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Contact electrification (triboelectrification) (CE) is a universal phenomenon in ambient environment and has been recorded for more than 2600 years. Nonetheless, the intrinsic mechanism of CE still remains controversial. Herein, based on first‐principles theory, the underlying mechanism in CE is systematically investigated between metallic MXenes and semiconductive MoS2. The results show that the work functions of contacting materials dominate the direction of electron transfer during CE process. That is, the electron will be transferred from the material with low work function to the one with high work function. The theoretical prediction is verified experimentally through investigating triboelectric probes based on MXenes and MoS2 nanomaterials. Additionally, it is noted that the interfacial potential barrier and the work function difference together modulate the amount of transferred electron. Electron transfer mainly occurs in the repulsive forces region where the interaction distance between the two materials is shorter than the normal bonding length. The quantum calculation results agree well with the Wang transition theory. Furthermore, it is also noticed that, due to the wave‐particle duality of electron, electron transfer will obviously occur at the attractive force region when the two contacting materials exhibit a larger work function difference. [ABSTRACT FROM AUTHOR]

This study introduces a novel self-powered metamaterial augmented nanogenerator for low-frequency acoustic telecommunication (MANLAT), which is designed to enhance acoustic communication capabilities by utilizing the local resonance mechanism to selectively amplify specific frequency bands of incident sound and generate large amplitude signals in a self-powered manner. The MANLAT device consists of a flexible bottom that responds to pressure differences by generating strong vibrations. Additionally, a lightweight cone-shaped component is attached to the central part of the flexible plate, thus increasing the surface area in that region. Through contact electrification and electrostatic induction mechanisms, a substantial electrical signal is generated, allowing the device to serve as a self-powered acoustic telecommunication receiver. To assess its performance in real-world scenarios, environmental interference was simulated by generating white noise added to the modulated waveform containing information, which was then transmitted through a loudspeaker. At the receiving end, a high-precision microphone sensor was used alongside the MANLAT device to capture the sound wave. The experimental results demonstrate that the MANLAT device surpassed the microphone sensor in mitigating noise interference and enabled the effective decoding of information even in the presence of high levels of white noise or background music. Consequently, the device simplifies communication systems, facilitates reliable and environmentally friendly communication, and enhances information security. [Display omitted] • A self-powered low frequency acoustic telecommunication device is proposed. • The device shows strong anti-interference capability. • Covert communication is demonstrated with background music. [ABSTRACT FROM AUTHOR]

We introduce an innovative designof a disk triboelectric nanogenerator(TENG) with segmental structures for harvesting rotational mechanicalenergy. Based on a cyclic in-plane charge separation between the segmentsthat have distinct triboelectric polarities, the disk TENG generateselectricity with unique characteristics, which have been studied byconjunction of experimental results with finite element calculations.The role played by the segmentation number is studied for maximizingoutput. A distinct relationship between the rotation speed and theelectrical output has been thoroughly investigated, which not onlyshows power enhancement at high speed but also illuminates its potentialapplication as a self-powered angular speed sensor. Owing to the nonintermittentand ultrafast rotation-induced charge transfer, the disk TENG hasbeen demonstrated as an efficient power source for instantaneouslyor even continuously driving electronic devices and/or charging anenergy storage unit. This work presents a novel working mode of TENGsand opens up many potential applications of nanogenerators for harvestingeven large-scale energy. [ABSTRACT FROM AUTHOR]

Aiming at harvesting ambient mechanicalenergy for self-poweredsystems, triboelectric nanogenerators (TENGs) have been recently developedas a highly efficient, cost-effective and robust approach to generateelectricity from mechanical movements and vibrations on the basisof the coupling between triboelectrification and electrostatic induction.However, all of the previously demonstrated TENGs are based on verticalseparation of triboelectric-charged planes, which requires sophisticateddevice structures to ensure enough resilience for the charge separation,otherwise there is no output current. In this paper, we demonstrateda newly designed TENG based on an in-plane charge separation processusing the relative sliding between two contacting surfaces. UsingPolyamide 6,6 (Nylon) and polytetrafluoroethylene (PTFE) films withsurface etched nanowires, the two polymers at the opposite ends ofthe triboelectric series, the newly invented TENG produces an open-circuitvoltage up to ∼1300 V and a short-circuit current density of4.1 mA/m2with a peak power density of 5.3 W/m2, which can be used as a direct power source for instantaneouslydriving hundreds of serially connected light-emitting diodes (LEDs).The working principle and the relationships between electrical outputsand the sliding motion are fully elaborated and systematically studied,providing a new mode of TENGs with diverse applications. Comparedto the existing vertical-touching based TENGs, this planar-slidingTENG has a high efficiency, easy fabrication, and suitability formany types of mechanical triggering. Furthermore, with the relationshipbetween the electrical output and the sliding motion being calibrated,the sliding-based TENG could potentially be used as a self-powereddisplacement/speed/acceleration sensor. [ABSTRACT FROM AUTHOR]