Polymer-assisted Deposition Method Research Articles

Orientation-dependent structural and photocatalytic properties of LaCoO3 epitaxial nano-thin films.

LaCoO3 epitaxial films were grown on (100), (110) and (111) oriented LaAlO3 substrates by the polymer-assisted deposition method. Crystal structure measurement and cross-section observation indicate that all the LaCoO3 films are epitaxially grown in accordance with the orientation of LaAlO3 substrates, with biaxial compressive strain in the ab plane. Owing to the different strain directions of CoO6 octahedron, the mean Co–O bond length increases by different amounts in (100), (110) and (111) oriented films compared with that of bulk LaCoO3, and the (100) oriented LaCoO3 has the largest increase. Photocatalytic degradation of methyl orange indicates that the order of photocatalytic activity of the three oriented films is (100) > (111) > (110). Combined with analysis of electronic nature and band structure for LaCoO3 films, it is found that the change of the photocatalytic activity is closely related to the crystal field splitting energy of Co3+ and Co–O binding energy. The increase in the mean Co–O bond length will decrease the crystal field splitting energy of Co3+ and Co–O binding energy and further reduce the value of band gap energy, thus improving the photocatalytic activity. This may also provide a clue for expanding the visible-light-induced photocatalytic application of LaCoO3.

Three-dimensional Mn–Cu–Ce ternary mixed oxide networks prepared by polymer-assisted deposition for HCHO catalytic oxidation

Mn–Cu–Ce ternary mixed oxide networks with a three-dimensional (3D) structure were developed by a polymer-assisted deposition method.

Polymer-assisted deposition of SrTiO3 film as cathode buffer layer in inverted polymer solar cells

Polymer-assisted deposition (PAD) method has been employed to prepare SrTiO3(STO) films on ITO substrates, which have been applied as cathode buffer layer in inverted polymer solar cells. ZnO and TiO2 films on ITO glass were also prepared via PAD and have been utilized as cathode buffer layers in the inverted polymer solar cells for comparison, which show better efficiency than those using ZnO and TiO2 as interfacial layers prepared through other methods. The power conversion efficiency (PCE) of ∼3.5% was achieved with STO as the cathode buffer layer as well as MoO3 as the anode buffer layer, which is comparable to that with ZnO and TiO2 prepared using the same method as cathode buffer layers. Our findings indicate that STO has the potential to be a candidate as interfacial layers in solar cell devices.

Development and characterization of a Drop-on-Demand inkjet printing system for nuclear target fabrication

A novel target preparation method based on Drop-on-Demand (DoD) inkjet printing has been developed. Conventional preparation methods like the electrochemical method “Molecular Plating” or the “Polymer-Assisted Deposition Method” are often limited, e.g., concerning the dimensions and geometries of depositions or by the requirement for electrically conducting substrates. Here, we report on the development of a new technique, which overcomes such limits by using a commercially available DoD dispenser. A variety of solutions with volumes down to 5 nL can be dispensed onto every manageable substrate. The dispensed volumes were determined with a radioactive tracer and the deposits of evaporated salt solutions were investigated on titanium and graphene foils. Additionally, the high precision of the printing system with which individual drops can be positioned was used to determine the spatial resolution of storage phosphor imaging plates with three tracers of different β-decay energies. The new technique is able to produce new kinds of targets with improved spatial geometries and thin layer deposits.

Novel visible-light-driven photoconductive properties of LaCoO3 epitaxial nano-thin films

LaCoO3 nano-thin films were grown on (001), (110) and (111) oriented SrTiO3 substrates by the polymer assisted deposition method, respectively. All the LaCoO3 films are in epitaxial growth in accordance with the orientation of STO, with biaxial tensile strain. The films, especially for (111) oriented film, exhibit excellent visible-light photoconductive properties. The strain-induced increase of Co-O bond length may contribute to reduce the t2g-eg gap of Co3+ and further increase the number of photoexcited eg itinerant electrons. The different photoconductive activity of LaCoO3 epitaxial films may be attributed to the different surface energies of crystal planes. It suggests that the LaCoO3 epitaxial film can be considered as a potential candidate for visible-light photodetector.

