the spherulitic structure for polymer film with high thickness. However, annealing above the melting point can not completely erase the tree-like structure for the thinner polymer film. Generally, the structure formation of thin polymer films of PCL is controlled not only by melting and crystallization but also by dewetting during thermal annealing procedures, and dewetting predominates in the structure formation of ultra-thin films. However, the presence of tree-like morphology at 75 ℃ may be due to the strong interaction between PCL and mica surface, which may stick the PCL chains onto the mica surface during thermal annealing process. Moreover, the growth of the dendrites was investigated and it was found that crystallization is followed from a dewetted sample, and the branches did not grow with the stems. The crystallization of polymer in the ultra- thin films is a diffusion-controlled process. Both melting and crystallization behaviors of PCL in thin films are influenced by film thickness.
基金This work was supported by the National Natural Science Foundation of China (No. 50173002 and 20274002).
文摘A kind of photosensitive ultra-thin film was fabricated from diazoresin (DR) and various calixarenes by using theself-assembly technique. Under UV irradiation both the ionic- and hydrogen bonds between the layers of the film will convert into covalent bonds. As a result, the stability of the film toward polar solvents increases dramatically.
基金This work is financially supported by NSFC(No.2027400250173002).
文摘A kind of azo-containing resin(Azo-R)was synthesized by a simple way through the coupling reaction of 2-nitro-N-methyldiphenylamine-4-diazoresin(NDR)with phenol,and a new covalentely attached multilayer film from Azo-R asH-donor and photosensitive diazoresin,diphenylamine-4-diazoresin(DR)as H-acceptor via H-bonding attraction by self-assembly technique has been fabricated.Following the decomposition of diazonium group of DR under exposure to UVlight,the H-bonds between the layers of the film convert to covalent bonds and the film becomes very stable toward polarsolvents or electrolyte aqueous solutions.Thus the UV-irradiated azo-containing films can be used to measure photocurrentin a conventional three-electrode photoelectrochemical cell using KCl as supporting electrolyte.It was confirmed that theazo-containing multilayer film is responsible for the photocurrent generation.
文摘The instability of thin ferroelectric films is discussed based on the close similarity of dielectric properties between bulk Bi-layered perovskites and thin BaTiO<sub>3</sub> films. The dielectric properties of pseudo-two-dimensional layered perovskites suggest that the bulk layered ferroelectric is a good model of ultra-thin ferroelectric film with a few perovskite units, free from any misfit lattice strain. It seems plausible that the ferroelectric interaction is still prominent but shows a crossover from ferroelectric to antiferroelectric along the unique c-axis (perpendicular to the film plane);with decreasing thickness, the ferroelectricity appears within the plane, which results in so-called “canted ferroelectricity”. An extra relaxation mode induced by surface effect of thin films correlates with soft mode, which results in a new intermediate phase between the paraelectric and ferroelectric phases. These evidences may indicate no critical thickness even for ferroelectric ultra- thin films.
基金Project(076044) supported by the Cultivation Fund of the Key Scientific and Technical Innovation Projects, Ministry of Education of ChinaProject(KF0602) supported by the Open Project Program of LDMAT (Xiangtan University), Ministry of Education, China
文摘A detailed investigation about the dependence of microstructure and electrical properties on annealing temperature was carried out for cerium oxide(CeO2) ultra-thin films(18 nm to 110 nm) on n-type Si(100) substrates by RF magnetron sputtering. Substrate temperature was kept constant at 400 ℃ for all samples. The as-deposited films were subsequently annealed in air ambient at 700,800 and 900 ℃ for 1 h respectively. The crystallinity and surface morphology of the CeO2 films were analyzed with X-ray diffractometer(XRD),scanning electron microscope(SEM),atomic force microscope(AFM) and Raman scattering measurement. Electrical properties of the Au/CeO2/Si/Au structure were examined by high frequency capacitance-voltage(C-V) characteristics at 1 MHz and leakage current density-electric field(J-E) characteristics. A Raman peak of the CeO2 thin films was seen at 463 cm-1. From C-V data,these films exhibit dielectric constants ranging from 18 to 23,the hysteresis width(-VFB) ranging from 0.015 V to 0.12 V and the density of trapped charges ranging from 1.45×1011 to 3.01×1011 cm-2. A leakage current of 4.75×10-8 -9.0×10-7 A/cm2 at 2 MV/cm was observed. The experimental results show that the CeO2 buffer layers are suitable for non-volatile metal-ferroelectric-insulator-semiconductor(MFIS) structure field-effect-transistors(FETs) memory applications.
