Tailoring of the electronic properties of ZnO-polyacrylonitrile nanofibers: Experiment and theory

2017

Abstract We report the study of ZnO-polyacrylonitrile (ZnO-PAN) nanofibers fabricated by the combination of electrospinning and atomic layer deposition. The latter technique enables us to control the size of the surface of ZnO 1D nanostructures and hence its effectiveness for energy and biosensor applications. We observe the tendency of ZnO to form nanograins with increase of the layer thickness, and investigate the influence of the grain size on the electronic properties of the nanofibers. It is demonstrated that the ZnO work function (Φ) is strongly affected by surface band bending in the ZnO layer. The observed change of Φ in ZnO layers results from the curvature of the grain surface as …

Optical properties of ultrathin Al2O3/ZnO nanolaminates

2015

Abstract Because of their high resistance against ultraviolet and high energy particles, ultrathin amorphous nanolaminates can be very attractive for aerospace application. Here we report on the optical and structural properties of ultrathin Al2O3/ZnO nanolaminates deposited by Atomic Layer Deposition. Structural properties of nanolaminates were studied by GIXRD and AFM. Optical characterization was performed by transmittance, spectroscopic ellipsometry and photoluminescence (PL) spectroscopy. Regression analysis of ellipsometric spectra has shown that absorption peak decreases and blue shifted with the decrease of bilayer thickness in the stack. On the basis of the analysis of structural a…

Tuning Optical Properties of Al 2 O 3 /ZnO Nanolaminates Synthesized by Atomic Layer Deposition

2014

Nanolaminates are of great interest for their unique properties such as high dielectric constants and advanced mechanical, electrical, and optical properties. Here we report on the tuning of optical and structural properties of Al2O3/ZnO nanolaminates designed by atomic layer deposition (ALD). Structural properties of nanolaminates were studied by SEM, GIXRD, and AFM. Optical characterization was performed by transmittance and photoluminescence (PL) spectroscopy. Complex study of monolayer properties was performed by ellipsometry. Optical constants for Al2O3 and ZnO monolayer were calculated. The band gap of ZnO single layers and the excitonic PL peak position were shifted to the UV region …

Synthesis, Optical, and Morphological Studies of ZnO Powders and Thin Films Fabricated by Wet Chemical Methods

2020

Zinc oxide nanoparticles were prepared from Zn5(CO3)2(OH)6 precursor, capped with poly(vinylpyrrolidone) (PVP), and annealed at 600 &deg

Grain size dependent bandgap shift of SnO2 nanofibers

2013

SnO2 nanofibers with various grain sizes ranging from 18.5 to 31.6 nm in diameter were fabricated by electrospinning a polymeric solution and subsequent controlled calcination of the as-spun fibers. The calcined fibers were polycrystalline and composed of densely packed nano-sized SnO2 grains. The effect of the nanograin size on the optical bandgap of SnO2 nanofibers was examined by ultraviolet-visible spectroscopy. The bandgap showed a strong dependence on the nanograin size. The bandgap decreased with increasing nanograin size. Some calculations were performed to understand the relationship between the experimentally obtained bandgaps of the SnO2 nanofibers and the theoretical ones. Quant…

Enhancement of Electronic and Optical Properties of ZnO/Al2O3 Nanolaminate Coated Electrospun Nanofibers

2016

International audience; Nanolaminates are new class of promising nanomaterials with outstanding properties. Here we explored on the tuning of structural properties and the enhancement of electronic and optical properties of 1D PAN ZnO/Al2O3 nanolaminates designed by atomic layer deposition (ALD) and electrospinning. The influence of ZnO/Al2O3 bilayer thicknesses on the fundamental properties of 1D PAN ZnO/Al2O3 nanolaminates has been investigated. Due to the quantum confinement effect, the shift of XPS peaks to higher energies has been observed. Work function of Al2O3 was mostly independent of the bilayers number, whereas the ZnO work function decreased with an increase of the bilayer numbe…

Novel Immune TiO2 Photoluminescence Biosensors for Leucosis Detection

2012

Abstract Novel immune photoluminescent biosensor, based on TiO2 nanoparticles, for retroviral leucosis detection has been developed. The photoluminescence spectra were excited by solid state laser with wavelength 355 nm and measured in the range of 370-800 nm. Original photoluminescence spectrum of TiO2 nanoparticles showed wide maximum at 515 nm. The biosensitive layer was formed by immobilization of retroviral leucosis antigens on the surface of TiO2 nanoparticles. Immobilization of antigens on TiO2 surface led to UV-shift of photoluminescence spectrum and increase of PL intensity. The response to different concentrations of retroviral leucosis antibodies has been measured. The decrease o…

Enhancement of calcium copper titanium oxide photoelectrochemical performance using boron nitride nanosheets

2020

International audience; Photoelectrochemical water splitting under visible light has attracted attention for renewable hydrogen production. Despite prevalent investigations, many challenges still hindered an efficient energy conversion, such as enhancing the reaction efficiency in visible light. Thus controlling the photoelectrode materials is an essential step in designing new materials for water splitting. CaCu3Ti4O12 (CCTO) has received great attention as photocatalyst under solar light due to its combined band gap as result of the presence in its structure of TiO2 active in UV light and CuO active under visible light. In this work, a cubic CCTO with different amount of exfoliated hexago…

Photoluminescence immunosensor based on bovine leukemia virus proteins immobilized on the ZnO nanorods