Electrical and optical properties of hydrogen plasma treated molybdenum-doped indium oxide films synthesized by polymer-assisted deposition method

Abstract In this paper, the effects of hydrogen (H 2 ) plasma treatment on the molybdenum (Mo)-doped indium oxide (InO) thin film that was formed on glass using the polymer-assisted deposition (PAD) process were investigated. The sheet resistance for the sample treated at the ICP power of 15 W was quenched to 167 Ω/sq. from the 680 Ω/sq. for the as-deposited sample. Compared with the as-deposited sample, both the mobility and the concentration of the sample treated at the 15 W ICP power were also increased simultaneously, resulting in an increased conductivity. From these results, it was concluded that the H 2 plasma treatment is an efficient method for the enhancement of the electrical property, as well as to remove nano-sized cracks on the surface of the PAD-Mo-doped InO without a deterioration the optical transmittance.

Insight into the enhancement of transport property for oriented La0.9MnO3 films

LaMnO3 has attracted significant attention as energy conversion and storage materials, and especially as a promising noble-metal-free oxide catalyst and a new kind of electrode material for supercapacitors. However, the poor electronic transport ability of LaMnO3 hinders its application. Thus, improvement of its electronic transport ability is essential to enhance the electron transfer from catalyst active sites to an electrode, which is effective to avoid ohmic potential drop and consequently energy loss. In this work, the high-quality epitaxial growth La-deficiency La0.9MnO3 films were obtained by a simple and low cost polymer assisted deposition method. It is found that the room-temperature conductivity (σ) of doping La0.9MnO3 increases nearly ten times compared to that of the parent LaMnO3. The oxygen-content-driven enhancement of the conductivity is discussed for the oriented La0.9MnO3 film. It is suggested that the existence of the LaAlO3 substrate is beneficial to stabilize the La-deficiency La0.9MnO3 compound and A-site La-deficiency extends the range of oxygen content. Both strain (including epitaxial strain and doping induced chemical strain) and annealing temperature are cooperating on the oxygen content, resulting in the oxygen stoichiometry independence of ambient conditions and the high conductivity. Following this process, conductivity and electronic state of the perovskite-related material can be tuned for the practical application.

Monolithic hierarchical gold sponges for efficient and stable catalysis in a continuous-flow microreactor

A monolithic hierarchical Au sponge is prepared by the polymer-assisted metal deposition method, showing excellent catalysis in intermittent and continuous-flow fashions.

Spin-phonon coupling in R2CoMnO6 (R = Pr, Nd, Sm) thin films under biaxial compressive strain

The R2CoMnO6 (R = Pr, Nd, Sm) thin films on (001) LaAlO3 substrates were fabricated successfully by a simple polymer assisted deposition method, confirming by atomic force microscopy, X-ray diffraction, and Raman spectroscopy. The study on the magnetic properties indicates that all the films are B-site ordering and show a single ferromagnetic transition at Curie temperature (Tc) with decreasing temperature. Meanwhile, an anomalous phonon softening related to the spin-phonon coupling is observed at around Tc in all the temperature-dependent Raman spectra. With the decreases of R-site ionic radius (rR) and/or the in-plane biaxial compressive strain, both the turning point TR of the temperature-dependent Δω(T) and Curie temperature Tc decrease, revealing the existence of spin-phonon coupling and its intensity in the decreasing order of Pr2CoMnO6 > Nd2CoMnO6 > Sm2CoMnO6 accompanied with the Co-O-Mn bond angle decreasing and the Co(Mn)-O bond length elongating. It is suggested that the existence of the biaxial compressive strain may be helpful to form the B-site ordered phase and suppress the formation of the disordered phase by decreasing the oxygen vacancies. Both the chemical strain and the biaxial compressive strain are cooperating on the magnetic interaction and spin-phonon coupling in the system, which are of special interest for application.

Enhancement of Low-field Magnetoresistance in Self-Assembled Epitaxial La0.67Ca0.33MnO3:NiO and La0.67Ca0.33MnO3:Co3O4 Composite Films via Polymer-Assisted Deposition.

