Sensor Applications Research Articles

PVA/chitosan-based multifunctional hydrogels constructed through multi-bonding synergies and their application in flexible sensors

PVA/chitosan-based multifunctional hydrogels constructed through multi-bonding synergies and their application in flexible sensors

Y, Yb, and Gd tri-doping on B-site of Ba(Zr, Ce)O3-δ with improved proton conduction performance

Perovskite-type proton conducting electrolytes are garnering significant attention due to its key role in protonic ceramic electrochemical cells (PCEC) and its application in hydrogen sensors (HS) used for metal melt measurements. Developing high proton conduction perovskite materials with good chemical stability is always a worldwide research focus. In this paper, Y, Yb and Gd triple-doping on B-site of BaCeO3-BaZrO3 solid solution were carried out to investigate the effect of gadolinium doping on the performance of protonic conducting electrolytes. BaZr0.1Ce0.7(Y0.5Yb0.5)0.2-xGdxO3-δ (x = 0, 0.1, 0.15 and 0.2), which were also referred as BZCYYbGdx (x = 0, 10, 15 and 20), were synthesized by solid-state reaction at 1600 °C for 10 h. It is found that BZCYYbGd15 has the highest proton conductivity and proton transfer number among the four prepared materials. The proton mobility of BZCYYbGd15 is 4.06 × 10−6 cm2/(Vꞏs) at 800 °C, which increases with an increased temperature. Its proton transfer number is higher than 0.9 at 500 °C under the atmosphere of PH2O = 0.018 atm. A moderate doping of gadolinium increases the temperature threshold for proton conduction. Proton, oxygen vacancy, electron hole and total conductivity activation energies of BZCYYbGd15 under the wet atmosphere are found to be 0.74, 1.58, 1.41 and 0.92 eV, respectively. Furthermore, the chemical stability of pellets is improved after gadolinium doping. This study provides a reference value for future research on high proton conduction electrolytes.

Environmentally stable and multi-functional conductive gelatin/PVA/black wattle bark tannin based organogel as strain, temperature and bioelectric sensor for multi-mode sensing

Conductive hydrogels are regarded as ideal candidates for the application of flexible sensors owing to their excellent flexibility, portability and conductivity. However, it is still challenging and meaningful to prepare multifunctional (self-healing, adhesion, anti-freezing, biocompatibility, antibacterial and conductivity properties) and multi-mode sensing hydrogel-based sensors. Herein, we developed an environmentally stable and multi-functional conductive organogel via dynamic crosslinks based on biomass materials gelatin, black wattle bark tannin and PVA in the propylene glycol/water binary solvent system. Thanks to the dynamic interactions in the system, the good mechanical strength and self-healing performance of the obtained organogel are simultaneously realized. Meanwhile, the organogel integrates many crucial properties such as adhesion, environmental stability (anti-freezing and water retention), biocompatibility, antibacterial behavior and conductivity capacity. Significantly, the organogel can be assembled as three-mode sensors for strain, bioelectricity and temperature sensing. This three-mode sensor can effectively monitor human health data, resulting in providing supplement human health information and conditions. This work displays an interesting approach to construct an intelligent multi-functional conductive biomass organogel based multi-mode flexible sensors.

Wearable Technology Applications and Methods to Assess Clinical Outcomes in Foot and Ankle Disorders: Achievements and Perspectives.

Foot and ankle disorders are a very common diseases, represent a risk factor for falls in older people, and are associated with difficulty performing activities of daily living. With an increasing demand for cost-effective and high-quality clinical services, wearable technology can be strategic in extending our reach to patients with foot and ankle disorders. In recent years, wearable sensors have been increasingly utilized to assess the clinical outcomes of surgery, rehabilitation, and orthotic treatments. This article highlights recent achievements and developments in wearable sensor-based foot and ankle clinical assessment. An increasing number of studies have established the feasibility and effectiveness of wearable technology tools for foot and ankle disorders. Different methods and outcomes for feasibility studies have been introduced, such as satisfaction and efficacy in rehabilitation, surgical, and orthotic treatments. Currently, the widespread application of wearable sensors in clinical fields is hindered by a lack of robust evidence; in fact, only a few tests and analysis protocols are validated with cut-off values reported in the literature. However, nowadays, these tools are useful in quantifying clinical results before and after clinical treatments, providing useful data, also collected in real-life conditions, on the results of therapies.

