Electrodeposition and characterization of PbSe films on indium tin oxide glass substrates

Electrodeposition of lead selenide (PbSe) thin films on indium tin oxide (ITO) covered glass is described. While disodium salt of ethylenediaminetetraaceticacid was used to complex the lead ions, well crystallized, nearly stoichiometric and mirror-like PbSe films were deposited on ITO glass in potentiostatic mode using aqueous acidic electrolyte containing Pb and Se precursors at different bath temperature. The improvement of crystallinity of the PbSe films deposited at different temperature was studied using X-ray diffraction and Raman scattering. The morphology and composition of the films were characterized by scanning electron microscopy and energy disperse analysis by X-ray, respectively. The optical property of the film was studied by optical measurement techniques.     

Development of silver/gold nanocages onto indium tin oxide glass as a reagentless plasmonic mercury sensor

We demonstrate the utilization of silver/gold nanocages (Ag/Au NCs) deposited onto transparent indium tin oxide (ITO) film glass as the basis of a reagentless, simple and inexpensive mercury probe. The localized surface plasmon resonance (LSPR) peak wavelength was located at ∼800 nm. By utilizing the redox reaction between Hg²⁺ ions and Ag atoms that existed in Ag/Au NCs, the LSPR peak of Ag/Au NCs was blue-shifted. Thus, we develop an optical sensing probe for the detection of Hg²⁺ ions. The LSPR peak changes were lineally proportional to the concentration of Hg²⁺ ions over the range from 10 ppb to 0.5 ppm. The detection limit was ∼5 ppb. This plasmonic probe shows good selectivity and high sensitivity. The proposed optical probe is successfully applied to the sensing of Hg²⁺ in real samples.     

Direct electrodeposition of gold nanoparticles onto indium/tin oxide film coated glass and its application for electrochemical biosensor

A novel electrochemical deposition method for growth of gold nanoparticles (GNPs) on indium tin oxide (ITO) thin film coated glass was investigated. The resulting electrode surface was characterized by SEM, UV–Vis spectroscopy and electrochemical methods. The GNPs directly attached on the electrode surface with a quasi-spherical shape and their sizes of diameters were in the range of 20–35 nm with a quite symmetric distribution. With increasing electrodeposition cycles of cyclic voltammetry, the density of GNPs on ITO electrode surface was increased. The potential utility of the GNPs modified ITO electrode was investigated. Superoxide dismutase (SOD) was successfully immobilized on GNPs modified ITO electrode and the direct electron transfer between enzyme and electrode surface realized. The enzyme electrode exhibited a rapid and high response to superoxide anion.     

Electrodeposition of gold nanoparticles on indium/tin oxide electrode for fabrication of a disposable hydrogen peroxide biosensor

A novel disposable third-generation hydrogen peroxide (H₂O₂) biosensor based on horseradish peroxidase (HRP) immobilized on the gold nanoparticles (AuNPs) electrodeposited indium tin oxide (ITO) electrode is investigated. The AuNPs deposited on ITO electrode were characterized by UV-vis, SEM, and electrochemical methods. The AuNPs attached on the ITO electrode surface with quasi-spherical shape and the average size of diameters was about 25 nm with a quite symmetric distribution. The direct electron chemistry of HRP was realized, and the biosensor exhibited excellent performances for the reduction of H₂O₂. The amperometric response to H₂O₂ shows a linear relation in the range from 8.0 μmol L⁻¹ to 3.0 mmol L⁻¹ and a detection limit of 2 μmol L⁻¹ (S/N = 3). The value of HRP immobilized on the electrode surface was found to be 0.4 mmol L⁻¹. The biosensor indicates excellent reproducibility, high selectivity and long-term stability.     

Photoelectrochemical sensing for hydroquinone based on gold nanoparticle-modified indium tin oxide glass electrode

Gold nanoparticles (GNPs) were deposited directly onto the surface of indium tin oxide (ITO) thin film-coated glass by electrochemical method. It was used as a photoanode in a photoelectrochemical (PEC) cell for sensitive detection of hydroquinone (HQ) at an applied bias potential of 0.15 V vs. saturated calomel electrode. This heterostructure showed dramatically enhanced PEC properties due to the introduction of the Au/ITO interface. Under the irradiation, the marked photocurrent response was observed at the GNPs/ITO photoelectrode compared with bare ITO electrode. The anodic photocurrent could be further largely enhanced by HQ. A new PEC strategy for sensitive detection of HQ at a relative low potential was developed. The linear range for HQ determination was 0.25 to 150 μM, with a detection limit of 0.1 μM. The sensitivity on the GNPs/ITO electrode at the irradiation was ~ 3.3 times higher than that in dark. These results demonstrate that the simple GNPs/ITO electrodes have great potential for PEC analysis application.     