Polymer-assisted deposition method has been used to fabricate self-assembled epitaxial La0.67Ca0.33MnO3:NiO and La0.67Ca0.33MnO3:Co3O4 films on LaAlO3 substrates. Compared to pulsed-laser deposition method, polymer-assisted deposition provides a simpler and lower-cost approach to self-assembled composite films with enhanced low-field magnetoresistance effect. After the addition of NiO or Co3O4, triangular NiO and tetrahedral Co3O4 nanoparticles remain on the surface of La0.67Ca0.33MnO3 films. This results in a dramatic increase in resistivity of the films from 0.0061 Ω•cm to 0.59 Ω•cm and 1.07 Ω•cm, and a decrease in metal-insulator transition temperature from 270 K to 180 K and 172 K by the addition of 10%-NiO and 10%-Co3O4, respectively. Accordingly, the maximum absolute magnetoresistance value is improved from −44.6% to −59.1% and −52.7% by the addition of 10%-NiO and 10%-Co3O4, respectively. The enhanced low-field magnetoresistance property is ascribed to the introduced insulating phase at the grain boundaries. The magnetism is found to be more suppressed for the La0.67Ca0.33MnO3:Co3O4 composite films than the La0.67Ca0.33MnO3:NiO films, which can be attributed to the antiferromagnetic properties of the Co3O4 phase. The solution-processed composite films show enhanced low-field magnetoresistance effect which are crucial in practical applications. We expect our polymer-assisted deposited films paving the pathway in the field of hole-doped perovskites with their intrinsic colossal magnetoresistance.

Tuning of magnetic properties for epitaxial Y2NiMnO6 thin film: Substrate is crucial

The effects of epitaxial strain induced by lattice mismatch and substrate type on the structure and magnetic properties of Y2NiMnO6 thin films have been systematically investigated. Y2NiMnO6 thin films grown on (001)-oriented LaAlO3 (LAO), (La,Sr)(Al,Ta)O3 (LSAT), and SrTiO3 (STO) substrates with varying film thickness are obtained by a simple polymer assisted deposition method. X-ray diffraction and Raman scattering observations indicate that the single-phase epitaxial films are successfully obtained. By magnetic measurements, it is found that all the films show an obvious ferromagnetic transition with a lower transition temperatures (Tc) than that of the Y2NiMnO6 bulk. With the biaxial tensile strain decreasing or the film thickness increasing, the Tc of the film increases. Besides, due to the different strain states of the films and the different surface migrations of the substrates, the structure and magnetic properties show a strong dependence on the type of substrate. It is suggested that the biaxial tensile strain and substrate type have crucial effects on the structure, magnetic properties and the related Tc of the thin film, which can be utilized to engineer the magnetic properties of the films and the related ferroelectricity.

Photocatalytic Treatment of Desalination Concentrate Using Optical Fibers Coated With Nanostructured Thin Films: Impact of Water Chemistry and Seasonal Climate Variations.

Treatment of desalination concentrate can reduce concentrate volume for disposal, increase water recovery and convert waste to resource. However, concentrate treatment is costly and energy intensive due to high concentrations of salt and recalcitrant organic matter in concentrate. Photocatalytic oxidation provides a novel energy neutral technology for concentrate treatment by degrading organic contaminants. Polymer-assisted hydrothermal deposition method was used to synthesize innovative pure and Fe-doped TiO2 mixed-phase nanocomposite thin films on side-glowing optical fibers (SOFs). The properties of the photocatalysts-coated SOF were characterized by surface morphology, nanostructure, crystallite size and phase and zeta potential. Photodegradation efficiency and durability of the photocatalysts treating different types of desalination concentrate was studied under natural sunlight. Synthetic solutions and reverse osmosis (RO) concentrates from brackish water and municipal wastewater desalination facilities were tested to elucidate the impact of water chemistry, operating conditions and seasonal climate variations (solar irradiation intensity and temperature) on photocatalytic efficiency. High ionic strength and divalent electrolyte ions in RO concentrate accelerated photocatalytic process, whereas the presence of carbonate species and organic matter hindered photodegradation. Outdoor testing of immobilized continuous-flow photoreactors suggested that the catalyst-coated SOFs can utilize a wide spectrum ofnatural sunlight and achieved durable photocatalytic performance.

