Sensor Electrode Research Articles

Development of a sustainable and disposable modified Bi-CdFe2O4 electrode for electrochemical sensing of lead (II) and Acetaminophen drug molecule

The study of research proposes a systematic pattern for optimization and fabrication of a sustainable-cost effective electrochemical sensor made by Bi-CdFe2O4 (BCDF) nanoparticle and graphite powder. The structural examinations of synthesized BCDF materials were analyzed by specific spectral techniques viz.; P-XRD, SEM-EDX, TEM, XPS, FT-IR and DRS techniques. The modified sensor electrode offer a significant electrochemical properties that can improve the material selectivity and sensitivity actions measured by Cyclic Voltammetric (CV) and Electrochemical Impedance Spectral (EIS) plots. We demonstrated a developed highly-purity BCDF-graphite paste electrode for sensing actions on Paracetamol and Lead (Pb2+) ions under 0.1 M KCl. The excellent sensing activity towards Lead ions and Paracetamol confirmed by its redox potential peaks at scan rate of 1–5 V/s with maximum sensitivity of -0.61 V and 0.69 V respectively. The excellent photo-dye-degradation action of BCDF (98.2%) than those of host CDF (81.6%) on Rose Bengal (RB) dye was demonstrated. Its kinetic study reveals that this process follows first order kinetics and rate constants of the host (18.1 × 10−3 min−1) and BCDF (39.2 × 10−3 min−1) were measured. Thus, the synthesized BCDF electrode provides a new perception for developing specific nano-sensor towards detection of toxic metals.

Gold-coated Impedance Spectroscopy Sensors on PCB and PET for Real-Time Monitoring of Cancer Cells

Abstract Electrical cell-substrate impedance sensing (ECIS) biosensors are widely used for in vitro cancer cell monitoring as they are label-free, require small sample volumes, and allow real-time monitoring. ECIS electrodes are typically made of pure gold, but the usage of pure gold electrodes is too costly for single-use applications. As an alternative, this work proposes the use of gold coatings on a printed sensor's electrodes. The interdigitated electrode design was used on glass fiber-reinforced epoxy resin for printed circuit boards (PCB), and polyethylene terephthalate (PET). The Cu/Ni electrodes on PCB were electroplated with Au, while the Cu/Ni electrodes on PET were coated with Au using an electroless technique. The physicochemical properties were studied using optical microscopy, scanning electron microscopy, and energy-dispersive spectroscopy. Electrochemical characterization was done using cyclic voltammetry and electrochemical impedance spectroscopy. Biocompatibility assessment and sensor functionality tests were done by culturing SiHa cervical cancer cell lines on these sensors and impedance measurements. The results show that both electroplated and electroless sensors were biocompatible and suitable to monitor SiHa cell growth. Electrochemical migration effect was observed on the sensors where the reaction occurred at 1.2V DC for the PCB sensor and 1.0V DC for the PET sensor.

Low-temperature Deposited Highly Sensitive Integrated All-Solid Electrodes for Electrochemical pH Detection

This article describes the process of fabricating an integrated all-solid electrode (IASE) by integrating thin films of titanium dioxide (TiO<i>2</i>) and silver/silver chloride (Ag/AgCl) onto an indium tin oxide (ITO) substrate. The fabrication of a pH sensing electrode (SE) involved utilizing a spin-coated thin film composed of TiO<i>2</i>. Thermally produced thin films of Ag/AgCl were used to develop solid reference electrodes (RE). The present work examined the impact of the drying process on the pH sensitivity and linearity of the low-temperature deposited IASE. The drying procedure was carried out within a temperature range from room temperature to 100°C. The investigation involved the examination of crystallinity, surface morphology, and thin film composition through the utilization of field effect scanning electron microscopy (FESEM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) methods. In addition, a comparison was made between the pH sensing performance of the IASE and a commercially available Ag/AgCl RE. The findings of this research demonstrate that the IASE sample, which underwent a drying process at a temperature of 100°C, exhibited remarkable sensitivity and linearity values of 66.7 mV/pH and 0.9827, separately, when compared to the commercially available RE.

