Film Modified Indium Tin Oxide Research Articles

Porous Copper Oxide Thin Film Electrodes for Non-Enzymatic Glucose Detection

The present work describes novel copper oxide thin film-modified indium tin oxide electrodes prepared by magnetron sputtering and their application for glucose sensing. Copper oxide-modified sensors were characterized by electrochemical techniques, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The deposited thin film (of about 400 nm of thickness) consisted of Cu2O/CuO nanocolumns of ca. 80 nm in diameter. After optimizing the main experimental parameters, the electrodes showed noteworthy electrocatalytic properties for glucose detection (sensitivity ca. 2.89 A M−1 cm−2 and limit of detection ca. 0.29 μM (S/N = 3)). The sensor showed negligible response against common electroactive species and other sugars. Finally, recovery experiments in commercial soda drinks and the determination of glucose content in different commercial drinks, such as soda, tea, fruit juices, and sports drinks, are described.

Imaging Single Nanobubbles of H2 and O2 During the Overall Water Electrolysis with Single-Molecule Fluorescence Microscopy

In this work, we describe the preparation and use of a thin metal film modified Indium Tin Oxide (ITO) electrode as a highly conductive, transparent, and electrocatalytically active electrode material for studying nanobubbles generated at the electrode/solution interface. Hydrogen and oxygen nanobubbles were generated from water electrolysis on the surface of a Au/Pd alloy modified ITO electrode. The formation of single H2 and O2 nanobubbles was imaged in real time during a potential scan using single-molecule fluorescence microscopy. Our results show that while O2 nanobubbles can be detected at an early stage in the oxygen evolution reaction (OER), the formation of H2 nanobubbles requires a significant overpotential. Our study shows that thin-film-coated ITO electrodes are simple to make and can be useful electrode substrates for (single molecule) spectroelectrochemistry research.

An electrochemically-driven dual-mode display device with both reflective and emissive modes using poly(p-phenylenevinylene) derivatives

We demonstrate a novel electrochemical dual-mode displaying (DMD) device, which enables control of both coloration and light emission using an electrochemical reaction. The coloration control of the DMD device was based on an electrochromic (EC) reaction, whereas the light emission of the device was caused by an electrochemiluminescence (ECL) mechanism. This novel DMD device consisted of a pair of facing conductive polymer-modified electrodes: comb-shaped interdigitated Au electrodes modified with poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) layers and poly(2,3-dihydrothieno-1,4-dioxin)–poly(styrene sulfonate) (PEDOT/PSS) film-modified indium tin oxide (ITO) electrodes. When a bias voltage was applied between the PEDOT/PSS film-modified ITO electrode and the comb-shaped electrodes, a color change of the device was observed by the EC reaction of the MEH-PPV and PEDOT/PSS. On the other hand, an emission was obtained when the bias voltage was applied between two comb-shaped interdigitated electrodes. The orange emission was ascribed to the ECL reaction of the MEH-PPV layer, which resulted from the formation of a p–i–n junction in this layer.

Electrocatalytic self-assembled film of a dinucler Ru(II) complex for highly selective and sensitive nitrite detection

An electrostatic film composed of [(bpy)2Ru(tpphz)Ru(bpy)2]4+ {bpy=2,2’-bipyridine; tpphz=tetrapyrido[3,2-a:2’,3’-c:3”,2”-h:2”‘,3”‘-j]phenazine} and poly(sodium-p-styrenesulfonate), was prepared, and the film-modified indium-tin oxide electrode was applied to detect nitrite in an aqueous solution. The modified electrode showed highly selective and sensitive electrocatalytic detection of nitrite in an aqueous solution buffered with 0.1M H2PO42− at pH 2.5.

White-light-exciting, layer-by-layer-assembled ZnCdHgSe quantum dots/polymerized ionic liquid hybrid film for highly sensitive photoelectrochemical immunosensing of neuron specific enolase.

