Nanohybrid Thin Films Research Articles

Effect of 105 MeV gold ion irradiation on dielectric properties of PVC/PVDF@BaZrO3 nanohybrid thin film

The PVC/PVDF@BaZrO3 nanohybrid thin films were prepared by solution grown method. The dielectric constant of the films was higher due to BaZrO3 incorporation in the PVC/PVDF matrix. The PVDF and PVC/PVDF nanohybrid films were irradiated with 105 MeV Au2+ ion beam under vacuum condition at room temperature with two ion fluence. The irradiated thin film of PVC/PVDF@BaZrO3 exhibits relatively low dielectric constant with low loss at different temperature because of thermodynamic stability of β-phase. However, almost complete amorphization was observed in BaZrO3 filler in PVC/PVDF@BaZrO3 nanohybrid samples. After being irradiated with a 105 MeV Au2+ ion beam, the (ϵ′) dielectric constant, FTIR and SEM parameters were used to evaluate changes in dielectric and structural properties for all the samples. In FTIR spectra, new peaks appeared at 1705 cm−1, disappeared or minutely shifted due to high energy of ion beam. It is interesting to note that BaZrO3 phase becomes amorphized through 105 MeV Au2+ ion irradiation that causes an increased dielectric constant along with cross-linking effect of nanohybrid films.

Air-brush spray coated Ti3C2-MXene-graphene nanohybrid thin film based electrochemical biosensor for cancer biomarker detection

Cancer is a significant health hazard worldwide and poses a greater threat to the quality of human life. Quantifying cancer biomarkers with high sensitivity has demonstrated considerable potential for compelling, quick, cost-effective, and minimally invasive early-stage cancer detection. In line with this, efforts have been made towards developing an f-graphene@Ti3C2-MXene nanohybrid thin-film-based electrochemical biosensing platform for efficient carcinoembryonic antigen (CEA) detection. The air-brush spray coating technique has been utilized for depositing the uniform thin films of amine functionalized graphene (f-graphene) and Ti3C2-MXene nanohybrid on ITO-coated glass substrate. The chemical bonding and morphological studies of the deposited nanohybrid thin films are characterized by advanced analytical tools, including XRD, XPS, and FESEM. The EDC-NHS chemistry is employed to immobilize the deposited thin films with monoclonal anti-CEA antibodies, followed by blocking the non-specific binding sites with BSA. The electrochemical response and optimization of biosensing parameters have been conducted using CV and DPV techniques. The optimized BSA/anti-CEA/f-graphene@Ti3C2-MXene immunoelectrode showed the ability to detect CEA biomarker from 0.01 pg mL−1 to 2000 ng mL−1 having a considerably lower detection limit of 0.30 pg mL−1.

Photocatalytic thin films based on Au nanoparticles covered by iron oxyhydroxides by hydrothermal process

The use of ultrathin nanohybrid films in photocatalytic applications to decompose pollutants is a desirable and effective approach for industrial and practical purposes. In this study, ultrathin films composed of Fe2O3 oxyhydroxides with Au nanoparticles (NPs; Au–FeOOH) were prepared by Au evaporation deposition, a hydrothermal process, and thermal annealing. Transmission electron microscopy, elemental mapping, and X-ray photoelectron spectroscopy studies confirmed the attachment of the FeOOH matrix to the Au nanoparticles. Au–FeOOH thin films exhibited outstanding photodecomposition ability toward rhodamine 6G in a 0.5 µM aqueous solution under artificial light illumination (120 min; 1000 W m−2); such performance is the best reported thus far for Fe2O3 thin films. The superior photocatalytic activity of the Au–FeOOH nanohybrid thin films is attributed to their broad absorption encompassing the deep ultraviolet-to-near infrared regions and efficient charge transfer between the Au NPs and FeOOH NPs.

