Progressive NO2 Sensors with Rapid Alarm and Persistent Memory-Type Responses for Wide-Range Sensing Using Antimony Triselenide Nanoflakes

Antimony triselenide (Sb₂Se₃) nanoflake-based nitrogen dioxide (NO₂) sensors exhibit a progressive bifunctional gas-sensing performance, with a rapid alarm for hazardous highly concentrated gases, and an advanced memory-type function for low-concentration (<1 ppm) monitoring repeated under potentially fatal exposure. Rectangular and cuboid shaped Sb₂Se₃ nanoflakes, comprising van der Waals planes with large surface areas and covalent bond planes with small areas, can rapidly detect a wide range of NO₂ gas concentrations from 0.1 to 100 ppm. These Sb₂Se₃ nanoflakes are found to be suitable for physisorption-based gas sensing owing to their anisotropic quasi-2D crystal structure with extremely enlarged van der Waals planes, where they are humidity-insensitive and consequently exhibit an extremely stable baseline current. The Sb₂Se₃ nanoflake sensor exhibits a room-temperature/low-voltage operation, which is noticeable owing to its low energy consumption and rapid response even under a NO₂ gas flow of only 1 ppm. As a result, the Sb₂Se₃ nanoflake sensor is suitable for the development of a rapid alarm system. Furthermore, the persistent gas-sensing conductivity of the sensor with a slow decaying current can enable the development of a progressive memory-type sensor that retains the previous signal under irregular gas injection at low concentrations.     

Tin oxide nanosensors for highly sensitive toxic gas detection and their 3D system integration

We present nanosensors based on ultrathin SnO₂ films, which are very sensitive to the highly toxic gases SO₂ and H₂S. The SnO₂-sensing films are fabricated by a spray pyrolysis process on Si substrates with a thickness of 50 nm. The sensor resistance is decreased in the presence of the toxic gases. Exposure to 50 ppm SO₂ leads to a sensor resistance drop of ∼40% whereas a H₂S gas concentration of only 2.5 ppm decreases the resistance by ∼85%, which demonstrates the extraordinary sensitivity of the nanosensors. With respect to further system integration a CMOS technology based micro-hotplate containing heating element and sensing layer has been simulated. Preliminary results show that the micro-hotplates can provide operating temperatures of 400 °C with a power consumption of less than 5 mW. A concept for 3D system integration of the nanosensor chip and a CMOS chip based on Through-Silicon-Via (TSV) technology is proposed as potential roadmap towards smart nanosensor systems for daily life applications.     

Sensing Mechanism and Behavior of Sputtered ZnCdO Ozone Sensors Enhanced by Photons for Room- Temperature Operation

ZnCdO oxide thin films have been deposited by using the radiofrequency cosputtering method to prepare ozone sensors for room-temperature operation. The sensors were fabricated in the order: electrode/sensor/glass/illuminant. The mechanisms of photo-assisted oxidation and reduction on the surface of the ZnCdO ozone sensors were investigated. Free electrons and holes were generated by exposure of the surface of the ZnCdO ozone sensor to ultraviolet light, tending to enhance surface absorption of dissociated O₂ molecules and dissociation of adsorbed oxygen ions, respectively. Thereby, the sensitivity of the ZnCdO ozone sensor was increased. This photon exposure method can replace the conventional heating mode used in ozone sensors. Moreover, 405-nm light from a light-emitting diode, corresponding to photon energy of 3.061 eV, was found to assist the processes of oxidation and reduction due to the chemical reaction of the ozone gas. We present a possible route for fabrication of portable ZnCdO ozone sensors for room-temperature operation.     

Highly sensitive H2S sensors based on ultrathin organic single-crystal microplate transistors

Based on ultrathin dinaphtho[3,4-d:3′,4′-d′]benzo[1,2-b:4,5-b′]dithiophene (Ph5T2) single-crystal microplates, the highly sensitive organic field-effect H₂S sensors are realized at room temperature. The response is as high as 1.2 × 10⁶% in 50 ppm H₂S. This value is extremely high for H₂S sensors, and is three orders of magnitude higher than that of the most reported semiconductor gas sensors. The response/recovery time is respectively as low as 2 min and 1 min in 50 ppm H₂S. The detect limitation is as low as 0.5 ppm. The ultrathin single-crystal microplates provide direct and efficient ways for the analytes' activities within the conducting channel, and therefore mainly account for the improved sensing performance. The excellent sensing performance of ultrathin Ph5T2 single-crystal microplate transistors reveals the capacity of developing highly sensitive room-temperature sensors.     

