Sensor Applications Research Articles

Electrical Properties of Textured Bismuth Layer-Structured Ferroelectric Ceramics with Large Number of Layers (m = 5)

Bismuth layer-structured ferroelectrics (BLSF) ceramics are attractive materials for high temperature sensor applications, because of their high Curie temperature Tc (300–900 °C), and the large anisotropy of their electromechanical coupling factor kt/kp or k33/k31. In this study, BLSF ceramics with a large number of layers, namely, (K0.5Bi0.5)2Bi4Ti5O18 + MnCO3 0.3 wt%+ Bi2O3 0.025 wt% (KBT5) and Sr0.75Ca0.25Na0.5Bi4.5Ti5O18 + CeO2 1 wt% [(SC)NBT5] ceramics, were prepared by ordinary firing (OF) and hot forging (HF) methods, and their electrical and piezoelectric properties were examined. Both KBT5 and (SC) NBT5 ceramics showed high Tc values of 545 and 424 °C, respectively. The OF-KBT5 ceramic had an electromechanical coupling factor k33 of 0.14 and a piezoelectric constant d33 of 20 pC/N, whereas the HF-KBT5 ceramic had k33 of 0.17 and d33 of 31 pC/N. On the other hand, the OF-(SC) NBT5 ceramic had k33 of 0.13 and d33 of 17 pC/N, whereas the HF-(SC) NBT5 ceramic had k33 that increased to 0.32 and d33 to 41 pC/N. The k33 and d33 of the HF ceramics were improved compared with those of the OF ceramics. Thus, the KBT5 and (SC) NBT5 ceramics with oriented grains were shown to have good piezoelectric properties with high Tc.

Stretchable Metamaterials with Tamm/Fano Resonances for Tunable, Efficient Mechanochromic Color Shifting

AbstractNext‐generation wearable and optoelectronic technologies requires highly adaptable light manipulation capabilities for applications in sensors, displays, and optical switches on flexible substrates. Here, a cost‐effective approach is presented for realizing a Tamm Plasmon (TP) resonant device on a flexible platform by combining nanoimprint lithography with layer‐by‐layer assembly. The TP device incorporates a stretchable, 1D bragg (BRG) stack coupled with a gold (Au) and aluminum (Al) metasurface, whose dimensions are designed to enable tunability in the visible and near‐infrared (NIR) regions of the spectrum. The device exhibits substantial reflected intensities (≈75%) and a well‐defined, narrow TP minimum of approximately 30 nm. Both TP and Fano resonances can be clearly observed by incorporating symmetry‐broken metasurface features with the BRG stack. The integrated system is subjected to both uniaxial (up to 37% strain) and biaxial (up to 25% strain) stretching, demonstrating dynamic chromatic responses in both the visible and near‐infrared regimes with sensitivities of ≈6.2 nm/%. This work clearly demonstrates a cost‐effective route for the fabrication of multi‐plasmon resonant devices with tunable colors on a flexible platform.

Transition Metal (Cu, Pd, and Ag)-Modified Nb2S2C Monolayer for Highly Efficient Catechol Sensing: A First-Principles Investigation.

Motivated by recent advancements and the escalating application of two-dimensional (2D) gas or molecule sensors, this study explores the potential of the 2D Nb2S2C monolayer for detecting biomolecule catechol (Cc), whose excess concentration is highly dangerous to living beings. We use first-principles density functional theory (DFT) calculations to assess the Cc sensing performance of pure and transition metal (TM = Cu, Pd, Ag)-modified Nb2S2C monolayers. The Nb2S2C monolayer belonging to the new class of synthesized 2D materials, TM carbo-chalcogenides (TMCC), combines distinctive properties from both TM dichalcogenides and TM carbides and exhibits physisorption (-0.66 eV) toward the Cc molecule. Notably, the surface modifications with these TMs significantly enhanced the adsorption energy of Cc. The chemisorption of the Cc molecule on the Pd to Cu-modified monolayer is demonstrated with adsorption energies ranging from -1.09 to -1.3 eV and is due to the robust charge transfer and orbital interactions between the valence orbitals of TMs and Cc. In addition, the modification of the surface by TM leads to an increased work function sensitivity toward the Cc molecule. The study establishes the thermal stability at 300 K and dynamic stability of TM-Nb2S2C through ab initio molecular dynamics (AIMD) simulations and Phonon calculations, respectively. The theoretical estimation of achievable recovery time at 400 and 450 K for Pd and Ag and at 500 K for the Cu-modified Nb2S2C monolayer, respectively, confirms the potential practical application of the sensor for Cc detection. These compelling characteristics position the Nb2S2C monolayer as a promising nanomaterial for detecting Cc molecules in the environment.