2019

Bovine leukaemia virus (BLV) proteins gp51, which are serving as antigens for specific antibodies against BLV proteins (anti-gp51), were applied as biological recognition part in the design of immunosensor devoted for the determination of anti-gp51. The efficiency of the immobilization of BLV proteins gp51 on ZnO nanorod (ZnO- NR) modified glass (ZnO-NR/glass) surface was evaluated. The formation of antigen-antibody complex on the ZnO/glass modified by the BLV proteins gp51 (gp51/ZnO-NR/glass) was investigated by the determination of changes in ZnO photoluminescence. The applicability of gp51/ZnO-NR/glass in the design of photoluminescence based immunosensor was evaluated. Bovine serum albu…

Development of optical WGM resonators for biosensors

2017

Whispering Gallery Mode (WGM) resonators are very sensitive to nanoparticles attaching to the surface. We simulate this process using COMSOL Wave Optics module. Our spherical WGM resonators are produced by melting a tip of an optical fiber and we measure optical Q factors in the 105 range. Molecular oxygen lines of the air in the 760 nm region are used as reference markers when looking for the shifts of the WGM resonance lines. We demonstrate WGM microresonator surface coating with a layer of ZnO nanorods as well as with polystyrene microspheres. Coatings produce increased contact surface. Additional layer of antigens/antibodies will be coated to make high-specificity biosensors.

Affinity Sensors for the Diagnosis of COVID-19

2021

The coronavirus disease 2019 (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was proclaimed a global pandemic in March 2020. Reducing the dissemination rate, in particular by tracking the infected people and their contacts, is the main instrument against infection spreading. Therefore, the creation and implementation of fast, reliable and responsive methods suitable for the diagnosis of COVID-19 are required. These needs can be fulfilled using affinity sensors, which differ in applied detection methods and markers that are generating analytical signals. Recently, nucleic acid hybridization, antigen-antibody interaction, and change of reactive oxyge…

Tailoring the Structural, Optical, and Photoluminescence Properties of Porous Silicon/TiO2 Nanostructures

2015

The structural, optical, and photoluminescence properties of porous silicon (PSi)/titanium dioxide (TiO2) nanostructures were investigated. PSi structures consisting of macro- and mesoporous layers were fabricated by metal-assisted chemical etching, and then TiO2 was introduced inside the PSi matrix using the atomic layer deposition technique. We performed scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction, energy dispersive X-ray spectroscopy, Raman spectroscopy, ellipsometry, and photoluminescence (PL) spectroscopy to characterize the prepared and annealed PSi/TiO2 nanostructures. TEM and Raman analyses revealed that TiO2 had a crystalline anatase stru…

Optical and structural properties of Al 2 O 3 doped ZnO nanotubes prepared by ALD and their photocatalytic application

2018

Abstract Al2O3 doped ZnO nanotubes with controlled ratio of Al2O3 were successfully designed by combining the two techniques of atomic layer deposition (ALD) and electrospinnig. In order to study the effect of Al2O3 doping on optical and structural properties of Al2O3 doped ZnO nanotubes, the prepared samples were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared (FTIR), reflectance emission and room temperature photoluminescence (PL). The photocatalytic activity and stability of these materials under UV light was studied by the photodegradation of methyl orange (MO). The results indicate that Al2O…

Optical properties of ZnO deposited by atomic layer deposition (ALD) on Si nanowires

2018

International audience; In this work, we report proof-of-concept results on the synthesis of Si core/ ZnO shell nanowires (SiNWs/ZnO) by combining nanosphere lithography (NSL), metal assisted chemical etching (MACE) and atomic layer deposition (ALD). The structural properties of the SiNWs/ZnO nanostructures prepared were investigated by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopies. The X-ray diffraction analysis revealed that all samples have a hexagonal wurtzite structure. The grain sizes are found to be in the range of 7-14 nm. The optical properties of the samples were investigated using reflectance and photoluminescence spectroscopy. The study o…

Whispering gallery mode resonators covered by a ZnO nanolayer

2020

Abstract The exceptional ability of whispering gallery mode resonators (WGMRs) to confine light within makes them interesting for sensing applications. The small size and high values of quality (Q) factors of the WGMR can be combined with a broad range of supporting optical elements. The surface of the resonator can be coated to enhance the desired attributes. In this paper, the impact of the ZnO layer thickness on the Q-factor of the WGMR has been studied. WGMRs were fabricated on a tip of a standard telecom fiber melted with an oxyhydrogen flame. The surface of the WGMR was coated with ZnO nanolayers of different thickness (5–100 nm) by atomic layer deposition (ALD). The Q-factor of as-pr…

Photoluminescence ZnO nanorod biosensors for medical and food safety applications

2017

Photoluminescence (PL) ZnO nanorods (NR) are prospect materials for biosensor applications. They can be deposited on solid state substrates and/or dispersed in liquid media. ZnO NRs demonstrate strong UV emission (3.28–3.3 eV), which depends on surface charge, formed by adsorbed molecules. In the present work we report on ZnO NRs, deposited on glass slides, used as biosensor templates for detection food pathogens. Change of ZnO PL after interaction with biomolecules was recorded. Dependence of PL intensity vs concentration of biomolecules was obtained. In the second part, ZnO nanorods were used as PL biomarkers. A suspension of ZnO NRs, conjugated with SSEA-4 antibodies (aSSEA-4) in PBS buf…

Whispering gallery mode resonators coated with Au nanoparticles

2019

Whispering gallery mode resonators (WGMRs) are very interesting for sensing because a resonance shift could be caused by any perturbation of the surrounding environment. Additionally such a resonator is coated with nanomaterials to tailor and enhance the sensitivity for a specific purpose. WGMR were fabricated using standard telecommunication fiber and a hydrogen flame, characterized using the scan method to obtain the quality factors and then coated with gold nanoparticles (Au NPs) using dip coating method and characterized again for comparison. Au NPs were chosen because their positive impact on microresonator sensitivity has been mentioned before and the surface can later be functionaliz…