Room temperature NO2 gas sensing properties of DBSA doped PPy–WO3 hybrid nanocomposite sensor

We demonstrate the chemiresistive NO₂ gas sensor based on DBSA doped PPy–WO₃ hybrid nanocomposites operating at room temperature. The sensor was fabricated on glass substrate using simple and cost effective drop casting method. The gas sensing performance of sensor was studied for various toxic/flammable analytes like NO₂, C₂H₅OH, CH₃OH, H₂S and NH₃. The sensor shows higher selectivity towards NO₂ gas with 72% response at 100 ppm. Also the sensor can successfully detect low concentration of NO₂ gas upto 5 ppm with reasonable response of 12%. Structural, morphological and compositional analyses evidenced the successful formation of DBSA doped PPy–WO₃ hybrid nanocomposite with uniform dispersion of DBSA into PPy–WO₃ hybrid nanocomposite and enhance the gas sensing behavior. We demonstrated that DBSA doped PPy–WO₃ hybrid nanocomposite sensor films shows excellent reproducibility, high stability, moderate response and recovery time for NO₂ gas in the concentration range of 5–100 ppm. A gas sensing mechanism based on the formation of random nano p–n junctions distributed over the surface of the sensor film has been proposed. In addition modulation of depletion width takes place in sensor on interaction with the target NO₂ gas has been depicted on the basis of schematic energy band diagram. Impedance spectroscopy was employed to study bulk, grain boundary resistance and capacitance before and after exposure of NO₂ gas. The structural and intermolecular interaction within the hybrid nanocomposites were explored by Raman and X-ray photoelectron spectroscopy (XPS), while field emission scanning electron microscopy (FESEM) was used to characterize surface morphology. The present method can be extended to fabricate other organic dopent-conducting polymer–metal oxide hybrid nanocomposite materials and could find better application in the gas sensing.     

Nanoparticle-Based Strain Gauges: Anisotropic Response Characteristics,Multidirectional Strain Sensing,and Novel Approaches to Healthcare Applications

Directional strain sensing is essential for advanced sensor applications in the field of human-machine interfaces and healthcare. Here, the angle dependent anisotropic strain sensitivity caused by charge carriers percolating through cross-linked gold nanoparticle (GNP) networks is studied and these versatile materials are used for the fabrication of wearable triaxial pulse and gesture sensors. More specifically, the anisotropic response of 1,9-nonanedithiol cross-linked GNP films is separated into geometric and piezoresistive contributions by fitting the measured data with an analytic model. Hereby, piezoresistive coefficients of g₁₁ ∼ 32 and g₁₂ ∼ 21 are extracted, indicating a slightly anisotropic response behavior of the GNP-based material. To use the material for healthcare applications, arrangements of three GNP transducers are patterned lithographically and fully embedded into a highly flexible silicone polymer (Dragon Skin 30). The new encapsulation method ensures good and robust electrical contacts and enables facile handling and protection from external influences. A facile read-out with wireless data transmission using off-the-shelf electrical components underlines the great potential of these devices for applications as skin-wearable healthcare sensors.     

Controllable gas selectivity at room temperature based on Ph5T2-modified CuPc nanowire field-effect transistors

A dinaphtho[3,4-d:3′,4′-d′]benzo[1,2-b:4,5-b′]dithiophene (Ph5T2)-modified copper phthalocyanine (CuPc) single crystal nanowire field-effect transistor (FET) with gas dielectric was fabricated as an organic gas sensor. This device exhibits the high response and the excellent controllable selectivity at room temperature. Its detection limit for NO₂, NO, and H₂S is down to sub-ppm level. Prior to surface modification, the CuPc nanowire FET shows the response as high as 1088% to 10 ppm H₂S, but only 97.5% to 10 ppm NO₂. After Ph5T2 modification, the response to 10 ppm H₂S is decreased by one order of magnitude, but is dramatically improved up to 460% to 10 ppm NO₂. The responses towards H₂S and NO₂ respectively for pristine and the modified sensor are higher than those of most reported organic sensors. The gas-sensing results reveal that Ph5T2 modification can transform the selectivity of the sensor from H₂S to NO₂. The controllable modulation of gas selectivity is related to the formed organic heterojunctions between CuPc and Ph5T2, where the hole carriers of CuPc nanowire are modulated by these heterojunctions, resulting in the changed adsorption behavior towards different gases.     

