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.

Ambipolar tribotronic transistor of MoTe_(2)

Two-dimensional(2D)tribotronic devices have been successfully involved in electromechanical modulation for channel conductance and applied in intelligent sensing system,touch screen,and logic gates.Ambipolar transistors and corresponding complementary inverters based on one type of semiconductors are highly promising due to the facile fabrication process and readily tunable polarity.Here,we demonstrate an ambipolar tribotronic transistor of molybdenum ditelluride(MoTe_(2)),which shows typical ambipolar transport properties modulated by triboelectric potential.It is comprised of a MoTe_(2)transistor and a lateral sliding triboelectric nanogenerator(TENG).The induced triboelectric potential by Maxwell’s displacement current(a driving force for TENG)can readily modulate the transport properties of both electrons and holes in MoTe_(2)channel and effectively drive the transistor.High performance tribotronic properties have been achieved,including low cutoff current below 1 pA·μm^(−1)and high current on/off ratio of~103 for holes and electrons dominated transports.The working mechanism on how to achieve tribotronic ambipolarity is discussed in detail.A complementary tribotronic inverter based on single flake of MoTe_(2)is also demonstrated with low power consumption and high stability.This work presents an active approach to efficiently modulate semiconductor devices and logic circuits based on 2D materials through external mechanical signal,which has great potential in human–machine interaction,intelligent sensor,and other wearable devices.

Tribotronic triggers and sequential logic circuits

In this paper, a floating-gate tribotronic transistor （FGTT） based on a mobile triboelectric layer and a traditional silicon-based field-effect transistor （FET） is proposed. In the FGTT, the triboelectric charges in the layer created by contact electrification can be used to modulate charge carrier transport in the transistor. Based on the FGTTs and FETs, a tribotronic negated AND （NAND） gate that achieves mechanical-electrical coupled inputs, logic operations, and electrical level outputs is fabricated. By further integrating tribotronic NAND gates with traditional digital circuits, several basic units such as the tribotronic S-R trigger, D trigger, and T trigger have been demonstrated. Additionally, tribotronic sequential logic circuits such as registers and counters have also been integrated to enable external contact triggered storage and computation. In contrast to the conventional sequential logic units controlled by electrical signals, contact-triggered tribotronic sequential logic circuits are able to realize direct interaction and integration with the external environment. This development can lead to their potential application in micro/nano-sensors, electromechanical storage, interactive control, and intelligent instrumentation.

Tribotronic transistor sensor for enhanced hydrogen detection

Hydrogen detection with a high sensitivity is necessary for preventing potential explosions and fire.In this study,a novel ZnO tribotronic transistor is developed by coupling a ZnO field effect transistor （FET） and triboelectric nanogenerator in free-standing mode and is used as a sensor for hydrogen detection at room temperature.Tribotronic modulated performances of the hydrogen sensor are demonstrated by investigating its output characteristics at different sliding distances and hydrogen concentrations.By applying an external mechanical force to the device for sliding electrification,the detection sensitivity of the ZnO tribotronic transistor sensor is improved,with a significant enhancement achieved in output current by 62 times at 500 ppm hydrogen and 1 V bias voltage.This study demonstrates an extension of the applications of emerging tribotronics for gas detection and a prospective approach to improve the performance of the hydrogen sensor via human-interfacing.

A self-powered temperature-sensitive electronic-skin based on tribotronic effect of PDMS/PANI nanostructures

A new self-powered temperature-sensitive electronic-skin(e-skin) for real-time monitoring body temperature without external electricity power was fabricated from patterned polydimethylsiloxane/polyaniline(PDMS/PANI) nanostructures. The e-skin can be feasibly attached on the human body and driven by the mechanical motion energy through triboelectric effect. The outputting triboelectric impulse of the PDMS/PANI units is significantly dependent on the local surface temperature of the eskin, serving as both the power source and temperature sensing signal. The outputting current of the e-skin increases with increasing surface temperature of the device. Under applied bending deformation,the response of the e-skin is up to 63.6 for 38.6℃. The e-skin can detect minimum temperature change of 0.4℃. The working mechanism can be ascribed to the coupling effect of triboelectric and semiconductor properties(tribotronic effect). A practical application of the e-skin attaching on the human body for detecting the body temperature range of 36.5–42.0℃ has been simply demonstrated. This work provides a viable method for real-time monitoring body temperature, and can promote the development of wearable temperature sensors and self-powered multifunctional nanosystems.