Scientists Create Super-Thin 'Sheet' That Could Charge Our Phones (theguardian.com)

An anonymous reader quotes a report from The Guardian: Scientists at Massachusetts Institute of Technology (MIT) have created super-thin, bendy materials that absorb wireless internet and other electromagnetic waves in the air and turn them into electricity. The lead researcher, Tomas Palacios, said the breakthrough paved the way for energy-harvesting covers ranging from tablecloths to giant wrappers for buildings that extract energy from the environment to power sensors and other electronics. Details have been published in the journal Nature. Palacios and his colleagues connected a bendy antenna to a flexible semiconductor layer only three atoms thick. The antenna picks up wifi and other radio-frequency signals and turns them into an alternating current. This flows into the molybdenum disulphide semiconductor, where it is converted into a direct electrical current. [M]olybdenum disulphide film can be produced in sheets on industrial roll-to-roll machines, meaning they can be made large enough to capture useful amounts of energy.

Ambient wifi signals can fill an office with more than 100 microwatts of power that is ripe to be scavenged by energy-harvesting devices. The MIT system has an efficiency of between 30% and 40%, producing about 40 microwatts when exposed to signals bearing 150 microwatts of power in laboratory tests. "It doesn't sound like much compared with the 60 watts that a computer needs, but you can still do a lot with it," Palacios said. "You can design a wide range of sensors, for environmental monitoring or chemical and biological sensing, which operate at the single microwatt level. Or you could store the electricity in a battery to use later."

Comments

Diode

[lazarus]

...bendy antenna to a flexible semiconductor layer only three atoms thick...

I believe this is called a diode and we've been converting signals to electricity with them for a very long time (rectifiers). Seems like what they've done is come up with a way to incorporate them into an antenna that could be manufactured in large flexible sheets suitable for deployment on available flat surfaces. Interesting.

Diode

Re:Diode

[Rick Schumann]

..in fact, I've seen a schematic for an amplified TRF AM radio receiver that uses a second tuned wideband receiver to harvest RF energy to power a FET RF amplifier stage for the actual AM receiver, improving it's sensitivity. Old ideas.

Re:fake news again .

[MachineShedFred]

I think the idea is that you would put this on surfaces inside a home or office. The problem is that these radio waves are not "free energy" - there are potentially devices that want to receive those radio waves that will no longer be able to if this is deployed between them and the transmitter.

So now you are buying more access points and transmitters (and plugging them in, and powering them up) to cover the dead spots you just created in order to recharge your phone with "free" energy.

Or you could just plug in your $10 phone charger like all of us have been doing for 20 years and skip overhauling your (and other people's) wireless infrastructure.