Tribotronics: an emerging field by coupling triboelectricity and semiconductors

Tribotronics is an emerging research field that focuses on the coupling of triboelectricity and semiconductors.In this review,we summarise and explore three branches of tribotronics.Firstly,we introduce the tribovoltaic effect,which involves direct-current power generation through mechanical friction on semiconductor interfaces.This effect offers significant advantages in terms of high power density compared to traditional insulator-based triboelectric nanogenerators.Secondly,we elaborate on triboelectric modulation,which utilises the triboelectric potential on field-effect transistors.This approach enables active mechanosensation and nanoscale tactile perception.Additionally,we present triboelectric management,which aims to improve energy supply efficiency using semiconductor device technology.This strategy provides an effective microenergy solution for sensors and microsystems.For the interactions between triboelectricity and semiconductors,the research of tribotronics has exhibited the electronics of interfacial friction systems,and the triboelectric technology by electronics.This review demonstrates the promising prospects of tribotronics in the development of new functional devices and self-powered microsystems for intelligent manufacturing,robotic sensing,and the industrial Internet of Things.

A Flexible Tribotronic Artificial Synapse with Bioinspired Neurosensory Behavior

As key components of artificial afferent nervous systems,synaptic devices can mimic the physiological synaptic behaviors,which have attracted extensive attentions.Here,a flexible tribotronic artificial synapse(TAS)with bioinspired neurosensory behavior is developed.The triboelectric potential generated by the external contact electrification is used as the ion-gel-gate voltage of the organic thin film transistor,which can tune the carriers transport through the migration/accumulation of ions.The TAS successfully demonstrates a series of synaptic behaviors by external stimuli,such as excitatory postsynaptic current,paired-pulse facilitation,and the hierarchical memory process from sensory memory to short-term memory and long-term memory.Moreover,the synaptic behaviors remained stable under the strain condition with a bending radius of 20 mm,and the TAS still exhibits excellent durability after 1000 bending cycles.Finally,Pavlovian conditioning has been successfully mimicked by applying force and vibration as food and bell,respectively.This work demonstrates a bioinspired flexible artificial synapse that will help to facilitate the development of artificial afferent nervous systems,which is great significance to the practical application of artificial limbs,robotics,and bionics in future.

A near-zero quiescent power breeze wake-up anemometer based on a rolling-bearing triboelectric nanogenerator

Wind sensors have always played an irreplaceable role in environmental information monitoring and are expected to operate with lower power consumption to extend service lifetime.Here,we propose a breeze wake-up anemometer(B-WA)based on a rolling-bearing triboelectric nanogenerator(RB-TENG)with extremely low static power.The B-WA consists of two RB-TENGs,a self-waking-up module(SWM),a signal processing module(SPM),and a wireless transmission unit.The two RB-TENGs are employed for system activation and wind-speed sensing.Once the ambient wind-speed exceeds 2 m/s,the wake TENG(W-TENG)and the SWM can wake up the system within 0.96 s.At the same time,the SPM starts to calculate the signal frequency from the measured TENG(M-TENG)to monitor the wind speed with a sensitivity of 9.45 Hz/(m/s).After the wind stops,the SWM can switch off the B-WA within 0.52 s to decrease the system energy loss.In quiescent on-duty mode,the operating power of the B-WA is less than 30 nW,which can greatly extend the service lifetime of the B-WA.By integrating triboelectric devices and rolling bearings,this work has realized an ultralow quiescent power and self-waked-up wireless wind-speed monitoring system,which has foreseeable applications in remote weather monitoring,IoT nodes,and so on.

Self-powered wireless body area network for multi-joint movements monitoring based on contact-separation direct current triboelectric nanogenerators

Body area network has attracted extensive attention for its applications in athletics,medical,diagnosis,and rehabilitation training in the next generation personalized health care solutions.Here,a contact-separation direct current triboelectric nanogenerators(CSDC-TENGs)based selfpowered wireless body area network(SWBAN)is reported that enables multi-joint movements monitoring for human motion.The CSDC-TENG is designed as a flexible active sensor with an internal contact switch,and the flexible substrate makes the TENG-sensor stick onto skin easily.Due to the internal switch,the CSDC-TENG could generate a DC current,a large instantaneous output voltage exceeds 700 V,and an instantaneous power can reach 1.076 W,which is more than 23000 times higher than that of the traditional contact-separation mode TENG in same size and materials without the switch.By coupling with flexible coil,the fixed high-frequency radio signals can be modulated and emitted clearly ranging from 6 to 16 MHz,which can be wirelessly received and demodulated through a reader.Moreover,the SWBAN is demonstrated in a real time monitoring system for joints motion.This work has realized the wearable TENG for self-powered wireless real-time monitoring of body movements driven by low-frequency human daily activities,which may promote a tremendous development of intelligent healthcare,wireless sensing system and body area network.

