Light-Emitting Diodes Based on All-Quantum-Dot Multilayer Films and the Influence of Various Hole-Transporting Layers on the Performance

We present a systematic analysis of the exciton-recombination zone within all-quantum-dot （QD） multilayer films using sensing QD layers in QD-based light-emitting diodes （QLEDs）, and demonstrate the a11-QD multilayer films with different sequences of layers prepared by inserting a sensing blue QD layer denoted as B at various positions within four red QD multilayers denoted as R. We also use different hole transporting layers （PVK, CBP as well as poly-TPD） to prevent the formation of leakage current and to improve the luminance. The results show that the total EL emission is mostly at the fourth （60%） and fifth （40%） QD monolayers, adjacent to ITO. This presents both decreasing current density and increasing brightness with different hole transporting layers, thus resulting in more efficient performance.

Cellular response to titanium discs coated with polyelectrolyte multilayer films

The purpose of this study was to investigate the effects ofpolyelectrolyte multilayer （PEM） coatings on the biological behavior of titanium （Ti） substrates. Collagen type I/hyaluronic acid （Col/HA） and chitosan/hyaluronic acid （Chi/HA） multilayer PEM coatings were introduced onto Ti substrates using layer-by-layer assembly. Contact angle instruments and quartz crystal microbalance were used for film characterization. The results obtained showed that both Col/HA and Chi/HA surfaces had high hydrophilicity and promoted cell adhesion in MC3T3-E1 pre-osteoblast and human gingival fibroblast cells. In addition, the synthesis of function-related proteins and gene expression levels in both MC3T3-E1 and fibroblast cells was higher for the Col/HA coating compared with the Chi/HA coating, indicating better cellular response to the Col/HA coating.

Effects of spacer layers on magnetic properties and exchange couplings of Nd-Fe-B/Nd-Ce-Fe-B multilayer films

The influences of the spacer-layer Ta on the structures and magnetic properties of NdFeB/NdCeFeB multilayer films are investigated via DC sputtering under an Ar pressure of 1.2 Pa. An obvious （00l） texture of the hard phase is observed in each of the films, which indicates that the main phase of the film does not significantly change with Ta spacer-layer thickness. As a result, both the remanence and the saturation magnetization of the magnet first increase and then decrease, and the maximum values of 4π Mr and Hcj are 10.4 kGs （1 Gs=10^-4 T） and 15.0 kOe （1 Oe=79.5775 A·m^-1） for the film with a 2-nm-thick Ta spacer-layer, respectively, where the crystalline structures are columnar shape particles. The measured relationship between irreversible portion D （H）=-△ Mirr/2Mr and H indicates that the nucleation field of the film decreases with spacer layer thickness increasing, owing to slightly disordered grains near the interface between different magnetic layers.

Temperature Dependence of Magnetic Properties of SmCo/FeCo Multilayer Films

Sm22Co78/Fe65Co35/Sm22Co78/Fe65Co35 multilayer films were prepared by magnetron sputtering. The temperature dependence of coercivity (Hc), remanence (Mr) and reduced remanence (Mr/Ms) has been measured. The coercivity decreases with increasing of temperature. The remanence decreases with increasing the temperature from 26 to 100℃, and then increases with continuously increasing the temperature from 100 to 150℃. The reduced remanence increases with increasing the temperature.

Syntheses and Tribological Property of CrMoN/MoS2 Multilayer Films on Piston Rings of Heavy Vehicle Engine

In order to prolong the service life of piston rings of heavy vehicle engine and decrease the friction and wear of piston rings and cylinder liner,CrMoN/MoS_2 multilayer films were deposited on the surface of rings by magnetron sputtering and low temperature ion sulfuration.FESEM equipped with EDX was adopted to analyze the compositions and morphologies of surface,cross-section,and wear scars of the multilayer films.The nano-hardness and Young＇s modulus of the films were measured by a nano tester.Tribologicalproperties of the films were tested by an SRV~174;4 wear tester.The experimentalresults indicate that the structures of the multilayer films are dense and compact.The films possess nano hardness value of approximately 26.7 GPa and superior ability of plastic deformation resistance.The multilayer films can activate solid lubricating,and possess an excellent antifriction and wear resistance under the conditions of heavy load,high frequency,high temperature,and dynamic load.