Sensitive determination of hydroquinone and catechol using an electrochemical sensor based on nitrogen-doped malic acid carbon quantum dots

This study introduces an advanced electrochemical sensor fabricated by immobilizing nitrogen-doped malic acid carbon quantum dots (N-MCQDs) onto a glassy carbon electrode (GCE) via microwave-assisted synthesis and electrodeposition. The N-MCQDs were comprehensively characterized using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and atomic force microscopy (AFM), confirming their successful synthesis and uniform distribution on the GCE surface. The N-MCQDs-modified GCE electrode (N-MCQDs/GCE) sensor displayed a remarkable linear detection range of 1–500 μM for hydroquinone (HQ) and 1–200 μM for catechol (CC), with ultra-low detection limits of 0.18 μM for HQ and 0.13 μM for CC. It also exhibits commendable stability, interference resistance, and the capability to accurately measure in complex real sample. These superior characteristics were attributed to the enhanced electrical conductivity and increased active sites due to nitrogen doping. This study not only broadens the application spectrum of carbon quantum dots but also offers a novel perspective for the design of high-performance electrochemical sensors for environmental analysis.

Studying the Defects in Spinel Compounds: Discovery, Formation Mechanisms, Classification, and Influence on Catalytic Properties.

Spinel ferrites demonstrate extensive applications in different areas, like electrodes for electrochemical devices, gas sensors, catalysts, and magnetic adsorbents for environmentally important processes. However, defects in the real spinel structure can change the many physical and chemical properties of spinel ferrites. Although the number of defects in a crystal spinel lattice is small, their influence on the vast majority of physical properties could be really decisive. This review provides an overview of the structural characteristics of spinel compounds (e.g., CoFe2O4, NiFe2O4, ZnFe2O4, Fe3O4, γ-Fe2O3, Co3O4, Mn3O4, NiCo2O4, ZnCo2O4, Co2MnO4, etc.) and examines the influence of defects on their properties. Attention was paid to the classification (0D, 1D, 2D, and 3D defects), nomenclature, and the formation of point and surface defects in ferrites. An in-depth description of the defects responsible for the physicochemical properties and the methodologies employed for their determination are presented. DFT as the most common simulation approach is described in relation to modeling the point defects in spinel compounds. The significant influence of defect distribution on the magnetic interactions between cations, enhancing magnetic properties, is highlighted. The main defect-engineering strategies (direct synthesis and post-treatment) are described. An antistructural notation of active centers in spinel cobalt ferrite is presented. It is shown that the introduction of cations with different charges (e.g., Cu(I), Mn(II), Ce(III), or Ce(IV)) into the cobalt ferrite spinel matrix results in the formation of various point defects. The ability to predict the type of defects and their impact on material properties is the basis of defect engineering, which is currently an extremely promising direction in modern materials science.

A microphysiological system for studying barrier health of live tissues in real time

Epithelial cells create barriers that protect many different components in the body from their external environment. Increased gut barrier permeability (leaky gut) has been linked to several chronic inflammatory diseases. Understanding the cause of leaky gut and effective interventions are elusive due to the lack of tools that maintain tissue’s physiological environment while elucidating cellular functions under various stimuli ex vivo. Here we present a microphysiological system that records real-time barrier permeability of mouse colon in a physiological environment over extended durations. The system includes a microfluidic chamber; media composition that preserves microbiome and creates necessary oxygen gradients across the barrier; and integrated sensor electrodes for acquiring transepithelial electrical resistance (TEER). Our results demonstrate that the system can maintain tissue viability for up to 72 h. The TEER sensors can distinguish levels of barrier permeability when treated with collagenase and low pH media and detect different thickness in the tissue explant.

ZnFe(PBA)@Ti3C2Tx nanohybrid-based highly sensitive non-enzymatic electrochemical sensor for the detection of glucose in human sweat

The ZnFe prussian blue analogue [ZnFe(PBA)] was infused with Ti3C2Tx (MXene) denoted as ZnFe(PBA)@Ti3C2Tx and was prepared by an in-situ sonication method to use as a non-enzymatic screen printed electrode sensor. The advantage of non-enzymatic sensors is their excellent sensitivity, rapid detection, low cost and simple design. The synthesized ZnFe(PBA)@Ti3C2Tx was characterized for its physical and chemical characterization by XRD, Raman, XPS, EDAX, and FESEM analysis. It possessed multiple functionalized layers and a cubic structure in the nanohybrid. Further, the sensor was investigated by using electroanalytical studies such as cyclic voltammetry and chronoamperometry analysis. The enhanced surface area with a cubic structure of ZnFe(PBA) and the excellent electrical response of Ti3C2 nanosheet support the advancement of a non-enzymatic electrochemical glucose sensor with improved sensitivity of 973.42 µA mM−1 cm−2 with the limit of detection (LOD) of 3.036 µM (S/N = 3) and linear detection range (LDR) from 0.01 to 1 mM.

