Linear and nonlinear optical properties of transfer ribonucleic acid (tRNA) thin solid films

We successfully obtained transfer ribonucleic acid (tRNA) thin solid films (TSFs) using an aqueous solution precursor in an optimized deposition process. By varying the concentration of RNA and deposition process parameters, uniform solid layers of solid RNA with a thickness of 30 to 46 nm were fabricated consistently. Linear absorptions of RNA TSFs on quartz substrates were experimentally investigated in a wide spectral range covering UV–VIS–NIR to find high transparency for λ > 350 nm. We analyzed the linear refractive indices, n(λ) of tRNA TSFs on silicon substrates by using an ellipsometer in the 400 to 900 nm spectral range to find a linear correlation with the tRNA concentration in the aqueous solution. The thermo-optic coefficient (dn/dT) of the films was also measured to be in a range −4.21 × 10⁻⁴ to −5.81 × 10⁻⁴ °C⁻¹ at 40 to 90 °C. We furthermore characterized nonlinear refractive index and nonlinear absorption of tRNA TSFs on quartz using a Z-scan method with a femtosecond laser at λ = 795 nm, which showed high potential as an efficient nonlinear optical material in the IR spectral range.

Optical measurements of one of the vital biological molecules (RNA) in the human body.     

Identification of the local electrical properties of crystalline and amorphous domains in electrochemically doped conjugated polymer thin films

Doped polymer thin films have several applications in electronic, optoelectronic and thermoelectric devices. Often the electrical properties of doped conjugated polymer thin films are affected by their local physical and mechanical characteristics. However, investigations into the effects of doping on local domain properties have not been carried out. Here, we study the physical, mechanical and optical properties of electrochemically doped P3HT thin films at the nanoscale and establish a relation between doping level and the physical properties of P3HT thin films. Bulk crystallinity of both pristine and doped P3HT thin films, characterized using grazing incidence X-ray diffraction, shows a clear loss in crystallinity upon doping. Nanoscale crystalline and amorphous domains in the films are visualized by multimode atomic force microscopy (AFM). It is apparent that the crystalline domains are most affected by doping and have a higher degree of doping compared to amorphous domains. This results in crystalline domains exhibiting superior electrical conductivity at a local level. These results are further supported by Raman mapping and elemental analysis of doped films. A direct relation is established between the physical, mechanical and electrical properties of doped P3HT thin films based on the AFM data. The findings demonstrate that higher dopant concentrations are found in crystalline domains compared to amorphous domains, which has not been shown before to the best of our knowledge. This study can be used to optimize the electronic properties of doped P3HT thin films for use in electronic and optoelectronic device applications.

The effects of electrochemical doping on the local domain properties of conjugated polymer films are investigated. Nanoscale crystalline domains are most affected by doping and have a higher degree of doping compared to amorphous domains.     

Dielectric properties of poly-(3-octylthiophene) thin films mixed with oleic acid capped cadmium selenide nanoparticles

Hybrid heterojunction thin films, based on poly-(3-octylthiophene) (P3OT) polymer and oleic acid (OA)-capped cadmium selenide (CdSe) nanoparticles (NPs) are prepared by a spin-coating method. The structural and morphological properties of the CdSe NPs and of the hybrid thin films are investigated. The results of the dielectric characterization show that conductivity of the hybrid thin films is dependent on frequency and CdSe NP concentration. The Nyquist plots of the impedance characteristics of the layers exhibit circular features irrespective of the NP concentration. The dependence of the dielectric permittivity on frequency and CdSe NP concentration are studied.

Hybrid heterojunction thin films, based on poly-(3-octylthiophene) (P3OT) polymer and oleic acid (OA)-capped cadmium selenide (CdSe) nanoparticles (NPs) are prepared by a spin-coating method.     

