Use Of Films Research Articles

Tailoring silk-based covering material with matched mechanical properties for vascular tissue engineering

Vascular covered stents play a significant therapeutic role in cardiovascular diseases. However, the poor compliance and biological inertness of commercial materials cause post-implantation complications. Silk fibroin (SF), as a biomaterial, possesses satisfactory hemocompatibility and tissue compatibility. In this study, we developed a silk film for use in covered stents by employing a layer-by-layer self-assembly strategy with regenerated SF on silk braiding fabric. We investigated the effects on the mechanical properties of the silk films in detail, which were closely correlated with fabric parameters and layer-by-layer self-assembly. The results showed that there was a significant relationship between these factors and both the compliance and mechanical strength. The 1 × 2/90°/100/SF6 film exhibited excellent mechanical properties. Notably, compliance reached 2.6%/100 mmHg, matching that of the human saphenous vein. Thus, this strategy shows promise in developing a novel covered stent, with biocompatible and comprehensive mechanical properties, and significant potential for clinical applications.

Swellable Plasma Polymer Films for Use in Hydrogel-Based Biomedical Devices

Swellable Plasma Polymer Films for Use in Hydrogel-Based Biomedical Devices

Plasma-enhanced atomic layer deposition of indium-free ZnSnOx thin films for thin-film transistors

An appropriate synthesis technique for growing high-quality indium-free ZnSnOx (ZTO) films should be developed to achieve high-performance thin-film transistors (TFTs) utilizing ZTO films. This study investigated the growth characteristics and electrical properties of ZTO thin films grown via plasma-enhanced atomic layer deposition (PEALD) using bis(1-dimethylamino-2-methyl-2-propoxide)Sn, diethylzinc, and O2 plasma to optimize the composition and enhance the device performance. Deviations were observed in the growth per cycle when using PEALD for ZTO, compared with binary oxides. In the PEALD of the ZTO films, the introduction of the SnO2 sub-cycle enhanced the mass gain in the ZnO sub-cycle, whereas the mass gain in the SnO2 sub-cycle decreased with the addition of the ZnO sub-cycle. This was attributed to changes in the density of the functional groups on the reaction surface. Precise control over the composition was achieved, enabling the identification of the optimal Zn58Sn42Ox composition. Post-deposition annealing significantly improved the TFT performance, with devices showing enhanced mobility, positive shifts in the threshold voltage, and reduced subthreshold swing values. These improvements stemmed from reductions in oxygen vacancies and sub-gap defect states. These findings highlight the potential of PEALD-grown ZTO films for use in high-performance, cost-effective TFTs, facilitating their integration into modern semiconductor electronics.

Insights into the effect of carboxylated cellulose nanocrystals on mechanical and barrier properties of gelatin films for flexible packaging applications

In this study, gelatin/carboxylated cellulose nanocrystal (cCNC) bionanocomposite films were developed as an eco-friendly alternative to non-biodegradable flexible plastic packaging. Cellulose nanocrystals were modified by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation (cCNC) to strategically interact with amino groups present in the gelatin macromolecular backbone. Gelatin/cCNC bionanocomposite films (0.5–6.0 wt% cCNC) obtained by solution casting were transparent to visible light while displayed high UV-blocking properties. The chemical compatibility between gelatin and cCNC was deepened by electrostatic COO−/NH3+ interactions, as detected by FTIR spectroscopy and morphologically indicated by scanning electron microscopy (SEM). Accordingly, Young's modulus and tensile strength of films were largely increased by 80 and 64 %, respectively, specifically near the cCNC percolation threshold (4 wt%), whereas the water vapor permeability (WVP) was reduced by 52 % at the optimum 6.0 wt% cCNC content in relation to the non-reinforced gelatin matrix (0.10 vs. 0.18 g H2O mm m−2 h−1 kPa−1). The oxygen transmission rates (OTR) of the gelatin/cCNC bionanocomposites were < 0.01 cm3 m-2 day−1, making them technically competitive to most promising biopolymers like polycaprolactone (PCL) and poly(lactic acid) (PLA). This study reveals how TEMPO-oxidized cellulose nanocrystals can broaden the performance of biodegradable gelatin films for use in packaging. The gelatin/cCNC bionanocomposites also represent an effective approach for designing newly sustainability-inspired flexible materials from the surface modification of nanocelluloses targeting specific interactions with protein structures.

