Scientists have been searching for more efficient ways to power electric light bulbs ever since Thomas Edison invented them. Major advancements in the fields of electronics and energy technology have been made as a result of this search. Large-scale electric utility services, rechargeable batteries, and tools for capturing renewable energy from the environment around us, including wind turbines and solar panels, have all been made possible by the quest for ever-better power sources. Electronics engineers are constantly looking for ways to make products more affordable, more powerful, more energy-efficient than their forerunners. What if we could create electricity using the energy that our bodies make simply by existing?
Imagine being able to charge your iPod just by tapping your fingers to the beat of the music or by donning a hoodie with an inbuilt pulse-sensing circuit board. Nanogenerators are making such power sources a reality, despite the fact that they can sound like science fiction. Researchers refer to a tiny electronic device that can create power from bodily motions, like a light pinch of the finger, as a "nanogenerator." Similar to the components on the circuit boards inside of your computer, the chip contains an integrated circuit etched onto a flexible surface. These generators are a form of nanotechnology, or technology so tiny that its dimensions are measured in nanometers, as the "nano-" prefix suggests. Therefore, even the most sophisticated and potent nanogenerators currently in use are small enough to fit between two fingers.
A nanogenerator's essential parts are nanowires or a structure somewhat similar built of a piezoelectric ceramic substance. Simply being bent or under stress can cause piezoelectric materials to produce an electric current. Hundreds of nanowires can be stacked side by side in an area no larger than the width of a human hair, as shown in How Nanowires Work. Due to the flexibility of all the components of the nanogenerator at that scale, even the smallest movement can produce current. Nanogenerators are becoming more and more potent, in addition to being exceedingly compact and quick. Researchers assessed the output of five nanogenerators that were placed together in March 2011. The energy produced by this little stack was three volts, almost equivalent to the output of two AA batteries, at a current of one microampere. Are you interested in learning more about the development of nanogenerators and how they will impact our daily lives? Let's begin with a brief overview of the study on nanogenerators.
The Evolution of Nanogenerators
Leading authority in nanogeneration is Georgia Institute of Technology's Dr. Zhong Lin Wang. Wang and his team have been striving to create exceedingly small circuits that can generate electrical current for more than ten years. The equipment needed to generate, handle, and monitor the output of microscopic electronic components are so small that researchers must use microscopes to see what they are working on in nanotechnology projects like those created by the Georgia Tech team. The nanogenerators that Dr. Wang's team creates are totally created in-house. After producing the necessary materials, Wang and his team manufacture, examine, measure, and package each nanogenerator prototype. This pioneering research team has successfully used nanogenerated power to run an LED, an alaser diode, and a liquid crystal display.
While researching nanogenerators, various teams have experimented with various piezoelectric materials. Lead zirconate titanate, or PZT, has been used by scientists Michael McAlpine from Princeton University and Prashant Purohit from the University of Pennsylvania. Despite the fact that PZT is incredibly brittle, McApline and Purohit managed to form the substance so that it could extend by up to 10% without breaking. Wang was the first scientist to use zinc oxide as the piezoelectric substance in the nanogenerators in 1999. In a 2009 article, Wang's team attributed their ongoing success in perfecting nanogenerators to the use of ZnO. We are aware that the essential element of a nanogenerator is piezoelectric material. Let's now check inside closely to learn more about how it produces electricity.
What Takes Place Inside a Nanogenerator?
An integrated circuit with silicone and piezoelectric ceramic parts is what makes up a nanogenerator. The integrated circuit is etched onto a flexible surface known as a substrate. The circuitry is where the magic happens, even if the strength and other characteristics of the substrate are crucial when designing a nanogenerator. With the naked eye, we may first make out a flat, two-dimensional image composed of a number of lines and boxes. However, a microscopic examination of the bendable chip's inner layers reveals an entirely other three-adimensional scene.
Wang's team uses a silicone electrode at the opposite end of an array of nanowires that are attached to the substrate to create their nanogenerators. The electrode's surface is covered in zigzag lines. Each nanowire flexes and produces an electrical charge when the nanogenerator is subjected to a modest amount of physical pressure. This charge is captured by the electrode and sent along to the other components of the nanogenerator circuit. Multiple electrodes could be used to collect electricity from millions of nanowires throughout the entire nanogenerator.
McAlpine and Purohit have used PZT to make nanoribbons in their respective research groups in order to tackle nanogenerators in a different way. Each nanoribbon is between 250 and 500 nm thick and around 10 microns broad. On a surface made of magnesium oxide, the nanoribbons are first created, and subsequently they are removed using phosphoric acid. The nanoribbons are then attached to a silicone rubber surface that has been previously stretched; when relaxed, this surface causes the nanoribbons to buckle without breaking. The nanoribbons' movement when bent produces electricity without causing them to separate from the surface.
The basic idea of creating flexible wires from piezoelectric material has been the foundation for research into ways to increase the output of each generator. For instance, Wang's lab has enhanced both the circuitry and the nanowires in each new design. According to Wang, output has increased over the past ten years to be more than a billion times better than it was when he first started. You've seen how the nanogenerator functions from the inside up to this point. Let's now look at some potential locations where nanogenerators could be used in the next years.
Medicine Applications for Nanogenerators and Beyond
To power implanted medical devices that govern or monitor patients' health, doctors need reliable technology. Pacemakers and continuous glucose monitoring systems are two examples of such devices. Implant devices have a built-in difficulty: They may deteriorate over time, call for replacement batteries, or require a bulky external power source. Doctors might implant a new generation of these gadgets with the ability to stay energized and survive a long period with little intrusion into the body by using nanogenerators. The energy of such movements, such as a heartbeat or lung expansion, would be captured. In other words, you can be using your body to sustain a machine that in turn supports your continued survival.
Additionally, the likelihood of implanting a nanogenerator without causing injury to the body is increased by using non-toxic materials like ZnO as the piezoelectric material. So what else can nanogenerators do besides medicine? Nanogenerators, according to researchers, may soon power your smartphone or iPod. Nanogenerators are so small that they could easily be woven into a T-shirt or hoodie's fabric, allowing your iPod to utilize your heartbeat to recharge its internal battery. Within five years, according to Wang, the nanogenerators his team has created will be included into such goods and will be for sale.
The potential for nanogenerators to have a beneficial effect on the environment is a side benefit. Kinetic energy from bodily motion is a renewable resource used by nanogenerators. They are made of more environmentally friendly materials than batteries, and they may lessen the waste generated during the manufacture and disposal of batteries. Nevertheless, the influence is negligible due to the small size and weak power of nanogenerators. We'll have to wait and see if nanogenerators can power larger gadgets like laptops.
Batteries won't likely be replaced by nanogenerators any time soon, at least. For gadgets like alarm clocks that you don't frequently come into contact with physically, you nevertheless require battery backups. Additionally, you want to make sure that some gadgets, like your smartphone, keep running even when you aren't using or touching them. Perhaps manufacturers will combine rechargeable battery systems with nanogenerators in the future to produce a dependable power source with minimal environmental impact.