Preparation of PAAS/GL/GO anti-freezing conductive hydrogels based on chemical cross-linking networks and their application in wearable sensors

Preparation of PAAS/GL/GO anti-freezing conductive hydrogels based on chemical cross-linking networks and their application in wearable sensors

Helical Long-Period Grating Through a Commercial CO2 Laser Fiber Processing Machine for Torsion Sensor Applications

Helical Long-Period Grating Through a Commercial CO₂ Laser Fiber Processing Machine for Torsion Sensor Applications

AgNPs/CNTs modified nonwoven fabric for PET-based flexible interdigitated electrodes in pressure sensor applications

Intelligent wearable sensing technology plays a pivotal role in the era of the Internet of Things and artificial intelligence, especially for human–machine interaction, physiological monitoring, and intelligent robotics. However, achieving a wide sensing range, high sensitivity, and ultra-long durability in pressure sensors while maintaining a simple and cost-effective fabrication remains challenging. This study presents a novel pressure sensor using silver nanoparticles (AgNPs) and carbon nanotubes (CNTs) modified nonwoven fabric for polyethylene terephthalate (PET) flexible interdigitated electrodes (IDEs). A low-cost spray-coating method was employed to deposit AgNPs/CNTs onto nonwoven fabric as the sensing layer, which was then combined with PET-based IDEs and encapsulated using polyimide (PI) film. The resulting piezoresistive sensor exhibits an extensive sensing range up to 90 kPa, high sensitivity up to 20 kPa−1 within 0–2 kPa, rapid response/recovery times (48 ms/44 ms), and outstanding repeatability over 6000 cycles. It can be assembled into an electronic skin tactile sensor array for mapping tactile size and orientation, and integrated into clothing for real-time monitoring of physiological signals like pulse, heartbeat, and grasp force. This work proposes a novel approach for developing wearable, highly sensitive, and wide-ranging pressure sensors, showing potential for multifunctional applications in next-generation artificial electronic skin, personal health monitoring, intelligent robotics, and human–machine interaction

Review and analysis on numerical simulation and compact modeling of InGaZno thin-film transistor for display SENSOR applications

Recent years have seen an increase in the use of Organic Thin Film Transistors (OTFTs), with applications ranging from flexible, low-cost displays to organic memory, RFID tag components, low-cost electronic appliances, and polymer circuits and sensors. Thin-film transistors (TFTs) have developed into a critical business on the grounds levels to their wide scope of utilizations in display; Radio-Frequency ID labels (RFID SENSOR), intelligent computation, and different areas. Reduced models are basic in the turn of events and execution of TFTs on the grounds that they overcome any barrier between the manufacture cycle and circuit plan. The motivation behind this exploration is to assemble a hypothetical structure for nanoscale TFT models made of polysilicon, indistinct silicon, natural, and In-Ga-Zn-O (IGZO) semiconductors. Extraordinary consideration is paid to surface-expected based smaller models of silicon-based TFTs. Surface-potential-based compact models and parameter extraction approaches were presented based on our knowledge of charge transport characteristics and TFT needs in organic and IGZO TFTs.

Enhancing Low-Temperature Sensor Applications: Synergistic Effects of Ni Doping and SnO2 Interlayer on Spin-Coated ZnO Thin Films on Glass Substrate

This study investigates the effects of Nickel doping and a SnO2 interlayer on the structural, morphological, optical, and electrical properties of ZnO thin films. Undoped and Ni-doped ZnO films were fabricated on glass substrates, with and without an SnO2 interlayer, using the sol-gel spin coating method. The samples—denoted as ZG (undoped ZnO), NZG (Ni-doped ZnO), ZSG (undoped ZnO with SnO2 interlayer), and NZSG (Ni-doped ZnO with SnO2 interlayer)—underwent comprehensive characterization via XRD, AFM, PL, UV-Vis spectroscopy, Hall effect measurements, Hot probe, and Two-point method. XRD analysis confirmed successful Ni incorporation and enhanced ZnO crystallinity, particularly in the presence of the SnO2 interlayer. AFM analysis revealed improved grain distribution and size due to the synergistic effects of Ni doping and the SnO2 interlayer. UV-Vis results indicated significant impacts on transparency and the Urbach energy, with Ni doping alone broadening the bandgap. PL measurements showed that the synergistic effects quenched UV luminescence associated with the glass substrate, enhancing visible luminescence. Chromaticity analysis suggested that ZSG and NZSG samples are suitable for warm blue region applications. Electrical measurements revealed n-type conductivity across all films except NZG, with Ni doping increasing resistivity. Additionally, the ZSG (PTC) sensor exhibited a slightly higher sensitivity (0.3852 Ω/°C) compared to the NZSG sensor (0.3782 Ω/°C), with a similar trend observed in NTC sensors. These findings suggest that Ni-doped ZnO films with SnO2 interlayers could potentially serve as thermistors and RTDs, offering promising applications in temperature sensing and optoelectronics.