Syntheses and performance study of three POM-viologen compounds with photo- and electric-stimulation response

In recent years, stimulus responsive materials have received widespread attention. Under solvothermal conditions, three polyoxometalates-viologen organic–inorganic hybrid compounds were successfully constructed by combining a viologen ligand 1-(3-Nitro-benzyl)-[4,4′]bipyridinyl-1-ium bromide (1,3-nibipy·Br) with octamolybdate, namely [Cu2(1,3-nibipy)4(H2O)2(β-Mo8O26)2]·2H2O (1), [Cu2(1,3-nibipy)4(H2O)4(β-Mo8O26)]·(β-Mo8O26) (2) and (1,3-Hnibipy)2·(β-Mo8O26) (3). These three compounds can exhibit color changing properties under both light and electrical stimulation. Through characterizations of PXRD, FT-IR, UV–vis spectra, XPS, EPR, CV, and other tests, the photochromic and electrochromic properties of these three compounds are caused by the generation of viologen radicals. Compounds 1–3 have a rapid photoresponse efficiency and can be made into mixed matrix films for use as ultraviolet detectors. In addition, coated filter paper synthesized from acetonitrile and compounds can serve as an innovative erasable ink-free printing material medium, which is suitable for various erasable ink-free printing and anti-counterfeiting fields. We further investigated the electrochromic devices prepared from compounds 1–3, which achieved color change at a voltage of around −0.2 V and exhibited good stability after 500 cycles.

Enhanced enzymatic electrochemical detection of an organophosphate Pesticide: Achieving Wide linearity and femtomolar detection via gold nanoparticles growth within polypyrrole films

The indiscriminate use of pesticides in agriculture demands the development of devices capable of monitoring contaminations in food supplies, in the environment and biological fluids. Simplicity, easy handling, high sensitivities, and low limits-of-detection (LOD) and quantification are some of the required properties for these devices. In this work, we evaluated the effect of incorporating gold nanoparticles into indigo carmine-doped polypyrrole during the electropolymerization of films for use as an acetylcholinesterase (AChE) enzyme-based biosensor. As proof of concept, the pesticide methyl parathion was tested towards the inhibition of AChE. The enzyme was immobilized simply by drop-casting a solution, eliminating the need for any prior surface modification. The biosensors were characterized with cyclic voltammetry, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The assays for the detection of methyl parathion with films containing polypyrrole, indigo carmine and AChE (PPy–IC–AChE) presented a sensitivity of 5.7 μA cm−2 g−1 mL and a LOD of 12 nmol L−1 (3.0 ng L−1) with a linear range from 1.3 x 10−7 mol L−1 to 1.0 x 10−5 mol L−1. The introduction of gold nanoparticles (AuNP) into the film (PPy–IC–AuNP-AChE) led to remarkable improvements on the overall performance, such as a lower redox potential for the enzymatic reaction, a 145 % increase in sensitivity (14 μA cm−2 g−1 mL), a wider detection dynamic range (from 1.3x10−7 to 1.0x10−3 mol L−1), and a very low LOD of 24 fmol L−1 (64 ag mL−1). These findings underscore the potential of using AuNPs to improve the enzymatic performance of biosensor devices.