Optical biosensors based on ZnO nanostructures: advantages and perspectives. A review

2016

This review article highlights the application of beneficial physico-chemical properties of ZnO nanostructures for the detection of wide range of biological compounds. As the medical diagnostics require accurate, fast and inexpensive biosensors, the advantages inherent optical methods of detection are considered. The crucial points of the immobilization process, responsible for biosensor performance (biomolecule adsorption, surface properties, surface defects role, surface functionalization etc.) along with the interaction mechanism between biomolecules and ZnO are disclosed. The latest achievements in surface plasmon resonance (SPR), surface enhanced Raman spectroscopy (SERS) and photolumi…

Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition.

2013

A study of transmittance and photoluminescence spectra on the growth of oxygen-rich ultra-thin ZnO films prepared by atomic layer deposition is reported. The structural transition from an amorphous to a polycrystalline state is observed upon increasing the thickness. The unusual behavior of the energy gap with thickness reflected by optical properties is attributed to the improvement of the crystalline structure resulting from a decreasing concentration of point defects at the growth of grains. The spectra of UV and visible photoluminescence emissions correspond to transitions near the band-edge and defect-related transitions. Additional emissions were observed from band-tail states near th…

Application of Thin ZnO ALD Layers in Fiber-Optic Fabry-Pérot Sensing Interferometers

2016

International audience; In this paper we investigated the response of a fiber-optic Fabry-Pérot sensing interferometer with thin ZnO layers deposited on the end faces of the optical fibers forming the cavity. Standard telecommunication single-mode optical fiber (SMF-28) segments were used with the thin ZnO layers deposited by Atomic Layer Deposition (ALD). Measurements were performed with the interferometer illuminated by two broadband sources operating at 1300 nm and 1550 nm. Reflected interference signal was acquired by an optical spectrum analyzer while the length of the air cavity was varied. Thickness of the ZnO layers used in the experiments was 50 nm, 100 nm, and 200 nm. Uncoated SMF…

Application of Room Temperature Photoluminescence From ZnO Nanorods for Salmonella Detection

2014

ZnO nanorods grown by gaseous-disperse synthesis are confirmed by XRD analysis to have the wurtzite crystal structure. The obtained crystallites, as found from SEM studies, are 57 +/- 9 nm in diameter and 470 +/- 30 nm long on the average. Two emission bands of photoluminescence from ZnO nanorods observed at room temperature are centered at 376 and 520 nm. A biosensitive layer is prepared by immobilization of anti-Salmonella antibodies from liquid solutions on the ZnO surface. Immobilization of the biosensitive layer onto ZnO nanorods is found to increase the intensity of PL. After further reaction with Salmonella antigens (Ags), the PL intensity is found to decrease proportional to Ag conc…

Gold coated porous silicon nanocomposite as a substrate for photoluminescence-based immunosensor suitable for the determination of Aflatoxin B1.

2017

Abstract A rapid and low cost photoluminescence (PL) immunosensor for the determination of low concentrations of Aflatoxin B1 (AFB1) has been developed. This immunosensor was based on porous silicon (PSi) covered by thin gold layer (Au) and modified by antibodies against AFB1 (anti-AFB1). PSi layer was formed on silicon substrate, then the surface of PSi was covered by 30 nm layer of gold (PSi/Au) using electrochemical and chemical deposition methods and in such ways PSi/Au (El.) and PSi/Au (Chem.) structures were formed, respectively. In order to find PSi/Au the most efficiently suitable for PL-based sensor design, structure several different PSi/Au (El.) and PSi/Au (Chem.) structures were…

Influence of PDA Coating on the Structural, Optical and Surface Properties of ZnO Nanostructures

2020

Polydopamine (PDA) is a new biocompatible material, which has prospects in biomedical and sensor applications. Due to functional groups, it can host wide range of biomolecules. ZnO nanostructures are well known templates for optical sensors and biosensors. The combination of ZnO and PDA results in a change of optical properties of ZnO&ndash

The influence of localized plasmons on the optical properties of Au/ZnO nanostructures

2015

Optical and structural experiments have been carried out on Si/ZnO thin films modified with ultra-thin gold layers of different thicknesses. ZnO was produced via Atomic Layer Deposition (ALD) and Au via Physical Vapor Deposition (sputtering). The structural properties of nanostructures were studied by XRD and AFM. Optical characterization was performed by absorbance, photoluminescence (PL) and spectroscopic ellipsometry (SE). A transition from cluster-to-thin films with the increase of Au thickness has been revealed from an analysis of optical and structural parameters. The analysis of optical features of the system has shown that slight changes of the localized plasmon absorption peaks in …

Highly textured boron/nitrogen co-doped TiO2 with honeycomb structure showing enhanced visible-light photoelectrocatalytic activity

2020

International audience; In this work, we report a novel photocatalyst based on boron and nitrogen co-doped TiO2 rutile (1 1 0) honeycomb structures. The photocatalyst has been prepared by simultaneously oxidizing and doping a Ti-foil substrate at 750 degrees C. The unit cell volume and the crystallite size of grown TiO2 films were measured by Rietveld refinement analysis. The co-doping by boron and nitrogen was achieved simultaneously with the oxidation of the titanium, resulting in a rutile (1 1 0) textured TiO2 film. X-ray photoelectron spectroscopy analysis revealed the presence of Ti-O-N and Ti-O-B-N bonds, and the presence of crystal defects in the lattice was detected and displayed by…

Improved Crystalline Structure and Enhanced Photoluminescence of ZnO Nanolayers in Bi2Se3/ZnO Heterostructures

2019

The Bi2Se3/ZnO heterostructure is a new combination of high- and low-band-gap nanomaterials that can be implemented for optoelectronic devices. The influence of the Bi2Se3 substrate on crystallizat...