Direct electrodeposition of gold nanoparticles onto indium tin oxide film coated glass: Application to the detection of arsenic(III).

Gold nanoparticle modified indium tin oxide (ITO) film coated glass electrodes were prepared for the first time through direct electrochemical deposition from 0.5 M H2SO4 containing 0.1 mM HAuCl4. The resulting electrode surfaces were characterized with AFM. Cyclic voltammetry and linear sweep voltammetry (LSV) of arsenic(III) on the modified electrodes were performed. After optimization, a LOD of 5 +/- 0.2 ppb was obtained with 60 s deposition at -0.6 V (vs. SCE) in 1 M HNO3 using LSV.     

Self-assembly of ultra-small gold nanoparticles on an indium tin oxide electrode for the enzyme-free detection of hydrogen peroxide

A novel enzyme-free electrochemical sensor for H₂O₂ was fabricated by modifying an indium tin oxide (ITO) support with (3-aminopropyl) trimethoxysilane to yield an interface for the assembly of colloidal gold. Gold nanoparticles (AuNPs) were then immobilized on the substrate via self-assembly. Atomic force microscopy showed the presence of a monolayer of well-dispersed AuNPs with an average size of ~4 nm. The electrochemical behavior of the resultant AuNP/ITO-modified electrode and its response to hydrogen peroxide were studied by cyclic voltammetry. This non-enzymatic and mediator-free electrode exhibits a linear response in the range from 3.0?×?10^?5 M to 1.0?×?10^?3 M (M?=?mol?·?L^?1) with a correlation coefficient of 0.999. The limit of detection is as low as 10 nM (for S/N?=?3). The sensor is stable, gives well reproducible results, and is deemed to represent a promising tool for electrochemical sensing.

Synthesis of tin and tin oxide nanoparticles of low size dispersity for application in gas sensing

Nanocomposite core-shell particles that consist of a Sn0 core surrounded by a thin layer of tin oxides have been prepared by thermolysis of [(Sn(NMe2)2)2] in anisole that contains small, controlled amounts of water. The particles were characterized by means of electronic microscopies (TEM, HRTEM, SEM), X-ray diffraction (XRD) studies, photoelectron spectroscopy (XPS), and Mossbauer spectroscopy. The TEM micrographs show spherical nanoparticles, the size and size distribution of which depends on the initial experimental conditions of temperature, time, water concentration, and tin precursor concentration. Nanoparticles of 19 nm median size and displaying a narrow size distribution have been obtained with excellent yield in the optimized conditions. HRTEM, XPS, XRD and Mossbauer studies indicate the composite nature of the particles that consist of a well-crystallized tin beta core of approximately equals 11 nm covered with a layer of approximately equals 4 nm of amorphous tin dioxide and which also contain quadratic tin monoxide crystallites. The thermal oxidation of this nanocomposite yields well-crystallized nanoparticles of SnO2* without coalescence or size change. XRD patterns show that the powder consists of a mixture of two phases: the tetragonal cassiterite phase, which is the most abundant, and an orthorhombic phase. In agreement with the small SnO2 particle size, the relative intensity of the adsorbed dioxygen peak observed on the XPS spectrum is remarkable, when compared with that observed in the case of larger SnO2 particles. This is consistent with electrical conductivity measurements, which demonstrate that this material is highly sensitive to the presence of a reducing gas such as carbon monoxide.     

Shape- and size-dependent refractive index sensitivity of gold nanoparticles

Gold nanoparticles of different shapes and sizes, including nanospheres, nanocubes, nanobranches, nanorods, and nanobipyramids, were dispersed into water-glycerol mixtures of varying volume ratios to investigate the response of their surface plasmon peaks to the refractive index of the surrounding medium. The refractive index sensitivities and figures of merit were found to be dependent on both the shape and the size of the Au nanoparticles. The index sensitivities generally increase as Au nanoparticles become elongated and their apexes become sharper. Au nanospheres exhibit the smallest refractive index sensitivity of 44 nm/RIU and Au nanobranches exhibit the largest index sensitivity of 703 nm/RIU. Au nanobipyramids possess the largest figures of merit, which increase from 1.7 to 4.5 as the aspect ratio is increased from 1.5 to 4.7.     