Li@C60 thin films: characterization and nonlinear optical properties

Organic materials have attracted considerable attention in nonlinear optical (NLO) applications as they have several advantages over inorganic materials, including high NLO response, and fast response time as well as low-cost and easy fabrication. Lithium-containing C₆₀ (Li@C₆₀) is promising for NLO over other organic materials because of its strong NLO response proven by theoretical and experimental studies. However, the low purity of Li@C₆₀ has been a bottleneck for applications in the fields of solar cells, electronics and optics. In 2010, highly purified Li@C₆₀ was finally obtained, encouraging further studies. In this study, we demonstrate a facile method to fabricate thin films of Li@C₆₀ and their strong NLO potential for high harmonic generation by showing its comparatively strong emission of degenerate-six-wave mixing, a fifth-order NLO effect.

A facile way is shown to obtain thin films of Li@C₆₀ as well as their characterization and nonlinear optical properties. Our results suggest Li@C₆₀ to be a suitable candidate for high-harmonic generation.     

Copper-nanoparticle-dispersed amorphous BaTiO3 thin films as hole-trapping centers: enhanced photocatalytic activity and stability

Nobel metal (Au and Ag) nanoparticles are often used in semiconductor photocatalysis to enhance the photocatalytic activity, while inexpensive Cu attracts less attention due to its easy oxidization. Herein, an elaborate study was conducted using Cu-nanoparticle-dispersed amorphous BaTiO₃ films as photocatalysts. Photocatalytic and photoelectrochemical measurements demonstrated that the degradation efficiency and photocurrent density of the nanocomposite films are approximately 3.5 and 10 times as high as the pristine BaTiO₃ film, respectively, which can be ascribed to a synergetic effect of the surface plasmon resonance and interband excitation. In addition, a good stability was also demonstrated by cyclic tests for the degradation of rhodamine B, which may be due to the amorphous nature of the BaTiO₃ matrix providing hole-trapping centers. The high photocatalytic stability suggests that Cu is a promising alternative metal to replace Au and Ag for the development of cost-effective photocatalysts. Our work demonstrates a simple and promising strategy for improving the photostability of Cu nanomaterials and may provide a useful guideline for designing Cu-based composite materials toward various photocatalytic applications such as water pollution treatment.

The photocatalytic degradation activity and photoelectrochemical performance of amorphous BaTiO₃ films can be improved after introducing Cu NPs, and the oxidation of Cu is strongly hindered when dispersing in the amorphous BaTiO₃ films that serve as h⁺-trapping centers.     

Local atomic order of the amorphous TaOx thin films in relation to their chemical resistivity

The experimental and theoretical studies of the local atomic order and chemical binding in tantalum oxide amorphous films are presented. The experimental studies were performed on thin films deposited at the temperature of 100 °C by atomic layer deposition on silicon (100) and glass substrates. Thin films of amorphous tantalum oxide are known to exhibit an extremely large extent of oxygen nonstoichiometry. Performed X-ray absorption and photoelectron studies indicated the oxygen over-stoichiometric composition in the considered films. Surplus oxygen atoms have 1s electron level with binding energy about 1 eV higher than these in reference Ta₂O₅ oxide. The density functional theory was applied to find the possible location of additional oxygen atoms. Performed calculation indicated that additional atoms may form the dumbbell defects, which accumulate the dangling oxygen bonds in orthorhombic structure and lead to increase of oxygen 1s level binding energy. The presence of this kind of oxygen–oxygen bonding may be responsible for increase of amorphous film chemical resistivity which is very important in many applications.

The experimental and theoretical studies of the local atomic order and chemical binding in tantalum oxide amorphous films are presented.     