SnO2 decorated SiO2 chemical sensors: Enhanced sensing performance toward ethanol and acetone

SnO₂ decorated SiO₂ chemical sensors with different Sn/Si ratios were synthesized by micro-emulsion followed by ultrasonic-assisted deposition-precipitation method and used for highly sensitive and selective detection of ethanol and acetone. XRD, EDS, SEM, and TEM were used to characterize the samples. The results confirm deposition of small crystalline tin oxide particles on the surface of silica particles. Using these formed materials for detection of ethanol and acetone resulted in significant enhancement of the sensitivity and reducing temperature of maximum response in comparison to the pure SnO₂. The selectivity of the sample with the highest sensitivity to ethanol and acetone, i.e. 80 wt% SnO₂/SiO₂, was examined by measuring its sensitivity to some interfering gases including carbon monoxide, methane, toluene, Trichloroethylene (TCE) and propane; the results showed very high selectivity of the sensor to ethanol and acetone, especially at low temperatures. The sensor responses to traces of acetone in the air with the concentration ranging from 0.5 to 5 ppm at different temperatures of 70, 170 and 270, and 370 °C were measured to evaluate the capability of the sensor for detection of acetone in the breath of human, which is helpful in the diabetes diagnosis. The sensor could effectively show high enough sensitivity even to these very low concentrations of acetone which reveals its high potential for being used in acetone detection devices. Finally, the effect of humidity on the sensitivity of sensor to acetone was investigated. Increasing the humidity of background air, caused the sensor response to decrease and the operating temperature of maximum response of the sensor to increase.     

A Self-Powered,Rechargeable, and Wearable Hydrogel Patch for Wireless Gas Detection with Extraordinary Performance

Flexible gas sensors play an indispensable role in diverse applications spanning from environmental monitoring to portable medical electronics. Full wearable gas monitoring system requires the collaborative support of high-performance sensors and miniaturized circuit module, whereas the realization of low power consumption and sustainable measurement is challenging. Here, a self-powered and reusable all-in-one NO₂ sensor is proposed by structurally and functionally coupling the sensor to the battery, with ultrahigh sensitivity (1.92%/ppb), linearity (R² = 0.999), ultralow theoretical detection limit (0.1 ppb), and humidity immunity. This can be attributed to the regulation of the gas reaction route at the molecular level. The addition of amphiphilic zinc trifluoromethanesulfonate (Zn(OTf)₂) enables the H₂O-poor inner Helmholtz layer to be constructed at the electrode–gel interface, thereby facilitating the direct charge transfer process of NO₂ here. The device is then combined with a well-designed miniaturized low-power circuit module with signal conditioning, processing and wireless transmission functions, which can be used as wearable electronics to realize early and remote warning of gas leakage. This study demonstrates a promising way to design a self-powered, sustainable, and flexible gas sensor with high performance and its corresponding wireless sensing system, providing new insight into the all-in-one system of gas detection.     

Low-Intensity Sensitive and High Stability Flexible Heart Sound Sensor Enabled by Hybrid Near-Field/Far-Field Electrospinning

Low-cost and wearable heart sound sensors can facilitate early detection and monitoring of cardiovascular and respiratory diseases. Such sensors are currently limited by either the complexity of fabrication processes or low sensitivity and reliability for weak signal detection. Here, a hybrid near-field/far-field electrospinning approach is demonstrated that enables low-cost fabrication and optimization of triboelectric heterostructures for heart sound sensing. Specifically, by combining the far-field produced highly polarized and porous polyvinylidene difluoride network for triboelectric electrification and near-field patterned polyurethane grid spacers for vibration enhancement and charge trapping, the greatly improved sensor output at the heart sound frequency (50–150 Hz) and intensity (<80 dB) range, demonstrating record high sensitivity of 7027 mV Pa⁻¹ and low detection limit of 47 dB. The sensor exhibits excellent stability under both sudden physical disturbance and long-term cycling stress, showing no degradation during 7 h of continuous operation. It is demonstrated that the sensor can be integrated with apparel and capture high-quality heart sound signals at all five diagnostic auscultation points and distinguish characteristic heart sound patterns caused by different cardiovascular diseases.     