Preparation of Gd2Zr2O7 buffer layers for coated conductor by polymer-assisted chemical solution deposition

Gd2Zr2O7 (GZO) buffer layers with a thickness of about 300nm have been directly deposited on bi-axially textured Ni-5at%W (NiW) alloy substrate and the Y2O3 buffered NiW substrate by a newly developed polymer-assisted chemical solution deposition (PA-CSD) method. The solution prepared from metal nitrate precursor has been achieved by a simple, low cost, and effective method. The Y2O3 thin film was deposited as the seed layer by dc reactive sputtering technique. The films have been studied with X-ray diffraction (XRD) and AFM analyses. It is found that only GZO buffer layer on Y2O3/NiW can be grown with highly c-axis oriented. Highly epitaxial 500-nm-thick YBa2Cu3O7−x (YBCO) thin film, deposited on GZO/Y2O3/NiW, reaches a maximum self-field critical current density (Jc) of 1.5 MA/cm2 at 77K the possible reasons are discussed in detail.

Strain effect on the transport properties of epitaxial PrNiO3 thin films grown by polymer-assisted deposition

Epitaxial PrNiO3 (PNO) thin films were grown on single-crystal LaAlO3, (LaAlO3)0.3(SrAlTaO6)0.7, and SrTiO3 substrates, respectively, by the polymer-assisted deposition method. It is found that compared with that of PNO bulk, the c-axis parameter of PNO film increases under compressive strain and decreases under tensile strain. Moreover, under tensile strain, the c-axis first decreases and then increases. All the PNO films exhibit metal–insulator (MI) transition with a thermal hysteresis in the temperature-dependent resistivity. At room temperature, the resistivity of the PNO films shows an increasing trend with the lattice mismatch strain changing from compressive to tensile. The MI transition temperature TMI of the PNO films under both compressive and tensile strains is lower than that of PNO bulk. However, the trend of TMI dependent on the lattice mismatch between the film and the substrate under tensile strain is decreasing. The conduction mechanism fits very well with the Mott’s variable range hopping (VRH) model in temperatures below 35 K. It is suggested that strain relaxation increases with the strain increasing from compressive to tensile, which results in the increase of oxygen vacancies compensated by more Ni2+ changed from Ni3+ in the film. The competing and joint effects of the bending of the Ni–O–Ni bond angle, the elongation of the Ni–O bond length, and the change of Ni valence dominate the transport properties of the PNO films.

Facile surfactant driven fabrication of transparent WO3 photoanodes for improved photoelectrochemical properties

A facile polymer-assisted direct deposition method is reported for fabrication of transparent WO3 films for photoelectrochemical water oxidation. Addition of Triton X 114 as a polymer additive brings a significant impact on morphology, optical property and crystallinity of WO3 film that leads to improved photoelectrochemical activity. An optimum amount of Triton X 114 added during the WO3 synthesis makes a photoanode with near glass-like transparency with activity improvement. Moreover, bulk charge separation efficiency as high as 80% at 1.23VRHE is obtained by Triton X 114 addition by forming preferentially (200) oriented WO3 crystals of better bulk charge transfer property.

Highly infrared-transparent and p-type conductive CuSc1−xSnxO2 thin films and a p-CuScO2:Sn/n-ZnO heterojunction fabricated by the polymer-assisted deposition method

We fabricated a series of infrared (IR)-transparent and conductive Sn-doped CuScO2 thin films using a polymer-assisted deposition (PAD) method.