Localized Surface Plasmon Resonance (LSPR) of Nanomaterials for Colorimetric Detection: A Review

Colorimetric sensors are attracting considerable interest across diverse fields owing to their ease of use, cost-effectiveness, and rapidity. Within this realm, Localized Surface Plasmon Resonance (LSPR) stands out as a favorable method for designing colorimetric sensing techniques. Sensors based on LSPR control the plasmonic characteristics of metallic Nanoparticles (NPs) to produce a noticeable alteration in color when a target analyte is detected. This article explores recent advancements in this field, including the integration of LSPR sensors with microfluidics and smartphone-based detection systems. The paper also investigates the applications of LSPR-based colorimetric sensors in diverse domains, such as environmental monitoring, biomedical diagnostics, food safety, and chemical detection. Furthermore, it sheds light on the potential limitations and prospects associated with LSPR-based colorimetric sensors, with a particular emphasis on the need for improved sensitivity, selectivity, and stability to facilitate broader practical applications.

Mapping dose distribution in small radiation field using dual-generation optical fiber X-ray sensor array technology

Small-field radiotherapy is an emerging technique that offers the potential to reduce damage to normal tissue, yet accurately measuring the dose distribution of small radiation fields presents a significant challenge. This study aims to develop an optical fiber X-ray sensor array (OFXSA) with high spatial resolution for dosimetry in small fields, thereby enhancing the effectiveness and safety of small-field radiotherapy treatments. The OFXSA combines the precision of single-point dosimeters with the ability to detect dose distribution across a small area. Two generations of sensor arrays were designed: the first-generation OFXSA comprises 7 optical fibers arranged in a hexagonal configuration (10.8 × 9.84 mm2), and the second-generation OFXSA consists of 37 optical fibers in a four-layer hexagonal distribution. These arrays were used to measure small field sizes of 1 × 1 cm2 and 0.8 × 0.8 cm2. Results from the first-generation OFXSA indicate dose distribution attenuation from the center to the periphery, while the second-generation OFXSA, with higher spatial resolution, captures more detailed and irregular dose attenuation, as well as non-uniform distribution across the field. This study demonstrates the viability of OFXSA for precise measurements in radiotherapy, particularly within small field dimensions, and lays the groundwork for future advancements in improving spatial resolution of sensor applications in small fields through complex fiber optic configurations.

Reduced graphene oxide/zinc oxide composite as an electrochemical sensor for acetylcholine detection

Acetylcholine (ACh) plays a pivotal role as a neurotransmitter, influencing nerve cell communication and overall nervous system health. Imbalances in ACh levels are linked to neurodegenerative diseases, such as Alzheimer's and Parkinson's. This study focused on developing electrochemical sensors for ACh detection, utilizing graphene oxide (GO) and a composite of reduced graphene oxide and zinc oxide (rGO/ZnO). The synthesis involved modified Hummers' and hydrothermal methods, unveiling the formation of rGO through deoxygenation and the integration of nano-sized ZnO particles onto rGO, as demonstrated by XPS and TEM. EIS analysis also revealed the enhancement of electron transfer efficiency in rGO/ZnO. Cyclic voltammograms of the electrode, comprising the rGO/ZnO composite in ACh solutions, demonstrated prominent oxidation and reduction reactions. Notably, the composite exhibited promise for ACh detection due to its sensitivity, low detection threshold, reusability, and selectivity against interfering compounds, specifically glutamate and gamma-aminobutyric acid. The unique properties of rGO, such as high specific surface area and electron mobility, coupled with ZnO's stability and catalytic efficiency, contributed to the composite's potential in electrochemical sensor applications. This research, emphasizing the synthesis, fabrication, and characterization of the rGO/ZnO composite, established itself as a reliable platform for detecting the acetylcholine neurotransmitter.