Investigation of upward speed and thickness effects on optical and mechanical properties of hard transparent thin films deposited on polycarbonate substrate

In the present work, nanomechanical behaviors and optical properties of the nanohybrid thin films coated on the polycarbonate (PC) substrates were investigated. Tetraethyl orthosilicate (TEOS), 3-glycidoxypropyl-trimethoxysilane (GPTMS) and aluminum tri sec-butoxide were used as main precursors through very simple and repeatable sol-gel process. Optical, chemical, structural, morphological and mechanical characteristics of the samples were studied by ellipsometry, UV/vis spectroscopy, ATR-FTIR, EDS, XRD, FE-SEM, TEM and nanoindentation-nanoscratch methods. It was found that upward speed had an important effect on the nanomechanical properties while optical properties remained constant. The obtained results indicated that the refractive index of the prepared thin films were significantly lower (1.483) than PC substrate (1.58) led to increase the transmittance that was measured 89 % compared to pristine PC (86 %). Nanohybrid thin films increased PC hardness and elastic modulus to 0.45 and 7.4 GPa respectively at upward speed 5 mm/s. The friction coefficient was decreased to 0.23 and the pencil hardness was 5H at 1887 nm thickness coating at 9 mm/s upward speed.

Structural and Optical Properties of Graphene-ZnO Nanohybrid Thin Films Synthesized by Spray Pyrolysis

Graphene-ZnO nanohybrid thin films were prepared by spray pyrolysis technique at 350 °C. Different graphene nanoplate concentrations of 0.1, 0.2, 0.3, 0.4, and 0.5 wt.% were used to deposit films on quartz substrates. The Structural and optical properties of the nanohybrid films have been investigated. X-ray diffraction XRD results show that the films have a hexagonal wurtzite polycrystalline structure and no secondary phases were observed. The structural parameters of crystallite size, dislocation density, and microstrain have indicated that the addition of graphene has a strong effect on the microstructure of zinc oxide films. Surface morphological analysis of the ZnO-graphene films reveals that the graphene content effectively modifies the morphologies and grain growth of the ZnO microstructure. It was also found from the optical properties that the maximum energy gap for pure ZnO films was 3.4 eV which decreases to 2.7 eV as the concentration of graphene increases to 0.5 wt.%. Results confirmed that graphene can be used as an efficient modifier for band gap engineering and the microstructure of ZnO thin films for enhanced photovoltaic applications.

Sexual pheromone detection using PANI·Ag nanohybrid and PANI/PSS nanocomposite nanosensors.

In this study, polyaniline/poly(styrene sulfonate) (PANI/PSS) nanocomposite and polyaniline·silver (PANI·Ag) nanohybrid thin films were obtained in cantilever nanosensors surface. The developed films were characterized in relation to topography, roughness, thickness, height, and structural properties. The topography study revealed that both films have a globular morphology, thickness and height in nanoscale. The gas sensing performance was investigated for sexual pheromone from the neotropical brown stink bug, Euschistus heros (F.). The sensitivities of both nanosensors based on PANI/PSS nanocomposite and PANI·Ag nanohybrid films were similar. The PANI·Ag nanohybrid nanosensor had a limit of detection of less than 3.1 ppq and limit of quantification of 10.05 ppq. The nanosensor layers were analyzed by UV-vis and FTIR showing the incorporation of Ag nanoparticles in the nanohybrid. We found that pheromone compound was adsorbed in sensing layer resulting in a reduction in the resonance frequency. The detection mechanism help us understand the good results of LOD, LOQ, sensitivity, selectivity and repeatability. The presented device has great potential for detection of the sexual pheromone from E. heros.

Formation of bioactive nano hybrid thin films on anodized titanium via electrophoretic deposition intended for biomedical applications

