Publications

We have developed a nanowire nanogenerator that is driven by an ultrasonic wave to produce continuous direct-current output. The nanogenerator was fabricated with vertically aligned zinc oxide nanowire arrays that were placed beneath a zigzag metal electrode with a small gap. The wave drives the electrode up and down to bend and/or vibrate the nanowires. A piezoelectric-semiconducting coupling process converts mechanical energy into electricity. The zigzag electrode acts as an array of parallel integrated metal tips that simultaneously and continuously create, collect, and output electricity from all of the nanowires. The approach presents an adaptable, mobile, and cost-effective technology for harvesting energy from the environment, and it offers a potential solution for powering nanodevices and nanosystems.

Realizing active interaction with external environment/stimuli is a great challenge for current electronics. In this paper, a tribotronic tuning diode (TTD) is proposed by coupling a variable capacitance diode and a triboelectric nanogenerator in free-standing sliding mode. When the friction layer is sliding on the device surface for electrification, a reverse bias voltage is created and applied to the diode for tuning the junction capacitance. When the sliding distance increases from 0 to 25 mm, the capacitance of the TTD decreases from about 39 to 8 pF. The proposed TTD has been integrated into analog circuits and exhibited excellent performances in frequency modulation, phase shift, and filtering by sliding a finger. This work has demonstrated tunable diode and active analog signal modulation by tribotronics, which has great potential to replace ordinary variable capacitance diodes in various practical applications such as signal processing, electronic tuning circuits, precise tuning circuits, active sensor networks, electronic communications, remote controls, flexible electronics, etc.

With a promising prospect of light-emitting diodes as an attractive alternative to conventional light sources, remaining challenges still cannot be addressed owing to their limited efficiency. Among the continued scientific efforts, significant improvement on the emission efficiency has been achieved via either piezo-phototronic effect-based strain modulation or resonant excitation of plasmons in metallic nanostructures. Here, we present the investigation on the coupling process between piezo-phototronic effect and localized surface plasmonic resonance for enhancing the photoluminescence of InGaN/GaN quantum wells coated with Ag nanoparticles. The underlying physical mechanism of experimental results originates from tuning plasmonic resonance controlled by the shift of emission wavelength via piezo-phototronic effect, and it is further confirmed with the support of theoretical calculations. As a result, our research provides an approach to the integration of plasmonics with piezo-phototronic effect and brings widespread applications to high-efficiency artificial lighting, on-chip integrated plasmonic circuits, subwavelength optical communication, and micro-optoelectronic mechanical systems.

Triboelectric nanogenerators (TENGs) are demonstrated to possess great superiority in the field of low-frequency and high-entropy energy harvesting. Here, a kind of friction material, super-light clay (SLC), with outstanding stretchability and shape/size changeability is introduced to develop contact-separation triboelectric nanogenerators (SLC-TENGs), which exhibit outstanding flexible, shape-changeable, and adaptable properties but simple preparation processes. A high and stable electrical output can be achieved from the simple-structured SLC-TENG. The peak power density of the SLC-TENG output reaches up to 0.33 W/m2 under an effective contact with an area of 9 cm2 and an external load resistance of 50 MΩ. In addition, a balloon-structured TENG was also prepared with the filling of several SLC balls. The electrical signals can be generated even just by a slight shaking, revealing great application potential in the Internet of Things systems and self-powered sensors by energy harvesting from wind, ocean, human body movements, etc.

Generation of direct current (DC) from mechanical kinetic energies is crucial for realizing self-powered wearable electronics. Here, we report a flexible textile-based DC generator based on the tribovoltaic effect at a dynamic metal-semiconducting polymer interface. The tribovoltaic effect refers to a phenomenon in which an energy "quantum" is released once an atom–atom bond is formed at the dynamic interface of two contacting materials; such released "binding" energy excites electron–hole pairs at metal–semiconductor interfaces or semiconductor–semiconductor pn junctions. This textile DC generator, based on the dynamic Schottky junction between an Al slider and a poly(3,4-ethylenedioxythiophene)-coated textile, can output a voltage of approximately 0.45–0.70 V. The voltage and current can be increased by simply connecting multiple generators in series or in parallel. Seven generators in series can power an electronic watch constantly without any conditioning circuit. These findings offer an efficient strategy for harvesting mechanical energies and realizing self-powered electronics.