Insight into deposition duration-varied crystallinity, optical parameters, morphology and electrical properties of solution-processed nanostructured CdSSe thin films

Nanostructured cadmium sulpho selenide (CdSSe) films have been grown onto glass substrates for different deposition durations via a facile solution-based method known as chemical bath deposition (CBD). XRD studies revealed that the crystallites in the films possessed hexagonal (wurtzite) structures with predominant orientation along the (002) plane. The crystallite size increased from ∼5.95 nm to ∼16.69 nm with the increase in deposition duration from 1 h to 4 h. The absorbance, transmittance and reflectance measurements were carried out. A transparency of ∼(50–80) % was obtained for the films. The direct optical energy band gap was found to decrease from 1.982 eV to 1.952 eV with the increment of deposition duration from 1 h to 4 h. SEM micrographs of the films revealed the presence of nano spherical-shaped grains with an average size ranging from ∼305 nm to ∼612 nm. HRTEM images illustrated the presence of compact nano-spherical grains and nano-crystallites distributed in random orientations. Raman spectroscopy divulged the presence of CdSe and CdS vibrational Raman modes and overtones in the films. PL spectra revealed a prominent red emission band along with weak luminescent bands in the yellow-red emission region. The presence of Cd–Se and Cd–S bonds in the films was validated using FTIR analysis. Electrical investigation revealed the linear current‒voltage relationship for the films with the rise in conductivity with deposition duration. Hence, deposition duration stands out as a vital parameter for modulating the properties of CdSSe thin films for use in photovoltaic devices and optoelectronics.

The Undocumented and Archipelagic Universal in Miko Revereza's No Data Plan

This article argues that the archipelagic serves as a potent cultural geographic figure challenging resurgent nationalisms in two specific ways. First, it enables us to explore a simultaneous proximity and distance in cultural politics; second, it leads us astray from the conceptual binary that would insist that it is simply other to the nation. In doing so, it arrives at a universalism that is fundamentally differentiated. The essay pursues this framework through an analysis of Miko Revereza's recent documentary film, No Data Plan (2019), which explores Revereza's undocumented status in the United States, and its repertoire of aesthetic techniques, including its erratic and partial framing of his train journey across the country as well as its disjointed soundtrack. Above all, the essay draws attention to the film's use of captions, through which Revereza's mother's story is narrated, and which cannot be reconciled with the rest of the film. Her captions hover in proximity to the filmic diegesis without seeking presence, rejecting a dialectical engagement with a presence in the film that stands in for a documented presence in the nation. By choosing instead to “speak nearby,” she disturbs conventional cultural political logics and dwells within an archipelagic relation to the film, her son, and the world.

Liquid-Phase Exfoliation of Arsenic Trisulfide (As2S3) Nanosheets and Their Use as Anodes in Potassium-Ion Batteries.

Here, we demonstrate the production of 2D nanosheets of arsenic disulfide (As2S3) via liquid-phase exfoliation of the naturally occurring mineral, orpiment. The resultant nanosheets had mean lateral dimensions and thicknesses of 400 and 10 nm, and had structures indistinguishable from the bulk. The nanosheets were solution mixed with carbon nanotubes and cast into nanocomposite films for use as anodes in potassium-ion batteries. These anodes exhibited outstanding electrochemical performance, demonstrating an impressive discharge capacity of 619 mAh/g at a current density of 50 mA/g. Even after 1000 cycles at 500 mA/g, the anodes retained an impressive 94% of their capacity. Quantitative analysis of the rate performance yielded a capacity at a very low rate of 838 mAh/g, about two-thirds of the theoretical capacity of As2S3 (1305 mAh/g). However, this analysis also implied As2S3 to have a very small solid-state diffusion coefficient (∼10-17 m2/s), somewhat limiting its potential for high-rate applications.

