Interdigitated Electrodes Research Articles

Reversible electronic modulation of polydiacetylenes for sensing in dynamic conditions

AbstractPolydiacetylenes (PDAs) are renowned for their exceptional optical properties intricately linked to the polymer conformation, yet they exhibit poor conductivity in their undoped state. Despite this drawback, PDAs have garnered significant interest as sensing materials owing to their ability to undergo colorimetric shifts from blue to red in response to external stimuli. However, the irreversible nature of this transition has limited their utility in dynamic environments. In this study, we augment the sensing capabilities of PDA films beyond their irreversible optical response by inducing a reversible electronic response through conductivity modulation. We investigated polyamine‐substituted PDAs with enriched hydrogen‐bonding interaction sites for the concurrent changes in colorimetry and conductivity upon acetic acid (AA) vapor exposure. Coated on a flexible interdigitated electrode (IDE), we monitor the conductivity change throughout the blue‐to‐red phase transition. Remarkably, AA molecules act as dopants, significantly amplifying the system's conductivity. Although the PDA coating retains its red phase at postdopant removal, the electronic response reverts to its initial state, demonstrating reversibility. This reversible electronic response offers invaluable real‐time insights into the specific triggers within dynamic environments, underscores the adaptability of responsive conjugated polymers, and highlights a promising avenue for their utilization in various sensing and monitoring applications.

Development of conductive carbon-based interdigitated electrode array integrated with microfluidic channel for blood glucose sensing

PurposeThis study aims to provide a microfluidic blood glucose sensing platform based on integrated interdigitated electrode arrays (IDEAs) on a flexible quartz glass substrate, adhering closely to pertinent electrochemical characterizations.Design/methodology/approachSensors are the key elements of the modern electronics era through which all the possible physical quantities can be detected and converted into their equivalent electrical form and processed further. But to make the sensing environment better, various types of innovative architectures are being developed nowadays and among them interdigitated electrodes are quite remarkable in terms of their sensing capability. They are a well-qualified candidate in the field of gas sensing and biosensing, but even their sensitivities are getting saturated due to their physical dimensions. Most of the thin film IDEAs fabricated by conventional optical lithographic techniques do not possess a high surface-to-volume ratio to detect the target specified and that reduces their sensitivity factor. In this context, a classic conductive carbon-based highly sensitive three dimensional (3D) IDEA-enabled biosensing system has been conceived on a transparent and flexible substrate to measure the amount of glucose concentration present in human blood. 3D IDEA possesses a way better capacitive sensing behavior compared to conventional thin film microcapacitive electrodes. To transmit the target biological analyte sample property for the detection purpose to the interdigitated array-based sensing platform, the design of a microfluidic channel is initiated on the same substrate. The complex 3D Inter Digital array structure improves the overall capacitance of the entire sensing platform and the reactive surface area as well. The manufactured integrated device displays a decent value of sensitivity in the order of 5.6 µA mM−1 cm−2.FindingsDevelopment of a low-cost array-based integrated and highly flexible microfluidic biochip to extract the quantity of glucose present in human blood.Originality/valuePotential future research opportunities in the realm of integrated miniaturized, low-cost smart biosensing systems may arise from this study.

Embroidered Interdigitated Electrodes (IDTs) with Wireless Readout for Continuous Biomarker Monitoring.

Non-invasive continuous health monitoring has become feasible with the advancement of biosensors. While monitoring certain biomarkers such as heart rate or skin temperature are now at a certain maturity, monitoring molecular biomarkers is still challenging. Progress has been shown in sampling, measurement, and interpretation of data toward non-invasive molecular sensors that can be integrated into daily wearable items. Toward this goal, this paper explores the potential of embroidered interdigitated transducer (IDT)-based sensors for non-invasive, continuous monitoring of human biomarkers, particularly glucose levels, in human sweat. The study employs innovative embroidery techniques to create flexible fabric-based sensors with gold-coated IDTs. In controlled experiments, we have shown the variation of glucose concentration in water can be wirelessly detected by tracking the resonant frequency of the embroidered sensors. The current sensors operate at 1.8 GHz to 2 GHz and respond to the change in glucose concentration with a sensitivity of 0.17 MHz/(mg/dL). The embroidered IDT-based sensors with wireless sensing will be a new measurement modality for molecular wearable sensors. The establishment of a wireless sensing mechanism for embroidered IDT-based sensors will be followed by an investigation of sweat for molecular detection. This will require adding functionalities for sampling and interpretation of acquired data. We envisage the embroidered IDT-based sensors offer a unique approach for seamless integration into clothing, paving the way for personalised, continuous health data capture.