Highly Selective SAM–Nanowire Hybrid NO2 Sensor: Insight into Charge Transfer Dynamics and Alignment of Frontier Molecular Orbitals

Organic–inorganic hybrid gas sensors can offer outstanding performance in terms of selectivity and sensitivity towards single gas species. The enormous variety of organic functionalities enables novel flexibility of active sensor surfaces compared to commonly used pure inorganic materials, but goes along with an increase of system complexity that usually hinders a predictable sensor design. In this work, an ultra‐selective NO₂ sensor is realized based on self‐assembled monolayer (SAM)‐modified semiconductor nanowires (NWs). The crucial chemical and electronic parameters for an effective interaction between the sensor and different gas species are identified using density functional theory simulations. The theoretical findings are consistent with the experimentally observed extraordinary selectivity and sensitivity of the amine‐terminated SnO₂ NW towards NO₂. The energetic position of the SAM–gas frontier orbitals with respect to the NW Fermi level is the key to ensure or impede an efficient charge transfer between the NW and the gas. As this condition strongly depends on the gas species and the sensor system, these insights into the charge transfer mechanisms can have a substantial impact on the development of highly selective hybrid gas sensors.     

Single Platinum Atoms Immobilized on Monolayer Tungsten Trioxide Nanosheets as an Efficient Electrocatalyst for Hydrogen Evolution Reaction

Monolayer WO₃·H₂O (ML-WO₃·H₂O) nanosheets are synthesized via a space-confined strategy, and then a single-atom catalyst (SAC) is constructed by individually immobilizing Pt single atoms (Pt-SA) on monolayer WO₃ (ML-WO₃). The Pt-SA/ML-WO₃ retains the monolayer structure of ML-WO₃·H₂O, with a quite high monolayer ratio up to ≈ 93%, and possesses rich defects (O and W vacancies). It exhibits excellent electrocatalytic performance, with a small overpotential (η) of − 22 mV to drive − 10 mA cm⁻² current, a low Tafel slope of ≈ 27 mV dec⁻¹, an ultrahigh turnover frequency of ≈ 87 H₂ s⁻¹ site⁻¹ at η  =   − 50 mV, and long-term stability. Of particular note, it exhibits an ultrahigh mass activity of ≈ 87 A mg_Pt⁻¹ at η  =   − 50 mV, which is ≈ 160 times greater than that of the state-of-the-art commercial catalyst, 20 wt% Pt/C ( ≈ 0.54 A mg_Pt⁻¹). Experimental and DFT analyses reveal that its excellent performance arises from the strong synergetic effect between the single Pt atoms and the support. This work provides an effective route for large-scale fabrication of ML-WO₃ nanosheets, demonstrates ML-WO₃ is an excellent support for SACs, and also reveals the great potential of SACs in reducing the amount of noble metals used in catalysts.     

Rational Design of All Resistive Multifunctional Sensors with Stimulus Discriminability

A rational approach is proposed to design soft multifunctional sensors capable of detection and discrimination of different physical stimuli. Herein, a flexible multifunctional sensor concurrently detecting and distinguishing minute temperature and pressure stimuli in real time is developed using electrospun carbon nanofiber (CNF) films as the sole sensing material and electrical resistance as the only output signal. The stimuli sensitivity and discriminability are coordinated by tailoring the atomic- and device-level structures of CNF films to deliver outstanding pressure and temperature sensitivities of ? 0.96 kPa^?1 and ? 2.44%  ° C^?1, respectively, enabling mutually exclusive sensing performance without signal cross-interference. The CNF multifunctional sensor is considered the first of its kind to accomplish the stimulus discriminability using only the electrical resistance as the output signal, which is most convenient to monitor and process for device applications. As such, it has distinct advantages over other reported sensors in its simple, cost-effective fabrication and readout system. It also possesses other invaluable traits, including good bending stability, fast response time, and long-term durability. Importantly, the ability to simultaneously detect and decouple temperature and pressure stimuli is demonstrated through novel applications as a skin-mountable device and a flexible game controller.     

Study of sensitivity and selectivity of α-Fe2O3 thin films for different toxic gases and alcohols

This paper presents a detailed study on the sensitivity and selectivity of α-Fe₂O₃ thin films produced by deposition of Fe and post-deposition annealed at two temperatures of 600 °C and 800 °C with flow of oxygen for application as a sensor for toxic gases including CO, H₂S, NH₃ and NO₂ and alcohols such as C₃H₇OH, CH₃OH, and C₂H₅OH. The crystallographic structure of the samples was studied by X-ray diffraction (XRD) method while an atomic force microscope (AFM) was employed for surface morphology investigation. The electrical response of the films was measured while they were exposed to various toxic gases and alcohols in the temperature range of 50–300 °C. The sample annealed at higher temperature showed higher response for different gases and alcohols tested in this work which can be due to the higher resistance of this sample. Results also indicated that the α-Fe₂O₃ thin films show higher selectivity to NO₂ gas relative to the other gases and alcohols while the best sensitivity is obtained at 200 °C. The α-Fe₂O₃ thin film post-deposition annealed at 800 °C also showed a good stability and reproducibility and a detection limit of 10 ppm for NO₂ gas at the operating temperature of 200 °C.     

