Publications

Reconfigurable devices based on two-dimensional materials are considered as one of the ways to extend Moore's Law. However, most reconfigurable devices use a gate voltage to dope the channel electrostatically, and the continuously applied gate voltage poses the problem of high device power consumption. Here, for the first time, we propose a tribotronic reconfigurable MoTe2 field effect transistor, where the power consumption of the device is greatly reduced by using triboelectric potentials generated by external mechanical operations instead of gate voltages. The drain current noise spectral density test proves that no additional current noise interferes with the output current during mechanical operation. Mechanical operation allows easy modulation of four different channel polarities, n-n, p-p, p-n, n-p, in a single transistor. We demonstrate the potential application of a tribotronic p-n diode for photovoltaic device. The logic circuit composed of two tribotronic reconfigurable transistors realizes the logic functions of inverter, AND gate and NOT gate. Our device extends tribotronic logic and demonstrates great potential for human-machine interaction, intelligent sensors, and wearable devices.

Abstract Wind is one of the most important sources of green energy, but the current technology for harvesting wind energy is only effective when the wind speed is beyond 3.5–4.0 m s −1 . This is mainly due to the limitation that the electromagnetic generator works best at high frequency. This means that light breezes cannot reach the wind velocity threshold of current wind turbines. Here, a high‐performance triboelectric nanogenerator (TENG) for efficiently harvesting energy from an ambient gentle wind, especially for speeds below 3 m s −1 is reported, by taking advantage of the relative high efficiency of TENGs at low‐frequency. Attributed to the multiplied‐frequency vibration of ultra‐stretchable and perforated electrodes, an average output of 20 mW m −3 can be achieved with inlet wind speed of 0.7 m s −1 , while an average energy conversion efficiency of 7.8% at wind speed of 2.5 m s −1 is reached. A self‐charging power package is developed and the applicability of the TENG in various light breezes is demonstrated. This work demonstrates the advantages of TENG technology for breeze energy exploitation and proposes an effective supplementary approach for current employed wind turbines and micro energy structure.

Nanowire solar cells are promising candidates for powering nanosystems and flexible electronics. The strain in the nanowires, introduced during growth, device fabrication and/or application, is an important issue for piezoelectric semiconductor (like CdS, ZnO, and CdTe) based photovoltaic. In this work, we demonstrate the first largely enhanced performance of n-CdS/p-Cu(2)S coaxial nanowire photovoltaic (PV) devices using the piezo-phototronics effect when the PV device is subjected to an external strain. Piezo-phototronics effect could control the electron-hole pair generation, transport, separation, and/or recombination, thus enhanced the performance of the PV devices by as high as 70%. This effect offers a new concept for improving solar energy conversation efficiency by designing the orientation of the nanowires and the strain to be purposely introduced in the packaging of the solar cells. This study shed light on the enhanced flexible solar cells for applications in self-powered technology, environmental monitoring, and even defensive technology.

Efficient scavenging the kinetic energy from air-flow represents a promising approach for obtaining clean, sustainable electricity. Here, we report an elasto-aerodynamics-driven triboelectric nanogenerator (TENG) based on contact electrification. The reported TENG consists of a Kapton film with two Cu electrodes at each side, fixed on two ends in an acrylic fluid channel. The relationship between the TENG output power density and its fluid channel dimensions is systematically studied. TENG with a fluid channel size of 125 × 10 × 1.6 mm(3) delivers the maximum output power density of about 9 kW/m(3) under a loading resistance of 2.3 MΩ. Aero-elastic flutter effect explains the air-flow induced vibration of Kapton film well. The output power scales nearly linearly with parallel wiring of multiple TENGs. Connecting 10 TENGs in parallel gives an output power of 25 mW, which allows direct powering of a globe light. The TENG is also utilized to scavenge human breath induced air-flow energy to sustainably power a human body temperature sensor.

Abstract The internet of things in the context of the ocean is vitally important. For ships sailing on the wide ocean in adverse weather conditions, evasion of marine islands and reefs is crucial to ensure safe navigation. Here, a hybrid wave energy harvesting nanogenerator is proposed (HW‐NG) as a power source for long‐distance wireless transmission, and demonstrated a self‐powered route avoidance warning system for ocean navigation. The HW‐NG is developed based on a triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG), integrated by a pendulum structure. The TENG based on a contact‐separation mode is designed into a spring‐assisted multilayered structure, in which the EMG unit is well hybridized. Simply relying on the energy extracted from water waves, the HW‐NG can establish long‐distance (1.5 km) communication nodes on the sea. In application, a large HW‐NG network could be developed in the adjacent water areas of islands or reefs. With a network formed by hundreds of thousands of HW‐NGs, the forewarning signal transmission could be realized per second on the sea. More importantly, the wireless emitting is spontaneous through the designed automatic switch module. This work demonstrates a practicable strategy for ensuring safety of sea transportation based on wave energy collection.

Multifunctional electronic textiles (E-textiles) with embedded electric circuits hold great application prospects for future wearable electronics. However, most E-textiles still have critical challenges, including air permeability, satisfactory washability, and mass fabrication. In this work, we fabricate a washable E-textile that addresses all of the concerns and shows its application as a self-powered triboelectric gesture textile for intelligent human–machine interfacing. Utilizing conductive carbon nanotubes (CNTs) and screen-printing technology, this kind of E-textile embraces high conductivity (0.2 kΩ/sq), high air permeability (88.2 mm/s), and can be manufactured on common fabric at large scales. Due to the advantage of the interaction between the CNTs and the fabrics, the electrode shows excellent stability under harsh mechanical deformation and even after being washed. Moreover, based on a single-electrode mode triboelectric nanogenerator and electrode pattern design, our E-textile exhibits highly sensitive touch/gesture sensing performance and has potential applications for human–machine interfacing.

A hybrid magnetic energy harvester is demonstrated for self-powered sensors in transmission lines, showcasing unprecedented power density, compact size, lightweight, waterproofing, resilience to current fluctuations, and environmental robustness.

'Prenucleation Clusters' published in 'Encyclopedia of Nanotechnology'

Abstract As an emerging technology for harvesting mechanical energy, low surface charge density greatly hinders the practical applications of triboelectric nanogenerators (TENGs). Here, a high-performance TENG based on charge shuttling is demonstrated. Unlike conventional TENGs with static charges fully constrained on the dielectric surface, the device works based on the shuttling of charges corralled in conduction domains. Driven by the interaction of two quasi-symmetrical domains, shuttling of two mirror charge carriers can be achieved to double the charge output. Based on the mechanism, an ultrahigh projected charge density of 1.85 mC m −2 is obtained in ambient conditions. An integrated device for water wave energy harvesting is also presented, confirming its feasibility for practical applications. The device provides insights into new modes of TENGs using unfixed charges in domains, shedding a new light on high-performance mechanical energy harvesting technology.