The current commercial wireless charging technology is somewhat of a chicken rib, the device needs to be placed on a limited range of charging pillows, and direct plug-in port charging does not bring much portability. But the MIT team has sketched out a blueprint for true wireless charging, using ambient radiation scattered in the air to charge devices.
Terahertz radiation is made up of high-frequency waves located between infrared and microwave. They are made from many electronic devices and basically include any device that sends a Wi-Fi signal.
But existing technology is struggling to make the most of the “energy-gold mine”, and MIT’s new plan seems to have found a new breakthrough. But it’s still in the blueprint phase and hasn’t been tested.
Hiroki Isobe, lead author of the study, said: “We are surrounded by electromagnetic waves of terahertz. If we can convert this energy into energy that can be used in everyday life, it will help solve the energy challenges we face today. “
The team developed a prototype device called the terahertz rectifier, which consists of a small square of graphene and a layer of boron nitride below, flanked by antennas. The antenna collects terahertz radiation from the surrounding air, which enhances the signal and transmits it to graphene. This in turn causes all electrons in graphene to flow in the same direction, resulting in direct current (DC).
Graphene needs to be as pure as possible, the team said, because any impurities scatter electrons. The boron nitride layer is to prevent this from happening. Normally, electrons in graphene will be equally affected in all directions, but the boron and nitrogen atoms in the lower layer redirect their paths in a direction that moves them together.
Although any terahertz rectifier may generate only a small amount of power, it is initially sufficient to power a small device. The first use could be to power implantable devices, such as pacemakers, which currently require surgery to replace batteries, the team suggests.
Of course, the ultimate goal of this technology is to passively replenish our phones and laptops when using them. For years, researchers have been trying to find ways to collect signals such as radio waves, but common problems include low output power, long charging times or specially built rooms. For now, we’ll have to wait years before we see this technology coming into commercial use.