Skin-inspired interlocked microstructures with soft-hard synergistic effect for high-sensitivity and wide-linear-range pressure sensing

Flexible pressure sensors have shown great application potential in intelligent robotics, healthcare monitoring, and human–machine interfaces. However, critical challenge exists in reconciling the trade-off between high sensitivity and wide linear sensing range. Here, inspired by the delicate microstructures of human skin, a piezoresistive pressure sensor with soft-hard synergistic interlocked (SHSI) microstructures is proposed to enhance the sensitivity while maintaining broad linear sensing range. The proposed SHSI sensor is face-to-face assembled by a soft sensing layer with spinosum microstructures and a hard interdigital electrode layer with dome microstructures. The design of SHSI microstructures enables efficient mechanical stimulus amplification and consistent compressibility of the sensor under pressure. Consequently, the as-prepared SHSI sensor simultaneously exhibits a maximum sensitivity as high as 67.1 kPa−1 and a wide linear working range up to 650 kPa. Meanwhile, low limit of detection (7 Pa), fast response (40 ms) and recovery (37 ms), as well as prominent stability and durability over 10,000 cycles of the sensor are realized. Owing to these outstanding sensing performances, the successful applications of the SHSI sensor in physiological signal monitoring and wearable human–machine interfaces are demonstrated. This work offers a general design approach to achieve coordination of high sensitivity and broad linear range of flexible pressure sensors.

A closed-loop patch based on bioinspired infection sensor for wound management

Pathogenic wound infections remain a major global health challenge. When skin tissue is wounded, some colonizing pathogenic bacteria secrete large amounts of hyaluronidase (HAase) to degrade the extracellular matrix (ECM), enabling their diffusion and proliferation. Current clinical techniques for detecting infection rely on basic visual cues or analysis of wound fluids, enabling only reactive treatment once severe signs manifest. Herein, we present the use of a closed-loop patch (CLP) for advanced wound management. The patch contains a bio-inspired sensor based on an engineered hyaluronic acid (HA) hydrogel that detects HAase secreted by invading pathogens. This detection triggers a quantifiable change in the capacitance of the interdigital electrode and achieving in-time detection of Staphylococcus aureus (S. aureus) infection in a murine wound model before obvious visual signs appear. In response, the release of titanium hydride (TiH1.924) nanodots from hydrogel decomposition can eradicate pathogens under ultrasound (US) irradiation. Concurrently, the product, HA fragments further promoted cell migration and angiogenesis to significantly improve wound healing by ∼14.6-fold rates in 12 days. Overall, the CLP provides a sensory act-treat effect according to the wound status, which facilitate the closed-loop integration of monitoring and rehabilitation. This strategy may provide additional possibilities for the design of future wound management systems.

Sputtered thin film deposited laser induced graphene based novel micro-supercapacitor device for energy storage application

Pioneering flexible micro-supercapacitors, designed for exceptional energy and power density, transcend conventional storage limitations. Interdigitated electrodes (IDEs) based on laser-induced graphene (LIG), augmented with metal-oxide modifiers, harness synergies with layered graphene to achieve superior capacitance. This study presents a novel one-step process for sputtered plasma deposition of HfO2, resulting in enhanced supercapacitance performance. Introducing LIG-HfO2 micro-supercapacitor (MSC) devices with varied oxygen flow rates further boosts supercapacitance performance by introducing oxygen functional groups. FESEM investigations demonstrate uniform coating of HfO2 on LIG fibers through sputtering. Specific capacitance measurements reveal 6.4 mF/cm2 at 5 mV/s and 4.5 mF/cm2 at a current density of 0.04 mA/cm2. The LIG-HfO2 devices exhibit outstanding supercapacitor performance, boasting at least a fourfold increase over pristine LIG. Moreover, stability testing indicates a high retention rate of 97% over 5000 cycles, ensuring practical real-time applications.

