Publications

Abstract A practical, highly flexible capillary‐tube triboelectric nanogenerator (ct‐TENG) is reported as a microfluidic sensor. The ct‐TENG is composed of an ultrafine tubular sandwich structure of polytetrafluoroethylene capillary tube, double helix aluminum foil, and silicon rubber hermetic tube. For the first time, microliter sampling (sampling volume, 0.5 µL), nondestructive and highly flexible, is achieved simultaneously for a microliquid sensing device. The self‐powered ct‐TENG is capable of outputting selectable electrical signals (1.1 V, 10 nA, 0.9 nC) used for sensing a volume of 0.5 µL microliquid due to Maxwell's displacement current generated with energy converted from microliquid flow. It also achieves both total aerobic count monitoring and electrical conductivity (κ) detection. Moreover, the ct‐TENG is ultrafine/highly flexible structure and enables its application as a microliter magnitude active sensor for qualitative/quantitative detection. This work provides new opportunities for multifunctional sensing and potential applications in microliquid biological and chemical monitoring/detection technology.

Intelligent actuating materials with vapor-stimulated mechanical response usually require complicated synthesizing processes or have a high cost. Here, we found that the UV/O3-modified poly(dimethylsiloxane) PDMS) film can show spontaneous curling deformation when it encounters small alcohol molecules such as ethanol vapor. Based on the coupling of the vapor-responsive PDMS film and triboelectric nanogenerator (TENG), a flexible actuator for object transport and a double-finger gripper for loading small objects are designed. The deformation and size change induced by vapor stimulation help these devices to adapt to the target objects of different sizes, while the electrostatic force provided by TENG can move or control the target object, for instance, the double-finger gripper can clamp an object of a weight of 6 g.

Self-assembled ZnO quantum dots (QDs) were achieved by a vapor phase transport process. ZnO nanodots were naturally formed on solid substrates in the Volmer-Weber growth mode. Size control of nanodots could be readily realized by varying the growth time. The as-prepared ZnO QDs are of high quality and very stable after formation. The blueshift of band gap energies derived from quantum confinement effects was confirmed by optical absorption spectra. Photoluminescence spectra revealed the tunable behavior of ultraviolet luminescence due to exciton localization. The realization of size-tuned color from ZnO QDs makes them more promising for practical applications.

Abstract Zinc oxide is potentially a useful material for ultraviolet detectors; however, a relatively long response time hinders practical implementation. Here by designing and fabricating a self-powered ZnO/perovskite-heterostructured ultraviolet photodetector, the pyroelectric effect, induced in wurtzite ZnO nanowires on ultraviolet illumination, has been utilized as an effective approach for high-performance photon sensing. The response time is improved from 5.4 s to 53 μs at the rising edge, and 8.9 s to 63 μs at the falling edge, with an enhancement of five orders in magnitudes. The specific detectivity and the responsivity are both enhanced by 322%. This work provides a novel design to achieve ultrafast ultraviolet sensing at room temperature via light-self-induced pyroelectric effect. The newly designed ultrafast self-powered ultraviolet nanosensors may find promising applications in ultrafast optics, nonlinear optics, optothermal detections, computational memories and biocompatible optoelectronic probes.

Tribovoltaic direct-current (DC) nanogenerator made of dynamic semiconductor heterojunction is emerging as a promising mechanical energy harvesting technology. However, fundamental understanding of the mechano-electronic carrier excitation and transport at dynamic semiconductor interfaces remains to be investigated. Here, we demonstrated for the first time, that tribovoltaic DC effect can be tuned with metal-insulator transition (MIT). In a representative MIT material (vanadium dioxide, VO2), we found that the short-circuit current (ISC) can be enhanced by >20 times when the material is transformed from insulating to metallic state upon static or dynamic heating, while the open-circuit voltage (VOC) turns out to be unaffected. Such phenomenon may be understood by the Hubbard model for Mott insulator: orders' magnitude increase in conductivity is induced when the nearest hopping changes dramatically and overcomes the Coulomb repulsion, while the Coulomb repulsion giving rise to the quasi-particle excitation energy remains relatively stable.

<title>Abstract</title> Background Bread wheat (<italic>Triticum aestivum</italic> L.) endosperm contains starch and proteins, which determine the final yield, quality, and nutritional value of wheat grain. The endosperm-specific expressed genes can precisely provide targets in the endosperm for improving wheat grain quality and nutrition using modern bioengineering technologies. However, the genes specifically expressed in developing endosperms remain largely unknown. Results In this study, 315 preferentially expressed endosperm genes (PEEGs) in the spring wheat cultivar, Chinese Spring, were screened using data obtained from an open bioinformatics database, which reveals a unique grain reserve deposition process and special signal transduction in a developing wheat endosperm. Furthermore, transcription and accumulation of storage proteins in the wheat cultivar, XC26 were evaluated. The results revealed that PEEG plays a critical role in storage protein fragment deposition and is a potential candidate for modifying grain quality and nutrition. Conclusion These results provide new insights into endosperm development and candidate genes and promoters for improving wheat grain quality through genetic engineering and plant breeding techniques.

Sensors capable of monitoring dynamic mechanics of tendons throughout a body in real time could bring systematic information about a human body’s physical condition, which is beneficial for avoiding muscle injury, checking hereditary muscle atrophy, and so on. However, the development of such sensors has been hindered by the requirement of superior portability, high resolution, and superb conformability. Here, we present a wearable and stretchable bioelectronic patch for detecting tendon activities. It is made up of a piezoelectric material, systematically optimized from architectures and mechanics, and exhibits a high resolution of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>5.8</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>5</mml:mn> </mml:mrow> </mml:msup> <mml:mtext> </mml:mtext> <mml:mtext>N</mml:mtext> </mml:math> with a linearity parameter of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mo>=</mml:mo> <mml:mn>0.999</mml:mn> </mml:math> . Additionally, a tendon real-time monitoring and healthcare system is established by integrating the patch with a micro controller unit (MCU), which is able to process collected data and deliver feedback for exercise evaluation. Specifically, through the patch on the ankle, we measured the maximum force on the Achilles tendon during jumping which is about 16312 N, which is much higher than that during normal walking (3208 N) and running (5909 N). This work not only provides a strategy for facile monitoring of the variation of the tendon throughout the body but also throws light on the profound comprehension of human activities.

Abstract In situ harvesting undersea energy is a vital method for undersea detector to realize its long‐term and real‐time undersea research. Herein, inspired by the fins with excellent hydrodynamic characteristic and the triboelectric nanogenerator (TENG) with the merits of light‐weight and high‐efficiency at low frequency, an energy harvesting device is designed to harvest undersea energy by bionic‐fin‐structure assisted with multilayer‐structured triboelectric nanogenerator (BFM‐TENG). The good design of geometry and structure enable BFM‐TENG to harvest energy efficiently by the driving of water‐flow from multidirections. Besides, based on the multiarea contact structure and ultrathin dielectric material, the BFM‐TENG could achieve a peak power density of 444 W m −3 under ideal test condition, which is about 1–2 orders of magnitude higher than that of previous work for harvesting wave energy. The findings not only provide a new in situ undersea energy harvesting method for undersea detectors to realize the real‐time, long‐term, and self‐powered undersea research, but also provide a potential strategy to achieve large‐scale undersea energy harvesting.