ALD thin ZnO layer as an active medium in a fiber-optic Fabry–Perot interferometer

2015

Abstract A novel optical fiber sensor of temperature using a thin ZnO layer fabricated by atomic layer deposition (ALD) is demonstrated for the first time. The thin ZnO layer was grown on the face of a standard optical telecommunication fiber SMF-28 and operates as a Fabry–Perot interferometer sensitive to temperature. The interferometer characterization was made in the temperature range extending from 50 to 300 °C with resolution equal to 1 °C. The output signal was analyzed by measurement of the shift of the maxima in spectral pattern. The sensitivity of temperature measurement is about 0.05 nm/°C. Furthermore, very good linearity of the sensor was achieved with correlation coefficient R2…

Whispering gallery mode resonator sensors referenced to saturated absorption lines in rubidium atoms and a fs frequency comb

2019

Optical Whispering Gallery Mode Resonators (WGMR) can be produced by many methods, for example, by flame melting of silica fibers [1], by polishing of crystals [2], by optical lithography, by solidifying transparent materials, or using commercially available microspheres. They confine light by the total internal reflection and do not need mirror coatings. A part of radiation is traveling outside the WGMR as an evanescent wave and it is used for sensing applications. WGMRs are becoming increasingly popular as biosensors [3] when their surface is covered with antibodies to provide selectivity. Advantage is that light circulates in the resonator and interacts many times with a few molecules at…

Hybrid electrochemical/electrochromic Cu(II) ion sensor prototype based on PANI/ITO-electrode

2017

Abstract Conducting polymer polyaniline (PANI) based electrochromic films were electrochemically synthesized on indium tin oxide (ITO) covered glass electrodes and their electrochromic performances were investigated by spectroscopic methods before and after the incubation in Cu(II) ion containing aqueous solution. Chemical structure of synthesized PANI layer was evaluated by FTIR. The electrochromic performance of PANI film was determined by measuring of spectroscopic signals before and after the incubation of PANI film coated electrode in Cu(II) ion containing solution. During the change of potential, which was applied to PANI-modified electrode, the colour of PANI thin film turned from gr…

Application of polydopamine functionalized zinc oxide for glucose biosensor design

2021

Zinc oxide (ZnO) nanostructures are widely used in optical sensors and biosensors. Functionalization of these nanostructures with polymers enables optical properties of ZnO to be tailored. Polydopamine (PDA) is a highly biocompatible polymer, which can be used as a versatile coating suitable for application in sensor and biosensor design. In this research, we have grown ZnO-based nanorods on the surface of ITO-modified glass-plated optically transparent electrodes (glass/ITO). Then the deposition of the PDA polymer layer on the surface of ZnO nanorods was performed from an aqueous PDA solution in such a way glass/ITO/ZnO-PDA structure was formed. The ZnO-PDA composite was characterized by S…

Tuning of ZnO 1D nanostructures by atomic layer deposition and electrospinning for optical gas sensor applications

2015

We explored for the first time the ability of a three-dimensional polyacrylonitrile/ZnO material—prepared by a combination of electrospinning and atomic layer deposition (ALD) as a new material with a large surface area—to enhance the performance of optical sensors for volatile organic compound (VOC) detection. The photoluminescence (PL) peak intensity of these one-dimensional nanostructures has been enhanced by a factor of 2000 compared to a flat Si substrate. In addition, a phase transition of the ZnO ALD coating from amorphous to crystalline has been observed due to the properties of a polyacrylonitrile nanofiber template: surface strain, roughness, and an increased number of nucleation …

The membrane toxicology of rods and spheric zinc oxide nanoparticles

2018

Photoelectrocatalysis of paracetamol on Pd–ZnO/ N-doped carbon nanofibers electrode

2021

Abstract The presence of pharmaceuticals in water bodies has become a major concern in recent years. An efficient and innovative way of eliminating these pollutants is through photoelectrocatalytic (PEC) degradation owing to its environmental sustainability and its ability to remove recalcitrant pollutants. In this study, palladium loaded zinc oxide/carbon nanofibers (CZnO–Pd) were employed as a novel photoanode for PEC degradation of paracetamol. The CZnO–Pd composite was prepared through electrospinning and atomic layer deposition (ALD). The obtained materials were characterized. Photoelectrochemical studies were carried out with linear sweep voltammetry and chronoamperometry. The removal…

Biosensors for the determination of SARS-CoV-2 virus and diagnosis of COVID-19 infection

2022

Monitoring and tracking infection is required in order to reduce the spread of the coronavirus disease 2019 (COVID-19), induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To achieve this goal, the development and deployment of quick, accurate, and sensitive diagnostic methods are necessary. The determination of the SARS-CoV-2 virus is performed by biosensing devices, which vary according to detection methods and the biomarkers which are inducing/providing an analytical signal. RNA hybridisation, antigen-antibody affinity interaction, and a variety of other biological reactions are commonly used to generate analytical signals that can be precisely detected using electro…

Segregation of copper oxide on calcium copper titanate surface induced by Graphene Oxide for Water splitting applications