ZnCdHgSe quantum dots (QDs) functionalized with N-acetyl-l-cysteine were synthesized and characterized. Through layer-by-layer assembling, the ZnCdHgSe QDs was integrated with a polymerized 1-decyl-3-[3-pyrrole-1-yl-propyl]imidazolium tetrafluoroborate (PDPIT) ionic liquid film modified indium tin oxide (ITO) electrode to fabricated a photoelectrochemical interface for the immobilization of rabbit antihuman neuron specific enolase (anti-NSE). After being treated with glutaraldehyde vapor and bovine serum albumin successively, an anti-NSE/ZnCdHgSe QDs/PDPIT/ITO sensing platform was established. Simplely using a white-light LED as an excitation source, the immunoassay of neuron specific enolase (NSE) was achieved through monitoring the photocurrent variation. The polymerized ionic liquid film was demonstrated to be an important element to enhance the photocurrent response of ZnCdHgSe QDs. The anti-NSE/ZnCdHgSe QDs/PDPIT/ITO based immunosensor presents excellent performances in neuron specific enolase determination. The photocurrent variation before and after being interacted with NSE exhibits a good linear relationship with the logarithm of its concentration (log cNSE) in the range from 1.0 pg mL(-1) to 100 ng mL(-1). The limit of detection of this immunosensor is able to reach 0.2 pg mL(-1) (S/N = 3). The determination of NSE in clinical human sera was also demonstrated using anti-NSE/ZnCdHgSe QDs/PDPIT/ITO electrode. The results were found comparable with those obtained by using enzyme-linked immunosorbent assay method.

Selective patterning of Prussian blue on N-[3-(trimethoxysilyl)propyl]ethylenediamine capped gold nanoparticle film for electrocatalysis of hydrogen peroxide reduction

In this work, we have demonstrated selective patterning of electrodes coated with N-[3-(trimethoxysilyl)propyl]ethylenediamine (EDAS) stabilised gold nanoparticles (Sil-AuNps) films with Prussian blue (PB) by continuous electrochemical cycling of Sil-AuNps film modified Indium Tin Oxide (ITO) electrode in K3[Fe(CN6)] solution. The PB formed on gold nanoparticles (PB@Sil-AuNps) exhibits an electrochemical response similar to the PB formed on a bare ITO surface. However, the high spin iron redox state in PB formed on Sil-AuNps shows almost zero peak to peak separation (ΔEp) value in contrast to the finite ΔEp for PB formed on bare ITO. In addition, this selectively patterned PB on Sil-AuNps modified ITO electrode shows characteristic voltammetric responses of both PB and gold in 0.1 M KNO3 and 0.5 M H2SO4 respectively. In order to see the coverage of PB over gold nanoparticles, ITO electrode surface was characterised using scanning electron microscopy (SEM) and energy dispersive X-rays analysis (EDX) techniques. Selective patterning of redox mediator on noble metal nanoparticles results in lower film resistivity, which favours high electrocatalytic activity towards hydrogen peroxide electro-reduction. The sensitivity of this modified electrode towards H2O2 is 3.4 nA nM−1.

Effect of Ag ion irradiation on the performance of single-walled carbon nanotubes thin film modified Indium tin oxide sensor

Effect of Ag ion irradiation on the performance of single-walled carbon nanotubes thin film modified Indium tin oxide sensor

Photoelectrocatalytic regeneration of NADH at poly(4,4′-diaminodiphenyl sulfone)/nano TiO 2 composite film modified indium tin oxide electrode