Gas‐sensing properties of polyaniline‐based nanocomposites for d‐limonene detection

AbstractThis paper introduces a novel wearable flexible gas sensor designed specifically for the detection of d‐limonene. The sensor utilizes materials recognized for their high efficiency‐to‐cost ratio, notably polyaniline (PANI) combined with carboxylated multiwalled carbon nanotubes (MWCNT) and graphene oxide (GO) as sensing layers. The study conducts a comprehensive analysis of the nanocomposite layers, examining their functional groups, morphology, topography, thickness, crystallinity, thermal behavior, surface area, as well as the size and volume of their pores. This examination showed distinctions among the nanocomposite layers. PANI/GO exhibited larger pore size and thickness, while PANI/MWCNT_COOH demonstrated a higher surface area. The analysis of thermal stability demonstrated that the film employing the DBSA dopant exhibited the lowest stability. Morphological characterizations showed a globular structure for PANI, tubular characteristics for PANI/MWCNT_COOH, and a flat nature for PANI/GO. When detecting d‐limonene, nanocomposite films doped with HCl demonstrated notably superior response levels. The gas sensors exhibited high sensitivity (>2.24 mV/ppm), a narrow range for the limit of detection (0.12–0.52 ppm), and excellent reversibility, stability, and selectivity. These findings suggest the possibility of broadening the application of gas sensors to monitor additional volatile compounds, with a particular emphasis on the online monitoring of agricultural products.

Magnetic anisotropy of NiFeP/Cu composite wire induced by chemical plating under DC current

NiFeP/Cu composite wires were fabricated by chemical plating under DC current. In this work, DC current was adjusted from 0 to 100 mA and the influence of current on the surface morphology, magnetic properties and GMI effect was investigated. It is found that the DC current has little impact on the composition of the coating. However, with the change of current, the surface morphology, plating rate and magnetic properties of the coating have undergone significant changes which in turn affect the GMI effect. As a result, when the appropriate current is applied, a transverse magnetic structure with an anisotropy angle of approximately 26 degrees can be generated, enabling a maximum GMI ratio of 1964 % and a field sensitivity of 463 %/Oe, which shows potential practical application in the magnetic sensors.

A universal electrochemical sensor for detection of nucleic acids and protein based on host-guest recognition of β-cyclodextrin polymer

A novel electrochemical sensing approach was developed to detect DNA, RNA, and protein targets, utilizing the host–guest interaction between methylene blue (MB)-labeled probe and β-cyclodextrin-based nanocomposite (rGO/β-CDP). During the assay, the MB-labeled probe interacted with the corresponding target to form a probe/target complex. Due to steric hindrance, the formation of this complex reduced the amount of MB-labeled probes that can be captured by the β-cyclodextrin-based nanocomposite on the electrode surface, resulting in a measurable decrease in the electrochemical signal. Upon optimization, the sensing platform exhibited satisfactory analytical performance for three cancer-related model analytes: p53 DNA, microRNA-21 RNA, and thrombin protein, achieving low detection limits of 3.4 nM, 4.4 nM, and 5.7 pM, respectively. In this work, the electrochemical assay separates the detection process into two stages: target recognition in solution and signal transduction on the electrode surface. This fabrication effectively circumvents the issues associated with nonspecific conformational changes and the complicated probe installation procedures on electrode surfaces that are common in traditional sensing platforms. Integrating host–guest recognition with electrochemical assay, the developed approach not only advances the understanding of host–guest chemistry in sensor applications but also establishes a foundation for future innovations in the detection of biomarkers.

Low-Cost Source Measure Unit (SMU) to Characterize Sensors Built on Graphene-Channel Field-Effect Transistors.

This study introduces a flexible and low-cost solution for a source measure unit (SMU), which is presented as an alternative to conventional source meter units and a blueprint for sensor FET drivers. An SMU collects current-voltage (I-V) curves with an additional variable voltage or current and is commonly used to characterize semiconductors. We present the hardware design, interfacing, and test results of our SMU. Specifically, we present representative I-V curve measurements for graphene-channel FETs to demonstrate the SMU's capability to efficiently characterize these devices with minimal noise and sufficient accuracy. This cost-effective solution presents a promising avenue for researchers and developers seeking reliable tools for sensor development and characterization. We demonstrate, with the example of surface illumination, how the sensing behavior of graphene-channel FETs can be characterized without the need for expensive equipment. Additionally, the SMU was validated with known passive and active components, along with probe station integration for semiconductor die-scale connection. The SMU's focus on collecting I-V curves, coupled with its ability to identify device defects, such as parasitic Schottky junctions or a failed oxide, contributes to its utility in quality testing for semiconductor devices. Its low-cost nature makes it accessible for various research endeavors, enabling efficient data collection and analysis for graphene-based and other nanomaterial-based sensor applications.