2020

Abstract Photoelectrochemical cells (PEC) are promising devices for hydrogen production via sunlight energy. One of the important challenges in this area is to design photoactive electrodes able to absorb visible light. A good photoelectrochemical behavior depends on the presence of surface active sites to photogenerate current at the lower possible potential for water splitting. Recent investigations in this field are focusing on perovskite materials such as CaCu3Ti4O12 (CCTO) as visible light active electrode due its outstanding structure in which CCTO encloses in its structure a visible light absorbance component (CuO). The presence CuO on the material surface is mainly responsible for t…

Synthesis and photoluminescence properties of hybrid 1D core–shell structured nanocomposites based on ZnO/polydopamine

2020

In the present work, we report on the modelling of processes at the zinc oxide and polydopamine (ZnO/ PDA) interface. The PDA layer was deposited onto ZnO nanorods (NRs) via chemical bath deposition. The defect concentrations in ZnO before and after PDA deposition were calculated and analysed. The ZnONRs/PDA core–shell nanostructures were studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman and Fourier-transform infrared (FTIR) spectroscopy, photoluminescence (PL) measurements, and diffuse reflectance spectroscopy. The TEM and electron energy loss spectroscopy (EELS) measurements confirmed the conformal coating of PDA, while the PL emission from ZnO and ZnONRs/P…

Porous silicon based photoluminescence immunosensor for rapid and highly-sensitive detection of Ochratoxin A.

2017

A rapid and low cost photoluminescence (PL) immunosensor for the determination of low concentrations of Ochratoxin A (OTA) has been developed. This immunosensor was based on porous silicon (PSi) and modified by antibodies against OTA (anti-OTA). PSi layer was fabricated by metal-assisted chemical etching (MACE) procedure. Main structural parameters (pore size, layer thickness, morphology and nanograins size) and composition of PSi were investigated by means of X-Ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. PL-spectroscopy of PSi was performed at room temperature and showed a wide emission band centered at 680 ± 20nm. Protein A was covalently immobilized …

Porous silicon photoluminescence biosensor for rapid and sensitive detection of toxins

2017

A rapid and low cost photoluminescence (PL) immunosensor for the determination of low concentrations of Ochratoxin A(OTA) and Aflatoxine B1 (AfB1) has been developed. This biosensor was based on porous silicon (PSi) fabricated by metal-assisted chemical etching (MACE) and modified by antibodies against OTA/AfB1 (anti-OTA/anti-AfB1). Biofunctionalization method of the PSi surface by anti-OTA/ anti-AfB1 was developed. The changes of the PL intensity after interaction of the immobilized anti-OTA/anti-AfB1with OTA/AfB1 antigens were used as biosensor signal, allowing sensitive and selective detection of OTA/AfB1 antigens in BSA solution. The sensitivity of the reported optical biosensor towards…

ZnO/polyaniline composite based photoluminescence sensor for the determination of acetic acid vapor

2020

In this study, we report a novel ZnO/polyaniline (PANI) nanocomposite optical gas sensor for the determination of acetic acid at room temperatures. ZnO nanorods, synthesized in powder form were coated by PANI (ZnO/ PANI) by chemical polymerization method. The obtained nanocomposites were deposited on glass substrate and dried overnight at room temperature. Structure and optical properties of ZnO/PANI nanocomposite have been studied by using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, diffuse reflectance and photoluminescence spectroscopy. Tests towards acetic acids were performed in the range of concentrations 1–13 ppm. The adsorption of acetic a…

Photoluminescence: A very sensitive tool to detect the presence of anatase in rutile phase electrospun TiO 2 nanofibers

2015

Abstract This paper reports on the synthesis and the characterization of titanium dioxide (TiO2) nanofibers prepared by electrospinning. The samples were annealed at various temperatures in air for 4 h. The as-spun and annealed TiO2/PVP composite nanofibers were characterized by scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy analysis (EDX), X-ray diffraction (XRD), Raman spectroscopy and photoluminescence (PL). The results show that the heat treatment has an effect on the crystallization process. Even if the XRD data shows a complete anatase-to-rutile transition in the TiO2 nanofibers at 900 °C, photoluminescence reveals a small portion of anatase in rutile sample.…

Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology

2016

The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered,…

Photoluminescence Study of Defects in ZnO-Coated Polyacrylonitrile Nanofibers

2020

International audience; Core-shell nanostructures of one-dimensional (1D) polyacrylonitrile (PAN)/zinc oxide (ZnO) were obtained by combining atomic layer deposition (ALD) and electrospinning. Nanofibers with different ZnO thicknesses were synthesized and investigated. The present work offers novel information about 1D ZnO structural defects and activation energies (Ea) by performing photoluminescence (PL) measurements. PL measurements of 1D ZnO/PAN samples were investigated from 77 K to 273 K (room temperature). By analyzing the obtained data of the emission spectrum, Ea and temperature coefficients were calculated. The results let us suggest an approximate model of defects in 1D ZnO/PAN s…

From Microorganism-Based Amperometric Biosensors towards Microbial Fuel Cells

2021

This review focuses on the overview of microbial amperometric biosensors and microbial biofuel cells (MFC) and shows how very similar principles are applied for the design of both types of these bioelectronics-based devices. Most microorganism-based amperometric biosensors show poor specificity, but this drawback can be exploited in the design of microbial biofuel cells because this enables them to consume wider range of chemical fuels. The efficiency of the charge transfer is among the most challenging and critical issues during the development of any kind of biofuel cell. In most cases, particular redox mediators and nanomaterials are applied for the facilitation of charge transfer from a…