PREPARATION OF Fe/Ni MULTILAYER FILMS AND THEIR MAGNETIC PROPERTIES

FeNi multilayer films were prepared by EB-PVD technique. A modified TG-DSC apparatus was used to measure their Curie temperatures, which were around 7600C, lower than that of pure Fe thin films. The easy magnetization axis was in-plane. High temperature annealing in vacuum decreased the coercivity sharply. The saturation magnetization also changed with heat treatment. After annealing at the temperature equal to the substrate temperature during deposition, the saturation magnetization decreased.

Assembly and Characterization of Rare-earth-containing Polyoxometalate [Eu(P_2Mo_(17)O_(61))_2]^(17-) and Poly(allylamine hydrochloride) Multilayer Films

The ultrathin multilayer films of rare-earth-containing polyoxometalate cluster K_ 17[Eu(P_2Mo_ 17O_ 61)_2] (EuPMo) and poly(allylamine hydrochloride)(PAH) have been prepared by the Layer-by-Layer(LbL) self-assembly method. The photoluminescent behavior of the films investigated at room temperature shows the Eu 3+ characteristic emission pattern of 5D_0→ 7F_J(J=1—4). The occurrence of the photoluminescent activity confirms the potential of creating luminescent multilayer films with polyoxometalates(POMs).

Microstructure and properties of Nb/Ta multilayer films irradiated by a high current pulse electron beam

Nb/Ta multilayer films deposited on Ti6A14V substrate with Nb and Ta monolayer thicknesses of 30 nm, 120 nm, and 240 nm were irradiated by a high current pulse electron beam （HCPEB） to prepare Nb-Ta alloyed layers. The mi- crostructure and the composition of the outmost surface of melted alloyed layers were investigated using a transmission electron microscope （TEM） equipped with an X-ray energy dispersive spectrometer （EDS） attachment. The Ta content of the alloyed surface layer prepared from the monolayer of thickness 30 nm, 120 nm, and 240 nm was- 27.7 at.%, 6.37 at.%, and 0 at.%, respectively. It was found that the Ta content in the alloyed layer plays a dominant role in the microstructure of the films. The hardness and the wear rate of the alloyed layers decrease with the increasing content of Ta in the surface laver.

Hybrid Electrochromic Multilayer Films Based on Fe(II)-Metalloviologens and TiO_2 Nanoparticles

Metallosupramolecular coordination polyelectrolyte, Fe（II）-metalloviologen（FEN）, was prepared by the reaction of Fe（II） with a novel bisterpyridine ligand. As active components, FENs could be assembled into electrochromic multilayer films with negative charged polystyrene sulfate（PSS） by the sequential deposition layer-by-layer technique. Numerous analytical instruments, such as UV-Vis spectroscopy, atomic force microscopy（AFM）, tunneling electron microscopy（TEM）, zeta-potential measurement and electrochemical measurement have been utilized to characterize their morphology, optical and electrochromic properties. It has been observed that as-prepared films exhibited multi-colour changes by triggering with different potentials. However, the low optical contrast of multilayer films would limit their further applications. In order to overcome this problem, semiconductor TiO2 nanoparticles（TiO2） were incorporated into FEN multilayers by layer-by-layer approach. By carefully optimizing the film structure, as-resulted hybrid films containing FEN, TiO2 and PSS exhibited high optical contrast, suitable response time and long-term stability. Such hybrid films should be promising candidates to meet the requirements for developing flexible displays and electrochromic devices.

Chitosan/Sodium Alginate Multilayer pH-Sensitive Films Based on Layer-by-Layer Self-Assembly for Intelligent Packaging

The abuse of plastic food packaging has brought about severe white pollution issues around the world.Developing green and sustainable biomass packaging is an effective way to solve this problem.Hence,a chitosan/sodium alginate-based multilayer film is fabricated via a layer-by-layer(LBL)self-assembly method.With the help of superior interaction between the layers,the multilayer film possesses excellent mechanical properties(with a tensile strength of 50 MPa).Besides,the film displays outstanding water retention property(blocking moisture of 97.56%)and ultraviolet blocking property.Anthocyanin is introduced into the film to detect the food quality since it is one natural plant polyphenol that is sensitive to the pH changes ranging from 1 to 13 in food when spoilage occurs.It is noted that the film is also bacteriostatic which is desired for food packaging.This study describes a simple technique for the development of advanced multifunctional and fully biodegradable food packaging film and it is a sustainable alternative to plastic packaging.