Linking lignin source with structural and electrochemical properties of lignin-derived carbon materials

Valorization of lignin to high-value chemicals and products along with biofuel production is generally acknowledged as a technology platform that could significantly improve the economic viability of biorefinery operations. With a growing demand for electrical energy storage materials, lignin-derived activated carbon (AC) materials have received increasing attention in recent years. However, there is an apparent gap in our understanding of the impact of the lignin precursors (i.e., lignin structure, composition and inter-unit linkages) on the structural and electrochemical properties of the derived ACs. In the present study, lignin-derived ACs were prepared under identical conditions from two different lignin sources: alkaline pretreated poplar and pine. The lignin precursors were characterized using composition analysis, size exclusion chromatography, and 2D HSQC nuclear magnetic resonance (NMR). Distinctive distributions of numerous micro-, meso- and macro-porous channels were observed in the two lignin-derived ACs. Poplar lignin-derived ACs exhibited a larger BET surface area and total mesopore volume than pine lignin-derived AC, which contributed to a larger electrochemical capacitance over a range of scan rates. X-ray photoelectron spectroscopic analysis (XPS) results revealed the presence of oxygen-containing functional groups in all lignin-derived ACs, which participated in redox reactions and thus contributed to an additional pseudo-capacitance. A possible process mechanism was proposed to explain the effects of lignin structure and composition on lignin-derived AC pore structure during thermochemical conversion. This study provides insight into how the lignin composition and structure affect the derived ACs for energy storage applications.

This study demonstrates the effect of lignin source on the structural and electrochemical properties of lignin-derived carbon materials.     

Diazonium-functionalized thin films from the spontaneous reaction of p-phenylenebis(diazonium) salts

Salts of the diazonium coupling agent p-phenylenebis(diazonium) form diazonium-terminated conjugated thin films on a variety of conductive and nonconductive surfaces by spontaneous reaction of the coupling agent with the surface. The resulting diazonium-bearing surface can be reacted with various organic and inorganic nucleophiles to form a functionalized surface. These surfaces have been characterized with voltammetry, XPS, infrared and Raman spectroscopy, and atomic force microscopy. Substrates that can be conveniently and quickly modified with this process include ordinary glass, gold, and an intact, fully assembled commercial screen-printed carbon electrode. The scope and convenience of this process make it promising for practical surface modification.

We present a surface functionalization procedure based on diazonium-functionalized thin films produced by spontaneous surface grafting of p-phenylene-bis(diazonium) cation.     

ZnS coating for enhanced environmental stability and improved properties of ZnO thin films

Low environmental stability of ZnO nanostructures in hydrophilic systems is a crucial factor limiting their practical applications. ZnO nanomaterials need surface passivation with different water-insoluble compounds. This study describes a one-step passivation process of polycrystalline ZnO films with ZnS as a facile method of ZnO surface coating. A simple sulfidation reaction was carried out in gas-phase H₂S and it resulted in formation of a ZnS thin layer on the ZnO surface. The ZnS layer not only inhibited the ZnO dissolving process in water but additionally improved its mechanical and electrical properties. After the passivation process, ZnO/ZnS films remained stable in water for over seven days. The electrical conductivity of the ZnO films increased about 500-fold as a result of surface defect passivation and the removal of oxygen molecules which can trap free carriers. The nanohardness and Young''s modulus of the samples increased about 64% and 14%, respectively after the ZnS coating formation. Nanowear tests performed using nanoindentation methods revealed reduced values of surface displacements for the ZnO/ZnS system. Moreover, both ZnO and ZnO/ZnS films showed antimicrobial properties against Escherichia coli.

ZnS coating improves mechanical, electrical, antibacterial properties and environmental stability of ZnO nanofilms.     

