Researchers build a heat shield just 10 atoms thick to protect electronic devices

Stanford builds a heat shield just 10 atoms thick to protect electronic devices
This greatly magnified image shows four layers of atomically thin materials that form a heat-shield just two to three nanometers thick, or roughly 50,000 times thinner than a sheet of paper. Credit: National Institute of Standards and Technology

Excess heat given off by smartphones, laptops and other electronic devices can be annoying, but beyond that it contributes to malfunctions and, in extreme cases, can even cause lithium batteries to explode.

To guard against such ills, engineers often insert glass, plastic or even layers of air as insulation to prevent heat-generating components like microprocessors from causing damage or discomforting users.

Now, Stanford researchers have shown that a few layers of atomically , stacked like sheets of paper atop hot spots, can provide the same insulation as a sheet of glass 100 times thicker. In the near term, thinner heat shields will enable engineers to make even more compact than those we have today, said Eric Pop, professor of electrical engineering and senior author of a paper published Aug. 16 in Science Advances.

"We're looking at the heat in electronic devices in an entirely new way," Pop said.

Detecting sound as heat

The heat we feel from smartphones or laptops is actually an inaudible form of high-frequency sound. If that seems crazy, consider the underlying physics. Electricity flows through wires as a stream of electrons. As these electrons move, they collide with the atoms of the materials through which they pass. With each such collision an electron causes an atom to vibrate, and the more current flows, the more collisions occur, until electrons are beating on atoms like so many hammers on so many bells—except that this cacophony of vibrations moves through the at frequencies far above the threshold of hearing, generating energy that we feel as heat.

Thinking about heat as a form of sound inspired the Stanford researchers to borrow some principles from the physical world. From his days as a radio DJ at Stanford's KZSU 90.1 FM, Pop knew that music recording studios are quiet thanks to thick glass windows that block the exterior sound. A similar principle applies to the heat shields in today's electronics. If better insulation were their only concern, the researchers could simply borrow the music studio principle and thicken their heat barriers. But that would frustrate efforts to make electronics thinner. Their solution was to borrow a trick from homeowners, who install multi-paned windows—usually, layers of air between sheets of glass with varying thickness—to make interiors warmer and quieter.

"We adapted that idea by creating an insulator that used several layers of atomically thin materials instead of a thick mass of glass," said postdoctoral scholar Sam Vaziri, the lead author on the paper.

Atomically thin materials are a relatively recent discovery. It was only 15 years ago that scientists were able to isolate some materials into such thin layers. The first example discovered was graphene, which is a single layer of carbon atoms and, ever since it was found, scientists have been looking for, and experimenting with, other sheet-like materials. The Stanford team used a layer of graphene and three other sheet-like materials—each three atoms thick—to create a four-layered insulator just 10 atoms deep. Despite its thinness, the insulator is effective because the atomic heat vibrations are dampened and lose much of their energy as they pass through each .

To make nanoscale heat shields practical, the researchers will have to find some mass production technique to spray or otherwise deposit atom-thin layers of materials onto electronic components during manufacturing. But behind the immediate goal of developing thinner insulators looms a larger ambition: Scientists hope to one day control the vibrational energy inside materials the way they now control electricity and light. As they come to understand the heat in solid objects as a form of sound, a new field of phononics is emerging, a name taken from the Greek root word behind telephone, phonograph and phonetics.

"As engineers, we know quite a lot about how to control electricity, and we're getting better with light, but we're just starting to understand how to manipulate the high-frequency sound that manifests itself as at the atomic scale," Pop said.


Explore further

Very thin film could help manage heat flow in future devices

More information: "Ultrahigh thermal isolation across heterogeneously layered two-dimensional materials" Science Advances (2019). advances.sciencemag.org/content/5/8/eaax1325
Journal information: Science Advances

Citation: Researchers build a heat shield just 10 atoms thick to protect electronic devices (2019, August 16) retrieved 19 September 2019 from https://phys.org/news/2019-08-shield-atoms-thick-electronic-devices.html
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Aug 16, 2019
Why is excess heat always seen as a nuisance
Something that has to be got rid of as soon as possible
Convert this heat to electricity to recharge the battery that produced this heat
And
Then
You will be scrabbling around trying to keep these circuits and battery warm!

