As our need for electronic gadgets and sensors grows, scientists are inventing new ways to keep their devices longer with less energy.
The latest sensor, which will be invented in the laboratory, can operate all year round on a surge of energy, aided by a physical phenomenon known as quantum tunneling.
The tunnel aspect means that with the help of a jumping start of 50 million electrons, this simple and inexpensive device (consisting of only four capacitors and two transistors) can last for a long period of time.
The quantum rules of physics applied at the smallest atomic scale mean that electrons can behave both as particles and as waves, and scientists have been able to take advantage of this behavior to precisely control the electron flow on one side of the body. the chain to the other.
“If you want to get to the other side, you have to physically climb the hill,” said Shantanu Chakrabarti, an electrical engineer at the University of Washington in St. Louis.
“Quantum tunneling is more like crossing a hill.”
In order to generate current, devices must be able to give the electrons a strong enough pressure – something known as threshold energy, as this push must be above a certain threshold. When trying to make devices that run with as little power as possible, reaching this threshold can be difficult.
Here comes the part of quantum mechanics: by taking certain approaches to form the “hill” or barrier that needs to be overcome, it is possible to control the flow of electrons in a variety of ways.
In this case, the “hill” is what is called the Fowler-Nordheim tunnel barrier, with a thickness of less than 100 atoms. By building the barrier in this way, the scientists were able to slow down the flow of electrons straight down, while keeping the system (and device) stable and on.
“Imagine an apple hanging on a tree,” says Chakrabarti. “You can shake the tree a little, but the apple doesn’t fall. You have to give it enough pull to shake the apple.”
“This is the minimum amount of energy needed to move an electron over a barrier.”
The device has two dynamic systems, one with a sensor (energy converter). The team had to work backwards to form its own hill or barrier, first measuring the motion of the electrons and then improving the Fowler-Nordheim setup.
What the researchers completed was a device that uses the interaction between the two internal systems to sense and record data without using additional power. Something similar can be used, for example, to monitor blood glucose or to measure temperature for transporting vaccines – batteries are not needed.
In this case, the converter used is a piezoelectric accelerometer, which is felt and driven by the surrounding movement, but the basic principles of a long-lasting, highly efficient system can be applied to other types of energy collection.
“At the moment, the platform is common,” Chakrabarti said. “It just depends on what you’re connecting to the device. As long as you have a converter that can generate an electrical signal, it can power our data logger sensor on its own.”
The study was published in Nature Communications.