Lack of nano size effect on electrochemistry of dopamine at a gold nanoparticle modified indium tin oxide electrode

Nanometer sized materials have been shown to possess excellent chemical and electrochemical catalytic properties. In this work, a gold nanoparticle (AuNP) modified indium tin oxide (ITO) electrode was employed for investigating its electro-catalytic property. AuNP was deposited on the 3-aminopropyltriethoxysilane (APTES) modified ITO electrode by self-assembly, and was characterized by scanning electron microscopy and cyclic voltammetry. Although the electrochemical reaction of dopamine was very sluggish on the ITO/APTES electrode, it was significantly enhanced after AuNP deposition. The cyclic voltammogram exhibited apparent dependence on the surface coverage of 11 nm AuNPs, which could be rationalized by different modes of mass diffusion. Among the different sizes of AuNP investigated, the lowest anodic peak potential was observed on 11 nm AuNP. However, the potential was still about 50 mV more positive than that obtained on a bulk gold electrode of similar geometry. It is therefore concluded that there is no nanometer size effect of AuNP modified ITO on the electrochemistry of dopamine.     

Electrodeposition of polyaniline on high electroactive indium tin oxide nanoparticles-modified fluorine doped tin oxide electrode for fabrication of high-performance hybrid supercapacitor

In this study, hierarchical polyaniline (PANI) nanosheets were electrochemically deposited on indium tin oxide nanoparticles coated fluorine-doped tin oxide glass (ITONPs-FTO) substrate from an aqueous solution containing 0.5 M aniline and 1 M H₂SO₄. The ITONPs provide efficient support with high electroactive surface area in the electrochemical deposition of PANI and produce excellent PANI films. The developed PANI film deposited on the ITONPs-FTO electrode was characterized via field-emission scanning-electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. A hybrid supercapacitor (HSC) was fabricated using the developed PANI deposited ITONPs-FTO as a positrode and the jute sticks derived activated carbon nanosheets coated FTO (JAC-FTO) as a negatrode. Because of its high capacitive performance, unique structures of electrode materials, and optimum operating potential window, the fabricated PANI-ITONPs-FTO//JAC-FTO HSC performed excellently in 0.1 M HCl aqueous electrolyte, delivering a high areal capacitance of 318 mF/cm² at a 1.0 mA/cm² current density and exhibit a high energy density of 28 µWh/cm² at a high power density of 400 µW/cm². Moreover, the HSC exhibits excellent cyclic stability with ～ 87% Coulombic efficiency and ～ 91% capacitance retention after 1000 charge–discharge cycles.     

Preparation of polymer-dispersed liquid crystal doped with indium tin oxide nanoparticles

To study polymer-dispersed liquid crystal (PDLC) films doped with indium tin oxide (ITO) nanoparticles (NPs), samples were prepared by ultraviolet-initiated polymerisation based on the thiol–acrylate system. Owing to the interaction between PDLC system and ITO NPs, the content and the size of ITO NPs are the main determinants to the microstructure which plays an essential role on the electro-optical and anti-infrared properties of the PDLC films. In the polymer matrix, a novel microstructure consisting of a dense surface, micron-sized meshes and submicron meshes is found to benefit the better performances of the low driven voltage (20.7 V), the relatively high contrast ratio (8.3) and the lowest transmittance(500–2500 nm) on average at about 3.55% with maximum of merely 7.6%. Thus, it lays a solid foundation for the further investigations on the microstructure and the performance of the PDLC films. Meanwhile, it is proved that the PDLC film, improved performance through doping ITO NPs, is promising to be a superior choice in the field of energy-saving.     

Electrochemical sensing of CO by gold particles electrodeposited on indium tin oxide substrate

The gold submicroparticles (AuSMPs) electrodeposited on indium tin oxide (ITO) were used to develop an electrochemical method for determining the concentration of CO in gas phase. We demonstrated that the peak current for CO oxidation in cyclic voltammetry (CV) is proportionally dependent on the gas phase concentration of CO. Experimental results are in good agreements with the theoretical predictions over a wide concentration regime, providing a solid foundation for the quantitatively sensing of CO at AuSMPs/ITO electrodes.     

Simultaneous determination of guanosine and guanosine-5'-triphosphate in biological sample using gold nanoparticles modified indium tin oxide electrode

A nanogold modified indium tin oxide (ITO) electrode was used for the simultaneous determination of guanosine and GTP at pH 7.2. The electrode exhibited an effective catalytic response towards their oxidation and lowered the oxidation potential of guanosine by ∼120 mV and GTP by ∼183 mV. Linear concentration curves were obtained for guanosine with a detection limit of 9.8 × 10⁻⁸ M and 5.5 × 10⁻⁸ M for GTP. The concentration of guanosine and GTP were also estimated in the human blood plasma samples using gold nanoparticles modified ITO electrode with good reproducibility.     