Herein we report the photoelectrocatalytic regeneration of NADH at poly(4,4′-diaminodiphenyl sulfone)/nano TiO 2 (PDDS/TiO 2) composite modified indium tin oxide (ITO) electrode. The PDDS film growth was confirmed through in situ electrochemical quartz crystal microbalance (EQCM) studies. The prepared PDDS/TiO 2 composite was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) studies. SEM and AFM results confirmed that TiO 2 nanoparticles size is between 130 and 180 nm. XRD results showed that TiO 2 nanoparticles are crystalline and belong to anatase phase. Electrochemical impedance spectroscopy (EIS) and light induced EIS results substantiate a rapid electron transfer process at PDDS/TiO 2 composite surface. Cyclic voltammetry (CV) results demonstrated that composite film showed excellent response to the photoelectrocatalytic regeneration of NADH. The photoelectrocatalytic oxidation of NADH at composite film surface irradiated for 5 min (optimized irradiation time) produced a notable enhancement in anodic peak current and it was 18-fold higher than that of PDDS film and several folds higher than that of TiO 2 and bare ITO electrodes. Further, composite film showed higher sensitivity of 124.1 μA μM −1 for NADH. From Square wave voltammetry (SWV) results, sensitivity of the irradiated composite film was obtained as 0.252 μA nM −1 of NADH. The linear concentration range was between 23 and 39 nM NADH respectively. Further, the composite film exhibits good selectivity towards NADH and no significant interference effect was observed even when 200-fold excess of ascorbic acid (AA), dopamine (DA) and uric acid (UA) coexist in the same supporting electrolyte solution.

Photoelectric Response from D–π–A Dye's Langmuir-Blodgett Monolayer Film Modified Indium-Tin Oxide Electrode

Langmui-Blodgett (LB) monolayer films of two new amphiphilic D–π–A dyes were fabricated on both pure and acidic water subphases and transferred onto the ITO electrode by the LB) technique. The ultraviolet-visible absorption spectra and photocurrent properties of the ordered LB films were investigated.

Solid-state electrochemiluminescence sensor based on the Nafion/poly(sodium 4-styrene sulfonate) composite film

An effective electrochemiluminescence (ECL) sensor based on Nafion/poly(sodium 4-styrene sulfonate) (PSS) composite film-modified ITO electrode was developed. The Nafion/PSS/Ru composite film was characterized by atomic force microscopy, UV–vis absorbance spectroscopy and electrochemical experiments. The Nafion/PSS composite film could effectively immobilize tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy) 3 2+) via ion-exchange and electrostatic interaction. The ECL behavior of Ru(bpy) 3 2+ immobilized in Nafion/PSS composite film was investigated using tripropylamine (TPA) as an analyte. The detection limit (S/N = 3) for TPA at the Nafion/PSS/Ru composite-modified electrode was estimated to be 3.0 nM, which is 3 orders of magnitude lower than that obtained at the Nafion/Ru modified electrode. The Nafion/PSS/Ru composite film-modified indium tin oxide (ITO) electrode also exhibited good ECL stability. In addition, this kind of immobilization approach was simple, effective, and timesaving.

Electrocatalytic Oxidation of Guanine, Guanosine, and Guanosine Monophosphate

The electrochemical behavior of guanine, guanosine, and guanosine monophosphate (GMP) at redox polymer film modified indium tin oxide electrodes is examined by voltammetry and redox titration. Utilizing the redox polymer-coated electrodes as indicator electrodes, a new method for measuring the oxidation potentials, based on monitoring their catalytic oxidation by different redox polymer coated electrodes at different pH, was proposed in this work. The oxidation potentials of 0.81 V and 1.02 V versus normal hydrogen electrode were determined for guanine and guanosine/GMP under physiological conditions, the lowest oxidation potentials ever reported, to our knowledge.

Detection of guanine at a redox polymer modified indium tin oxide electrode

The electrochemical behavior of guanine at a redox polymer film modified indium tin oxide electrode is examined by voltammetry and amperometry. The results indicate that the modified electrode reduces the overpotential of guanine oxidation by as much as 550 mV. The oxidation of guanine is pH dependent and occurs at 0.61 V (versus Ag/AgCl) under physiological conditions, the lowest oxidation potential of guanine ever reported. Rotating disk electrode (RDE) experiments reveal that the kinetics of the electrocatalysis is very fast, and hence the oxidation current is solely controlled by mass-transport process in solution. Guanine is detected amperometrically at 0.65 V at the modified electrode with a sensitivity enhancement of two orders of magnitude over an unmodified electrode. A calibration curve is linear over the concentration range of 8.0 nM–100 μM with a correlation coefficient of 0.997 and a detection limit of 5.0 nM. The modified electrode also shows good anti-fouling properties towards the oxidation product of guanine and surfactants.