Self-powered Multifunctional Sensors Research Articles

A Self-Powered Multifunctional Sensor for Downhole Motor Based on Triboelectric Nanogenerator

The rotational state of the downhole motor is critical for monitoring its operational condition. In this work, a self-powered multifunctional sensor (hereafter referred to as SPMS) is proposed to monitor the rotational speed, angle, and direction of rotation of downhole motor without external power supply. The experimental results show that the SPMS can measure the rotational speed in the range of 0–750 r/min with an error rate of less than 2% and an excellent linearity. In addition to the speed measurement function, it can also measure the rotation direction and angle with a resolution of 22.5°. Furthermore, the possibility of the SPMS converting downhole motor rotation energy into electrical energy and powering other downhole devices is also explored. The experimental results show that the SPMS has an open-circuit voltage of about 1.2 kV and a peak power of 1.128 mW at 150 r/min. It can light up 601 series light-emitting diodes (LEDs) and force a low-power temperature sensor. Compared with traditional downhole sensors, the SPMS can achieve multiparameter measurement without external power supply, which expands the application range of downhole sensors and is more suitable for downhole working conditions.

Self-powered multifunctional flexible sensor for wearable biomonitoring

Wearable sensors advance toward the goal of multifunction and integration. Most previous researches focus on the pressure or temperature sensibility, while moisture perception enabling proximity sense and noncontact control of soft robotic and human-machine interfacing still remains a challenge. Herein, we reported a flexible self-powered multifunctional sensor (FSMS) based on fluoropolymer composites for simultaneously and actively detecting the moist, thermal and pressure stimuli. The inclusion of lithium chloride (LiCl) and polyvinyl alcohol (PVA) endows the fluoropolymer composites with excellent humidity sensing capabilities of low hysteresis (2.1%) and short response time (9 s). The as-prepared FSMS can be easily worn on versatile places of human body for wearable biomonitoring of arterial pulse and respiration as well as human-machine interaction. A moist-thermal coupling (MTC) mode is invented to boost the sensitivity for respiratory monitoring and noncontact human-machine interaction. This work opens up a new paradigm to develop multifunctional biomonitoring devices and artificial skin for next-generation wearable electronics.

Flexible sensitive hydrogel sensor with self-powered capability

Flexible sensitive hydrogels gain comprehensive research interests in fabricating human-machine interfacial devices. However, they face a great challenge of incompatibility among high strength, ultra-toughness and good conductivity, and count on an external power supply. In the work, 4-(methacryloyloxy) ethyl-1- phenylene acid (MBA) and 1,4-(5-hexenyloxy) benzene (RM26) are synthesized as supramolecular crosslinker and inserted into polyvinyl alcohol (PVA) hydrogel. A series of conductive hydrogels (PVA-PMR-NaCls) are produced by salt immersion method. The optimal PVA-PMR-NaCl exhibits the toughness of 15.92MJ·m−3, the elongation at break of 600%, the tensile strength of 5.61 MPa and the Young's modulus of 2.16 MPa. It withstands the side effect of saline ions because the defined molecules with flexible chain segment and rigid group intervene. The conductivity for PVA-PMR-NaCl is 3.0 S·m−1 prior to original PVA-NaCl owing to the carboxyl in network. It shows high gauge factor (GF) toward tensile strain, which achieves 6.24 above 200% strain. The PVA-PMR-NaCl sensor presents high sensitivity, stability and quick responsiveness during detecting human movement. Furthermore, the self-powered PVA-PMR-NaCl sensor by assembling with zinc foil and copper foil achieves the open circuit voltage of 0.809 V, and can likewise trace the stretching, bending and compressing movement according to current change. So, it will be a promising candidate as a self-powered multi-functional sensor.

Self-Powered Multifunctional Sensor of Positive Displacement Motor Based on Triboelectric Nanogenerator

In response to the testing requirements of downhole positive displacement motor (PDM), this research proposes a self-powered multifunctional sensor based on the triboelectric nanogenerator that can simultaneously measure the rotating speed, rotating angle and abrasion. Tests, including speed measurement tests, angle measurement tests, abrasion tests and reliability tests, were respectively tested after the sensor is manufactured. Speed tests results show that the measurement range is 0 to 900 r/min, the measurement error is less than 3%, and the maximum output voltage amplitude can reach 5.5 V. Angle tests results show that the minimum resolution is 60 degrees, and the measurement error is less than 5%. Abrasion tests results show that three abrasion thresholds of 0 mm, 0 to 20 mm and greater than 20 mm can be detected. Reliability tests results show that the sensor can work normally in an environment where the temperature is less than 250 degrees Celsius and the humidity is less than 90%. In addition, the power generation performance had also been tested, and the results show that the friction model and the sensing model of the sensor can output a maximum power of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$28.3 \times 10.9\text{W}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5.7 \times 10.9\text{W}$ </tex-math></inline-formula> respectively when connected in series with a 1000M <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> load. Compared with the traditional downhole sensors, this research can working normally in self-powered model at higher temperatures, and has more measurement parameters.