Machine learning framework for selective and sensitive metal ion sensing with nitrogen-doped graphene quantum dots heterostructure

This study introduces a machine learning (ML) framework to optimize photodetector performance for sensor applications. Using the data from the fabricated photodetector with the heterostructure of nitrogen-doped graphene quantum dot and gold nanoparticles (Au@N-GQDs), various supervised ML models (more than 20 models) are trained and tested for the selection and refinement of the most effective algorithm for our work. Depending on the best-performed ML model, the optimized working wavelength of the photodetector is found for the detection of metal ions. Remarkably, the ML-based sensor shows a high level of selectivity and sensitivity in nM level towards Fe3+ ions in Brahmaputra river water. A strong alignment between model predictions and experimental outcomes validates the efficacy of the proposed ML-based framework. Moreover, data visualization techniques such as heatmaps, classification algorithms, and confusion matrices are introduced to identify the trends in the database. The mechanistic insight of the sensor performance towards Fe3+ ion sensing is further explained with heatmap analysis and experimental verification, which emphasizes the role of photo-induced charge transfer and Fe–O bond formation between metal ions and Au@N-GQDs due to the high electron affinity of Fe3+ ions.

Research on N, Ne, and P adsorption on boron-germanene nanoribbons for nano sensor applications

The study investigated the adsorption of N, P, and Ne atoms on boron-germanene nanoribbons (BGeNRs) using density functional theory (DFT) and the Vienna Ab initio Simulation Package (VASP). Results indicated that both the pristine and adsorbed configurations exhibited metallic behavior. While the pristine and Ne-adsorbed configurations were nonmagnetic, the N- and P-adsorbed configurations displayed magnetic moments of 1.81 μB and 1.21 μB, respectively. The N-adsorbed configuration had the lowest adsorption energy, whereas the Ne-adsorbed configuration exhibited a positive adsorption energy. Multi-orbital hybridization analysis revealed that hybridization processes predominantly occurred in the conduction band at energy levels corresponding to the σ bond. Charge density difference analysis showed significant charge transfer between the substrate and the adsorbed elements. Additionally, optical properties, including the real and imaginary parts of the dielectric function, absorption coefficient, and electron-hole density, were systematically examined to highlight the variations. The findings underscore the potential application of BGeNR materials in nanosensors.

Transition Edge Sensors: Physics and Applications

Transition Edge Sensors (TESs) are amongst the most sensitive cryogenic detectors and can be easily optimized for the detection of massive particles or photons ranging from X-rays all the way down to millimetre radiation. Furthermore, TESs exhibit unmatched energy resolution while being easily frequency domain multiplexed in arrays of several hundred pixels. Such great performance, along with rather simple and sturdy readout and amplification chains make TESs extremely compelling for applications in many fields of scientific endeavour. While the first part of this article is an in-depth discussion on the working principles of Transition Edge Sensors, the remainder of this review article focuses on the applications of Transition Edge Sensors in advanced scientific instrumentation serving as an accessible and thorough list of possible starting points for more comprehensive literature research.

3D-Printed Multi-Axis Alignment Airgap Dielectric Layer for Flexible Capacitive Pressure Sensor

Flexible pressure sensors are increasingly recognized for their potential use in wearable electronic devices, attributed to their sensitivity and broad pressure response range. Introducing surface microstructures can notably enhance sensitivity; however, the pressure response range remains constrained by the limited volume of the compressible structure. To overcome this limitation, this study implements an aligned airgap structure fabricated using 3D printing technology. This structure, designed with a precisely aligned triaxial airgap configuration, offers high deformability under pressure, substantially broadening the pressure response range and improving sensitivity. This study analyzes the key structural parameters—the number of axes and pore size—that influence the compressibility and stability of the dielectric material. The results indicate that the capacitive pressure sensor with an aligned airgap structure, manufactured via 3D printing, exhibits a wide operating pressure range (50 Pa to 500 kPa), rapid response time (100 ms), wide limit of detection (50 Pa), and approximately 21 times enhancement in sensitivity (~0.019 kPa−1 within 100 kPa) compared with conventional bulk structures. Furthermore, foot pressure monitoring trials for wearable sensor applications demonstrated exceptional performance, indicating the sensor’s suitability as a wearable device for detecting plantar pressure. These findings advocate for the potential of 3D printing technology to supplant traditional sensor manufacturing processes.

Chemical-Physical Synergistic Assembly of MXene/CNT Nanocoatings in Silicone Foams for Reliable Piezoresistive Sensing in Harsh Environments.