Electret mechano-sensor array integrated with tribopotential-modulated thin film transistors for precise spatiotemporal pressure perception

Spatiotemporal pressure perception is a key function of electronic skins. Electret mechano-sensors, as active sensors for E-skins, have garnered significant interest, with outstanding sensing performance in dynamic pressure measurement. However, their high output impedance poses a challenge in accurately and simply measuring low-frequency or static pressure distribution. Herein, we proposed an electret mechano-sensor array, in which each sensing cell is based on an electret sensor integrated with an IGZO TFT. The high input impedance of the TFT facilitates the sensor signal readout and enables the measurement of static pressure. The super-linear amplification feature of the TFTs improves the sensitivity and linearity of the sensors. An IGZO TFT layer with the lower electrodes of the electret sensor was fabricated through microfabrication process and assembled with a pre-charged electret film to achieve a mechano-sensor array with a high density. The fabricated TFT-integrated electret mechano-sensor array has achieved pattern detection and spatial tactile perception. Moreover, the sensor array can record spatiotemporal static pressure and arterial pulse waves simultaneously, exhibiting high resolution in detecting subtle changes and potentially offering various physiological information regarding the cardiovascular system. This work demonstrated that the proposed mechano-sensor array has capabilities for broad-scale pressure distribution detection in healthcare monitoring and human-computer interaction.

Development and Manufacturing Method of Electrodes for a High Temperature Oxygen Sensor

The article discusses the use of zirconium dioxide stabilized with yttria as an electrolyte for the formation of a high-temperature ceramic oxygen concentration sensor. The fundamental possibility of using such a material is due to the high electrical conductivity caused by the mobility of oxygen ions in the vacancies of the solid electrolyte. The operating principle of such a sensor as an electrochemical concentration element is discussed. It has been shown that the use of such sensors is relevant for various industries (including chemical, metallurgical, oil and gas, energy and others). Options for forming electrodes of an electrochemical sensor using various materials and deposition methods are considered. A method for forming a platinum coating using a chemical method using isopropyl alcohol and subsequent pyrolysis was tested. It has been experimentally shown that the chemical method is applicable for the formation of electrodes of an electrochemical sensor. The electrical characteristics of the resulting coatings were measured. The optimal composition of the reaction mixture and the required number of layers to create a stable operating electrochemical sensor have been determined. The dependence of the potential of the formed electrochemical sensor from stabilized zirconium oxide on oxygen concentration in a wide temperature range has been studied. It has been shown that when using a scheme of sequential transformations, hydrolysis of platinum tetrachloride - deposition on a substrate - reductive pyrolysis, it is possible to obtain a high-quality conductive coating for the formation of gas sensor electrodes. The optimal composition of the reaction mixture for the formation of platinum electrodes has been selected. The optimal number of layers was determined to ensure the required level of electrical conductivity of the electrodes. It has been shown that an electrochemical element based on zirconium dioxide and platinum electrodes, formed according to the scheme developed in this work, can be used as a high-temperature oxygen sensor.

Green synthesis of Oscimum Sanctum mediated silver nanoparticles to fabricate sensors for hydrogen peroxide detection

In this study, silver nanoparticles (Ag NPs) of an average size of ∼15 nm have been produced using the green synthesis technique with Oscimum Sanctum leaf extract. Further, these nanoparticles have been used to prepare electrodes for electrochemical sensors to monitor hydrogen peroxide. Hydrogen peroxide sensors have many applications in different sectors, such as medical, agriculture, and industry. The optical and structural characteristics of the Ag NPs have been investigated by UV–visible absorption spectroscopy and XRD patterns. Particle size, shape, and morphology of as-synthesized Ag NPs have been analyzed using transmission and scanning electron microscopic techniques. These nanoparticles were deposited onto an indium-tin-oxide glass substrate using the electrophoretic technique, which was used as an electrode to assess the electro-oxidation of Ag NPs by cyclic voltammetry. The sensitivity of the sensor has been estimated to be 4.16 µA/mM-cm2. The limit of detection of the sensor is estimated to be 40 µM within the linear range of 5–28 mM. The lattice parameter, interplanar spacing, and crystallite size of Ag NPs have been quantified and estimated against pH variation.