Mesoporous ZnFe2O4@TiO2 Nanofibers Prepared by Electrospinning Coupled to PECVD as Highly Performing Photocatalytic Materials

2017

International audience; Zinc ferrite @ titanium dioxide (ZnFe2O4@TiO2) composite nanofibers were elaborated by combining the two different techniques: electrospinning and plasma-enhanced chemical vapor deposition (PECVD). The nanofiber compositions were controlled using different ratios of zinc to iron. Their structural, morphological, and optical properties were analyzed by scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, BET surface area, Raman spectroscopy, and UV–visible spectrophotometry. The photocatalytic activity has been investigated by the degradation of methylene blue under visible light. The results indicate that the combination of spinel st…

Analytical, thermodynamical and kinetic characteristics of photoluminescence immunosensor for the determination of Ochratoxin A

2017

Ochratoxin A (OTA) is one of the most widespread and dangerous food contaminants. Therefore, rapid, label-free and precise detection of low OTA concentrations requires novel sensing elements with advanced bio-analytical properties. In the present paper we report photoluminescence (PL) based immunosensor for the detection of OTA. During the development of immunosensor photoluminescent ZnO nanorods (ZnO-NRs) were deposited on glass substrate. Then the ZnO-NRs were silanized and covalently modified by Protein-A (Glass/ZnO-NRs/Protein-A). The latest structure was modified by antibodies against OTA (Anti-OTA) in order to form OTA-selective layer (Glass/ZnO-NRs/Protein-A/Anti-OTA). In order to im…

Space charge limited current mechanism in Bi2S3 nanowires

2016

We report on the charge transport properties of individual Bi2S3 nanowires grown within the pores of anodized aluminum oxide templates. The mean pore diameter was 80 nm. Space charge limited current is the dominating conduction mechanism at temperatures below 160 K. Characteristic parameters of nanowires, such as trap concentration and trap characteristic energy, were estimated from current-voltage characteristics at several temperatures.

Photoluminescent Detection of Human T-Lymphoblastic Cells by ZnO Nanorods.

2020

The precise detection of cancer cells currently remains a global challenge. One-dimensional (1D) semiconductor nanostructures (e.g., ZnO nanorods) have attracted attention due to their potential use in cancer biosensors. In the current study, it was demonstrated that the possibility of a photoluminescent detection of human leukemic T-cells by using a zinc oxide nanorods (ZnO NRs) platform. Monoclonal antibodies (MABs) anti-CD5 against a cluster of differentiation (CD) proteins on the pathologic cell surface have been used as a bioselective layer on the ZnO surface. The optimal concentration of the protein anti-CD5 to form an effective bioselective layer on the ZnO NRs surface was selected. …

Enhanced photocatalytic performance of novel electrospun BN/TiO 2 composite nanofibers

2017

International audience; High activity boron nitride/titanium dioxide (BN/TiO2) composite nanofiber photocatalysts were synthesized for the first time via the electrospinning technique. The as-spun nanofibers with a controlled ratio of boron nitride nanosheets (BN) were calcined under air at 500 °C for 4 hours. Their morphological, structural and optical properties were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), BET surface area, Fourier-transform infrared (FTIR), Raman spectroscopy, UV-Visible spectrophotometry and room temperature photoluminescence (PL). The effect of loading different BN sheet amounts on the photocat…

BN/GdxTi(1-x)O(4-x)/2 nanofibers for enhanced photocatalytic hydrogen production under visible light

2019

Abstract BN/GdxTi(1-x)O(4-x)/2 nanofibers were elaborated via electrospinning technique. The properties of the prepared nanofibers were controlled using different ratios of gadolinium. All the prepared nanofibers exhibit the tetragonal structure of anatase TiO2 phase. An increase in the unit cell volume and a decrease in the crystallite size were observed with increasing the doping amount of Gd3+ as revealed by Rietveld refinement analysis. The defect in TiO2 lattice was observed by Raman. The Gd3+ incorporation inside TiO2 lattice, which is accompanied by the creation of Ti-O-Gd bond, was characterized by the X-ray photoelectron spectra. Scanning electron microscopy demonstrates that the a…

Tuning of Structural and Optical Properties of Graphene/ZnO Nanolaminates

2016

International audience; Zinc Oxide (ZnO) and graphene (G) have been extensively studied because of their unique physical properties. Here, Graphene-Zinc Oxide (G/ZnO) nanolaminates were fabricated, respectively, by chemical vapor deposition and low temperature atomic layer deposition technique. The number of obtained G/ZnO layers was tuned from 1 to 11 with a total thickness of 100 nm for all prepared nanolaminates. The structure, optical properties and interaction between G and ZnO were studied by X-ray methods, TEM, AFM, Raman and optical spectroscopy. The obtained results were interpreted and analysed taking into account strain and charge effects of graphene in G/ZnO nanostructures. We d…

Study on Structural, Mechanical, and Optical Properties of Al2O3–TiO2 Nanolaminates Prepared by Atomic Layer Deposition

2015

Structural, optical, and mechanical properties of Al2O3/TiO2 nanolaminates fabricated by atomic layer deposition (ALD) were investigated. We performed transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray reflectivity (XRR), energy dispersive X-ray spectroscopy (EDX), ellipsometry, UV–vis spectroscopy, photoluminescence (PL) spectroscopy, and nanointendation to characterize the Al2O3/TiO2 nanolaminates. The main structural, optical, and mechanical parameters of Al2O3/TiO2 nanolaminates (thickness, grain size, refractive index, extinction coefficient, band gap, hardness, and Young’s module) were calculated. It was established that with decreasing of the layer thickness, the …