Synthesis,oxide formation,properties and thin film transistor properties of yttrium and aluminium oxide thin films employing a molecular-based precursor route

Combustion synthesis of dielectric yttrium oxide and aluminium oxide thin films is possible by introducing a molecular single-source precursor approach employing a newly designed nitro functionalized malonato complex of yttrium (Y-DEM-NO₂1) as well as defined urea nitrate coordination compounds of yttrium (Y-UN 2) and aluminium (Al-UN 3). All new precursor compounds were extensively characterized by spectroscopic techniques (NMR/IR) as well as by single-crystal structure analysis for both urea nitrate coordination compounds. The thermal decomposition of the precursors 1–3 was studied by means of differential scanning calorimetry (DSC) and thermogravimetry coupled with mass spectrometry and infrared spectroscopy (TG-MS/IR). As a result, a controlled thermal conversion of the precursors into dielectric thin films could be achieved. These oxidic thin films integrated within capacitor devices are exhibiting excellent dielectric behaviour in the temperature range between 250 and 350 °C, with areal capacity values up to 250 nF cm⁻², leakage current densities below 1.0 × 10⁻⁹ A cm⁻² (at 1 MV cm⁻¹) and breakdown voltages above 2 MV cm⁻¹. Thereby the increase in performance at higher temperatures can be attributed to the gradual conversion of the intermediate hydroxy species into the respective metal oxide which is confirmed by X-ray photoelectron spectroscopy (XPS). Finally, a solution-processed Y_xO_y based TFT was fabricated employing the precursor Y-DEM-NO₂1. The device exhibits decent TFT characteristics with a saturation mobility (μ_sat) of 2.1 cm² V⁻¹ s⁻¹, a threshold voltage (V_th) of 6.9 V and an on/off current ratio (I_on/off) of 7.6 × 10⁵.

Transformation of a new molecular precursor allows the formation of yttrium oxide under moderate conditions displaying high voltage breakthrough behaviour.     

On the morphological,structural and electrochemical properties of entangled Cu-filled carbon nano-onions

In this work we demonstrate an advanced chemical vapour synthesis approach in which the synthesis of Cu-filled carbon nano-onions (CNOs) is achieved by direct sublimation and pyrolysis of a not previously used precursor, namely chloro(1,5-cyclooctadiene)copper(i) dimer. The cross-sectional morphology and filling-ratio of the as grown CNOs were characterized by detailed transmission electron microscopy (TEM), high resolution TEM analyses, Fourier transform and lattice profile analyses. The structural graphitic arrangement and electronic properties of the CNOs were then investigated by means of X-ray diffraction and absorption spectroscopy. The electrochemical impedance spectroscopy and cyclic voltammetry of presented structures were also investigated and reveal a high electrical resistance. Finally the electrochemical performances of this type of CNOs were compared with those of another type of CNOs filled with different metal-carbide materials.

We demonstrate an advanced CVS approach in which the synthesis of Cu-filled carbon nano-onions (CNOs) is achieved by direct sublimation and pyrolysis of a not previously used precursor, namely chloro(1,5-cyclooctadiene)copper(i) dimer.     

The influence of hydrogen concentration in amorphous carbon films on mechanical properties and fluorine penetration: a density functional theory and ab initio molecular dynamics study

Amorphous carbon (a-C) films have attracted significant attention due to their reliable structures and superior mechanical, chemical and electronic properties, making them a strong candidate as an etch hard mask material for the fabrication of future integrated semiconductor devices. Density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations were performed to investigate the energetics, structure, and mechanical properties of the a-C films with an increasing sp³ content by adjusting the atomic density or hydrogen content. A drastic increase in the bulk modulus is observed by increasing the atomic density of the a-C films, which suggests that it would be difficult for the films hardened by high atomic density to relieve the stress of the individual layers within the overall stack in integrated semiconductor devices. However, the addition of hydrogen into the a-C films has little effect on increasing the bulk modulus even though the sp³ content increases. For the F blocking nature, the change in the sp³ content by both atomic density and H concentration makes the diffusion barrier against the F atom even higher and suppresses the F diffusion, indicating that the F atom would follow the diffusion path passing through the sp² carbon and not the sp³ carbon due to the significantly high barrier. For the material design of a-C films with adequate doped characteristics, our results can provide a new straightforward strategy to tailor the a-C films with excellent mechanical and other novel physical and chemical properties.

Amorphous carbon films have attracted significant attention due to their superior mechanical and electronic properties, making them a strong candidate as an etch hard mask material for the fabrication of future integrated semiconductor devices.     

