Piezoelectric Transducer• Ability to create electrical potential when compressed, expanded or changed in shape (Mechanical energy to Electrical energy).• The voltage generated can be quiet high.• Made up of piezoelectric crystals like quartz and topaz.• Unaffected by external electromagnetic fields.• Can be used both as generators and actuators.
Developers of Nanogenerators Dr. Zhong Lin (Z.L.) Wang and his colleagues at Georgia Institute of Technology, Georgia State, USA have made significant leaps in developing nanogenerators over the last decade.
A Nano Scale Piezoelectric Transducer(Nanogenerator)• Harnesses the bodys energy.• Made of Zinc Oxide (ZnO) wires called Nanowires.• Produces 45 millivolts whenever the zinc wire is pulled back and forth.• With simultaneous output from many nanowires, we can generate high power.• The wires have a diameter of 100 to 300 nm and length of about 10 to 100 micron.
Inside A Nanogenerator• Consists of an integrated circuit.• Components are made from ITO (Indium tin oxide) and a piezoelectric ceramic.• Nanowire bends and generates an electrical charge.• ITO electrode captures that charge.• Several electrodes capture power from millions of nanowires.
Inside A Nanogenerator• Piezoelectric effect creates an electrical field inside the nanostructure.• Relative displacement of cations with respect to anions in its crystalline structure. Potential distribution for a ZnO NW at a lateral bending force of 80 nanonewtons is shown.
1. Vertical nanowire Integrated Nanogenerator(VING)• 3 parts : a. base electrode, b. vertical piezoelectric nanostructure, & c. counter electrode.• Nanowires grown from the base electrode to the counter electrode.• Counter electrode motion induces the deformation of the nanowire.
2. Lateral nanowire Integrated Nanogenerator(LING)• 3 parts : a. base electrode, b. lateral piezoelectric nanostructure, & c. counter electrode.• Integrated on a flexible substrate.• Individual NW is subjected to high tensile strain.• Allows for amplification by series connection of units.
DC Nanogenerator Driven by Ultrasonic Waves • Integrating a Platinum (Pt) coated electrode with vertically aligned ZnO NW. • Pt enhances the conductivity of the electrode. • Nanowire arrays were placed beneath a zigzag metal electrode with a small gap.
DC Nanogenerator Driven by Ultrasonic Waves • Top electrode moves downward and pushes the NW leading to a lateral bending. • Due to the rectifying action caused by partial contact, the output electric signal exhibits a DC characteristic.
Sources which Nanogenerators can exploit• For Large scale applications (from wherever periodic kinetic energy exists) : 1. Wind, 2. Ocean Waves.• Small scale applications : 1. Tiny physical motion, 2. Inhalation of lung, 3. Heartbeat, 4. Muscle movement, i.e. Any kind of movement!!
Applications• Powering conventional electronics : 1. Light Emitting Diode (LED), 2. Liquid Crystal Display (LCD), and 3. Laser Diode.• To power your personal gadgets and phones.• Self-powered nano/micro devices.• Implantable power devices.• Smart Wearable Systems.
Applications• Smart Wearable Systems – Power Shoes
Applications• Smart Wearable Systems – A Power Shirt