A Portable and Flexible Self-Powered Multifunctional Sensor for Real-Time Monitoring in Swimming.

A portable and flexible self-powered biosensor based on ZnO nanowire arrays (ZnO NWs) and flexible PET substrate has been designed and fabricated for real-time monitoring in swimming. Based on the piezoelectric effect of polar ZnO NWs, the fabricated biosensor can work in both air and water without any external power supply. In addition, the biosensor can be easily attached to the surface of the skin to precisely monitor the motion state such as joint moving angle and frequency during swimming. The constant output piezoelectric signal in different relative humidity levels enables actual application in different sports, including swimming. Therefore, the biosensor can be utilized to monitor swimming strokes by attaching it on the surface of the skin. Finally, a wireless transmitting application is demonstrated by implanting the biosensor in vivo to detect angiogenesis. This portable and flexible self-powered biosensor system exhibits broad application prospects in sport monitoring, human–computer interaction and wireless sport big data.

Highly Flexible, Stretchable, and Self-Powered Strain-Temperature Dual Sensor Based on Free-Standing PEDOT:PSS/Carbon Nanocoils-Poly(vinyl) Alcohol Films.

The wearable and self-powered sensors with multiple functions are urgently needed for energy saving devices, economical convenience, and artificial human skins. It is a meaningful idea to convert excess heat sources into power supplies for wearable sensors. In this report, we have fabricated a series of free-standing self-powered temperature-strain dual sensors based on poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS)/carbon nanocoils (CNCs)-poly(vinyl) alcohol composite films by a simple drop casting method. The Seebeck coefficients of the composite films were measured to be 19 μV/K. The sensor, with the addition of CNCs, showed a superior sensing performance to that without CNCs. PEDOT:PSS is used to provide a thermoelectric power to detect temperature changes and strain deformations. The minimum detect limit for the temperature difference was 0.3 K. Under a constant temperature gradient of 30 K, strains from 1 to 10% were detected without any external power supply. The films can be easily made into an array to detect the temperature of the fingers and motions of the wrist by attaching it to the human wrist directly. For the first time, due to the independent action of the thermoelectric material and strain sensing material, the thermoelectric voltage which is generated by a constant temperature difference is maintained under different strains. This kind of free-standing self-powered multifunctional sensors has great application prospects in the fields of healthcare and artificial intelligence in the future.

A self-powered multi-functional sensor based on triboelectric nanogenerator for monitoring states of rotating motion

Abstract The promptly growing technique of powerless devices based on triboelectric nanogenerator (TENG) offers an opportunity to get rid of external power sources. Especially, plenty of self-powered rotating sensors are proposed but short of the capability to simultaneously detect multi-rotating parameters. A self-powered states of rotating motion sensor (SRM-Sensor) is developed for synchronously monitoring rotating displacement, speed, acceleration. It is mainly constructed by rack-shaped plates and incomplete gears. Symmetrical setup of incomplete gears design amplifies triboelectric output signal twofold and the sensitivity is 580 mV/rpm. After connecting to rectified bridge and filter capacitor circuit, the output voltage shows an intuitionistic relationship with rotating speed. The calculated integral and derivation of output voltage curve perfectly fit the rotating displacement and acceleration. The proposed SRM- Sensor potentially paves the way for a rotating motion sensing system with self-powered characteristics to the fields of industrial revolve detecting.

Self-Powered, Hybrid, Multifunctional Sensor for a Human Biomechanical Monitoring Device

For personal and daily activities, it is highly desirable to collect energy from multiple sources, not only for charging personal electronics but also for charging devices that may in the future sense and transmit information for healthcare and biomedical applications. In particular, hybridization of triboelectric and piezoelectric energy-harvesting generators with lightweight components and relatively simple structures have shown promise in self-powered sensors. Here, we present a self-powered multifunctional sensor (SPMS) based on hybridization with a novel design of a piezoelectrically curved spacer that functions concurrently with a zigzag shaped triboelectric harvester for a human biomechanical monitoring device. The optimized SPMS had an open-circuit voltage (VOC) of 103 V, short-circuit current (ISC) of 302 µA, load of 100 kΩ, and maximum average power output of 38 mW under the operational processes of compression/deformation/touch/release. To maximize the new sensor’s usage as a gait sensor that can detect and monitor human motion characteristics in rehabilitation circumstances, the deep learning long short-term memory (LSTM) model was developed with an accuracy of the personal sequence gait SPMS signal recognition of 81.8%.

