Publications

Abstract Tribovoltaic nanogenerators (TVNGs), an emerging high‐entropy energy harvesting technique, present great features such as low matching resistance, high current density, and continuous output performance. Here, an MXene layer and a semiconducting silicon wafer are assembled into a tribovoltaic nanogenerator (named MS‐TVNG). The output peak current of the MS‐TVNG reaches up to 22 µA for a P‐type (0.1–0.5 Ω cm) silicon wafer under a normal force of 4.56 N and a sliding speed of 2 m s −1 . Owing to the unique metal characteristics of the MXene layer, the performance is superior to those previously reported TVNGs using traditional metals. The layered structure of MXene endows the real‐time MS‐TVNG with outstanding wear‐resistance and stable output properties. The performance of the MS‐TVNG can be tuned by the doping type and concentration of the silicon wafer, as well as by the pressure and the relative sliding speed between two friction surfaces. The MS‐TVNG has proven to be a solid foundation for high‐performance self‐powered speed sensors and has excellent potentials for applications in displacement, tension, oscillation angle, and vibration detection.

Mechanosensitive electronics aims at replicating the multifunctions of human skin to realize quantitative conversion of external stimuli into electronic signals and provide corresponding feedback instructions. Here, we report a mechanosensation-active matrix based on a direct-contact tribotronic planar graphene transistor array. Ion gel is utilized as both the dielectric in the graphene transistor and the friction layer for triboelectric potential coupling to achieve highly efficient gating and sensation properties. Different contact distances between the ion gel and other friction materials produce different triboelectric potentials, which are directly coupled to the graphene channel and lead to different output signals through modulating the Fermi level of graphene. Based on this mechanism, the tribotronic graphene transistor is capable of sensing approaching distances, recognizing the category of different materials, and even distinguishing voices. It possesses excellent sensing properties, including high sensitivity (0.16 mm–1), fast response time (∼15 ms), and excellent durability (over 1000 cycles). Furthermore, the fabricated mechanosensation-active matrix is demonstrated to sense spatial contact distances and visualize a 2D color mapping of the target object. The tribotronic active matrix with ion gel as dielectric/friction layer provides a route for efficient and low-power-consuming mechanosensation in a noninvasive fashion. It is of great significance in multifunction sensory systems, wearable human–machine interactive interfaces, artificial electronic skin, and future telemedicine for patient surveillance.

'Polymer Pen Lithography' published in 'Encyclopedia of Nanotechnology'

A self-powered pressure-sensor matrix based on ZnS:Mn particles for more-secure signature collection is presented, by recording both handwritten signatures and the pressure applied by the signees. This large-area, flexible sensor matrix can map 2D pressure distributions in situ, either statically or dynamically, and the piezophotonic effect is proposed to initiate the mechanoluminescence process once a dynamic mechanical strain is applied.

Tactile sensing is of great importance in developing human-machine interface, remote control, and security systems. Here, a self-triggered alarm system based on the one-piece triboelectric nanosensor (TENS) is reported. By using nitrocellulose (NC) membrane as the triboelectric material, the as-designed TENS can not only sensitively respond to physical contacts in a self-triggered mode but also securely detect the third-level details of latent fingerprint. The self-triggered idea based on the triboelectric nanogenerator is compatible with intelligent interactive interface. Besides, this TENS can be conveniently fabricated and integrated into arrays at a large scale due to its freestanding, simple, and low-cost characteristics. This work presents alternative perspectives for the practical applications of the multifunctionalized TENS.

Abstract Energy harvesting from mechanical vibrations, thermal gradients, electromagnetic radiations, and solar radiations has experienced rapid progress in recent times not only to develop an alternative power source that can replace conventional batteries to energize portable and personal electronics smartly but also to achieve sustainable self‐sufficient micro/nanosystems. Utilizing micro‐electromechanical system (MEMS) and microfluidics technologies through selective designs and fabrications effectively, those energy harvesters can be considerably downsized while ensuring a stable, portable, and consistent power supply. Although ambient energy sources such as solar radiation are harvested for decades, recent developments have enabled ambient vibrations, electromagnetic radiation, and heat to be harvested wirelessly, independently, and sustainably. Developments in the field of microfluidics have also led to the design and fabrication of novel energy harvesting devices. This paper reviews the recent advancements in energy harvesting technologies such as piezoelectric, electromagnetic, electrostatic, thermoelectric, radio frequency, and solar to drive self‐powered portable electronics. Moreover, the potential application of MEMS and microfluidics as well as MEMS‐based structures and fabrication techniques for energy harvesting are summarized and presented. Finally, a few crucial challenges affecting the performance of energy harvesters are addressed.

Electrifying: A fiber-based hybrid nanogenerator for simultaneous or independent harvesting of mechanical and biochemical energy is presented. The hybrid system consists of a nanogenerator (FNG) and a biofuel cell (FBFC) and provides a peak output of 3.1 V and 200 nA. It also serves as a self-powered sensor for the quantification of pressure variations. Detailed facts of importance to specialist readers are published as "Supporting Information". Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.