Minute level ultra-rapid and thousand copies level high-sensitive pathogen nucleic acid identification based on contactless impedance detection microsensor

Early screening for pathogens is crucial during pandemic outbreaks. Nucleic acid testing (NAT) is a valuable method for keeping pathogens from spreading. However, the long detection time and large size of the instruments involved significantly limited the efficiency of detection. This work described an integrated NAT microsensor that facilitated rapid and extremely sensitive detection based on nucleic acid amplification (NAA) on a chip. The biochip consisted of two layers incorporating a heater, a thermometer, an interdigital electrode (IDE) and a reaction chamber. The Pt electrode based heater and thermometer were utilized to maintain a specific temperature for the sample in the chamber. The thermometer exhibited a good linear correlation with a sensitivity of 9.36 Ω/°C and the heater achieved a heating efficiency of approximately 6.5 °C/s. Multiple ions were released during NAA, resulting in a decrease in the impedance of the amplification system solution. A large signal of impedance was generated by the released ions due to its linear correlation with the logarithm of the ion concentration. With this detection principle, IDE was employed for real-time monitoring of the in-chip reaction system impedance and NAA process. Specific nucleic acids from two pathogens (SARS-CoV-2, Vibrio vulnificus) were detected with this microsensor. The samples were qualitatively analyzed on microchip within 3 min, with a limit of detection (LOD) of 103 copies/μL. The proposed sensor presented several advantages, including reduced NAT time and increased sensitivity. Consequently, it has shown significant potential in rapid and high-quality nucleic acid testing for the field of epidemic prevention.

Monoolein-Based Wireless Capacitive Sensor for Probing Skin Hydration.

Capacitive humidity sensors typically consist of interdigitated electrodes coated with a dielectric layer sensitive to varying relative humidity levels. Previous studies have investigated different polymeric materials that exhibit changes in conductivity in response to water vapor to design capacitive humidity sensors. However, lipid films like monoolein have not yet been integrated with humidity sensors, nor has the potential use of capacitive sensors for skin hydration measurements been fully explored. This study explores the application of monoolein-coated wireless capacitive sensors for assessing relative humidity and skin hydration, utilizing the sensitive dielectric properties of the monoolein-water system. This sensitivity hinges on the water absorption and release from the surrounding environment. Tested across various humidity levels and temperatures, these novel double functional sensors feature interdigitated electrodes covered with monoolein and show promising potential for wireless detection of skin hydration. The water uptake and rheological behavior of monoolein in response to humidity were evaluated using a quartz crystal microbalance with dissipation monitoring. The findings from these experiments suggest that the capacitance of the system is primarily influenced by the amount of water in the monoolein system, with the lyotropic or physical state of monoolein playing a secondary role. A proof-of-principle demonstration compared the sensor's performance under varying conditions to that of other commercially available skin hydration meters, affirming its effectiveness, reliability, and commercial viability.

Microfluidic flow sensor based on chronoamperometric measurements in a microchannel

Microfluidics explores the fluid behavior at micron scale and is therefore suited to applications that need precise manipulation of fluids at small length or volume scales. In a span of over two decades, microfluidics has become an essential tool for modern genome sequencing platforms, single-cell analysis and common diagnostic tests. Despite many successful applications, the field has various challenges: Fabrication processes are yet to transition to commercial materials, microfluidic systems are reliant on skilled operators, and supporting equipment. Technological innovations in automation are needed to enable easy to use, completely on-chip microfluidic systems. Sensors are a critical component of any automated system. Fluid and flow properties such as flow rate, pressure, temperature, viscosity are critical to applications in drug development, and material/chemical synthesis. The flow rate (μL/min or nL/min) predictions based on external (off-chip) flow measurements can lead to erroneous calculations. The present work explores a technique based on chronoamperometry to measure flow rates inside a microchannel. Chronoamperometry based redox cycling of aqueous NaCl was performed by using interdigitated electrodes (IDE). The sensor measures current transients (which are modulated by the flow rate of the solution) effected by redox reactions on surface of the electrodes. The sensor demonstrated a sensitivity of 0.016 (μL/min)−1 change in charge transfer per unit change in flow rate and 3σ resolution of 9.3 μL/min. The calibration curve is linear in the range 0 – 200 μL/min, with a limit of detection (LoD) of 5 μL/min, making it suitable for various microfluidics applications.