Identifying the enhancement mechanism of Al/MoO_(3) reactive multilayered films on the ignition ability of semiconductor bridge using a one-dimensional gas-solid two-phase flow model

Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement mechanism of RMFs on semiconductor bridge(SCB)during the ignition process is crucial for the engineering and practical application of advanced initiator and pyrotechnics devices.In this study,a one-dimensional(1D)gas-solid two-phase flow ignition model was established to study the ignition process of ESCB to charge particles based on the reactivity of Al/MoO_(3) RMFs.In order to fully consider the coupled exothermic between the RMFs and the SCB plasma during the ignition process,the heat release of chemical reaction in RMFs was used as an internal heat source in this model.It is found that the exothermal reaction in RMFs improved the ignition performance of SCB.In the process of plasma rapid condensation with heat release,the product of RMFs enhanced the heat transfer process between the gas phase and the solid charge particle,which accelerated the expansion of hot plasma,and heated the solid charge particle as well as gas phase region with low temperature.In addition,it made up for pressure loss in the gas phase.During the plasma dissipation process,the exothermal chemical reaction in RMFs acted as the main heating source to heat the charge particle,making the surface temperature of the charge particle,gas pressure,and gas temperature rise continuously.This result may yield significant advantages in providing a universal ignition model for miniaturized ignition devices.

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quan- titatively estimate the interfacial energy of the nanostructured multilayer films （NMFs） adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be ~ 5.0 J/m2 for Cu/Cr, ~4.1 J/m2 for Cu/Ta, ~ 2.8 J/m2 for Cu/Mo, ~ 1.1 J/m2 for Cu/Nb, and ~ 1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.

Near-infrared electrochromism of multilayer films of a cyclometalated diruthenium complex prepared by layer-by-layer deposition on metal oxide substrates

A cyclometalated diruthenium complex 2 bridged by 1,2,4,5-tetra(pyrid-2-yl)benzene with six carboxylic acid groups at two ends was synthesized.Monolayer and multilayer films FTO/TiO2/(2)n(Zr)(n=1,2)and FTO/SnO2:Sb/(2)n(Zr)(n=1-4)have been prepared via interfacial layer-by-layer coordination assembly of 2 with zirconium(IV)ions.All films show two consecutive redox couples in the potential range between 0 and+1.0 V vs.Ag/AgCl.These films exhibit reversible near-infrared electrochromism upon switching of redox potential.The response time of the films on SnO2:Sb is around a few seconds,while that on TiO2 is around a few tens of seconds.The film deposition cycles were found to have a great impact on the electrochromic performance.Among six films examined,the two-layered film on SnO2:Sb displays the best balanced performance with a contrast ratio of 56%at 1,150 nm and good cyclic stability(9%loss of contrast ratio after 1,000 continuous double-potential-switching cycles),which is superior to that of the previously reported electropolymerized films of a related diruthenium complex with the same bridging ligand.In addition,the X-ray photoelectron spectroscopy,scanning electron microscopy,and electron transfer mechanism of these films have been investigated.

Formation of ZnGa_2O_4 films by multilayer deposition and subsequent thermal annealing

The Ga203/ZnO multilayer films are deposited on quartz substrates by magnetron sputtering, the thickness values of Ga203 layers are in a range of 19 nm-2.5 nm and the thickness of ZnO layer is a constant of 1 nm. Formation of spinel ZnGa204 film is achieved via the annealing of the Ga203/ZnO multilayer film. The influences of original Ga203 sublayer thickness on the optical and structural properties of Ga203/ZnO multilayer films and annealed films are studied. With the decrease of the thickness of Ga203 sublayer, the optical band-gap of Ga203/ZnO multilayer film decreases, the intensity of UV emission diminishes and the intensity of violet emission increases. The annealed film displays the enlarged optical band gap and the quenched violet emission. UV fluorescence bands are observed from Ga203 and ZnGa204.