Ultrahighly Sensitive Flexible Pressure Sensors with Dual-Mode Response Based on Monolayer Films of Calcium Niobate Nanosheets.

Flexible pressure sensors present enormous potential for applications in health monitoring, human-machine interfacing, and electronic skins (e-skin). However, at the cost of flexibility, the design of flexible pressure sensors has been facing the trade off between high sensitivity and wide sensing range. Herein, we propose a sandwiched structure composed of monolayer films of calcium niobate nanosheets to endow the device with both ultrahigh sensitivity and a wide sensing range. Tunable contact between the two electrodes of the pressure sensor through the gaps in the insulative monolayer film and precise thickness modulation of the monolayer films at the nanoscale result in an ultrahigh sensitivity and wide sensing range of the sensors. By virtue of these two traits, the pressure sensor distinguishes itself with unprecedented performances of ultrahigh sensitivity (6.43 × 104 kPa-1), a wide sensing range (1.94-60.00 kPa), a fast response time (<165 ms), and reliable repeatability. In addition, the sensor has a sensing mechanism transition from capacitive mode to piezoresistive mode from low pressure to high pressure. The sensors demonstrates the ability for motion detection of the human body. This work sheds light on the development of highly sensitive flexible pressure sensors.

3-Electrode Setup for the Operando Detection of Side Reactions in Li-Ion Batteries: The Quantification of Released Lattice Oxygen and Transition Metal Ions from NCA

Detecting parasitic side reactions is paramount for developing stable cathode active materials (CAMs) for Li-ion batteries. This study presents a method for the quantification of released lattice oxygen and transition metal ions (TMII+ ions). It is based on a 3-electrode cell design employing a Vulcan carbon-based sense electrode (SE) that is held at a controlled voltage against a partially delithiated lithium iron phosphate (LFP) counter electrode (CE). At this SE, reductive currents can be measured while polarizing a CAM working electrode (WE), here a LiNi0.80Co0.15Al0.05O2 (NCA), against the same LFP CE. In voltammetric scans, we show how the SE potential can be selected to specifically detect a given side reaction during CAM charge/discharge, allowing, e.g., to discriminate between lattice oxygen and dissolved TMs. Furthermore, it is shown via online electrochemical mass spectrometry (OEMS) that O2 reduction in the here-used LP47 electrolyte consumes ∼2.3 electrons/O2. Using this value, the lattice oxygen release deduced from the 3-electrode setup upon charging of the NCA WE is in good agreement with OEMS measurements up to NCA potentials >4.65 VLi. At higher potentials, the contributions from the reduction of TMII+ ions can be quantified by comparing the integrated SE current with the O2 evolution from OEMS.

Multifunctional organohydrogels enabling sensitive strain sensing and self-powered triboelectricity

Hydrogels have broad application prospects in portable strain sensors and triboelectric nanogenerators (TENG), and have attracted great attention in the field of wearable electronic devices and energy transfer devices. However, the development of multifunctional gels that can meet a variety of application scenarios is still a challenging problem. In this study, a multifunctional poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid)/lignosulfonate/Zr4+ organohydrogel noted as “P(AM-co-AMPS)/LS/Zr4+” was fabricated based on dynamic metal coordination bonds and hydrogen bonds, which could be used as flexible strain sensor and TENG electrode material. The organohydrogel based strain sensor could monitor both large and tiny human movements due to the high sensitivity (GF = 4.37, up to 200 %) and circulation stability. The assembled organohydrogel-based triboelectric nanogenerator (O-TENG) could generate an open-circuit voltage of 70.47 V and a short-circuit current of 25.21 μA. It is worth mentioning that the O-TENG could light up 44 LED bulbs by tapping with the palm at −20 °C, and the electronic output performance of the O-TENG after self-healing was unaffected. Additionally, the O-TENG exhibited enormous potentials in the biomechanical energy harvesting and self-powered motion sensors in the areas of human movements detection, human–computer interaction, electronic skin and self-powered devices.