High‐Performance,Transparent Thin Film Hydrogen Gas Sensor Using 2D Electron Gas at Interface of Oxide Thin Film Heterostructure Grown by Atomic Layer Deposition

A high‐performance, transparent, and extremely thin (<15 nm) hydrogen (H₂) gas sensor is developed using 2D electron gas (2DEG) at the interface of an Al₂O₃/TiO₂ thin film heterostructure grown by atomic layer deposition (ALD), without using an epitaxial layer or a single crystalline substrate. Palladium nanoparticles (≈2 nm in thickness) are used on the surface of the Al₂O₃/TiO₂ thin film heterostructure to detect H₂. This extremely thin gas sensor can be fabricated on general substrates such as a quartz, enabling its practical application. Interestingly, the electron density of the Al₂O₃/TiO₂ thin film heterostructure can be tailored using ALD process temperature in contrast to 2DEG at the epitaxial interfaces of the oxide heterostructures such as LaAlO₃/SrTiO₃. This tunability provides the optimal electron density for H₂ detection. The Pd/Al₂O₃/TiO₂ sensor detects H₂ gas quickly with a short response time of <30 s at 300 K which outperforms conventional H₂ gas sensors, indicating that heating modules are not required for the rapid detection of H₂. A wide bandgap (>3.2 eV) with the extremely thin film thickness allows for a transparent sensor (transmittance of 83% in the visible spectrum) and this fabrication scheme enables the development of flexible gas sensors.     

ZnO spintronics and nanowire devices

ZnO is a very promising material for spintronics applications, with many groups reporting room-temperature ferromagnetism in films doped with transition metals during growth or by ion implantation. In films doped with Mn during pulsed laser deposition (PLD), we find an inverse correlation between magnetization and electron density as controlled by Sn-doping. The saturation magnetization and coercivity of the implanted single-phase films were both strong functions of the initial anneal temperature, suggesting that carrier concentration alone cannot account for the magnetic properties of ZnO:Mn and factors such as crystalline quality and residual defects play a role. Plausible mechanisms for ferromagnetism include the bound magnetic polaron model or exchange that is mediated by carriers in a spin-split impurity band derived from extended donor orbitals. The progress in ZnO nanowires is also reviewed. The large surface area of nanorods makes them attractive for gas and chemical sensing, and the ability to control their nucleation sites makes them candidates for microlasers or memory arrays. Single ZnO nanowire depletion-mode metal-oxide semiconductor field effect transistors exhibit good saturation behavior, threshold voltage of ∼−3 V, and a maximum transconductance of 0.3 mS/mm. Under ultraviolet (UV) illumination, the drain-source current increased by approximately a factor of 5 and the maximum transconductance was ∼5 mS/mm. The channel mobility is estimated to be ∼3 cm²/Vss, comparable to that for thin film ZnO enhancement mode metal-oxide semiconductor field effect transistors (MOSFETs), and the on/off ratio was ∼25 in the dark and ∼125 under UV illumination. The Pt Schottky diodes exhibit excellent ideality factors of 1.1 at 25°C, very low reverse currents, and a strong photoresponse, with only a minor component with long decay times thought to originate from surface states. In the temperature range from 25°C to 150°C, the resistivity of nanorods treated in H₂ at 400°C prior to measurement showed an activation energy of 0.089 eV and was insensitive to ambient used. By contrast, the conductivity of nanorods not treated in H₂ was sensitive to trace concentrations of gases in the measurement ambient even at room temperature, demonstrating their potential as gas sensors. Sensitive pH sensors using single ZnO nanowires have also been fabricated.     

SnO2 gas sensor fabricated by low frequency alternating field electrophoretic deposition

SnO₂ thick film gas sensor has been prepared by applying low frequency (0.1 Hz) AC electric fields to a stable suspension of SnO₂ nanoparticles in acetylacetone. Parallel gold electrodes were used as the deposition substrate. Effect of CO, O₂ and H₂ gas exposure as well as ethanol vapor on conductivity of the SnO₂ film at 300 °C is investigated. Results show that the sensor is sensitive and its response is repeatable. This work shows that ACEPD can be used as an easy and cheap technique for fabrication of electronic devices such as ceramic-based gas sensors.     