Conversion of preferred crystalline orientation by annealing and its impacts on the structural, electronic, and optical properties of pulsed laser-deposited CdO thin films

The impact of annealing on the preferred crystalline orientation as well as the structural, electronic, and optical properties of pulsed laser-deposited 150 ± 3 nm thick cadmium oxide (CdO) films was studied. X-ray diffraction analysis revealed that the annealed CdO films have smaller crystallite sizes, as their molecules at the grain boundaries possessed enough kinetic energy to rearrange their preferred crystalline orientation between (111) and (200). The atomic force microscopy and field emission scanning electron microscopy analyses revealed an enhancement in the active surface area with optimized grain boundaries by annealing which facilitates gas adsorption/desorption. DC electrical conductivity depends on the annealing process and reveals two different conduction mechanisms. The direct optical energy gap was decreased from 3.41 eV to 2.76 eV by annealing at 473 K which is greater than the theoretical value, i.e. 2.2 eV, for bulk CdO. The findings agree with the Burstein-Moss effect as a result of the increased carrier concentration following the generation of numerous oxygen vacancy sites and Cd interstitials. However, mutual charge carrier-impurity interaction and charge carrier Columb interaction contributed to narrowing the band gap by increasing the annealing temperature. The enhanced values of Urbach energy, optical packing density, dispersion parameters, optical conductivity, dissipation factor, oscillator strength, and lattice dielectric constant supported the effectiveness of the annealing process on tailoring optoelectronic responses in the infrared region for the CdO thin films for use in optoelectronic devices. Moreover, the calculated linear optical susceptibility, and nonlinear constants (i.e. third-order optical susceptibility and nonlinear refractive index) were the highest for CdO films annealed at 473 K. The improved value of the figure of merit, solar material protection factor, and solar skin protection factor for the CdO films, annealed at 473 K supports its use in several photovoltaic applications, including solar cells.

Electrical, Optical and Thermal Properties of Ge-Si-Sn-O Thin Films.

This work evaluates the electrical, optical and thermal properties of Sn-doped GexSi1-xOy thin films for use as microbolometer sensing materials. The films were prepared using a combination of a radio frequency (RF) magnetron and direct current (DC) sputtering using a Kurt J Leskar Proline PVD-75 series sputtering machine. Thin films were deposited in an O2+Ar environment at a chamber pressure of 4 mTorr. The thicknesses of the thin films were varied between 300 nm-1.2 µm by varying the deposition time. The morphology and microstructure of thin films were investigated by atomic force microscope (AFM) imaging and X-ray diffraction (XRD), while the atomic composition was determined using the energy dispersive spectroscopy (EDS) function of a scanning electron microscope. The thin film with an atomic composition of Ge0.45Si0.05Sn0.15O0.35 was found to be amorphous. We used the Arrhenius relationship to determine the activation energy as well as temperature coefficient of resistance of the thin films, which were found to be 0.2529 eV and -3.26%/K, respectively. The noise voltage power spectral density (PSD) of the film was analyzed using a Primarius-9812DX noise analyzer using frequencies ranging from 2 Hz to 10 kHz. The noise voltage PSD of the film was found to be 1.76 × 10-11 V2/Hz and 2.78 × 10-14 V2/Hz at 2 Hz and 1KHz frequencies, respectively. The optical constants were determined using the ellipsometry reflection data of samples using an RC2 and infrared (IR) VASE Mark-II ellipsometer from J A Woollam. Absorption, transmission and reflection data for a wavelength range of 900 nm-5000 nm were also determined. We also determined the optical constant values such as the real and imaginary parts of refractive index (n and k, respectively) and real and imaginary part of permittivity (ε1 and ε2, respectively) for wavelength ranges between 193 nm to 35 µm. An optical band gap of 1.03 eV was determined from absorption data and using Tauc's equation. In addition, the thermal conductivity of the film was analyzed using a Linseis thin film analyzer employing the 3ω method. The thermal conductivity of a 780 nm thick film was found to be 0.38 Wm-1K-1 at 300 K. From the data, the Ge-Si-Sn-O alloy was found to be a promising material for use as a sensing material for microbolometers.

Strategy to Antibacterial, High-Mechanical, and Degradable Polylactic Acid/Chitosan Composite Film through Reactive Compatibilization via Epoxy Chain Extender.