In this investigation, we report the development of bioactive glass (BG) and reduced graphene oxide (rGO) - bioglass nano hybrid (G-BG) thin films over anodized TiO2 nanotubes via electrophoretic deposition method (EPD). Different parameters such as concentration of particle loading (BG and G-BG), concentration of sodium alginate (Na Al) - anionic charge donor and polyvinylpyrrolidone (PVP) - binder, voltage, deposition time and annealing temperature were analyzed. X-Ray Diffraction (XRD) studies revealed phases of anatase in anodized substrates, whereas in BG thin films along with anatase, combeite phase of bioactive glasses were also found. In the case of G-BG thin films in addition to anatase and combeite phases calcinate phase was also observed SEM results exhibited the anodized TiO2 pore diameter to be around 100 nm, whereas the thickness of the nanotube layer was found to be approximately 6 μm. The SEM analysis on BG and G-BG thin film layers over TiO2 layer was observed to be 2 μm in thickness. Due to the dissociation of sodium ions from BG thin films, cell lysis was observed to higher in hemocompatibility, antibacterial activity and cell proliferation analysis. This phenomenon of BG thin films were advantageous in antibacterial activity but deleterious in hemocompatibility and cell proliferation. However, the calcite phase in G -BG thin films suppressed this activity and showed better hemocompatibility and cell proliferation of MG-63 cell lines. From this study, it is evident that incorporation of rGO in BG thin films enhanced the HCA formation, hemocompatibility and MG-63 cell proliferation.

Reactive, Aqueous-Dispersible Polyfluorene-Wrapped Carbon Nanotubes Modulated with an Acidochromic Switch via Azide–Alkyne Cycloaddition

Decorating hydrophobic carbon nanotube surfaces efficiently in aqueous solution without adversely affecting nanotube optoelectronic properties remains a challenge. In this work, we designed a water-soluble polyfluorene derivative that contains azide groups and polyethylene glycol grafts in the side chains. This polyfluorene derivative was used to coat carbon nanotube surfaces, producing a latently reactive and aqueous-dispersible polymer–nanotube complex. Reaction progress of the aqueous polymer–nanotube dispersion with various polar and nonpolar alkyne derivatives was followed using infrared spectroscopy. Decoration of the polymer–nanotube complex with various small molecules or polymers was found to modulate the surface properties of the resulting nanohybrid thin films. Additionally, we developed a vanillin-derived indolinooxazolidine switch that is functionalized with a terminal alkyne and appended it to the polymer–nanotube complex. This switch possesses two long-lived states that are interchangeable ...

Fast Response and High Sensitivity of Reduced Graphene Oxide/Gold Nano-hybrid for LPG Sensors at Room Temperature

This work presents the sensing properties of reduced graphene oxide/gold (rGO/Au) nano-hybrid thin films under liquefied petroleum gas (LPG) at room temperature. The measurements of the electrical sensitivity of the films exhibit an extremely rapid response (∼ 5 s), fast recovery (∼ 35 s), good reproducibility, high sensitivity and remarkable stability when exposed to a 50 ppm concentration of LPG. The hybrid formation of rGO/Au is confirmed using x-ray diffraction (XRD) pattern, UV–visible absorption spectrometry, Fourier transform infrared (FTIR) spectrometry and scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) methods. The sensing behavior of the rGO/Au films is compared to graphene oxide and reduced graphene oxide nano-thin films, and the results indicate that the electrical conductivity of the film has significantly improved due to the presence of Au nanoparticles.

Reduced graphene oxide/iron oxide nanohybrid flexible electrodes grown by laser-based technique for energy storage applications

Porous reduced graphene oxide (rGO)/iron oxide nanohybrid thin films were grown through a laser-based technique onto flexible polymer, polydimethylsiloxane substrates. A frequency quadrupled pulsed Nd:YAG laser source (λ = 266 nm, τFWHM ~ 4 ns, υ = 10 Hz) was used for irradiation of dispersions containing the starting nano-materials, graphene oxide (GO) platelets and iron oxide nanoparticles (NPs), to be transferred to the substrates surface. The electrochemical response of the composite layers was investigated by cyclic voltammetry in dark and under UV/visible light illumination, as well as by electrochemical impedance spectroscopy. A comparative study was performed as a function of the nature of the GO base materials, monolayer or multilayer GO platelets, and relative concentration of GO/iron oxide NPs in the dispersions submitted to laser irradiation. The capacitance values of the nanohybrid materials which contain monolayer GO were found to be one order of magnitude higher as compared to their counterparts consisting of multilayer GO and iron oxide NPs. UV–visible light irradiation contributed to the significant enhancement of the electrochemical properties of the electrodes. These results indicate that the nanohybrid thin films are promising candidates as flexible electrodes in micro-supercapacitors and photoelectrochemical devices for simultaneous energy storage and solar energy conversion.