Chemiresistive Gas Sensors Based on Highly Permeable Sn-Doped Bismuth Subcarbonate Microspheres: Facile Synthesis,Sensing Performance,and Mechanism Study

Acetic acid (CH₃COOH) detection with high selectivity at low temperatures is significant due to its wide applications in the chemical, medical, and catering industries. Chemiresistive gas sensors based on metal oxide semiconductors (MOSs) are widely used in detecting various gases, but it is necessary to develop MOSs with novel nanostructures to enhance gas-sensing performance. Herein, a series of bismuth subcarbonate (Bi₂O₂CO₃, abbreviated as BCO) microspheres with highly permeable lamellar structure and tunable Sn-doping ratios (0–5 at%) is synthesized by controlling kinetics equilibrium of the hydrothermal reaction. The sensor based on 3 at% Sn-doped BCO microspheres exhibits excellent gas-sensing performances toward acetic acid (10 ppm), including high sensitivity (S = 8.3), fast recovery speed (10 s), long-term stability (over 30 days), and good selectivity at a low temperature (150 °C). The unique permeable lamellar structure assembled from 2D Sn-doped BCO nanosheets and rich Sn⁴⁺ doping-induced active sites is mainly responsible for the enhanced gas-sensing performances. Moreover, a new acetic acid reaction process is revealed via in situ diffuse reflectance infrared transform spectroscopy. Density functional theory calculations indicate that Sn-doped BCO has a higher acetic acid adsorption energy and a larger charge transfer than pristine BCO.     

Bubble‐Decorated Honeycomb‐Like Graphene Film as Ultrahigh Sensitivity Pressure Sensors

Recently, macroporous graphene monoliths (MGMs), with ultralow density and good electrical conductivity, have been considered as excellent pressure sensors due to their excellent elasticity with a rapid rate of recovery. However, MGMs can only exhibit good sensitivity when the strain is higher than 20%, which is undesirable for touch‐type pressure sensors, such as artificial skin. Here, an innovative method for the fabrication of freestanding flexible graphene film with bubbles decorated on honeycomb‐like network is demonstrated. Due to the switching effect depended on “point‐to‐point” and “point‐to‐face” contact modes, the graphene pressure sensor has an ultrahigh sensitivity of 161.6 kPa^?1 at a strain less than 4%, several hundred times higher than most previously reported pressure sensors. Moreover, the graphene pressure sensor can monitor human motions such as finger bending and pulse with a very low operating voltage of 10 mV, which is sufficiently low to allow for powering by energy‐harvesting devices, such as triboelectric generators. Therefore, the high sensitivity, low operating voltage, long cycling life, and large‐scale fabrication of the pressure sensors make it a promising candidate for manufacturing low‐cost artificial skin.     

Easy-Cone Magnetic State Induced Ultrahigh Sensitivity and Low Driving Current in Spin-Orbit Coupling 3D Magnetic Sensors

Measurement of 3D vector magnetic field is of vital importance for the development of magnetic navigation, biomedical diagnosis, and microimaging. Traditional 3D magnetic sensors require cooperation of multiple sensors on three orthogonal planes, resulting in disadvantages of bulky size and low spatial resolution. Recently proposed spin orbit torque sensor based on ferromagnetic/heavy-metal heterostructures can detect three magnetic field components individually due to the different symmetries of current-polarity-dependent magnetization dynamic. However, the large driving current density and complex driving procedure hinder their practical application, especially in AC magnetic field detection. Herein, 3D magnetic sensors with dramatically reduced driving current density are reported, one fifth of the original value, by exquisite engineering of the magnetic anisotropy in Pt/Co/Ta heterostructures. With further reduced perpendicular magnetic anisotropy, the sensor in the easy-cone state demonstrates a record-high sensitivity of 31196 V A⁻¹ T⁻¹. More importantly, the easy-cone state sensor can work with an ultralow driving current density of 3.8 kA cm⁻², which is three orders lower than previous results. Although easy-cone state sensor can only measure the z-axis field, highly compact 3D magnetic sensor can be realized by adoption of two anisotropic magnetoresistance sensors, promising great potential application in space- and energy-restricted scenarios.