Conductive polymer composites for resistive flexible strain sensors

The emergence of wearable devices has spurred demand for strain sensors that are flexible, stretchable, and sensitive. Traditional strain sensors often lack stretchability due to the brittle nature of their materials. Conductive polymer composites (CPCs) are well-suited for this application due to their excellent flexibility, stretchability, and sensitivity, making them the material of choice for strain sensors. Resistive strain sensors, a common type of CPCs-based sensor, are favored for their cost-effectiveness, straightforward manufacturing process, and ease of signal collection. This review explores the sensing mechanisms of various resistive strain sensors, including percolation, crack propagation, contact resistance change and tunneling effect. It examines the impact of different fabrication processes and structural designs on sensor performance parameters including sensitivity, stretchability, linearity, and repeatability. Additionally, the advantages and challenges of integrating discrete sensors into high-density strain sensor arrays are discussed. Finally, we introduce the wide-ranging applications of CPCs-based strain sensors in multiple fields.

Progress in The Application of Flexible and Wearable Electrochemical Sensors in Monitoring Biomarkers of Athletes

AbstractAthletes continuously seek out creative methods and technologies to improve their physical fitness and overall performance. Wearable technology's progress offers a swift and eco‐conscious way to consistently observe physiological changes evidenced by biomarkers, stemming from an athlete's internal exertion or external workload. However, there is still a long distance to further understand the internal physiology of athletes which may bring hope to tailor training and recovery programs individually. The ongoing challenges faced by sports healthcare personnel are in finding biomarkers safely and continuously to control athletes' physical condition and tailor their recovery and eating patterns. The summary of this review encompasses the development of flexible and wearable electrochemical sensors. This article provides an overview of biofluids, commonly detected by wearable biochemical sensors and their mutual anatomical formations, with a focus on sweat and its associated biomarkers. Following this, its real‐world application in sports medicine becomes apparent, both theoretically and potentially. The paper ends by highlighting challenges and imagining the possible development of this exciting emerging field.

Utilization of jarosite and manganite mineral as raw material to fabricate metal-oxide composite film for gas sensor application

This study explores the utilization of Indonesia’s abundant geological resources, specifically jarosite and manganite minerals, to develop composite films for ethanol gas sensing applications. With jarosite’s Fe2O3 composition and manganite’s diverse applications in manganese oxide minerals, these minerals serve as promising raw materials. Building on prior research that employed Fe2O3 and manganese oxide composites, our focus lies in creating a cost-effective composite film comprising iron, manganese, and zinc oxides to enhance ethanol gas sensing capabilities. The fabrication process involves mineral extraction through a precipitation method, followed by composite synthesis and film formation using a screen-printing technique. Analysis of the resulting composite film’s morphological and crystal structure through SEM and XRD machines provides porosity and crystallinity characteristics. Examining electrical characteristics reveals the gas sensor behavior, emphasizing sensitivity and response in an ethanol environment. This study aims to contribute to gas sensor technology advancements, leveraging Indonesia’s geological wealth, promoting cost efficiency, and addressing critical aspects of sensitivity in gas sensor applications.

A microfluidic platform for automatic continuous flow layer‐by‐layer assembly of polymer multilayered nanofilms