Owing to their high sensitivity across a wide stress range, mechanical reliability, and rapid response time, flexible polymer foam piezoresistive sensors have been extensively used in various fields. The reliable application of these sensors under harsh environments, however,is severely limited by structural devastation and poor interfacial bonding between polymers and conductive nanoparticles. To address the above issues, robust MXene/CNT nanocoatings on the foam surface, where the chemical assembly of MXene nanosheets and the physical anchoring of CNTs lead to strong interfacial bonding, are designed and described, which endows foams with structural reliability and unexpected multi-functionalities without compromising their instinct properties. The optimized foam nanocomposites thus maintain outstanding wide-temperature flexibility (-60-210 °C) and elasticity (≈3% residual strain after 1000 cycles). Moreover, the nanocomposites display good sensitivity at a relatively wide stress range of 0-70% and remarkable stability under acidic and alkaline settings. Furthermore, the foams with exceptional fire resistance (UL-94 V-0 rating) can provide stable sensing behavior (over 300 cycles) even after being exposed to flames for 5 s, making them one of the most reliable sensing materials so far. Clearly, this work widens applications of flexible piezoresistive sensors based on silicone foam nanocomposites for various harsh environments.

Nanomaterials in electronics: Advancements and challenges in high-performance devices

Nanomaterials, such as graphene, carbon nanotubes, and metal oxides, are revolutionizing the field of electronics by enabling the development of high-performance devices. This study provides a comprehensive overview of the synthesis, characterization, and application of these nanostructured materials. The unique properties of nanomaterials, including exceptional electrical conductivity, thermal management capabilities, and potential for device miniaturization, offer significant advantages over traditional materials. Graphene, for instance, exhibits remarkable electrical and thermal conductivity, making it an ideal candidate for applications in transistors and sensors. Carbon nanotubes, known for their strength and conductivity, enhance the performance of various electronic components, while metal oxides play a crucial role in semiconductor applications. Despite these advancements, several challenges remain. Issues related to scalability hinder the large-scale production of nanomaterials, while reproducibility concerns affect the reliability of devices fabricated from these materials. Moreover, the environmental impact of synthesizing and disposing of nanomaterials raises significant ethical considerations that must be addressed as the field progresses. This paper aims to provide insights into the current research trends and potential future directions, highlighting the need for sustainable practices in the synthesis and application of nanomaterials in electronics. By addressing these challenges, we can pave the way for the next generation of high-performance electronic devices that are not only efficient but also environmentally responsible.

Application of Electroencephalography Sensors and Artificial Intelligence in Automated Language Teaching.

This study developed an automated language learning teaching assessment system based on electroencephalography (EEG) and differential language large models (LLMs), aimed at enhancing language instruction effectiveness by monitoring learners' cognitive states in real time and personalizing teaching content accordingly. Through detailed experimental design, the paper validated the system's application in various teaching tasks. The results indicate that the system exhibited high precision, recall, and accuracy in teaching effectiveness tests. Specifically, the method integrating differential LLMs with the EEG fusion module achieved a precision of 0.96, recall of 0.95, accuracy of 0.96, and an F1-score of 0.95, outperforming other automated teaching models. Additionally, ablation experiments further confirmed the critical role of the EEG fusion module in enhancing teaching quality and accuracy, providing valuable data support and theoretical basis for future improvements in teaching methods and system design.

Triphenylene-Based 2D cMOFs: Unraveling the H2S Sensing Mechanism and Applications for a Real-Time Wireless Chemiresistive Sensor.

Two-dimensional conductive metal-organic frameworks (2D cMOFs) stand at the forefront of chemiresistive sensing innovations due to their high surface areas, distinctive morphologies, and substantial electronic conductivity. Particularly, 2D cMOFs crafted using 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) and 2,3,6,7,10,11-hexaiminotriphenylene (HITP) organic ligands have garnered a large amount of attention due to their designable active sites and proper conductive characteristics. Nevertheless, a deeper exploration into their sensing mechanisms is imperative for a comprehensive understanding of the intrinsic chemistry, which is crucial for the intricate design of specialized 2D cMOF chemiresistive sensors. In this study, we fabricate six M-HXTP (M = Co, Ni, and Cu; X = H and I) chemiresistive sensors, focusing on the application of hydrogen sulfide (H2S) detection. Among these, the 2D cMOFs incorporating Cu metal manifested a remarkably enhanced response to H2S. A combination of experimental and computational studies unveils the mechanisms of sulfur oxidation and Cu reduction, wherein distortion of the reduced MX4 cluster markedly amplifies the sensing response. Lastly, a real-time and portable wireless H2S sensing module has been demonstrated by using the Cu-HHTP composite material, highlighting the substantial practical significance and potential applicability.