Flexible self-powered multifunctional sensor for stiffness-tunable soft robotic gripper by multimaterial 3D printing

Proprioceptive sensation via embedded flexible sensors is essential for soft robotic grippers to realize safe and dexterous grasping. We demonstrate a self-powered, flexible multifunctional sensor by combining a polyvinylidene difluoride film with a microstructured jamming layer. The jamming layers and the finger body are fabricated by a multimaterial 3D printing technology. The sensor built into the soft finger can provide passive proprioceptive sensations of curvature and stiffness, with maximum sensitivity of 0.55 mV m and 0.09 Vm/N respectively. It also acted as an active jamming element to tune finger stiffness (15–44 N/m) while not affecting the dynamics of the robotic movement. We demonstrate the multifunctional sensor with a three-fingered robotic gripper to successfully record finger bending and stiffening in the ‘pick and place’ process. This work shows potential of greatly enhancing the way in which a gripper interacts with objects that are manipulated and provide a route to achieve anthropomorphic grippers. • Sensitive enhancing layer was printed with soft finger by multimaterial 3D printing. • The self-powered sensor can measure curvature and stiffness up to 10 m -1 and 44 N/m. • The multifunctional sensor is able to sense finger curvature and stiffness. • This work suggests a new way of designing sensors in robotic applications.

Self-powered triboelectric/pyroelectric multimodal sensors with enhanced performances and decoupled multiple stimuli

Abstract Self-powered multifunctional sensors have been receiving great attention for their potential use in sustainable wearable electronics. In this work, we demonstrate a facile approach for the development of self-powered multimodal pressure-temperature sensors based on an identical ferroelectric copolymer, poly (vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)) for the contact pair materials by switching the triboelectric polarity via ferroelectric polarization. This approach enables the identical material-based triboelectric devices with remarkably enhanced triboelectric and pyroelectric output performances. The inversely-polarized P(VDF-TrFE) device exhibits ~106 and ~12 times higher triboelectric and pyroelectric currents, respectively, compared to those of non-polarized devices. Consequently, our triboelectric device provides the highest pressure sensitivity of 40 nA kPa−1 and 1.4 V kPa−1 with a broad pressure detection range (98 Pa–98 kPa) as well as competitive temperature sensitivity of 0.38 nA °C−1 and 0.27 nA °C−1 in cooling and heating states, respectively, compared to previous PVDF-based self-powered sensors. Furthermore, our self-powered sensor can discriminate multiple stimuli including pressure as well as temperature without signal interference. Our sensor can be utilized for the monitoring of weak pulse pressure as well as multimodal finger touch. This work provides a facile fabrication approach to realize triboelectric and pyroelectric multimodal devices with outstanding output performances.

A Stretchable Yarn Embedded Triboelectric Nanogenerator as Electronic Skin for Biomechanical Energy Harvesting and Multifunctional Pressure Sensing.

Flexible and stretchable physical sensors capable of both energy harvesting and self-powered sensing are vital to the rapid advancements in wearable electronics. Even so, there exist few studies that can integrate energy harvesting and self-powered sensing into a single electronic skin. Here, a stretchable and washable skin-inspired triboelectric nanogenerator (SI-TENG) is developed for both biomechanical energy harvesting and versatile pressure sensing. A planar and designable conductive yarn network constructed from a three-ply-twisted silver-coated nylon yarn is embedded into flexible elastomer, endowing the SI-TENG with desired stretchability, good sensitivity, high detection precision, fast responsivity, and excellent mechanical stability. With a maximum average power density of 230 mW m-2 , the SI-TENG is able to light up 170 light-emitting diodes, charge various capacitors, and drive miniature electronic products. As a self-powered multifunctional sensor, the SI-TENG is adopted to monitor human physiological signals, such as arterial pulse and voice vibrations. Furthermore, an intelligent prosthetic hand, a self-powered pedometer/speedometer, a flexible digital keyboard, and a proof-of-concept pressure-sensor array with 8 × 8 sensing pixels are successively demonstrated to further confirm its versatile application prospects. Based on these merits, the developed SI-TENG has promising applications in wearable powering technology, physiological monitoring, intelligent prostheses, and human-machine interfaces.