The Effects of Elements Doping on the Properties of YBCO Epitaxial Films Prepared by Chemical Solution Deposition

YBa2Cu3O7−δ (YBCO)-coated conductors have wide-ranging potential in large-scale applications such as superconducting magnets and superconducting electric cables, but low current carrying capability restrains the practical application of YBCO-coated conductors at high temperatures and high magnetic fields. It is crucial to develop YBCO-coated conductors with high flux pinning capabilities. In this paper, YBa2Cu3−x Fe x O7−δ (x = 0, 0.0005, 0.001, 0.002, 0.005) and YDy x Ba2Cu3O7−δ (x = 0∼0.5) films were prepared on a LaAlO3 (LAO) single crystal substrate via a fluorine-free polymer-assisted metal organic deposition (PA-MOD) method. The effects of elements doping on the properties of YBCO in different positions of the lattice were investigated. The superconducting critical temperature (T c) decreases, and the superconducting transition width broadens with the Fe and Dy doping. However, the critical current densities (J c) improve at 77 K with Fe doping quantities of xless than 0.005 and Dy doping quantities of xless than 0.5. It means that the current carrying capability of a YBCO film can be improved by doping with appropriate amounts of Fe and Dy.

Structural characteristics, magnetic properties of Re2NiMnO6 (Re = La, Pr, Nd, Sm, Y) thin films on (001) LaAlO3 by simple polymer assisted deposition

Re2NiMnO6 (Re=La, Pr, Nd, Sm, Y) epitaxial thin films grown on (001) LaAlO3 substrates were obtained via a simple polymer assisted deposition method. The XRD θ/2θ scans, ω scans, and φ scans indicate that the films are single-phase epitaxial films. It is found that there is a ferromagnetic (FM) transition with the temperature decreasing from room temperature for all the films. The Raman mode positions shift toward the low frequency with the substitution of La by a smaller rare earth element. The FM transition temperature Tc decreases as the A-site ionic radius decreasing. Moreover, all the FM transition temperatures (Tc) of the Re2NiMnO6 films are lower than those corresponding values of the bulks, indicating the ferromagnetic interaction weakening. It is suggested that the ferromagnetic interaction is affected by the strain existing in the film through affecting the B(B′)O6 octahedra and the cation disorder related to the ionic radius of Re, which can be used as an effective way to improve the magnetic properties of the film and obtain the higher Tc functional materials.

Preparation of Coated Conductors With Fluorine-Free CSD Method

Preparation of new architectures of coated conductors (CCs) with fluorine-free chemical solution deposition (CSD) method has been presented. Multifunctional buffer layers, such as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$\hbox{Sm}_{0.2}\hbox{Ce}_{0.8}\hbox{O}_{1.9-{\rm x}}$</tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$\hbox{SmBiO}_{3}/\hbox{NiO} $</tex-math></inline-formula> (200) have been fabricated via polymer-assisted chemical solution deposition (PACSD) method and surface oxidation epitaxial method. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$\hbox{YBa}_{2}\hbox{Cu}_{3}\hbox{O}_{7} $</tex-math></inline-formula> (YBCO) superconducting layers have been prepared by partial-melting process. A full process of making CCs using fluorine-free all-CSD method has been demonstrated on reel-to-reel facilities via slot-die coating and drying technology. Long CCs with critical current density <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$J_{c}&gt;1\ \hbox{MA/cm}^{2} $</tex-math></inline-formula> at 77 K in self-field have been fabricated, demonstrating the feasibility of the full CSD technology in making quality CCs.

The influence of substrate orientation and annealing condition on the properties of LaMnO3 thin films grown by polymer-assisted deposition

The epitaxial films of LaMnO3 were fabricated via a simple polymer-assisted deposition method. The effects of substrate orientation and annealing condition on the structure and properties of LaMnO3 films have been investigated. It is found by X-ray diffraction and Raman spectroscopy that increase in the oxygen content results in a decrease in unit cell volume along with a reduction in Jahn–Teller distortion. Besides, with increase in annealing temperature, the resistivity of the film decreases and the insulator–metal transition temperature TIM shifts to higher temperature. The maximum of the resistivity is highly substrate-orientation dependent in the ascending order of (100)<(110)<(111). Furthermore, the TIM of LaMnO3 film increases with the substrate orientation changing from (111) to (100). It is shown that magnetic order correlates well with an insulator to metal behavior. All results reveal that the lattice distortion of MnO6 octahedron can be tuned by different annealing condition and the substrate orientation, which can be effective methods to adjust the structure, electrical and magnetic properties of LaMnO3 films.