Influence of magnetic layer thickness on[Fe_(80)Ni_(20) O/SiO_2]_n multilayer thin films

In the present work, a series of [FesoNi20-O/SiO2]n multilayer thin films is fabricated using a reactive magnetron sputtering equipment. The thickness of SiO2 interlayer is fixed at 3 nm, while the thickness values of FesoNi20-O magnetic films range from 10 nm to 30 nm. All films present obvious in-plane uniaxial magnetic anisotropy. With increasing the FesoNi20-O layer thickness, the saturation magnetization increases slightly and the coercivity becomes larger due to the enlarged grain size, which could weaken the soft magnetic property. The results of high frequency magnetic permeability characterization show that films with thin magnetic layer are more suitable for practical applications. When the thickness of FesoNi20-O layer is 10 nm, the multilayer film exhibits the most comprehensive high-frequency magnetic property with a real permeability of 300 in gigahertz range.

Effect of chromium interlayer on magnetic exchange coupling of SmCo/Cr/TbFeCo multilayer thin films

A series of SmCo/Cr/TbFeCo multilayer thin films with perpendicular anisotropy were prepared by RF- magnetron sputtering system, and the effects of Cr interlayer thickness on magnetic properties and interlayer exchange coupling were investigated. It was found that the magnetic properties varied with the thickness of Cr interlayer, especially the values of saturation magnetization Ms and the coercivity Hc fluctuated periodically with the thickness of Cr interlayer. STM images revealed that the variation of coercivity Hc was attributed to the microstructure change of SmCo layer influenced by Cr interlayer, and the variation of Ms was related to interlayer exchange coupling.

Layer-by-layer Multilayer Films Self-assembled from a Rare-earth-containing Poly-oxometalate Na_9[Eu(W_5O_(18))_2] and Poly(allylamine hydrochloride) and Their Photoluminescent Properties

Ultrathin multilayer films of a rare-earth-containing polyoxo-metalateNa_9[Eu(W_5O_(18))_] (EW) and poly ( allylamine hydrochloride) (PAH) have been prepared bylayer-by-layer self-assembly from dilute aqueous solutions. The fabrication process of the EW/PAHmultilayer films was followed by UV-vis spec-troscopy and ellipsometry, which show that thedeposition process is linear and highly reproducible from layer to layer. An average EW/PAH bilayerthickness of ca. 2.1 nm was determined by ellipsometry. In addition, the scanning electronmicroscopy (SEM) image of the EW/PAH film indicates that the film surface is relatively uniform andsmooth. The photolumi-nescent properties of these films were also investigated by fluorescencespectroscopy.

Sandwich-type composite multilayer films of strontium titanate and barium strontium titanate and their controllable dielectric properties

It is a challenge to reduce the dielectric loss and increase the tunability of pure barium strontium titanate(BST)films for microwave tunable application because these two properties change simultaneously.Herein,a novel composite of strontium titanate(ST)and potassium-doped BST(KBST)has been designed as ST/KBST/ST sandwich-type film with various ST and KBST layers.X-ray diffraction patterns show that the film exhibits cubic perovskite polycrystalline structure composed of BST and ST phase,mainly grow along(110)crystal plane with average grain size of less than 20 nm and decreasing BST phase/ST phase ratio with increasing film thickness.Scanning electron microscope shows that no interfacial layer can be observed,indicating that ST and KBST are fully compounded.Low dielectric loss and high tunability at-10-10 V and stable and excellent dielectric properties at 1 GHz are achieved,meeting the needs of microwave tunable application at high frequency.The surface structures are also studied by other analysis methods,and ST/MgBST/ST sandwich-type film is compared.

The effect of the multi-period on the properties of deep-ultraviolet transparent conductive Ga_2O_3/ITO alternating multilayer films

Ga2O3/ITO alternating multilayer films were deposited on quartz glass substrates by rnagnetron sputtering. The effect of the multi-period on the structural, optical and electrical properties of Ga2O3/ITO alternating multilayer films was investigated by an X-ray diffractometer, a double beam spectrophotometer and the Hall system, respectively. A low sheet resistance of 225.5 Ω/□ and a high transmittance of more than 62.9% at a 300 nm wavelength were obtained for the two-period alternating multilayer film with a thickness of 72 nm.