AbstractCapillary flow layer‐by‐layer assembly is a microfluidic platform for high throughput preparation and screening of multilayered polymer nanofilms. However, it is time‐consuming and labor‐intensive, since the switching of polyelectrolyte solutions is done manually. As the emergence of flow chemistry and microdevices for artificial intelligence‐based lab automation, an automatic system that can switch polymer solutions and washing liquids is urgently needed for building functional LbL films inside microfluidic devices. Herein, we construct a continuous flow (ConF)‐layer‐by‐layer (LbL) device that can automatically fabricate polymer nanofilms inside a microfluidic device. By including a flow separator and a mixer (a model polyelectrolyte pair), chitosan and carboxymethyl cellulose can be deposited inside a microfluidic device using the ConF‐LbL system. Resulting nanofilms are studied by investigating thickness and surface roughness of the nanofilms and comparing with the other conventional LbL methods. The acid dissolution method was used to compare the differences in stability between nanofilms made from ConF‐LbL and static immersive method in similar conditions. Furthermore, by using one optimized film formulation for coating on the inside walls of a microfluidic chip, we successfully demonstrated the ability of this device to capture cancer cells in whole blood. This ConF‐LbL platform is expected to be a convenient tool to coat functional nanofilms inside microdevices for biomedical and sensor applications.

Enhancement of Excimer Formation Ability by Modulating the Length of Side-Chains in Polyhedral Oligomeric Silsesquioxane (POSS) and Application for Fluorescence Sensors for Metal Cations

Abstract Polyhedral oligomeric silsesquioxane (POSS) is a molecule with an inorganic cubic structure and organic side-chains and has attracted great attention for its application to luminescent materials by modifying luminophores. In this study, pyrenes-integrated POSSs with various lengths of side-chains were synthesized and the effect of the length on luminescent properties was evaluated. In optical measurements, highly efficient excimer emission was observed under dilute solution conditions. The higher value of the intensity ratio of the excimer emission to the monomer one was detected in the shortest side-chains. It is likely that the shorter side-chains of POSS lead to more efficient intramolecular interaction. Interestingly, we also found that the luminescence color was changed in response to metal cations in the dilute solutions. From the mechanistic study, metal cations such as Cu2+ can accelerate hydrolysis at the linker moiety. As a result, highly-sensitive luminescent sensors were obtained. These data represent that POSS can work as a reaction field where chemical reactions are accelerated through the accumulation of reactive species.

Disposable amperometric biotool for peanut detection in processed foods by targeting a chloroplast DNA marker

This work reports the development and application of a disposable amperometric sensor built on magnetic microcarriers coupled to an Express PCR strategy to amplify a specific DNA fragment of the chloroplast trnH-psbA. The procedure involves the selective capture of a 68-mer synthetic target DNA (or unmodified PCR products) through sandwich hybridization with RNA capture probe-modified streptavidin MBs and RNA signaling probes, labeled using antibodies specific to the heteroduplexes and secondary antibodies tagged with horseradish peroxidase. Amperometric measurements were performed on screen-printed electrodes using the H2O2/hydroquinone system. Achieving a LOD of 3 pM for the synthetic target, it was possible to detect 2.5 pg of peanut DNA and around 10 mg kg−1 of peanut in binary mixtures (defatted peanut flours prepared in spelt wheat). However, the detectability decreased between 10 and 1000 times in processed samples depending on the treatment. The Express PCR-bioplatform was applied to the detection of peanut traces in foodstuff.

Application of artificial intelligence Sensors based on random forest algorithm in financial recognition models

Due to the important role of financial information disclosed by enterprises in investor decision-making and economic policy formulation, the corporate market has set the latest standards and requirements for the quality of financial reports. In the current situation, financial recognition work is mainly completed manually, which is inefficient and prone to errors, and is not suitable for large-scale applications. Therefore, we conduct in-depth research on financial recognition models. Firstly, we analyzed the random forest algorithm and used the SMOTE algorithm to expand the sample data. We successfully constructed an optimized random forest algorithm model, which can better improve accuracy and reduce misjudgment rates. Secondly, combined with the current financial data analysis of artificial intelligence technology, the steps for data management and data extraction were designed. Finally, while establishing a financial recognition model, a channel for obtaining internet information and a program for processing this information were also established. After experimental verification, the random forest model has shown better fitting performance in the field of financial fraud identification, providing more reliable support for applications in this field. Therefore, the financial recognition model constructed using artificial intelligence technology based on random forest algorithm has significant value in both theoretical and practical aspects, effectively reducing corporate financial risks.

