Publications

We have noticed that the two equations appear in the manuscript 1 were typed with errors.

'Plasma' published in 'Encyclopedia of Nanotechnology'

High-quality CdSxSe1-x nanobelts of variable composition (0 ≤ x ≤ 1) were fabricated by a simple one-step thermal evaporation route. Photoluminescence measurements showed that all the CdSxSe1-x nanobelts have a single near-bandedge emission band, and their spectral maximum positions can be tuned from ∼508 nm (for pure CdS) to ∼705 nm (for pure CdSe). These kinds of nanobelts may have potential applications in adjustable nano/micro photoelectric devices in the visible region.

Triboelectric nanogenerator (TENG) is a newly invented technology that can effectively harvest ambient mechanical energy from various motions with promising applications in portable electronics, self‐powered sensor networks, etc. Here, by coupling TENG and a thin film of ferroelectric polymer, a new application is designed for TENG as a self‐powered memory system for recording a mechanical displacement/trace. The output voltage produced by the TENG during motion can polarize the dipole moments in the ferroelectric thin film. Later, by applying a displacement current measurement to detect the polarization density in the ferroelectric film, the motion information of the TENG can be directly read. The sliding TENG and the single‐electrode TENG matrix are both utilized for realizing the memorization of the motion trace in one‐dimensional and two‐dimensional space, respectively. Currently, the ferroelectric thin film with a size of 3.1 mm 2 can record a minimum area changing of 30 mm 2 and such resolution can still be possibly improved. These results prove that the ferroelectric polymer is an effective memory material to work together with TENG and thereby the fabricated memory system can potentially be used as a self‐powered displacement monitor.

Abstract A high-speed micromotor is usually actuated by a power source with high voltage and frequency. Here we report a triboelectric micromotor by coupling a micromotor and a triboelectric nanogenerator, in which the micromotor can be actuated by ultralow-frequency mechanical stimuli. The performances of the triboelectric micromotor are exhibited at various structural parameters of the micromotor, as well as at different mechanical stimuli of the triboelectric nanogenerator. With a sliding range of 50 mm at 0.1 Hz, the micromotor can start to rotate and reach over 1000 r min −1 at 0.8 Hz. The maximum operation efficiency of the triboelectric micromotor can reach 41%. Additionally, the micromotor is demonstrated in two scanning systems for information recognition. This work has realized a high-speed micromotor actuated by ultralow frequency mechanical stimuli without an external power supply, which has extended the application of triboelectric nanogenerator in micro/nano electromechanical systems, intelligent robots and autonomous driving.

We present that the electroluminescence (EL) properties of Mg-doped p-type GaN thin films can be tuned by the piezo-phototronic effect via adjusting the minority carrier injection efficiency at the metal-semiconductor (M-S) interface by strain induced polarization charges. The device is a metal-semiconductor-metal structure of indium tin oxide (ITO)-GaN-ITO. Under different straining conditions, the changing trend of the transport properties of GaN films can be divided into two types, corresponding to the different c-axis orientations of the films. An extreme value was observed for the integral EL intensity under certain applied strain due to the adjusted minority carrier injection efficiency by piezoelectric charges introduced at the M-S interface. The external quantum efficiency of the blue EL at 430 nm was changed by 5.84% under different straining conditions, which is 1 order of magnitude larger than the change of the green peak at 540 nm. The results indicate that the piezo-phototronic effect has a larger impact on the shallow acceptor states related EL process than on the one related to the deep acceptor states in p-type GaN films. This study has great significance on the practical applications of GaN in optoelectronic devices under a working environment where mechanical deformation is unavoidable such as for flexible/printable light emitting diodes.

Single-excitation dual-color coherent random lasing was achieved by tuning the resonance energy transfer process in porous structured nanowires.

An intelligent monitoring lubricant is essential for the development of smart machines because unexpected and fatal failures of critical dynamic components in the machines happen every day, threatening the life and health of humans. Inspired by the triboelectric nanogenerators (TENGs) work on water, we present a feasible way to prepare a self-powered triboelectric sensor for real-time monitoring of lubricating oils

Abstract In situ detection of contamination in liquid food production by intelligent sensing equipment in a factory is of great significance to ensure food safety, quality control, process optimization, and cost reduction. Current technologies require samples to be extracted and analyzed using bulky, expensive, and large instruments, which are time‐consuming, complex, and cannot be realized in situ detection. In this work, a high‐density array Triboelectric Nanogenerator (TENG) probe is fabricated by combining triboelectrification and charge transfer at liquid–solid interface, and interface charge transfer mapping (ICTM) is applied to the identification and safety detection of liquid foods. When a liquid food droplet slides across an insulated surface, the electrometer connected with the metal electrode array will record the electric signals, and the electric signals at each electrode will generate an ICTM. The ICTMs are sensitive to the compositions of various liquid food and additives, thus can be used to in situ detect contamination in liquid food production. Ten different liquid foods are successfully identified by ICTMs, as well as food additives and heavy metals in 5° white vinegar. The detection limit of Pb 2+ in 5° white vinegar is as low as 10 µg L −1 (in line with FDA standards), and the linear range is 0–10 µg L −1 . Finally, through the detection of 20 random samples, the detection accuracy of lead acetate in 5° white vinegar is 95%, and the detection accuracy of potassium sorbate is 90%. The array TENG probe and the generated ICTM open an approach for in situ and rapid food production and safety testing relying on cheap, portable, low‐tech instrumentation.

The localized coupling between piezoelectric and photoexcitation effects of a ZnO micro/nanowire device has been studied for the first time with the goal of designing and controlling the electrical transport characteristics of the device. The piezoelectric effect tends to raise the height of the local Schottky barrier (SB) at the metal−ZnO contact, while photoexcitation using a light that has energy higher than the band gap of ZnO lowers the SB height. By tuning the relative contributions of the effects from piezoelectricity via strain and photoexcitation via light intensity, the local contact can be tuned step-by-step and/or transformed from Schottky to Ohmic or from Ohmic to Schottky. This study describes a new principle for controlling the coupling among mechanical, photonic, and electrical properties of ZnO nanowires, which could be potentially useful for fabricating piezo-phototronic devices.

Peptide-based piezoelectric materials have emerged as a new class of intelligent biomaterials, and applying electric fields during growth was found to result in uniform polarization. Here, we explore in-depth the effect of electric fields on diphenylalanine peptide crystallization and epitaxial growth. The percentage of crystals with negative polarization is linearly proportional to the electric field strength, while the trend is slightly different when a positive electric field is applied. The minimum electric field strength needed to achieve peptides with a uniform polarization is about 200 kV/m. Due to the improved crystallinity and uniform polarization in peptides, the piezoelectric constant d33 increases linearly with the applied electric fields. The output voltage and current of peptide-based piezoelectric nanogenerators increase with the applied force on the device and with the electric field used for growth material, and the power density reaches 9.98 W/m3. Our work provides direct insight into the peptide self-assembly process under electric fields and guides the fabrication of high-performance materials for degradable energy devices.