Centimeter-level 2D ultra-small interdigital sensor for ESD detection of spacecraft

The spacecraft in geosynchronous orbit interacts with the space plasma environment, which is prone to electrostatic discharge and affects the safe operation of the spacecraft. In order to realize simple, accurate and reliable electrostatic discharge detection in space environment, based on the energy spectrum characteristics of spacecraft electrostatic discharge electromagnetic radiation electromagnetic pulse and the electromagnetic pulse sensing principle of interdigital electrode, a centimeter-level two-dimensional planar ultra-small interdigital sensor with a size of only 4 cm × 3 cm × 0.01 cm is developed. The impedance matching circuit is established to greatly improve the transmission efficiency of electromagnetic pulse, which is 59.34 % higher than that before the matching circuit is added. Finally, a spacecraft vacuum electrostatic discharge simulation experiment platform is built to test the frequency response characteristics of the sensor. The results show that the frequency response characteristics of the electromagnetic pulse signal perceived by the sensor developed in this paper are consistent with the main frequency characteristics of the spacecraft electrostatic discharge radiation electromagnetic pulse energy spectrum, which can be used for spacecraft electrostatic discharge detection in space environment.

Chemiresistive sensor based on PMMA/rGO composite for detection ammonia

Reduced graphene oxide (rGO) has been a promising material in sensing applications. However, rGO-based sensors have very high recovery time at room temperature (RT). Therefore, various materials combination needs to explored to address this issue. We have developed chemiresistive sensor based on a composite of Poly (methyl methacrylate) (PMMA) and rGO for detection of ammonia (NH3). To prepare more oxidized graphene oxide (GO), peroxidation of graphite oxide (PGO) was used from graphite by following Improved Hummer’s Method (IHM). Due to PGO, synthesized rGO was more conductive and high charge capacity. Synthesized PMMA/rGO composite was drop cast on fabricated interdigitated copper electrodes. Various characterization tools were used for materials confirmation. The chemiresistive sensor based on PMMA/rGO exhibited very good sensing behaviour towards NH3 analytes. The range of detection was 1–10 ppm with very good reproducibility. It was far below the Occupational Safety and Health Administration Permissible Exposer Limit (OSHA PEL) of NH3. A chemiresistive sensor based on PMMA/rGO composite revealed better sensing results than a pristine rGO sensor. The response time and recovery time for rGO based sensor was 122 s and 168 s respectively at 2 ppm of NH3 whereas for PMMA/rGO based sensor it was 50 s and 75 s respectively. Moreover, the PMMA/rGO based sensor exhibited repeatability at 2 ppm for NH3 at RT. This type of PMMA/rGO sensor will be very much useful for the detection of hazardous gases in chemical laboratories and industrial areas.

3D Printed Interdigitated Electrodes for Cardiac Biomarker Detection.

The identification of biomarkers has significant benefits for early disease diagnosis and treatment. Hence, there is an increasing demand for low-cost, disposable point-of-care diagnostic devices for rapid and specific biomarker detection, with good sensitivity and range. Interdigitated electrodes (IDEs) are among the most widely used transducers, especially in chemical and biological sensors, because of their high sensitivity, low cost, and straightforward manufacturing procedure. In this work, a simple 3D printed IDE structure has been developed for cardiac troponin I detection to indicate the risk of acute myocardial infarction (AMI). IDEs have been fabricated using 3D printing technique and the electrically conductive composite polylactic acid (PLA) filament being utilized for the fabrication of electrodes. The demonstrated cardiac troponin I sensor has a calculated quantification limit and detection limit of 0.233 ng ml-1 and 76.97 pg ml-1, respectively which are clinically significant ranges for AMI identification. Electrochemical analytical techniques, such as electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), were carried out for the detection of analyte concentration. Furthermore, using this fabrication methodology IDEs can be fabricated for under US$ 0.4 which can be utilized to detect several other biomarkers.

Optically transparent highly conductive contact based on ITO and copper metallization for solar cells

This paper presents the results of obtaining and studying the electrical and optical characteristics of an optically transparent highly conductive Ni/Cu/Ti/ITO contact in order to reduce electrical resistance losses on the front side of the silicon solar cell. The topology of the contact metallization is a square 50 × 50 mm2 with an interdigitated electrode structure. A Ni/Cu/Ti contact metallization formed on ITO layer reduces the surface resistance by more than 60 times. It has been shown that the use of a Ni/Cu/Ti contact with a finger thickness of at least 1.5 μm and a width of 17 μm was formed is a good alternative to traditional contacts for silicon solar cells based on silver paste.

