Microfibre–nanowire hybrid structure for energyscavenging

Kiarash Kiantaj04/07/08

Yong Qin, Xudong Wang & Zhong Lin Wang-10.1038/nature06601

Harvesting energy from environment Solar Thermal Mechanical (wind, friction, body

movement or any environment disturbance)

Foot steps Heartbeat Air flow

Low frequency

piezoelectric zinc oxide nanowires

Kevlar fibres coated with ZnO nanowires

Hydrothermal growth TEOS (Tetraethoxysilane )

Characteristics

Single crystalline nanowires hexagonal cross-section diameter in the range ,50–200 nm length of 3.5 um Distance of few hundred nm

double-fibre model systemas nanogenerator

300 nm gold layer Schottky barrier at

Au-ZnO interface +V( reverse biased) -V (forward biased)

switching polarity testing

Ri<250Mohm Two peaks 0.2 s delay

friction-inducedelectrostatic charges

Only Au coated ZnO nanowire fibers Only ZnO nanowire fibers

Frequency range: 80-240 rpm

Improvements: Reducing the inner resistance of the fiber

Deposition of a conductive layer directly onto the fiber reduction of inner resistance to 1 k-ohm

surface contact area single yarn made of 6 fibers average current of 0.2 nA 30–50 times larger than single-fiber

Series and parallel setup

Life time

Estimation of optimum output power density from textile fabrics:20–80mW per square meter

The end

“I-V characteristic of ZnO NW coated fiber measured using the circuit as presented at the right-hand side, where silver was used as the electrodes. The inner resistance of the 4 mm fiber used here is ~ 250 MΩ.”