Intrinsically Stretchable Organic-Tribotronic-Transistor for Tactile Sensing

Stretchable electronics are of great significance for the development of the next-generation smart interactive systems.Here,we propose an intrinsically stretchable organic tribotronic transistor(SOTT)without a top gate electrode,which is composed of a stretchable substrate,silver nanowire electrodes,semiconductor blends,and a nonpolar elastomer dielectric.The drain-source current of the SOTT can be modulated by external contact electrification with the dielectric layer.Under 0-50%stretching both parallel and perpendicular to the channel directions,the SOTT retains great output performance.After being stretched to 50%for thousands of cycles,the SOTT can survive with excellent stability.Moreover,the SOTT can be conformably attached to the human hand,which can be used for tactile signal perception in human-machine interaction and for controlling smart home devices and robots.This work has realized a stretchable tribotronic transistor as the tactile sensor for smart interaction,which has extended the application of tribotronics in the human-machine interface,wearable electronics,and robotics.

MXene based mechanically and electrically enhanced film for triboelectric nanogenerator

The development of triboelectric nanogenerator(TENG)technology which can directly convert ambient mechanical energy into electric energy may affect areas from green energy harvesting to emerging wearing electronics.And,the material of triboelectric layer is critical to the mechanical robustness and electrical output characteristics of the TENGs.Herein,a MXene enhanced electret polytetrafluoroethylene(PTFE)film with a high mechanical property and surface charge density is developed.The MXene/PTFE composite film was synthesized by spraying and annealing treatment.With the doping of MXene,the crystallinity of composite film could be tuned,leading to an enhancement in the tensile property of 450%and reducing the wear volume about 80%in the friction test.Furthermore,the as-fabricated TENG with this composite film outputs 397 V of open-circuit voltage,21µA of short-circuit current,and 232 nC of transfer charge quantity,which are 4,6,and 6 times higher than that of the TENG made by pure PTFE film,respectively.Therefore,this work provides a creative strategy to simultaneously improve the mechanical property and electrical performance of the TENGs,which have great potential in improving device stability under a complex mechanical environment.

Raindrop energy-powered autonomous wireless hyetometer based on liquid-solid contact electrification

Triboelectric nanogenerators(TENGs)can directly harvest energy via solid-liquid interface contact electrification,making them very suitable for harvesting raindrop energy and as active rainfall sensors.This technology is promising for realizing a fully self-powered system for autonomous rainfall monitoring combined with energy harvesting/sensing.Here,we report a raindrop energy-powered autonomous rainfall monitoring and wireless transmission system(R-RMS),in which a raindrop-TENG(R-TENG)array simultaneously serves as a raindrop energy harvester and rainfall sensor.At a rainfall intensity of 71 mm/min,the R-TENG array can generate an average short-circuit current,open-circuit voltage,and maximum output power of 15 pA,1800 V,and 325 pW,respectively.The collected energy can be adjusted to act as a stable 2.5 V direct-current source for the whole system by a power management circuit.Meanwhile,the R-TENG array acts as a rainfall sensor,in which the output signal can be monitored and the measured data are wirelessly transmitted.Linder a rainfall intensity of 71 mm/min,the R-RMS can be continuously powered and autonomously transmit rainfall data once every 4 min.This work has paved the way for raindrop energy-powered wireless hyetometers,which have exhibited broad prospects in unattended weather monitoring,field surveys,and the Internet of Things.

Tribotronic bipolar junction transistor for mechanical frequency monitoring and use as touch switch

Tribotronics,a new field that involves the coupling of triboelectricity and semiconductors,has attracted great interest in the nanoenergy and nanoelectronics domains.This paper proposes a tribotronic bipolar junction transistor(TBJT)that incorporates a bipolar junction transistor and a triboelectric nanogenerator(TENG)in the single-electrode mode.When the mobile triboelectric layer slides on the device surface for electrification,a bias voltage is created and applied to the emitter junction,and then the base current from the TENG is amplified.Based on the fabricated TBJT,a mechanical frequency monitoring sensor with high sensitivity and excellent stability and a finger-triggered touch switch were developed.This work demonstrated for the first time a tribotronic device with simultaneously controlled voltage and current voltage/current simultaneously controlled tribotronic device,which has promising potential applications in micro/nano-sensors,human-machine interactions,intelligent instrumentation,wearable electronics,and other applications.