Structural and optical properties of TiO2–Al2O3nanolaminates produced by atomic layer deposition

2015

Structural and optical properties of Al2O3/TiO2 nanolaminates fabricated by atomic layer deposition (ALD) were investigated. We performed Raman spectroscopy, transmission electron microscopy (TEM), X-Ray reflectivity (XRR), UV-Vis spectroscopy, and photoluminescence (PL) spectroscopy to characterize the Al2O3/TiO2 nanolaminates. The main structural and optical parameters of Al2O3/TiO2 nanolaminates were calculated. It was established that with decreasing of the layer thickness, the value of band gap energy increases due to the quantum size effect related to the reduction of the nanograins size. It was also shown that there is an interdiffusion layer at the Al2O3/TiO2 interface which plays a…

Cell and Tissue Response to Modified by Laser-induced Periodic Surface Structures Biocompatible Materials for Dental Implants

2016

The use of femtosecond laser-induced periodic surface structures (LIPSS) for dental implants surface modification for improving cell adhesion and proliferation is reported. Results demonstrated higher response of cells on modified surface compared to untreated ones.

ZnO Nanorods Room Temperature Photoluminescence Biosensors For Salmonella Detection

2012

Salmonella antibodies immobilized on ZnO nanostructures surface from liquid solutions, resulted in enhance of ZnO photoluminescence intensity. Biosensor reaction to salmonella antigens caused to decrease of PL intensity for all measured antigen concentrations.

Cell and tissue response to nanotextured Ti6Al4V and Zr implants using high-speed femtosecond laser-induced periodic surface structures

2019

In this paper, the effect of femtosecond laser nanotexturing of surfaces of Ti6Al4V and Zr implants on their biological compatibility is presented and discussed. Highly regular and homogeneous nanostructures with sub-micrometer period were imprinted on implant surfaces. Surfaces were morphologically and chemically investigated by SEM and XPS. HDFa cell lines were used for toxicity and cell viability tests, and subcutaneous implantation was applied to characterize tissue response. HDFa proliferation and in vivo experiments evidenced the strong influence of the surface topography compared to the effect of the surface elemental composition (metal or alloy). The effect of protein adsorption fro…

Biocompatibility and Antibacterial Properties of ZnO-Incorporated Anodic Oxide Coatings on TiZrNb Alloy

2020

In a present paper, we demonstrate novel approach to form ceramic coatings with incorporated ZnO nanoparticles (NPs) on low modulus TiZrNb alloy with enhanced biocompatibility and antibacterial parameters. Plasma Electrolytic Oxidation (PEO) was used to integrate ZnO nanoparticles (average size 12&ndash

Metal Oxide Nanostructures in Sensing

2019

Abstract Metal oxides are well-known materials for the sensor and biosensor applications. In fact, the surface of metal oxides is a key factor for effective interaction with target molecules. Tailoring of the surface properties of metal oxide allows improving sensitive properties. The recent advances in nanotechnology open new possibilities for applications of metal oxides. Reducing the grain size to nanoscale increases the active surface area and induces new effect due to the quantum confinement such as bandgap widening, room temperature photoluminescence, etc. The novel physical effects in metal oxide nanostructures could be used for the development of sensor tool with advanced parameters…

Zinc oxide nanorod based immunosensing platform for the determination of human leukemic cells.

2019

Zinc oxide (ZnO) based nanostructures owing unique physical properties – high photoluminescence, bio- compatibility and other characteristics, therefore, they attract attention as building blocks suitable for biosensor development. In this research as a target we have used human leukemic cell line IM9 (IM9). IM9 was derived from the patient with a multiple myeloma and expressed cluster of differentiation proteins СD19 on the surface of 85–95% here investigated cancer cells. As a control sample healthy human's peripheral blood mononuclear cells (PBMC) were used and the expression of CD19 protein was found only in 5–9% of these cells. Two types of antibodies labeled by f…

Scanning electrochemical microscopy and electrochemical impedance spectroscopy-based characterization of perforated polycarbonate membrane modified b…

2021

Abstract In this research, scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS) were applied for the evaluation of surface characteristics of electrochemical (amperometric) biosensor based on two composite structures consisting of perforated polycarbonate membrane modified by carbon-nanomaterials and glucose oxidase. The first structure consisted of the polycarbonate filter membrane, punctured by 400 nm holes (PCM) consequently modified with single walled carbon nanotubes (SWCNT) and graphene oxide (GO) layer (PCM/SWCNT/GO); and the other structure consisted of the same PCM, consequently modified with SWCNT and reduced graphene oxide (rGO) layer (PCM/S…

Toward development of optical biosensors based on photoluminescence of TiO2 nanoparticles for the detection of Salmonella

2017

Quality control of food and agriculture production is an inseparable part of human safety and wellbeing. Salmonella infections belong to one of the most monitored pathogens in the world, therefore advanced determination of this pathogen can decrease the risks of human diseases caused by this microorganism. In this research we introduce a novel optical immunosensor for determination of Salmonella typhimurium. The immunosensor is based on Titanium dioxide (TiO2) nanoparticles deposited on glass substrates (glass/TiO2)center dot TiO2 nanoparticles exhibit an intense photoluminescence (PL) in the visible range of spectrum at room temperature. The direct immobilization of antibodies (anti-S-Ab) …

Optical and structural properties of Al 2 O 3 /ZnO nanolaminates deposited by ALD method

2014

International audience; We report on the investigation of optical and structural properties of Al2O3/ZnO nanolaminates. The nanolaminates were deposited on Si and glass substrates by Atomic layer deposition method. Structural properties of nanolaminates were studied by SEM, GIXRD, and AFM. Optical characterization was performed by transmittance and photoluminescence spectroscopy. Complex analysis of monolayer properties was done by ellipsometry. Optical constants for Al2O3 and ZnO monolayer were calculated.