Fabrication and self-cleaning properties of reduced graphene oxide/TiO2:Nd nanohybrid thin films

ABSTRACTSelf-cleaning is an important technique for environmental purification. In this work, a series of reduced graphene oxide (rGO)-TiO2:Nd nanohybrid films were deposited and characterized by various analysis techniques. The rGO incorporation and Nd doping obviously enhanced the self-cleaning properties including photocatalytic activity, photo-induced superhydrophilicity, and conductivity of the TiO2 film. The effect of Nd content and rGO proportion on the self-cleaning properties was also studied. The efficient synergistic effect of rGO and Nd on the self-cleaning properties was observed and mainly ascribed to interface-induced effect. The measurement of band energy level and optical conductivity confirmed the interface-induced effect.

Improving photostability and efficiency of polymeric luminescent solar concentrators by PMMA/MgO nanohybrid coatings

ABSTRACTMgO nanocrystals were synthesized and doped with different concentrations in poly(methylmethacrylate) (PMMA) to prepare hybrid organic-inorganic coatings based on polymer nanohybrid thin films. The nanoparticles were found to be spherical with 62 nm diameter as determined by X-ray diffraction (XRD) and atomic force microscope (AFM). The coatings were characterized by spectroscopic tools such as optical absorption, transmission and fluorescence spectroscopy. The prepared nanohybrid films were spin-coated on cost-effective luminescent PMMA substrates doped with highly efficient luminescent dyes luminescent solar concentrators (LSCs). The outdoor photostability tests demonstrated enhanced protection against UVA radiation for coated LSCs compared to bare LSC substrates. The current–voltage characteristics of commercially produced LSC prototypes showed that the poor UV response of monocrystalline silicon solar cell can be improved by for LSCs coated by PMMA/MgO nanohybrid films which act as luminescent down shifting layer (LDSL).

Facile synthesis of Au-ZnO plasmonic nanohybrids for highly efficient photocatalytic degradation of methylene blue

Au-ZnO plasmonic nanohybrids were synthesized by a facile two step process. In the first step, nanostructured ZnO thin films were prepared by carbothermal evaporation followed by thermal annealing in oxygen atmosphere. Deposition of ultrathin Au films onto the nanostructured ZnO thin films by sputtering combined with thermal annealing resulted in the formation of Au-ZnO plasmonic nanohybrid thin films. The structural, optical, plasmonic and photocatalytic properties of the Au-ZnO nanohybrid thin films were studied. XRD studies on the Au-ZnO hybrid thin films revealed the presence of Au and ZnO nanostructures. UV–visible absorption studies showed two peaks corresponding to the excitonic absorption of ZnO nanostructures in the UV region and the surface plasmon resonance (SPR) absorption of Au nanoparticles in the visible region. The Au-ZnO nanohybrid thin films annealed at 400 °C showed enhanced photocatalytic activity as compared to nanostructrured ZnO thin films towards sun light driven photocatalytic degradation of methylene blue (MB) dye in water. The observed enhanced photocatalytic activity of Au-ZnO plasmonic nanohybrids is attributed to the efficient suppression of the recombination of photogenerated charge carriers in ZnO due to the strong electron scavenging action of Au nanoparticles combined with the improved sun light utilization capability of Au-ZnO nanohybrids coming from the plasmonic response of Au nanoparticles decorating ZnO nanostructures.

Iridium Oxide-reduced Graphene Oxide Nanohybrid Thin Film Modified Screen-printed Electrodes as Disposable Electrochemical Paper Microfluidic pH Sensors.

