first proposed and practiced the principle of ... · nano-piezotronics ¾piezoelectricity is the...
TRANSCRIPT
RL
I
VL+
-ZnO
First proposed and practiced the Principle of nanogenerator using ZnO nanowires
• By deflecting the aligned ZnOnanowires (NWs) grown on a polymer substrate using a conductive atomic force microscopy (AFM) tip in contact mode, the energy that was first created by the deflection force and later converted into electricity by piezoelectric effect has been measured for demonstrating nano-scale power generator.
• The approach presented has the potential of converting biological mechanical energy, acoustic/ultrasonic vibration energy, and biofluid hydraulic energy, into electricity, demonstrating a new path way for self-powering of wireless nanodevices and nanosystems.
Landmark publications:
Science, 312 (2006) 242.Nano Letters, 3 (2004) 423-426
First invented DC nanogenerator driven by ultrasonic wave
Wang et al., Science 316 (2007) 102-105
• Having replaced the use of an expensive and sophisticated AFM by ultrasonic wave/vibration for inducing the elastic deformation and vibration of the NWs, and demonstrated a cost-effective prototype technology for fabricating the nanogenerator;
• Having achieved a continuous and fairly stable DC output.
• The DC nanogenerator works in air and in liquid
• The principle demonstrated can be further optimized and improved for enhancing output power, establishing a basic method for harvesting/recycling energy from the environment, such as body movement, mechanical vibration, and sonic waves….
• The concept and prototype technology established by the DC nanogenerator set a platform for developing self-powering nanosystems with important applications in implantable in-vivo biosensing, wireless and remote sensing, nanorobotics, MEMS, sonic wave detection and more
ZnOnanowires
ZnO layerSupporting substrate
vibrating
W nanowires
Metal substrate
First Invented Textile fiber based nanogenerators• Using ZnO NWs grown on fibers, it is possible to
fabricate flexible, foldable and wearable power source in any shape (such as “power shirt”).
• The nanogenerator operates at (< 10 Hz) in the range of conventional mechanical vibration, foot steps and heart beating, greatly expanding the application range of nanogenerators.
Qin, Wang, WangNature 451 (2008) 809
Piezoelectric Nanogenerator – potential applications
Bending piezoelectric ZnO nanowire (NW) generates electrical potential along side surfaces
To deflect many NWs simultaneously for continuous output
Vertical aligned ZnO NW arrays
Zigzag silicon trench coated with platinum
Integrate with spacing control
Zigzag electrode
ZnO nanowires•Mechanical vibration triggers the bending of NWs;
•Piezoelectric potential collects by the trenches.
Mechanical energy sources
Wind
Wave
Blood flow & heart beating
Breath
Car running
Air conditioning
Body movements
Xudong Wang, et al., Science, 316 (2007) 102.
Biomedicine
MEMs & Nanodevices
Defense technology
Wireless sensors
Robots
Personal electronics
MP3sCell phones
Laptops
Nanosensors
MEMs
Nanogenerator converts mechanical waves into electricity
Implantable devices
+ + + + + +
- - - - - --
Vp+
Vp-
VF
- - -
PE-diode
VSD
VG
- - - -+ + + +
SiliconGate oxide
FET
VSD
VG
- - - -+ + + +
Silicon
Trapped carriers
+ + + + + +
- - - - - --
Vp+
Vp-
V
F
- - -
PE-FET
z
a Ez
Ez>0
Ez<0
Ez=0
c
Vp>0 (Vp )
Vp<0 (Vp )
Vp=0
+
-
dεz
ε>0
ε<0
ε=0
bF
Founder of Nano-Piezotronics
Materials Today, 10 (2007) 20-28;Adv. Mater., 19 (2007) 889-992
Nano Letters, 6 (2006) 2768-2772
Nano-PiezotronicsPiezoelectricity is the ability of certain crystals to generate a voltage in response to
applied mechanical stress. Electronics - the branch of physics that deals with the emission and effects of electrons
and with the use of electronic devices.
Piezotronics is a field of using piezoelectric-semiconducting coupled properties/effects for creating/fabricating novel and unique electronic devices and components (ZLW).
Piezoelectric-field effect transistor Piezoelectric-gated diode
V~Pt
ZnO Nanobelt
200 210 220 230 240 250 260 270 281 291 301 311
246.81MHz
270.44MHz
Frequency (MHz)
1st Harmonic
V~Pt
ZnO Nanobelt
V~V~Pt
ZnO Nanobelt
200 210 220 230 240 250 260 270 281 291 301 311
246.81MHz
270.44MHz
Frequency (MHz)
1st Harmonic
200 210 220 230 240 250 260 270 281 291 301 311
246.81MHz
270.44MHz
Frequency (MHz)
1st Harmonic
Piezoelectric resonator
Piezoelectric nanogenerator Piezoelectric FET sensors
DC nanogenerator
10 μm
(a) (c)
Morpho Peleides
Bio-interfacing, bio-inspired fabrication and bioengineering
Nano Letters, 6 (2006) 2325
350 450 550 650 750 850
30º
Incident light
Reflected light
Silicon substrate
60º
Wavelength (nm)
Ref
lect
ance
(a.u
.)
Tape on silicon substrate
Natural butterfly wing
605 nm alumina coated butterfly wing
Alumina replica
420 nm
390 nm
1 cm
Gecko foot
Tokay Gecko
(Autumn, 2000)
Nano-piezotronics;
Bio-interfacing, bio-inspired fabrication and bioengineering;
Solar energy;
Nanogenerators for harvesting mechanical energy; self-powered nanosystems
Microscopy and functional nanomaterials
BaMnO3 nanobelts
Near Future Research Directions