Research into the production of antibacterial, high strength, and environmentally friendly biobased films for use in food packaging is crucial due to growing concerns about food safety. Herein, the preparation of antibacterial, high mechanical, and degradable Polylactic acid/chitosan (PLA/CS) composite films with exceptional interfacial compatibility through reactive compatibilization via the epoxy chain extender ADR4468 is reported. A strong bond, in the form of a chemical bond between PLA and CS, is established by the cycloaddition opening reaction of ADR, which induces cross-linking between hydroxyl and carboxyl groups on the molecular chains. As a result, the elongation at break increased by 31.8% compared to the composite film without ADR. In addition, the composite films exhibited good compost degradability, with a mass reduction of 42-45% after 100 days of degradation.

Biofilms from poly-vinyl alcohol/palmyra root sprout with Boswellia serrata, carbon dots and anthocyanin for sensing the freshness of sardine fish

One of the main issues that customers worldwide have is food adulteration. In commercial packages, freshness cannot always be determined visually. Here, we propose sensitive films for use in food packaging that could alter colour to indicate a change in freshness. Hybrid, multifunctional, and eco-friendly films were prepared from polyvinyl alcohol/palmyra root sprout (PVA/PRS), fused with soy protein isolate carbon dot (CD), Boswellia serrata (BS), and Clitoriaternatea anthocyanin (CTE). The films showed pH sensitivity, antioxidant, and UV barrier properties. By creating hydrogen bonds between PRS and the other fillers, adding these substances makes PVA less crystallized. These interactions were verified by infrared Fourier-transform analysis. When compared to PVA, PRS films had significantly lower moisture content and swelling ratios. The UV-blocking capabilities of the films were greatly improved by the addition of CD, BS, and CTE without compromising their mechanical, thermal, or water vapor barrier properties. The composite film PVA/PRS/CD/BS/CTE exhibited a maximum tensile strength value of 69.47 ± 1.49 MPa. The CT extract provides the film with superior antioxidant properties. The colorimetric films PVA/PRS/CTE and PVA/PRS/CD/BS/CTE showed distinct pH-responsive colour-change properties as well as good colour stability. The colorimetric films were used to test the freshness of sardine fish, and they revealed unique colour changes that indicated whether the fish sample was spoiled or not.

Study on plasma-polymerized 1-(trimethylsilyl)pyrrolidine films deposited by plasma-enhanced chemical vapor deposition for use as a Cu diffusion barrier in multilevel metallization process

As integration continues in the modern semiconductor industry, copper (Cu) is used for metal lines and low dielectric constant (low-k) films are used for intermetal dielectrics (IMD) to reduce signal delays occurring in device interconnects. A diffusion barrier is essential between the Cu metal lines and the IMD to prevent Cu diffusion, and silicon carbon-nitride (SiCN) films with relatively low dielectric constants are being widely studied. In this study, SiCN films deposited from 1-(trimethylsilyl)pyrrolidine (TSPD) precursor by plasma-enhanced chemical vapor deposition (PECVD) were investigated for use as a Cu diffusion barrier in multilevel metallization process. This plasma-polymerized TSPD (ppTSPD) monolayer film as SiCN was deposited in plasma powers ranging from 15 to 30 W. The electrical properties of ppTSPD were measured and the chemical properties were analyzed by Fourier-transform infrared spectroscopy (FTIR). The dielectric constant increased with increased plasma power. The lowest dielectric constant of 3.70 and leakage current density at 1 MV/cm of 2.27×10−8 A/cm2 were found for ppTSPD film deposited at 15 W. To verify the Cu diffusion barrier characteristics of the ppTSPD films, a ppTSPD/ppOMCTS bilayer was introduced by using plasma-polymerized octamethylcyclotetrasiloxane (ppOMCTS) as porous low-k SiCOH films. The time-dependent dielectric breakdown (TDDB) characteristic was enhanced around five times than ppOMCTS monolayer used as a reference. The ppTSPD was suggested for fabricating SiCN films for use as a Cu diffusion barrier in multilevel metallization process.