Sensors for Smoking Detection in Epidemiological Research: Scoping Review.

The use of wearable sensors is being explored as a challenging way to accurately identify smoking behaviors by measuring physiological and environmental factors in real-life settings. Although they hold potential benefits for aiding smoking cessation, no single wearable device currently achieves high accuracy in detecting smoking events. Furthermore, it is crucial to emphasize that this area of study is dynamic and requires ongoing updates. This scoping review aims to map the scientific literature for identifying the main sensors developed or used for tobacco smoke detection, with a specific focus on wearable sensors, as well as describe their key features and categorize them by type. According to the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) protocol, an electronic search was conducted on the PubMed, MEDLINE, and Web of Science databases, using the following keywords: ("biosensors" OR "biosensor" OR "sensors" OR "sensor" OR "wearable") AND ("smoking" OR "smoke"). Among a total of 37 studies included in this scoping review published between 2012 and March 2024, 16 described sensors based on wearable bands, 15 described multisensory systems, and 6 described other strategies to detect tobacco smoke exposure. Included studies provided details about the design or application of wearable sensors based on an elastic band to detect different aspects of tobacco smoke exposure (eg, arm, wrist, and finger movements, and lighting events). Some studies proposed a system composed of different sensor modalities (eg, Personal Automatic Cigarette Tracker [PACT], PACT 2.0, and AutoSense). Our scoping review has revealed both the obstacles and opportunities linked to wearable devices, offering valuable insights for future research initiatives. Tackling the recognized challenges and delving into potential avenues for enhancement could elevate wearable devices into even more effective tools for aiding smoking cessation. In this context, continuous research is essential to fine-tune and optimize these devices, guaranteeing their practicality and reliability in real-world applications.

1D/2D Heterostructures: Synthesis and Application in Photodetectors and Sensors.

Two-dimensional (2D) semiconductor components have excellent physical attributes, such as excellent mechanical ductility, high mobility, low dielectric constant, and tunable bandgap, which have attracted much attention to the fields of flexible devices, optoelectronic conversion, and microelectronic devices. Additionally, one-dimensional (1D) semiconductor materials with unique physical attributes, such as high surface area and mechanical potency, show great potential in many applications. However, isolated 1D and 2D materials often do not meet the demand for multifunctionality. Therefore, more functionality is achieved by reconstructing new composite structures from 1D and 2D materials, and according to the current study, it has been demonstrated that hybrid dimensional integration yields a significant enhancement in performance and functionality, which is widely promising in the field of constructing novel electronic and optoelectronic nanodevices. In this review, we first briefly introduce the preparation methods of 1D materials, 2D materials, and 1D/2D heterostructures, as well as their advantages and limitations. The applications of 1D/2D heterostructures in photodetectors, gas sensors, pressure and strain sensors, as well as photoelectrical synapses and biosensors are then discussed, along with the opportunities and challenges of their current applications. Finally, the outlook of the emerging field of 1D/2D heterojunction structures is given.

Investigating the Suitability of Cu2ZnSnS4 Thin Films for Gamma Radiation Dosimetry Applications in Non-Medical Environments

Abstract The need for the replacement of cadmium, indium, and tellurium in their compounds for sensor applications is a novel study. The Cu2ZnSnS4 thin films were synthesized from Cu (99.99%), Sn (99.99%), and Zn (99.99%) using thermal evaporation method. The same volumetric parameters were maintained throughout the synthesis process. The films were further irradiated using an isotope of cesium-137 from a gamma source at different doses (0–0.6 kGy) and dose rates of 0.1007 kGy/hr at room temperature. Both the pristine and irradiated films were characterized with Raman spectroscopy, field emission scanning electron microscope (FESEM), energy dispersive X-rays (EDX), UV-Vis spectroscopy, and four-point probe techniques. The Raman results confirmed that all the films for both pristine and irradiated films have a main and secondary phases. The EDX results showed the pristine and 0.1 kGy films were Cu-rich film, while the 0.3 kGy and 0.6 kGy films turned out to be Zn-rich films with an increase in gamma dose. The optical property of all the films showed that the band gap decreased from 1.6 eV to 1.48 eV for the pristine and irradiated films. While the electrical resistivity results decreased after irradiation dose. The structural, optical, and electrical properties results responded linearly with the increasing gamma radiation dose, which suggested the possibility of using films as a new solid-state sensor to replace CdTe and CIGS thin films.