Solution based synthesis of Cu(In,Ga)Se2 microcrystals and thin films

Herein, for the first time, we report the synthesis of quaternary Cu(In,Ga)Se₂ microcrystals (CIGSe MCs) using a facile and economical one-pot heating-up method. The most important parameters such as reaction temperature and time were varied to study their influences on the structural, morphological, compositional and optical properties of the MCs. Based on the results, the formation of CIGSe was initiated from binary β-CuSe and then converted into pure phase CIGSe by gradual incorporation of In³⁺ and Ga³⁺ ions into the β-CuSe crystal lattice. As the reaction time increases, the band gap energy was increased from 1.10 to 1.28 eV, whereas the size of the crystals increased from 0.9 to 3.1 μm. Besides, large-scale synthesis of CIGSe MCs exhibited a high reaction yield of 90%. Furthermore, the CIGSe MCs dispersed in the ethanol was coated as thin films by a drop casting method, which showed the optimum carrier concentration, high mobility and low resistivity. Moreover, the photoconductivity of the CIGSe MC thin film was enhanced by three order magnitude in comparison with CIGSe NC thin films. The solar cells fabricated with CIGSe MCs showed the PCE of 0.59% which is 14.75 times higher than CIGSe NCs. These preliminary results confirmed the potential of CIGSe MCs as an active absorber layer in low-cost thin film solar cells.

Herein, for the first time, we report the synthesis of quaternary Cu(In,Ga)Se₂ microcrystals (CIGSe MCs) using a facile and economical one-pot heating-up method.     

Flexible high dielectric thin films based on cellulose nanofibrils and acid oxidized multi-walled carbon nanotubes

Flexible high dielectric materials are of prime importance for advanced portable, foldable and wearable devices. A series of flexible high dielectric thin films based on cellulose nanofibrils (CNF) and acid oxidized multi-walled carbon nanotubes (o-MWCNT) was prepared in aqueous solution. Though no organic solvent was involved during the preparation, the SEM images showed that o-MWCNTs have good distribution within the CNF matrix. The dielectric constant of CNF/o-MWCNT (6.2 wt%) composite films was greatly increased from 25.24 for pure CNF to 73.88, while the loss tangent slightly decreased from 0.70 to 0.68, and the AC conductivity decreased from 3.15 × 10⁻⁷ S cm⁻¹ for CNF to 1.77 × 10⁻⁷ S cm⁻¹ (at 1 kHz). The abnormal decrease of loss tangent and AC conductivity were attributed to the introduction of oxide-containing groups on the surface of MWCNTs. The nanocomposite films showed excellent flexibility such that they could be bent a thousand times without visible damage. The presence of MWCNTs also helped to improve the thermal stability of the composite films. The excellent dielectric and mechanical properties of the CNF/o-MWCNT composite film demonstrate its great potential to be utilized in the field of energy storage.

The acid oxidized MWCNTs have excellent dispersity in CNF, resulting in outstanding dielectric properties of the flexible CNF/o-MWCNT nanocomposite films.     

Novel tetrahedral cobalt(ii) silanethiolates: structures and magnetism

Three heteroleptic complexes of Co(ii) tri-tert-butoxysilanethiolates have been synthesized with piperidine [Co{SSi(OtBu)₃}₂(ppd)₂] 1, piperazine [Co{SSi(OtBu)₃}₂(NH₃)]₂(μ-ppz)·2CH₃CN 2, and N-ethylimidazole [Co{SSi(OtBu)₃}₂(etim)₂] 3. The complexes have been characterized by a single-crystal X-ray, revealing their tetrahedral geometry on Co(ii) coordinated by two nitrogen and two sulfur atoms. Complexes 1 and 3 are mononuclear, whereas 2 is binuclear. The spectral properties and thermal properties of 1–3 complexes were established by FTIR spectroscopy for solid samples and TGA. The magnetic properties of complexes 1, 2, and 3 have been investigated by static magnetic measurements and X-band EPR spectroscopy. These studies have shown that 1 and 3, regardless of the similarity in structure of CoN₂S₂ cores, demonstrate different types of local magnetic anisotropy. Magnetic investigations of 2 reveal the presence of weak antiferromagnetic intra-molecular Co(ii)–Co(ii) interactions that are strongly influenced by the local magnetic anisotropy of individual Co(ii) ions.