Development of antioxidant film based on gelatin and carboxymethylcellulose incorporated with Tecoma stans (L.) Juss. ex Kunth Petals extract for biodegradable food packaging

The aim of this research was to develop a novel combination of antioxidant blended film for use as biodegradable packaging in the food industry. The antioxidant film was prepared based on gelatin (G) and carboxymethyl cellulose (CMC) incorporated with Tecoma stans (L.) Juss. ex Kunth petals extract (TKE) at various concentrations (0.5, 1.0, and 2.0 mg∙L‒1) via solution casting method. The structural and surface morphology of G/CMC-TKE film were characterized using FTIR spectrometry technique and scanning electron microscopy (SEM), including determining antioxidant activity, water solubility, water vapor permeability, and biodegradability. According to FTIR analysis, the significant interaction between the gelatin and CMC chain is associated with hydrogen bonding. Adding TKE into the blended films significantly increased their roughness, thickness and antioxidant activity while decreasing their water solubility and water vapor transmission. Likewise, the biodegradability of the films containing antioxidants exhibited greater degradation values than the pure G/CMC film, and all of the biofilms was entirely degraded (&gt;80%) in 14 days. The G/CMC-TKE 2.0 demonstrated the best antioxidant (74.47%), biodegradable activity (95.85% in 14 days), and the lowest water solubility (61.80%) and water vapor transmission rate (3.2483 g∙m‒2∙day‒1), which could be a feasible candidate for the food active packaging.

Development of High Surface Area Organosilicate Nanoparticulate Thin Films for Use in Sensing Hydrophobic Compounds in Sediment and Water.

The scope of this study was to apply advances in materials science, specifically the use of organosilicate nanoparticles as a high surface area platform for passive sampling of chemicals or pre-concentration for active sensing in multiple-phase complex environmental media. We have developed a novel nanoporous organosilicate (NPO) film as an extraction phase and proof of concept for application in adsorbing hydrophobic compounds in water and sediment. We characterized the NPO film properties and provided optimization for synthesis and coatings in order to apply the technology in environmental media. NPO films in this study had a very high surface area, up to 1325 m2/g due to the high level of mesoporosity in the film. The potential application of the NPO film as a sorbent phase for sensors or passive samplers was evaluated using a model hydrophobic chemical, polychlorinated biphenyls (PCB), in water and sediment. Sorption of PCB to this porous high surface area nanoparticle platform was highly correlated with the bioavailable fraction of PCB measured using whole sediment chemistry, porewater chemistry determined by solid-phase microextraction fiber methods, and the Lumbriculus variegatus bioaccumulation bioassay. The surface-modified NPO films in this study were found to highly sorb chemicals with a log octanol-water partition coefficient (Kow) greater than four; however, surface modification of these particles would be required for application to other chemicals.

Magnetron-Sputtered Long-Term Superhydrophilic Thin Films for Use in Solid-State Cooling Devices

Pulse-magnetron-sputtered long-term superhydrophilic coatings have been synthesized to functionalize the surfaces of solid-state cooling devices, e.g., electrocaloric heat pumps, where not only a complete wetting of the surface by a fluid is intended, but also fast wetting and dewetting processes are required. The coatings consist of a (Ti,Si)O2 outer layer that provides lasting hydrophilicity thanks to the mesoporous structure, followed by an intermediate WO3 film that enables the reactivation of the wettability through visible light irradiation, and a W underlayer which can work as a top electrode of the electrocaloric components thanks to its suitable electrical and thermal conductivity properties. Process parameter optimization for each layer of the stack as well as the influence of the microstructure and composition on the wetting properties are presented. Finally, water contact angle measurements, surface energy evaluations, and a contact line dynamics assessment of evaporating drops on the coatings demonstrate that their enhanced wetting performance is attributed not only to their intrinsic hydrophilic nature but also to their porous microstructure, which promotes wicking and spreading at the nanometric scale.