Direct electrochemistry and electrocatalysis of hemoglobin on a gold ion implantation-modified indium tin oxide electrode

In this paper, a gold nanoparticle-modified indium tin oxide electrode (Au/ITO) was prepared without the use of any cross-linker or stabilizer reagent. The prepared Au/ITO was used as a new platform to achieve the direct electron transfer between Hb and the modified electrode. The proposed electrode exhibited a pair of well-defined redox peaks with a formal potential of ?0.073 V (vs. Ag/AgCl). The immobilized Hb showed excellent electrocatalytic activity toward H₂O₂ and the electrocatalytic current values were linear with the increasing concentration of H₂O₂ ranging from 1.0?×?10^?6?M to 7.0?×?10^?4?M. The detection limit was 2.0?×?10^?7?M (S/N?=?3) and the Michaelis–Menten constant was calculated to be 0.2 mM. The proposed electrode also showed high selectivity, long-term stability, and good reproducibility.     

A novel microchip based on indium tin oxide coated glass for contactless conductivity detection

A microfluidic chip manufactured from glass substrate and indium tin oxide (ITO) coated glass use for contactless conductivity detection was developed. The detecting electrodes were fabricated by screen-printing and chemical etching methods using an ITO-coated glass wafer. Then, the glass substrate containing separation channels was bonded with the bare side of the processed ITO-coated glass, thus producing an electrophoresis chip integrated with contactless conductivity detector. The prepared microchip displayed considerable stability and reproducibility. Sensitive response was obtained at optimal conditions (including the gap between electrodes, excitation frequency, and excitation voltage). The feasibility of this microfluidic device was examined by detection of inorganic ions, and further demonstrated by the quantification of aminopyrine and caffeine in a compound pharmaceutical. The two ingredients can be completely separated within 1 min. The detection limits were 8 μg mL⁻¹ and 3 μg mL⁻¹, respectively; with the correlation coefficient of 0.996-0.998 in the linear range from 10 μg mL⁻¹ to 800 μg mL⁻¹. The results have showed that the present method is sensitive, reliable and fast.     

Optical transmittance of indium tin oxide nanoparticles prepared by laser-induced fragmentation in water

Laser-induced fragmentation of indium tin oxide nanoparticles was performed in water by laser irradiation with various laser energies. Fragmentation of the nanoparticles proceeded with increased laser energy. The fragmented nanoparticles showed high transmittance in the visible region and lower transmittance in the ultraviolet and infrared regions. The optical band gap of the fragmented nanoparticles increased with decreasing average particle size. The increase of the band gap was possibly caused by the Burstein-Moss effect due to the increasing concentration of carriers generated by the surface defects of the oxygen vacancies on smaller nanoparticles.     

Controlled growth of two-dimensional and one-dimensional ZnO nanostructures on indium tin oxide coated glass by direct electrodeposition

A simple electrochemical deposition technique is used to deposit ZnO nanostructures with diverse morphology directly on ITO-coated glass substrates at 70 degrees C. The concentration of the Zn(NO 3) 2.6H 2O electrolyte is important to controlling the dimensionality of the nanostructures, with formation of one-dimensional (1D) nanospikes and nanopillars (with 50-500 nm diameter) below 0.01 M and of two-dimensional (2D) nanowalls and nanodisks (with 50-100 nm wall/disk thickness) above 0.05 M. Glancing-incidence X-ray diffraction study shows their wurtzite structure and confirms the change in the preferred crystal plane orientation with the dimensionality of ZnO nanostructures. UV-vis spectroscopy reveals a higher transmittance from 2D nanostructures than from 1D nanostructures and their optical direct band gaps estimated to be 3.12-3.27 eV. Depth-profiling X-ray photoemission studies show the presence of Zn(OH) 2 outer layers on the ZnO nanostructures, with a higher Zn(OH) 2 moiety for 2D nanostructures relative to 1D nanostructures. Furthermore, a substantial quantity of Cl (provided by the KCl supporting electrolyte) is detected throughout the 2D nanostructures only. The photoemission data therefore affirm our proposed growth mechanism that involves capping of the preferred [0001] growth direction by Cl (-) ions under fast hydroxylation kinetics condition as observed at a higher Zn(NO 3) 2.6H 2O electrolyte concentration.