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use integrated paper microfluidic electrochemical pH sensor for resource-limited settings. Taking advantages from both pH meters and strips, the pH sensing platform is composed of hydrophobic barrier-patterned paper micropad (µPAD) using polydimethylsiloxane (PDMS), screen-printed electrode (SPE) modified with IrO2-graphene films and molded acrylonitrile butadiene styrene (ABS) plastic holder. Repetitive cathodic potential cycling was employed for graphene oxide (GO) reduction which can completely remove electrochemically unstable oxygenated groups and generate a 2D defect-free homogeneous graphene thin film with excellent stability and electronic properties. A uniform and smooth IrO2 film in nanoscale grain size is anodically electrodeposited onto the graphene film, without any observable cracks. The resulting IrO2-RGO electrode showed slightly super-Nernstian responses from pH 2-12 in Britton-Robinson (B-R) buffers with good linearity, small hysteresis, low response time and reproducibility in different buffers, as well as low sensitivities to different interfering ionic species and dissolved oxygen. A simple portable digital pH meter is fabricated, whose signal is measured with a multimeter, using high input-impedance operational amplifier and consumer batteries. The pH values measured with the portable electrochemical paper-microfluidic pH sensors were consistent with those measured using a commercial laboratory pH meter with a glass electrode.

Iridium Oxide-reduced Graphene Oxide Nanohybrid Thin Film Modified Screen-printed Electrodes as Disposable Electrochemical Paper Microfluidic pH Sensors

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use integrated paper microfluidic electrochemical pH sensor for resource-limited settings. Taking advantages from both pH meters and strips, the pH sensing platform is composed of hydrophobic barrier-patterned paper micropad (µPAD) using polydimethylsiloxane (PDMS), screen-printed electrode (SPE) modified with IrO2-graphene films and molded acrylonitrile butadiene styrene (ABS) plastic holder. Repetitive cathodic potential cycling was employed for graphene oxide (GO) reduction which can completely remove electrochemically unstable oxygenated groups and generate a 2D defect-free homogeneous graphene thin film with excellent stability and electronic properties. A uniform and smooth IrO2 film in nanoscale grain size is anodically electrodeposited onto the graphene film, without any observable cracks. The resulting IrO2-RGO electrode showed slightly super-Nernstian responses from pH 2-12 in Britton-Robinson (B-R) buffers with good linearity, small hysteresis, low response time and reproducibility in different buffers, as well as low sensitivities to different interfering ionic species and dissolved oxygen. A simple portable digital pH meter is fabricated, whose signal is measured with a multimeter, using high input-impedance operational amplifier and consumer batteries. The pH values measured with the portable electrochemical paper-microfluidic pH sensors were consistent with those measured using a commercial laboratory pH meter with a glass electrode.

Reflectometric measurement of n-hexane adsorption on ZnO2 nanohybrid film modified by hydrophobic gold nanoparticles

Zinc-peroxide/poly(styrenesulfonate) nanohybrid thin films (containing 20 bilayers: [ZnO2/PSS]20, d∼500nm) were prepared using layer-by-layer (LbL) method. The thin film surface was functionalized by different surface modifying agents (silanes, alkylthiols and hydrophobized nanoparticles). Based on the experimental results of quartz crystal microbalance (QCM) and contact angle measurements (as prequalifications) the octanethiol covered gold nanoparticles (OT-AuNPs) were selected for further vapour adsorption studies. Reflectometric interference spectroscopy (RIfS) was used to measure n-hexane vapour adsorption on the original and modified nanohybrid films in a gas flow platform. The thin film provides only the principle of the measurement (by interference phenomenon), the selectivity and hydrophobicity is controlled and enhanced by surface functionalization (by dispersion interaction between the alkyl chains). The interference pattern shift (Δλ) caused by the increase of the optical thickness of the thin film due to vapour adsorption was investigated. It was found that due to the surface functionalization by hydrophobic nanoparticles the effect of water vapour adsorption decreased significantly, while for n-hexane opposite tendency was observed (the effective refractive index and thus the interference pattern shift increased drastically). The correlation between QCM technique and optical method (RIfS) was specified: linear specific adsorbed amount vs. wavelength shift calibration curves were determined in the pr=0–0.4 relative vapour pressure range. The thin film is suitable for sensorial application (e.g. volatile organic compound/VOC sensor).