Structural, spectral and thermal properties of three tetrahedral Co(ii) silanethiolates were established by XRD, FTIR for solid samples and TGA. The magnetic properties were investigated by static magnetic measurements and X-band EPR spectroscopy.     

Structural,optical and photocatalytic properties of erbium (Er3+) and yttrium (Y3+) doped TiO2 thin films with remarkable self-cleaning super-hydrophilic properties

The self-cleaning and super hydrophilic properties of pristine TiO₂ and of TiO₂ doped with Er³⁺ or Y³⁺ transparent thin films deposited onto glass substrates were investigated. The thin films prepared by multiple dipping and drying cycles of the glass substrate into the pristine TiO₂ sol and Er³⁺ or Y³⁺-doped TiO₂ sol were characterized by X-ray diffraction, UV-vis spectrophotometry, and atomic force microscopy (AFM). The self-cleaning photocatalytic activity of the thin films towards the removal of oleic acid deposited on the surface under UVA irradiation was evaluated. A remarkable enhancement was observed in the hydrophilic nature of the TiO₂ thin films under irradiation. The optical properties and wettability of TiO₂ were not affected by Er³⁺ or Y³⁺ doping. However, the photocatalytic degradation of oleic acid under UVA irradiation improved up to 1.83 or 1.95 fold as the Er³⁺ or Y³⁺ content increased, respectively, due to the enhanced separation of the photogenerated carriers and reduced crystallite size. AFM analysis showed that the surface roughness increased by increasing the Er³⁺ or Y³⁺ content due to the formation of large aggregates. This in turn contributes to the increase of the active surface area enhancing the photodegradation process. This study demonstrates that TiO₂ doped with low amounts of Er³⁺ or Y³⁺ down to 0.5 mol% can produce transparent, super-hydrophilic, thin film surfaces with remarkable self-cleaning properties.

The self-cleaning and super hydrophilic properties of pristine TiO₂ and of TiO₂ doped with Er³⁺ or Y³⁺ transparent thin films deposited onto glass substrates were investigated.     

Unraveling the microstructural and optoelectronic properties of solution-processed Pr-doped SrSnO3 perovskite oxide thin films

The inorganic stannous-based perovskite oxide SrSnO₃ has been utilized in various optoelectronic applications. Facilitating the synthesis process and engineering its properties, however, are still considered challenging due to several aspects. This paper reports on a thorough investigation of the influence of rare-earth (praseodymium) doping on the microstructural and optoelectronic properties of pure and Pr-doped SrSnO₃ perovskite oxide thin films synthesized by a two-step simple chemical solution deposition route. Structural analysis indicated the high quality of the obtained phase and the alteration generated from the insertion of impurities. Surface scanning illustrated the formation of homogenous and crack-free SrSnO₃ thin films with a nanorod morphology, with an augmentation in size as the dopant ratios increased. Optical properties analysis showed an enhancement in the samples optical absorption with wide-range bandgap tuning. First-principles calculations revealed the exchange interactions between the 3d–4f states and their impact on the electronic properties of the pristine material. Hall-effect measurements revealed an immense decrement in the resistivity of the films upon increment of doping ratios, passing from 7.3 × 10⁻² Ω cm for the undoped sample to 4.8 × 10⁻² Ω cm for 7% Pr content, while a reverse trend was observed on the carrier mobility, rising from 2.5 to 7.6 cm² V⁻¹ s⁻¹ for 7% Pr content. The results emphasized the efficiency of the simple synthesis route to produce high-quality samples. The current findings will contribute to paving the way towards expanding the utilization of simple and cost-effective chemical solution deposition methods for the fast and large area growth of stannous-based perovskite oxides for optoelectronic applications.