A comprehensive study of ferroelectric, dielectric and optical properties of europium-doped SBD metal- organic framework

The synthesis of Europium-doped Strontium based benzene dicarboxylate dimethylformamide metal–organic framework- Eu([Sr(μ-BDC)(DMF)])- with short form as Eu:SBD@MOF was carried out using the solvothermal method. The investigation involved characterization techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), CHN analysis, and energy-dispersive X-ray (EDX) elemental analysis. The results confirmed the formation of metal–organic crystals in the framework. The XRD characterization shows good alignment with the simulated pattern of SBD. The experimental absorption spectrum displays distinct transitions of the Eu (III) ion alongside transitions of the ligands. Calculations of line strengths for all observed transitions have been conducted. The Judd-Ofelt theory has been employed to determine intensity parameters, transition probabilities, branching ratios, and radiative lifetimes for the Eu: SBD@MOF. These JO parameters further aid in calculating various excited state properties. When excited by ultraviolet and visible photons, the complex exhibits emission in the red region respectively. The crystal’s dielectric loss and dielectric constant were investigated for their frequency dependence. It was observed that by virtue of DMF, a molecule linked to the crystal, a synthesized MOF exhibits a good dielectric characteristic and when the temperature is raised to 558 K, the dielectric constant drops sharply as DMF molecule could not stand after this temperature. Further ferroelectric studies reveal that the Eu: SBD@MOF has maximum polarization of 0.27 C/cm2 which is greater than Rochelle salt and other MOF’s. Exploring the broadband dielectric response of metal–organic frameworks (MOFs) open up new avenues in research, potentially leading to innovative applications in smart optoelectronics, terahertz sensors, high-speed telecommunications, and microelectronics.

Sweat-enhanced adhesive hydrogel enables interfacial exchange coupling for wearable strain sensor

PVA-based wearable hydrogels have emerged as promising candidate for motion sensors due to their skin-like softness and unique biocompatibility. However, an open question is whether and how the strain-sensitive hydrogel designing can prevent adhesive performance loss caused by sweat between devices and human-skin and reduce interfacial failure. Herein, a versatile sweat-enhanced adhesive hydrogel-based motion sensor (VDBA) paradigm is engineered consisting of sweat sensitivity and self-adhesive function components. Taking advantage of catechol chemistry inspired mussel, the VDBA hydrogel enhances substrate adhesion behavior. The borate ions (B(OH)4−) are found to efficient condensation form borate ester groups with phenolic hydroxyl. Interestingly, human sweat pH serves as a trigger for borate ester bonds protection-deprotection, whereby partial catechol primarily functions in non-sweating states and significantly activates during sweating. The VDBA hydrogel achieves a maximum adhesive strength of 13.45 kPa on skin at non-sweat, however, the maximum bonding strength increases to 24.0 kPa when sweating. The resultant VDBA hydrogel exhibits integration of exceptional mechanical properties and anti-freezing properties. Also, desirable conductivity appears in the hydrogel, allowing outputting accurate and repeatable signals for body motion sensing in various scenarios. Furthermore, VDBA hydrogel is demonstrated for use as a sports training times counter, which can achieve sensitive statistics for stretching and bending movements. This work provides a great hydrogel candidate for various motion sensor applications, particularly beneficial for people with sweaty skin and athletes.

DFT insights into the electronic properties and gas sensing performance of C19X (X = C, N, and Si) nanocages for the detection of CO2, CO, N2, and H2 gases

The development of carbon nanocage-based sensors for the detection of toxic and pollutant gases has attracted significant attention from researchers. In this computational study, the interactions of CO2, CO, N2, and H2 gases with the C19X nanocages (X = C, N, and Si) were evaluated using the M062X/6-31G(d) level of density functional theory (DFT) calculations. The results demonstrated a reduction in the energy gap (Egap) across all studied systems, especially pronounced in the C19N and C19Si nanocages, compared to the complexes with a higher priority of the C19Si nanocages. The gas molecules were found to have weak adsorption in all the C20 nanocage complexes, while the adsorption of CO gas was more pronounced in the C19N and C19Si nanocages compared to the other gases studied. A quantum theory of atoms in molecule (QTAIM) analysis was conducted to examine the interactions and their features, through which the physical interactions that contribute to the formation of the complexes were identified. Further electrical characterizations revealed that the C19Si nanocage has a high sensitivity for the detection of CO gas, making it a promising sensor material. In conclusion, the engineered C19N and C19Si nanocages demonstrated significant improvements over the original C20 nanocage in terms of adsorption capabilities for CO2, CO, N2, and H2 gases, making them promising candidates for sensor applications.