Cleanroom-free fabrication of flexible capacitive pressure sensors using paintable silver electrodes on stationery paper and random microstructured polydimethylsiloxane dielectric layer

Abstract In this work, we propose a facile, low-cost, and cleanroom-free approach for fabricating flexible capacitive pressure sensors based on paintable Ag electrodes on stationery paper substrates (Ag–paper electrodes) and a random microstructured polydimethylsiloxane (PDMS) dielectric layer transferred from emery paper. COMSOL Multiphysics simulations and experimental investigations suggest that the pressure sensor with random microstructured PDMS dielectric layer performs better than the sensor with ordered micropyramidal dielectric layer. The developed Ag–paper electrode and random microstructured PDMS dielectric layer-based pressure sensors are workable in a wide pressure range (up to 630 kPa) and exhibit a high sensitivity of 0.132 kPa−1 up to 1 kPa, low hysteresis (6.6%) with loading–unloading of ∼500 kPa pressure, high stability during a ∼5250 cyclic test, and the ability to sense a low pressure of ∼27 Pa. The developed sensor also successfully transduces arterial pulse wave forms when it is properly attached to the wrist. Using the proposed process, a flexible capacitive pressure sensor matrix of 4 × 4 array is also successfully developed for single- and multiple-point pressure mapping with minimal cross-talk. The proposed sensor process is simple and inexpensive to implement, and offers spatial pressure mapping for e-skin applications.

Fabrication of MnSnO2 intercalated TA-rGO modified sensor for selective electrochemical detection of chloramphenicol in real samples

Chloramphenicol (CAP), a potent antibiotic capable of inhibiting protein synthesis, presents significant challenges related to long-term dosing and its persistent leaching into the environment, raising concerns about environmental contamination and resistance development. To address this issue, we developed a reliable, low-cost, and biocompatible nanocomposite material comprising tannic acid (TA)-reduced graphene oxide (rGO) intercalated into manganese-doped tin oxide nanoparticles (MnSnO₂ NPs). The structural formation and catalytic activity of the MnSnO₂ NPs/TA-rGO nanocomposite were characterized using field emission-scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electrochemical techniques. This material exhibits robust interfacial interactions and synergistic effects, resulting in an admirable electrocatalytic reduction response for CAP sensing. The presence of co-interference molecules improved the selectivity performance of the MnSnO2 NPs/TA-rGO-modified glassy carbon electrode. The fabricated exhibited a two linear determination range (0.011–103.43 μmol L−1 and 103.43–1924.16 μmol L−1), with a detection limit (LOD) is 6.7 nmol L−1 and limit of quantification (LOQ) is 12.3 nmol L−1. Furthermore, this sensor demonstrated good sensitivity, admirable reproducibility, repeatability, and storage stability. Finally, the practicability of the fabricated MnSnO2 NPs/TA-rGO glassy carbon electrode sensor was evaluated by analyzing the CAP content in milk, honey, eye drops, biofluids (human serum and urine), and river water, and satisfactory recovery rates of 95.4 %–100.3 % were noted.

Dynamic detection of soluble intermediates during methanol electrooxidation

Methanol electrooxidation at a Pt band electrode is studied in a microfluidic flow cell (MFFC) with simultaneous electrochemical detection of formic acid at a down-stream sensor (detector) Pd electrode. Detection of formic acid at the Pd electrode is possible through either a fast voltammetry or a potential step procedure. In both cases, maximizing the detection signal (oxidation current) requires Pd oxide formation and reduction before detection. Pd oxide formation is needed to oxidize surface-bound carbonaceous species while Pd oxide reduction is needed to reactivate the electrode surface. Although formic acid alone is easily detected and provides a stable detection signal at the Pd sensor electrode, simultaneous formation of formaldehyde during methanol oxidation degrades the detection signal at the Pd electrode over time. We show that dynamic detection of sub-millimolar formic acid concentrations in 2M methanol is possible at a time resolution down to 2 s. Dynamic detection during methanol oxidation at platinum shows that production of soluble intermediates occurs at all potentials where an oxidation current is observed. Furthermore, a higher faradaic efficiency to formic acid occurs during the main methanol oxidation peak in the positive-going sweep compared to the negative-going sweep, and is higher still at potentials above 1V. This work shows that microfluidic flow cells can be used for fast and dynamic detection of soluble reaction intermediates by using down-stream electrodes with custom potential step or sweep sequences.

Self-Healing and Shear-Stiffening Electrodes for Wearable Biopotential Sensing and Gesture Recognition.