基金Supported by the National Natural Science Foundation of China(62275053,62275256)the National key Research and Development Program of China(2021YFB3701500)+1 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2023248)the Eastern Talent Plan Youth Project 2022,the Shanghai Key Laboratory of Optical Coatings and Spectral Modulation(23dz2260500).
文摘This study systematically investigated the influence of deposition rate on the structure,broadband opti⁃cal properties(1.0-13.0μm),and stress characteristics of Germanium(Ge)films.Additionally,a method for enhancing the performance of infrared filters based on rate-modulated deposition of Ge films was proposed.The optical absorption of Ge films in the short-wave infrared(SWIR)and long-wave infrared(LWIR)bands can be effectively reduced by modulating the deposition rate.As the deposition rate increases,the Ge films maintain an amorphous structure.The optical constants of the films in the 1.0-2.5μm and 2.5-13.0μm bands were precisely determined using the Cody-Lorentz model and the classical Lorentz oscillator model,respectively.Notably,high⁃er deposition rates result in a gradual increase in the refractive index.The extinction coefficient increases with the deposition rate in the SWIR region,attributed to the widening of the Urbach tail,while it decreases in the LWIR region due to the reduced absorption caused by the Ge-O stretching mode.Additionally,the films exhibit a tensile stress that decreases with increasing deposition rate.Finally,the effectiveness of the proposed fabrication method for an infrared filter with Ge films deposited at an optimized rate was demonstrated through practical examples.This work provides theoretical and technical support for the application of Ge films in high-performance infrared filters.
基金supported by the National Natural Science Foundation of China(No.52433009)the Fundamental Research Funds for the Central Universities(No.GK202501005)the State Key Laboratory of Polymer Science and Technology(No.PST-KF2025-07)。
文摘The scalable fabrication of stretchable conjugated polymer films via solution printing is essential for their practical application in largearea wearable electronics.However,the printed conjugated polymer films typically exhibit high crystallinity,limiting their mechanical deformability.Herein,we propose a plasticizer-assisted printing strategy to simultaneously enhance the stretchability and electrical performance of films based on the conjugated polymer poly(3-(5-(5-methylselenophen-2-yl)thiophen-2-yl)-6-(5-methylthiophen-2-yl)-2,5-bis(4-octyltetradecyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione)(P(TDPP-Se)).The incorporation of a plasticizer trioctyl trimellitate(TOTM)promotes P(TDPP-Se)aggregation in initial solution,facilitates chain alignment under flow field,and shorten solidification process,thereby restricting randomly polymer crystallization.Consequently,a low-crystallinity film with favorable edge-on orientation,strong chain alignment and improved chain dynamics is realized,which effectively alleviates crystallites fragmentation and crack propagation under large strain.The TOTM-plasticized film exhibits approximately 2-fold improvements in fracture strain and charge mobility,along with superior mobility retention under 100%strain in comparison to the neat film.This study provides a feasible approach for microstructure control in printed stretchable conjugated polymer film.
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funded by the European Union's Horizon 2020 research and innovation program under grant agreements no.824072(Harvestore project)no.101017709(EPISTORE)by the Centre of Excellence of Multifunctional Architectured Materials“CEMAM”no.ANR-10-LABX-44-01 as part of the“Investments for the Future”Program.