Biosynthesis, structural characterization and humidity sensing properties of cellulose/ZnO nanocomposite

The present work demonstrates the applications of a nanocomposite of the cellulose polymer and ZnO nanoparticles with 1:1 weight ratio, prepared by a green assisted precipitation method for a high-performance resistive type humidity sensor. The morphology and nanostructure of prepared cellulose/ZnO composite were characterization by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and transmission electron microscopy are confirmed the decoration of ZnO nanoparticles on cellulose polymer matrix surface. The humidity sensing martials was coated onto the interdigital electrodes. The sensitivity, response/recover and stability studies performance of fabricated humidity sensors have been monitored in 5 to 98% relative humidity (%RH) at room temperature (37 °C). The response and recovery times of the fabricated sensors are observed as ≈ 26 s and ≈ 53 s respectively, and the sensitivity factor (Sf) is 2656 ± 103 Ω. Possible mechanisms of the humidity sensor based on water-induced conductivity increase are discussed. Also, the energy band of cellulose/ZnO nanocomposite was simulated by density functional theory (DFT) studies. The cellulose/ZnO nanocomposite humidity sensor has great potential for practical field applications.

Low-Cost Flexible Graphene Oxide Humidity Sensor Fabricated Using Inkjet Printing and Aerosol Deposition

Flexible humidity sensors play a critical role in medical diagnostics and industrial control systems. In this study, a low-cost flexible humidity sensor is presented. The humidity sensor is developed by printing silver interdigitated electrodes (IDE) on a polyethylene terephthalate (PET) substrate using an Epson Stylus C88+ inkjet printer. The sensing layer of the humidity sensor was fabricated using graphene oxide (GO) ink, which is deposited onto the electrodes using an aerosol deposition technique. The GO humidity sensor achieves excellent sensing performance over a wide range of humidity levels from 11% to 97% RH range, with a fast response time of 2 s and recovery time of 17 s. The sensor also exhibits ultra-high sensitivity (243 kΩ/%RH), low hysteresis (2.16%), excellent repeatability, long-term stability, and high flexibility (tested at bending radiuses of 4 cm, 3.5 cm, 3 cm, and 2.5 cm). The humidity sensing mechanism of the proposed GO humidity sensor was also discussed. Furthermore, the sensor exhibited excellent capabilities in monitoring human respiration, distinguishing between nose and mouth breathing, detecting finger movements without physical contact, and even recognising basic spoken words. These features of the sensor possess significant potential for various applications in human healthcare.

A self-powered spring-based triboelectric vibration sensor

Abstract Self-powered vibration sensors have gained attention due to their versatility. However, a limitation of many existing self-powered sensors is their single-direction functionality, which hinders their effectiveness in capturing multidirectional human movement’s swinging motions. To address this, this study introduces an innovative self-powered vibration sensor based on the triboelectrification effect of an inverted pendulum metal ball. This novel sensor excels at detecting micro-vibrations through the freestanding sliding electrification of a metal ball using Kapton tape. The generated charge is transferred through interdigital electrodes arranged in a spiral pattern. To ensure adaptability to various motion types, the metal ball is affixed to a spring and configured as an inverted pendulum. This setup allows the sensor to detect both linear and rotary motions across a range of acceleration levels. The fabricated sensor exhibits remarkable sensitivity, measuring 0.203 V/mm. It was affixed to the human body to detect low-frequency vibrations, particularly those below 20 Hz. Impressively, it can detect millimeter-scale vibrations, even up to 3 mm, at different rotational angles (0°, 30°, 60°, and 90°). This outcome highlights the promising performance of our vibration sensor in the field of human motion monitoring, making it a significant advancement in the realm of self-powered vibration sensors.

Metal-Oxide Based Transparent Heater with Interdigitated Electrodes

Metal-Oxide Based Transparent Heater with Interdigitated Electrodes

Platinum Decorated Palladium Nanowires for Room‐Temperature Hydrogen Detection

AbstractThe use of hydrogen as an energy carrier will require low‐cost, low‐power hydrogen sensors. Toward this goal, penta‐twinned palladium nanowires (Pd NWs) are synthesized and fabricated sensors from them by drop‐casting. Pd NWs drop‐cast onto an interdigitated electrode (IDE) gave a response of 0.3% to 1 vol.% H2, with response and recovery times of 12 and 20 s, respectively. However, they exhibited a negative response (decreased resistance) at low H2 concentrations. Pd NWs on a paper substrate provided a tenfold higher response to 1 vol.% H2, with response and recovery times of 10 s each, but still exhibited negative response at low H2 concentration. Exposing the Pd NW‐on‐paper sensor to ozone‐generating UV light degraded the PVP used in Pd NW synthesis, eliminating the reverse sensing response, and providing a response of 5% to 1 vol.% H2, with response and recovery times of 15 s. This allowed reliable H2 detection down to 100 ppm H2. Finally, coating the Pd NWs with a small amount of Pt (<5%) reduced the response and recovery times to 5 s by catalyzing H2 dissociation. This work provides a path to low‐cost sensors to enable the safe use of H2 as an energy carrier.