The achievement of flexible skin electrodes for dynamic monitoring of biopotential is one of the challenging issues in flexible electronics due to the interference of large acceleration and heavy sweat that influence the stability of skin-electrode interfaces. This work presents materials and techniques to achieve self-healing and shear-stiffening electrodes and an associated flexible system that can be used for multichannel biopotential measurement on the skin. The electrode that is based on a composite of silver (Ag) flakes, Ag nanowires, and polyborosiloxane offers an electrical conductivity of 9.71 × 104 S/m and a rheological characteristic that ensures stable and fully conformal contact with skin and easy removal under different shear rates. The electrode can maintain its conductivity even after being stretched by more than 60% and becomes self-healed after mechanical damage. The combination of the electrodes with a screen-printed multichannel flexible sensor allows stable monitoring of both static and dynamic electromyography signals, leading to the acquisition of high-quality multilead biopotential signals that can be readily extracted to yield gesture recognition results with over 97.42% accuracy. The conductive self-healing materials and flexible sensors may be utilized in various daily biopotential sensing applications, allowing highly stable dynamic measurement to facilitate artificial intelligence-enabled health condition diagnosis and human-computer interface.

Current Mirror Improved Potentiostat (CMIPot) for a Three Electrode Electrochemical Cell.

This work presents a novel compact CMOS potentiostat-designed circuit for an electrochemical cell. The proposed topology functions as a circuit interface, controlling the polarization of voltage signals at the sensor electrodes and facilitating current measurement during the oxidation-reduction process of an analyzed solution. The potentiostat, designed for CMOS technology, comprises a two-stage amplifier, two current mirror blocks coupled to this amplifier, and a CMOS push-pull output stage. The electrochemical method of cyclic voltammetry is employed, operating within a voltage range of ±0.8 V and scan rates of 10 mV/s, 25 mV/s, 100 mV/s, and 250 mV/s. The circuit is capable of reading currents ranging from 10 µA to 500 µA. Experimental results were obtained using a potassium ferrocyanide K3[Fe(CN)6] redox solution with concentrations of 10, 15, and 20 mmol/L, and their corresponding voltammograms were evaluated. The experimental results from a discrete circuit demonstrate that the proposed potentiostat topology produces outcomes consistent with those of classical topologies presented in the literature and industrial equipment.

First voltammetric studies, spectrophotometric and molecular docking investigations of the interaction of an anticancer drug ribociclib-DNA and analytical applications of disposable pencil graphite sensor

Ribociclib (RIB) is a cyclin-dependent kinase inhibitor used in the treatment of breast cancer. In this study, for the first time, the electrochemical behavior, quantification and interaction of RIB with DNA were carried out using voltammetric, spectrophotometric and molecular docking techniques. An environmentally-friendly disposable pencil graphite electrode (PGE) sensor was used as the working electrode. Utilizing the cyclic voltammetry technique, RIB produced an irreversible anodic wave around +0.837 V and reversible signals around +0.278 V/+0.209 V on the PGE surface. Using the PGE sensor, the RIB compound gave a very distinct anodic signal at a potential of +0.77 V in PBS (pH 3.0). For this analytical signal, the limit of detection and limit of quantitation values of RIB in the concentration range of 0.0139 3 M–0.0973 3 M in PBS (pH 3.0) were determined as 2.84 nM and 9.46 nM, respectively. The interaction of RIB with DNA was studied by voltammetric, spectrophotometric and molecular docking techniques. In the evaluation of the results obtained with all three techniques, the interaction of the RIB molecule with DNA was determined to occur through minor groove binding.

Effects of structure and thickness of Ce0.9Pr0.1O2 electrodes of YSZ-based gas sensors on VOC-sensing properties

Dense CeO2-doped with 10 mol% Pr (Ce0.9Pr0.1O2, PCO) films were fabricated as sensing electrodes of YSZ-based gas sensors by using radio-frequency magnetron sputtering method, and their sensing properties to toluene were evaluated in this study. The microstructure of the SEs was basically dense, but the rod-like microstructure was observed when the chamber pressure during sputtering was low. The toluene response of the sensors attached with the rod-like structured PCO films showed a higher increase rate with toluene concentration than those with the dense-structured PCO films in the higher toluene-concentration range. On the other hand, the toluene response of the sensors attached with the dense-structured PCO films was much larger than with the rod-like structured PCO films in the lower toluene-concentration range. The electrochemical impedance measurements indicated that the toluene response is comprised of electrochemical reactions between the triple phase boundaries (PCO/YSZ/gas) and the double phase boundaries (DPBs, PCO/gas). In addition, the increased density of the thin PCO film enhances the contribution of DPBs on toluene response, resulting in the increased toluene response in the lower toluene-concentration range.