文摘This work explores the potential of La_(1-x)Pr_(x)NiO_(4+δ)thin films fabricated by Pulsed Injection Metal-Organic Chemical Vapor Deposition as oxygen electrodes for low-temperature solid oxide cells.La_(1-x)Pr_(x)NiO_(4+δ)materials offer promising mixed ionic and electronic conductivity and high oxygen reduction reaction kinetics.In this study,we focus on the microstructural and electrochemical properties of LaPrNiO_(4+δ)thin films deposited at various temperatures(600-650℃),revealing that a two-temperature deposition process yields nano-architectured films with a dense bottom film and a porous nano-columnar top layer of the same material.Electrochemical impedance spectroscopy and electrical conductivity relaxation experiments demonstrate enhanced surface exchange coefficients compared to bulk LaPrNiO_(4+δ)and La_(2)NiO_(4+δ)and high performance,with polarization resistances as low as 0.10Ωcm^(2) at 600℃ and 1.00 at 500℃.To better understand the electrochemical behavior of these electrodes,we investigated the limiting mechanisms of oxygen reduction by analyzing the kinetic response to varying oxygen partial pressures and performing detailed impedance analyses.These nano-columnar LaPrNiO_(4+δ)oxygen electrodes were also deposited on commercial half-cells,enabling the resulting full cells to operate successfully in both reversible solid oxide fuel cell and electrolysis cell modes,reaching a performance of 0.34 W cm^(-2) at 600℃ in reversible solid oxide fuel cell mode.This work underscores the promise of LaPrNiO_(4+δ)thin films for efficient low-temperature-solid oxide cells while addressing challenges in durability and stability.
基金supported by the National Natural Science Foundation of China(Grant Nos.12488201,12274390,12304035,and 51627901)the Anhui Initiative in Quantum Information Technologies(Grant No.AHY160000)+3 种基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302802)the National Key R&D Program of the MOST of China(Grant No.2022YFA1602600)the Basic Research Program of the Chinese Academy of Sciences Based on Major Scientific Infrastructures(Grant No.JZHKYPT-2021-08)the National Key R&D Program of China(Grant No.2023YFA1607701)。
文摘Chiral magnets have attracted considerable attention due to their intricate magnetic properties,among which B20compounds constitute a quintessential class that has gained significant focus,particularly in the study of skyrmions.MnGe,as a member of the B20 family,exhibits a more complex magnetic structure compared with other materials with similar crystal structures.In this work,we successfully synthesized high-quality MnGe thin films and characterized their magnetoresistance,M-H curves,magneto-Seebeck effect,and magnetic force microscopy(MFM)images,all of which demonstrate pronounced magnetic anisotropy.Notably,the Seebeck coefficient exhibits a plateau at low magnetic fields when the magnetic field is applied in the film plane,indicating a field region in which the magnetic structure remains stable.MFM imaging further reveals magnetic transitions within the MnGe films when the magnetic field is oriented along the film plane.These findings are crucial for advancing our understanding of the magnetic ground state of MnGe and the evolution of its magnetic structure under an applied external magnetic field.
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 the National Natural Science Foundation of China(21978196)Natural Science Foundation of Shanxi Province(201801D211008,202403021211018)+1 种基金Shanxi Provincial Education Department(S202413597023)Jincheng High Efficiency Conversion and Utilization Technology Innovation Center of CO2 Energy and Biomass Energy。
文摘This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi_(2)MoO_(6)/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodeposition of noble metal silver(Ag)onto the composite structure.The catalytic efficiency of semiconductor photocatalysts is greatly improved by utilizing the localized surface plasmon resonance(LSPR)effect observed in Ag nanoparticles(NPs).Furthermore,the noble metal Ag serves as an intermediary bridge facilitating charge transfer between Bi_(2)MoO_(6)and BiOBr,while the formation of a Schottky barrier effectively inhibits the recombination of photo-generated electron-hole pairs.As a result,the Ag-deposited Bi_(2)MoO_(6)/BiOBr film exhibits superior photocatalytic performance in the reduction of CO_(2)compared to its unmodified counterpart.Our experimental results indicate a non-linear relationship between Ag deposition and the efficiency of photocatalytic CO_(2)reduction to CO,characterized by an initial increase in efficiency followed by a decline.The optimized 1.5%-Ag/Bi_(2)MoO_(6)/BiOBr film demonstrates exceptional photocatalytic activity,attaining a CO production rate of 13.65μmol/(g·h).This research explores the fundamental mechanisms that lead to improved photocatalytic CO_(2)reduction capabilities of the Ag/Bi_(2)MoO_(6)/BiOBr film.Our research offers important perspectives for the thoughtful design and production of highly efficient photocatalysts,which are essential for advancing sustainable energy solutions.
