Power storage with nanowires

Batteries and batteries are loyal " servants " for electrical devices in case the main power systems are not suitable. However, the storage of electricity using batteries is in the downward phase, this includes the issue of storage time, short life time, and toxin problems, as well as click problems. ruler. Generator using ZnO nanowires (zinc oxide) can eliminate these weaknesses, and is extremely advantageous in controlling small components such as implantable biological sensors - according to Zhong. Lin Wang, an expert at Georgia Institute of Technology, USA.

Researchers are currently developing wireless nanoscale devices and components for a variety of applications, such as controlling changes in cancer cells, or gas exploration in areas that require remote control, transmission, direct measurement of blood pressure in the body, or ratio of blood sugar . All these applications require a power supply, for example, in the case of a wireless bio-sensor that needs to be supplied by a battery system, but the problem of chemical toxins in batteries is a problem that's difficult to solve because they can harm the body, and how to solve it. The best solution to these problems is to increase the " self-power " capability for the sensor.

Figure 1. Photograph of ZnO nanowire.

Unfortunately, other energy supplies at nanoscale are virtually non-existent, despite the large demands in the application. However, there are many different forms of energy that can control nanoscale components, such as the ability of body and muscle movement, energy fluctuating from sound waves and ultrasound waves, "hydro electricity " from blood and body fluids .

At the Georgia Institute of Technology in Atlanta (USA), Zhong Lin Wang's team invented a new technique based on ZnO nanowire matrices, allowing the extraction of energy from the surrounding environment. By combining the properties of semiconductors and piezoelectrics of ZnO, the large elastic deformation that can be created in nanowires can help convert from mechanical to electrical . Initially, the team created oriented ZnO nanowires, which are the building blocks for nanoscale generators using physical and chemical synthesis techniques. The physics of vapor-liquid - solid phase technology allows the creation of materials of the best quality, but the synthesis technique meets the higher requirements for size. The principle of generating electricity is to combine ZnO semiconductor and piezoelectric properties and create a Schttky barrier of metal and semiconductor contact layers.

Figure 2. Principle of testing power generation ability of ZnO nanowires.

The team used an atomic microscope probe to test and estimate the quality of this tiny generator by using a probe to bend individual wires. When the wire is bent, the two sides of the rope (one side is pulled, one side is compressed) will produce positive and negative charges. The barrier Schottktt created between the AFM probe and the nanowire will keep these terminals. The potential produced by each wire has been measured as soon as they leave the tip of the probe. Scanning of the probe allows the ability to discharge and charge the nanowire matrix. And the results showed that a system of about 500 ZnO nanowires on polymer substrates allows generation of currents up to 1 nA and electricity can also be generated by the action of ultrasonic waves.

Figure 3. Power conversion device and charge discharge result.

Wang's group is working on plans to improve the technology, and Wang says the technology will be rapidly developed at the commercial scale in the near future. This is a technology that converts energy from mechanical energy - small size and promising for nanosystems, such as MEMS, NEMS, bio-sensors .

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