Thermomechanical and mechanical properties of biocidal materials based on polyhexamethylene guanidine hydrochloride and polyvinyl alcohol

During the development of polymer science, attention has been attracted to different research areas. The current focus on polymer mixtures is due to their practical significance. Studying the physical and mechanical properties of polymer mixtures has led to a revision of existing basic concepts, the emergence of new research directions and the solution of practical problems. From this point of view, polymer mixtures are similar to copolymerization in achieving specific properties by combining different chemical structures. The use of polymer mixtures allows materials with the desired properties to be obtained at a faster rate than the synthesis of high-molecular compounds. In recent years, numerous studies have been published on the interaction of various polymers, particularly water-soluble and naturally occurring polymers that are safe for humans and the environment. The development of such materials is of great interest due to their high adhesive strength. These materials can be used to obtain polymer films with new valuable properties. This work investigates the potential of improving the thermomechanical and mechanical properties of films for use in construction as polymer biocidal additives by modifying polyhexamethylene guanidine hydrochloride with polyvinyl alcohol. Films based on a polymer-polymer mixture of polyhexamethylene guanidine hydrochloride and polyvinyl alcohol were used as a research object.

A Flexible Nickel-Oxide-Based RRAM Device Prepared Using the Solution Combustion Method

Binary metal oxide materials, such as nickel oxide, are widely used in flexible resistive variable memory devices due to advantages such as their easily controllable material composition, simple structural composition, and good compatibility between manufacturing processes and complementary metal oxide processes. In this work, a solution combustion method was employed to prepare NiOx thin films for use as a resistive switching layer of resistance random-access memory. The formation temperature of the NiOx layer in the RRAM device was kept as low as 175 °C, making the device compatible with flexible substrates. With polyethylene naphthalenediate as the substrate, the NiOx-based RRAM exhibited obvious bipolar resistance-switching properties, superb bending resistance, and good stability. Through theoretical fitting and structural characterization, the conduction mechanisms were attributed to the combination of the space-charge-limited current and Ohmic mechanisms, while the valence change mechanism was determined to be the resistive switching mechanism. This study demonstrates a low-temperature and scalable approach to constructing NiOx-based RRAM devices on flexible substrates.

Effect of silver doping on the band gap tuning of tungsten oxide thin films for optoelectronic applications

In the cutting-edge world, semiconductor metal oxides usually tend to have a high optical band gap (>3.0 eV), significantly acceptable for potential optoelectronic applications. The present study discusses the synthesize of pristine tungsten trioxide (WO3) and Silver (Ag) doped WO3 (Ag: WO3) thin films onto a glass substrate at 450 °C, with varying concentrations of Ag doping (2, 4, 6, 8 and 10 at.%) using a simple Spray Pyrolysis Technique. Field emission scanning electron microscopy (FESEM) analysis showed the presence of particles in the WO3 and Ag: WO3 materials. The X-ray diffraction (XRD) pattern confirmed that the samples' hexagonal structure remained intact. In addition, Rietveld refinement was used for the samples to study the crystal structure meticulously. Because of the surface plasmon resonance effect, the samples' distinguishing characteristics were visible in their optical nature. For pristine WO3, the experimental band gap was determined to be 3.20 eV, and for varying doping concentrations, it was found to be 3.15 eV–2.90 eV, respectively. Furthermore, the fracture has remained imperceptible at elevated concentrations, resulting in a substantial influence on the optical characteristics of 10% Ag: WO3 thin films. The estimated redox potential for 2% Ag: WO3 shows a considerable influence of the band edge potential of the Conduction Band (CB) and Valance Band (VB). The activation energy was determined using temperature-dependent electrical resistivity and exhibited an ohmic nature. The synthesized material exhibited a negative temperature coefficient (NTC) effect at higher concentrations of doping, suggesting its potential applicability as a thermistor. A comprehensive analysis of this present study indicates that Ag can be a viable candidate for doping on WO3 thin films for use in optoelectronic devices.