First Direct Gravimetric Detection of Perfluorooctane Sulfonic Acid (PFOS) Water Contaminants, Combination with Electrical Measurements on the Same Device—Proof of Concepts

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are pollutants of concern due to their long-term persistence in the environment and human health effects. Among them, perfluorooctane sulfonic acid (PFOS) is very ubiquitous and dangerous for health. Currently, the detection levels required by the legislation can be achieved only with expensive laboratory equipment. Hence, there is a need for portable, in-field, and possibly real-time detection. Optical and electrochemical transduction mechanisms are mainly used for the chemical sensors. Here, we report the first gravimetric detection of small-sized molecules like PFOS (MW 500) dissolved in water. A 100 MHz quartz crystal microbalance (QCM) measured at the third harmonic and an even more sensitive 434 MHz two-port surface acoustic wave (SAW) resonator with gold electrodes were used as transducers. The PFOS selective sensing layer was prepared from the metal organic framework (MOF) MIL-101(Cr). Its nano-sized thickness and structure were optimized using the discreet Langmuir–Blodgett (LB) film deposition method. This is the first time that LB multilayers from bulk MOFs have been prepared. The measured frequency downshifts of around 220 kHz per 1 µmol/L of PFOS, a SAW resonator-loaded QL-factor above 2000, and reaction times in the minutes’ range are highly promising for an in-field sensor reaching the water safety directives. Additionally, we use the micrometer-sized interdigitated electrodes of the SAW resonator to strongly enhance the electrochemical impedance spectroscopy (EIS) of the PFOS contamination. Thus, for the first time, we combine the ultra-sensitive gravimetry of small molecules in a water environment with electrical measurements on a single device. This combination provides additional sensor selectivity. Control tests against a bare resonator and two similar compounds prove the concept’s viability. All measurements were performed with pocket-sized tablet-powered devices, thus making the system highly portable and field-deployable. While here we focus on one of the emerging water contaminants, this concept with a different selective coating can be used for other new contaminants.

Wireless flexi-sensor using narrow band quasi colloidal 3D tin telluride (SnTe) for respiratory, environment, and proximity sensing

We developed a wireless and flexible humidity sensor based on three-dimensional (3D) narrow band quasi colloidal (NBQC) tin telluride (SnTe) material. Pristine SnTe granules were exfoliated into a homogeneous quasi colloidal (HQC) solution through mechanical liquid phase exfoliation (MLPE). Resulting HQC solution had a higher surface area with randomly shaped 3D NBQC SnTe particles that increased its humidity sensing ability by rendering more active sites and irregular pathways for interaction with water molecules. Fabrication of SnTe humidity sensor included highly conductive (2.5 μΩ/cm) and precise plasma sputtered gold (Au) inter-digital electrodes (IDEs) using a shadow mask on the flexible substrate followed by coating the thin film of 3D HQC SnTe. The SnTe humidity sensor showed variance in both capacitance and impedance with changing relative humidity (%RH). Impedance response of SnTe humidity sensor was more sensitive compared to its capacitance. We adjusted the operating frequency of our humidity sensor (1, 10, and 100 kHz) to maximize sensitivity, enhance accuracy, and reduce interference. The developed humidity sensor exhibited efficient performance, including a wide operating range (5–92 %RH), high sensitivity (85.6 kΩ/%RH), consistent stability (>48 days), and a fast response/recovery time (1.7/3.2 s). The narrow band gap of SnTe enabled strong interaction with water molecules, leading to a highly sensitive impedance response to %RH. To improve its mobility, portability, and measurability, the SnTe humidity sensor was made wireless for easy integration into a variety of devices. Our 3D NBQC SnTe humidity sensor showed its potential applications in environment monitoring, health monitoring, and proximity sensing.