Photoluminescent zinc oxide nanorods – a new tool for detection of human leukemic cells

2018

Bioanalytical system for detection of cancer cells with photoluminescent ZnO nanorods

2016

Using photoluminescent ZnO nanorods and carbohydrate marker SSEA-4, a novel cancer cell recognition system was developed. Immobilization of SSEA-4 antibodies (αSSEA-4) on ZnO nanorods was performed in buffer solution (pH = 7.1) over 2 h. The cancer cell line probes were fixed on the glass slide. One hundred microliters of ZnO-αSSEA-4 conjugates were deposited on the cell probe and exposed for 30 min. After washing photoluminescence spectra were recorded. Based on the developed methodology, ZnO-αSSEA-4 probes were tested on patient-derived breast and colorectal carcinoma cells. Our data clearly show that the carbohydrate SSEA-4 molecule is expressed on cancer cell lines and patient-derived c…

Whispering gallery mode resonator and glucose oxidase based glucose biosensor

2020

Abstract In this research whispering gallery mode resonators (WGMRs) were applied in new concept of glucose sensor based on the shift of WGM resonance frequency induced by enzymatic oxidation of glucose by glucose oxidase (GOx), which was immobilized on WGM-resonator surface. During the enzymatic reaction catalyzed by GOx electrons from glucose via GOx are transferred towards co-immobilized gold nanoparticles (Au-NPs). WGM-resonators were fabricated from standard telecommunication optical-fiber melted in a hydrogen flame. Whispering gallery mode resonance based optical signals generated by these WGM-resonators were evaluated. These WGM-resonators, which were characterized by sufficient qual…

Synthesis of novel ZnO/ZnAl2O4 multi co-centric nanotubes and their long-term stability in photocatalytic application

2016

Based on the Kirkendall effect, novel double, triple and quadruple co-centric nanotubes of ZnO/ZnAl2O4 have been successfully fabricated by combining the two techniques of electrospinning and atomic layer deposition. The as-prepared samples were annealed at 900 °C under air. Their morphological, structural and optical properties were studied by Scanning Electron Microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Energy-Dispersive X-ray spectroscopy (EDX), UV-visible spectrophotometry, Raman spectroscopy, photoluminescence (PL) and reflectance emission. The performances and long-term stability of these multi co-centric nanotubes for photocatalytic applications…

Photoelectrochemical Bisphenol S Sensor Based on ZnO‐Nanoroads Modified by Molecularly Imprinted Polypyrrole

2019

Molecularly imprinted polymers are important tools for the design of sensors and other molecular recognition based analytical systems. In this paper the development of a photoelectrochemical sensor for selective bisphenol determination is reported. The sensor is based on a glass/ZnO/MIP‐Ppy structure consisting of glass modified by a ZnO layer (glass/ZnO), which is functionalized by molecularly imprinted conducting polymer polypyrrole (MIP‐Ppy). The sensitivity of the sensor to bisphenol is in the range of 0.7–12.5 µm. Selectivity tests to other bisphenolic compounds are performed. Some aspects of a photoinduced response mechanism in glass/ZnO/MIP‐Ppy nanostructures are predicte…

High photodegradation and antibacterial activity of BN–Ag/TiO 2 composite nanofibers under visible light

2018

To develop material with good photocatalytic properties for organic compound degradation and bacterial removal, we produced Ag/TiO2 and BN–Ag/TiO2 composite nanofibers that included controlled amounts of boron nitride (BN) nanosheets and silver (Ag). After annealing at 500 °C under air, we used scanning electron microscopy, transmission electron microscopy, Brunauer–Emmet–Teller analysis, X-ray diffraction, energy-dispersive X-ray spectroscopy, Raman spectroscopy, UV-visible reflectance spectroscopy and room temperature photoluminescence to investigate the morphological, structural and optical properties of all samples. The photocatalytic tests using methylene blue under visible light, in r…

Influence of ZnO/graphene nanolaminate periodicity on their structural and mechanical properties

2018

International audience; Structural, electronic and mechanical properties of ZnO/Graphene (ZnO/G) nanolaminates fabricated by low temperature atomic layer deposition (ALD) and chemical vapor deposition (CVD) were investigated. We performed scanning and transmission electron microscopy (SEM/TEM), X-ray diffraction (XRD), electron energy loss spectroscopy (EELS), Raman spectroscopy, X-Ray photoelectron spectroscopy (XPS) and nanoindentation to characterize the ZnO/G nanolaminates. The main structural and mechanical parameters of ZnO/G nanolaminates were calculated. The obtained results were analyzed and interpreted taking into account mechanical interaction and charge effects occurring at the …

Bioactivity Performance of Pure Mg after Plasma Electrolytic Oxidation in Silicate-Based Solutions

2021

The biodegradable metals, including magnesium (Mg), are a convenient alternative to permanent metals but fast uncontrolled corrosion limited wide clinical application. Formation of a barrier coating on Mg alloys could be a successful strategy for the production of a stable external layer that prevents fast corrosion. Our research was aimed to develop an Mg stable oxide coating using plasma electrolytic oxidation (PEO) in silicate-based solutions. 99.9% pure Mg alloy was anodized in electrolytes contained mixtures of sodium silicate and sodium fluoride, calcium hydroxide and sodium hydroxide. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), contact angle (CA), …