All-Organic High-Performance Piezoelectric Nanogenerator with Multilayer Assembled Electrospun Nanofiber Mats for Self-Powered Multifunctional Sensors

Rapid development of wearable electronics, piezoelectric nanogenerator (PNG), has been paid a special attention because of its sustainable and accessible energy generation. In this context, we present a simple yet highly efficient design strategy to enhance the output performance of an all-organic PNG (OPNG) based on multilayer assembled electrospun poly(vinylidene fluoride) (PVDF) nanofiber (NF) mats where vapor-phase polymerized poly(3,4-ethylenedioxythiophene)-coated PVDF NFs are assembled as electrodes and neat PVDF NFs are utilized as an active component. In addition to the multilayer assembly, electrode compatibility and durability remain a challenging task to mitigate the primary requirements of wearable electronics. A multilayer networked three-dimensional structure integrated with a compatible electrode thereby provides enhanced output voltage and current (e.g., open-circuit voltage, Voc ≈ 48 V, and short-circuit current, Isc ≈ 6 μA, upon 8.3 kPa of the applied stress amplitude) with superior piezoelectric energy conversion efficiency of 66% compared to the single-mat device. Besides, OPNG also shows ultrasensitivity toward human movements such as foot strikes and walking. The weight measurement mapping is critically explored by principal component analysis that may have enormous applications in medical diagnosis to smart packaging industries. More importantly, fatigue test under continuous mechanical impact (over 6 months) shows great promise as a robust wearable mechanical energy harvester.

Rolling friction contact-separation mode hybrid triboelectric nanogenerator for mechanical energy harvesting and self-powered multifunctional sensors

Collecting mechanical energy in the surrounding environment to power small electronic devices is an ideal method as a green and clean power source. Based on the working mechanism and the advantages of triboelectric nanogenerator (TENG), a robust rolling friction contact-separation mode TENG (CS-TENG) has been fabricated for harvesting vertical rotation energy by utilizing the integrated cylindrical surface with the conjunction of rolling contact electrification and electrostatic induction. The output current of the CS-TENG can maintain 96% (origin: 1.72 μA, final: 1.66 μA) after two days continuous work a rotation speed of 300 r/min. Furthermore, an electromagnetic and triboelectric hybrid contact-separation mode nanogenerator (HCS-TENG) has been further designed by coupling magnets in the rolling cylinders with copper coils as an electromagnetic generator (EMG) in the acrylic cylinder to implement the multi-functional properties. The gear transmission structure makes the device more facile to be installed on the rotation objects. The output performances of CS-TENG and EMG under various rotation speeds were systematically studied. It shows that the CS-TENG with six units can deliver an output power of 0.15 mW/cm2 and the 100 μF capacitor can be charged to 6 V in less than 1 min by the hybridized nanogenerator at a rotating rate of 700 r/min. In addition, utilizing the output signal's intrinsic characteristics of CS-TENG, a self-powered rotation speed and displacement sensor using the dual cylinder structure TENG has been achieved for these rotating mobile devices that are inconvenient to get an additional power supply in the grimmest circumstances such as moon car or other celestial and tough environment detection equipment. This multifunctional TENG device reveals a significantly potential application in the grimmest circumstances as power source, self-powered electronics and sensor systems.

A wearable pyroelectric nanogenerator and self-powered breathing sensor

Wasted heat is one of the most abundant and widely available energy sources in our living environment and industrial activities. Pyroelectric nanogenerators (PyNGs) is emerging as a powerful tool to scavenge wasted heat. Here we designed and fabricated a wearable PyNG using PVDF thin film integrated in a N95 respirator for scavenging energy of human respiration. Due to the temperature fluctuation induced by human breathing at 5°C ambient temperature, the PyNG can generate output signals with an open-circuit voltage of 42V and a short-circuit current of 2.5μA, respectively. The maximal power reached up to 8.31μW with an external load of 50MΩ, which can be utilized to directly drive electronics, such as a liquid crystal display and light emitting diodes. This PyNG has also been demonstrated as self-powered human breathing and temperature sensors. The excellent performances and unencumbered wearable mode of the PyNG demonstrate that the device can be developed as a promising wearable energy harvester and self-powered multifunctional sensors for practical applications.

Self-powered hybrid humidity sensor and dual-band UV photodetector fabricated on back-contact photovoltaic cell

Self-powered multi-functional sensors were fabricated by integrating a crystalline Si interdigitated back-contact (IBC) photovoltaic (PV) cell with a vertically stacked structure into a single chip. The IBC PV cell was vertically connected with a humidity sensor and a photodetector (PD) in parallel. The measured humidity current of the WO3 thin-film humidity sensor increased monotonically when the relative humidity was increased from 30% to 95%. In addition, the humidity characteristics of the unannealed WO3 thin-film humidity sensor were better than those of the annealed samples. The cutoff wavelengths of WO3 and Ga2O3 thin-film PDs were around 370 and 250nm, respectively. The measured responsivity of WO3 and Ga2O3 thin-film PDs at the cutoff wavelength were 1.7×10−7 and 9.8×10−7A/W, respectively, under 1-sun illumination.