Organometallic precursor route for the fabrication of PtSn bimetallic nanotubes and Pt3Sn/reduced-graphene oxide nanohybrid thin films at oil–water interface and study of their electrocatalytic activity in methanol oxidation

This report discusses synthesis of PtSn nanotubes and Pt3Sn reduced-graphene oxide (RGO) nanohybrid thin films via a simple reduction of organometallic precursors including [PtCl2(cod)], (cod = cis, cis-1,5-cyclooctadiene), in the presence of [Sn(CH3)4] at toluene–water interface. The structure and morphology of the thin films were characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive analysis of X-ray (EDAX) techniques. TEM measurements revealed that the PtSn bimetallic thin films contain nanotubes with diameters in the 8–10 nm range and 200–800 nm in length. However, TEM image of Pt3Sn/RGO bimetallic nanohybrid thin films showed a good distribution of bimetallic nanoparticles (NPs) on the RGO support with average diameter of 8 nm. The electrocatalytical activities of tin alloys thin films were evaluated using methanol as model molecule. The PtSn nanotubes and Pt3Sn/RGO nanohybrid thin films show a higher catalytic activity in methanol oxidation reaction than that for the Pt NPs films with the lower Pt loading.

Architectured Morphologies of Chemically Prepared NiO/MWCNTs Nanohybrid Thin Films for High Performance Supercapacitors

The preparation of nanostructured metal oxide decorated on multiwalled carbon nanotubes (MWCNTs) nanohybrid films through simple, scalable, additive-free, binderless, and cost-effective route has fascinated significant attention not only in fundamental research areas but also its commercial applications, in order to reduce the growing environmental pollution and the cost of electrode fabrication. Here, we report the fabrication of highly flexible electrode with NiO/MWCNTs nanohybrid thin films directly on stainless steel substrate using successive ionic layer adsorption and reaction (SILAR) method. The impact of ratio of adsorption and reaction cycles on structural, surface areas and electrochemical properties of NiO/MWCNTs nanohybrids was investigated. X-ray diffraction measurements confirm the hybridization and face centered cubic (FCC) crystal structure of NiO in NiO/MWCNTs nanohybrids. In addition, these nanohybrids exhibit excellent surface properties such as uniform surface morphology, good surface area, pore volume, and uniform pore size distribution. The electrochemical tests demonstrate the highest specific capacitance of 1727 F g(-1) at 5 mA cm(-2) of current density with 91% capacitance retention after 2000 cycles. In addition, the Ragone plot confirms the better power and energy densities for all NiO/MWCNTs nanohybrids. The attractive electrochemical capacitive activity revealed by NiO/MWCNTs nanohybrid electrode proposes that it is an auspicious respondent for future energy storage application.

シクロデキストリンを配合した酸化チタンナノハイブリッド薄膜の分子選択性

シクロデキストリンを配合した酸化チタンナノハイブリッド薄膜の分子選択性

Improvement in thermo mechanical and optical properties of in situ synthesized PMMA/TiO2 nanocomposite

In this paper, transparent thin films of nano titania filled Poly(methyl methacrylate) (PMMA) composites were synthesized by solvent casting method using tetra hydro furan as a solvent, with in situ nonaqueous ‘sol-gel’ transformation involving the mixing of titanium isopropoxide (as sol-gel precursor) and methanol. The present research work is focused at studying the effect of titania loading on optical and mechanical behavior of transparent nano hybrid thin films. The effect of nano Titanium dioxide (TiO2) loading on PMMA morphology was studied by using a scanning electron microscope (SEM). Bowl shaped structures were obtained in pure PMMA thin film, which were deformed on incorporation of TiO2 nanoparticles. This nanocomposite exhibits enhanced optical and mechanical properties. The peak of UV absorption is blue shifted to 261 and 266 nm with the incorporation of TiO2. At this wavelength, the absorption is increased up to approximately 397%. The nanocomposites exhibit increased tensile strength up to 40% and modulus up to 16%. Tg of PMMA increased from 84.8 to 86.7 °C on adding 1.25% TiO2 nanoparticles.