Unraveling the optical, electronic and electrical properties of high-quality nanorod morphology spray-coated Pr-doped SrSnO₃ perovskite oxide thin films.     

Effect of localized UV irradiation on the crystallinity and electrical properties of dip-coated polythiophene thin films

Ensuring high performance in polymer devices requires conjugated polymers with interchain π–π stacking interactions via van der Waals forces, which can induce structural changes in the polymer thin film. Here, we present a systematic study of using simple localized UV irradiation to overcome the low crystallinity and poor charge carrier transport in dip-coated poly(3-hexylthiophene) (P3HT) thin films, which are consequences of the limited selection of solvents compatible with the dip-coating process. UV irradiation for only a few minutes effectively promoted P3HT chain self-assembly and association in the solution state. Brief UV irradiation of a P3HT solution led to well-ordered molecular structures in the resultant P3HT films dip-coated using a low boiling point solvent with rapid solvent evaporation. In addition, the position at which UV light was irradiated on the dip-coating solutions was varied, and the effects of the irradiation position and time on the crystallinity and electrical properties of the resultant P3HT thin films were investigated.

When the top part of the solution was irradiated with UV light, the dip-coated P3HT film showed enhanced crystallinity and electrical properties.     

Strain-effected physical properties of ferromagnetic insulating La0.88Sr0.12MnO3 thin films

The functional perovskite La_1−xSr_xMnO₃ (LSMO) possesses various exotic phases owing to competing physical parameters and internal degrees of freedom. In particular, the nature of the ferromagnetic insulating phase (FMI) has not been adequately explored, resulting in a limited understanding of the relationship between crystal structure and magnetism. To investigate this structure–property relationship, epitaxial La_0.88Sr_0.12MnO₃ thin films were grown on two different substrates, (001) SrTiO₃ and (001) (LaAlO₃)_0.3(Sr₂AlTaO₆)_0.7, by pulsed laser deposition. Element-specific and surface-sensitive techniques were applied in conjunction with bulk magnetometry to investigate the inextricable link between the structures and magnetic properties of the films and the effects of tuning the strain. The results unambiguously demonstrate that structure–property relationship of a FMI LSMO tuned by strain has a crucial role for manipulating the properties in the FMI regime.

The functional perovskite La_1−xSr_xMnO₃ (LSMO) possesses various exotic phases owing to competing physical parameters and internal degrees of freedom.     

Fabrication of graphene oxide/montmorillonite nanocomposite flexible thin films with improved gas-barrier properties

Nanocomposites are potential substitutes for inorganic materials in fabricating flexible gas-barrier thin films. In this study, two nanocomposites are used to form a flexible gas-barrier film that shows improved flexibility and a decreased water vapor transmission rate (WVTR), thereby extending the diffusion path length for gas molecules. The nanoclay materials used for the flexible gas-barrier thin film are Na⁺-montmorillonite (MMT) and graphene oxide (GO). A flexible gas-barrier thin film was fabricated using a layer-by-layer (LBL) deposition method, exploiting electronic bonding under non-vacuum conditions. The WVTR of the film, in which each layer was laminated by LBL assembly, was analyzed by Ca-test and the oxygen transmission rate (OTR) was analyzed by MOCON. When GO and MMT are used together, they fill each other''s vacancies and form a gas-barrier film with high optical transmittance and the improved WVTR of 3.1 × 10⁻³ g per m² per day without a large increase in thickness compared to barrier films produced with GO or MMT alone. Thus, this film has potential applicability as a barrier film in flexible electronic devices.

Nanocomposites are potential substitutes for inorganic materials in fabricating flexible gas-barrier thin films.