10-10-2012, 03:20 PM
Piezoelectric Nanogenerators Based on Zinc Oxide Nanowire Arrays
[attachment=35941]
Motivation & Background
Motivation—self-powered device can greatly reduce the size of integrated nanosystems for optoelectronics, biosensors and more.
Background—
1D ZnO nanomaterials
exhibits both semiconducting and piezoelectric(PZ) properties for electromechanically coupled sensors and transducers.
is relatively biosafe and biocompatible for biomedical applications.
exhibits the most diverse and abundant configurations of nanostructures knownsuch as NWs, nanobelts (NBs) ,nanosprings, nanorings, nanobows and nanohelices (10).
The mechanism of the power generator relies on the coupling of piezoelectric and semiconducting properties of ZnO as well as the formation of a Schottky barrier between the metal and ZnO contacts.
Experimental design
Aligned ZnO NWs grown on -Al2O3 substrate.
(B) TEM image showing the NW without an Au particle or with a small Au particle at the top. Each NW is a single crystal and has uniform shape. Inset at center: an electron diffraction pattern from a NW. Most of the NWs had no Au particle at the top. Inset at right: image of a NW with an Au particle
© The base of the NW is grounded and an external load of RL is applied, which is much larger than the resistance RI of the NW. The AFM scans across the NW arrays in contact mode
Theory --Transport is governed by a metal-semiconductor Schottky barrier for the PZ ZnO NW
(A) NW coordination system.
(B) Longitudinal strain z distribution (NW of length 1 µm and an aspect ratio of 10).
© induced electric field Ez distribution
(D) Potential distribution due to PZ effect.
Schottky rectifying behavior (E) is to separate and maintain the charges as well as build up the potential. The process in (F) is to discharge the potential and generates electric current.
The PZ potential is built up in the displacing process (G), and later the charges are released through the compressed side of the NW (H).
(I) Large Au particle: The charges are gradually "leaked" out, no accumulated potential will be created.
Conclusion
Self-powering nanotechnology ? Estimated power~ 10 pW/µm2 and much more power if drives resonantly!
Use flexible substrate for scavenging energy produced by acoustic waves, ultrasonic waves, or hydraulic pressure/force or environment etc. for applications such as implantable biomedical devices, wireless sensors, and portable electronics
Continued work published as “Direct-Current Nano generator Driven by Ultrasonic Waves ” Science 6 April 2007:Vol. 316. no. 5821, pp. 102 – 105
Nanogenerator is featured in the overview section in the NSF FY 2008 budget request to congress
[attachment=35941]
Motivation & Background
Motivation—self-powered device can greatly reduce the size of integrated nanosystems for optoelectronics, biosensors and more.
Background—
1D ZnO nanomaterials
exhibits both semiconducting and piezoelectric(PZ) properties for electromechanically coupled sensors and transducers.
is relatively biosafe and biocompatible for biomedical applications.
exhibits the most diverse and abundant configurations of nanostructures knownsuch as NWs, nanobelts (NBs) ,nanosprings, nanorings, nanobows and nanohelices (10).
The mechanism of the power generator relies on the coupling of piezoelectric and semiconducting properties of ZnO as well as the formation of a Schottky barrier between the metal and ZnO contacts.
Experimental design
Aligned ZnO NWs grown on -Al2O3 substrate.
(B) TEM image showing the NW without an Au particle or with a small Au particle at the top. Each NW is a single crystal and has uniform shape. Inset at center: an electron diffraction pattern from a NW. Most of the NWs had no Au particle at the top. Inset at right: image of a NW with an Au particle
© The base of the NW is grounded and an external load of RL is applied, which is much larger than the resistance RI of the NW. The AFM scans across the NW arrays in contact mode
Theory --Transport is governed by a metal-semiconductor Schottky barrier for the PZ ZnO NW
(A) NW coordination system.
(B) Longitudinal strain z distribution (NW of length 1 µm and an aspect ratio of 10).
© induced electric field Ez distribution
(D) Potential distribution due to PZ effect.
Schottky rectifying behavior (E) is to separate and maintain the charges as well as build up the potential. The process in (F) is to discharge the potential and generates electric current.
The PZ potential is built up in the displacing process (G), and later the charges are released through the compressed side of the NW (H).
(I) Large Au particle: The charges are gradually "leaked" out, no accumulated potential will be created.
Conclusion
Self-powering nanotechnology ? Estimated power~ 10 pW/µm2 and much more power if drives resonantly!
Use flexible substrate for scavenging energy produced by acoustic waves, ultrasonic waves, or hydraulic pressure/force or environment etc. for applications such as implantable biomedical devices, wireless sensors, and portable electronics
Continued work published as “Direct-Current Nano generator Driven by Ultrasonic Waves ” Science 6 April 2007:Vol. 316. no. 5821, pp. 102 – 105
Nanogenerator is featured in the overview section in the NSF FY 2008 budget request to congress