Aug 16, 2019
Comes December, I am predicting a long, hard winter for most countries north of the tropics. I think that all this summer heat and melting of glaciers is but a prelude to an 'ice age'. The water vapour that comes from all the melting will result in massive amounts of snow and ice that will cover the land masses, killing off much of the unprotected wild life. Sunlight will be reflected back to space due to the albedo effect, and there will be frost even down towards the Equator in higher altitudes. Starvation may result as winter crops freeze.

Aug 16, 2019
Why is excess heat always seen as a nuisance
Something that has to be got rid of as soon as possible
Convert this heat to electricity to recharge the battery that produced this heat
And
Then
You will be scrabbling around trying to keep these circuits and battery warm!


This isn't done because pyroelectric materials are very inefficient, and quite expensive. On top of that, you also have to add power converter electronics to make them usable, which further increases the cost. In short, it isn't practical.

Aug 16, 2019
The first thought that occurred to me is, if you trap heat, how do you get rid of it?

This is essential because heat must be removed from electronics to prevent thermal runaway. And conservation of energy and stuff.

Aug 16, 2019
Atomically thin sheets of graphene

With a single layer of carbon atoms three atoms thick
To create a four-layered insulator just 12 atoms deep
The atomic heat vibrations are dampened
Lose their energy as they pass through each layer

It is the vibrations that have to be dampened
By converting directly to electricity
As the vibrations pass through each layer
All energy is vibration
The layer will cool by making the graphene
Conduct electricity as the flow of electrons
Are consequences of the oscillations
Creating a potential difference
In fact once we get the hang of this technique
If the heat is too great for the electricity produced
Increasing the current will increase the heat flow

This all depends on where graphene is electrically conductive
By making the vibrations a flow of electrons

Difficult, but it has uses far greater than heat removal in mobiles

Aug 16, 2019
The first thought that occurred to me is, if you trap heat, how do you get rid of it?
This is essential because heat must be removed from electronics to prevent thermal runaway. And conservation of energy and stuff.
Heat shields must have low thermal conductivity but high emissivity to emit or reflect heat outwards through thermal radiation (rather than heat conduction). Good thermal stability is also required.

Heat shields are employed to protect certain components from *external* heat, not from their own heat. The latter use case is exactly the opposite, and for that materials with high thermal conductivity (like copper) and/or active cooling solutions are required. So heat shields "trap" only the external heat, or more accurately they isolate it.

Heat shields are also employed to limit heat loss when required. They are also used in spacecraft, where materials with very low thermal conductivity are needed to protect the body of the spacecraft.

Aug 16, 2019
Gville, energy PRODUCES vibrations via interaction with mass and/or other energy frequencies...

Aug 16, 2019
Shielding heat or conducting heat
WG> Gville, energy PRODUCES vibrations via interaction with mass and/or other energy frequencies...

For conducting heat by thermal conductivity
Heat is vibrations of atoms in the circuits transferred to vibrations in the atoms of the insulating layers
Whereas, using the vibrations of the atoms to create a flow of electrons
No longer relies on conductivity to transmit this heat through the insulating layers
Which speeds up heat flow and requires thinner layers

Aug 16, 2019
Our skin senses the vibrations of individual atoms

We had this at Staffordshire University
The hairs on our arm sense the individual atoms vibrations
As they strike your arm
As the atom rises in temperature by 1 degree
We are sensing the actual vibrations of these atoms on our skin
For our hairs on our skin turn these atomic vibrations into an electric currant
Which we perceive these oscillations as warmth or wind
All due to converting oscillations to electric currents on the femto-level in this atomic world
Foreth, Whydening Gyre
We are constructed of atoms that exist in this femto-world
As we live in this femto-world these atoms live in
Because we feel our atoms vibrate!

Aug 16, 2019
a freezing cold winter would actually improve temperate crops
if you wonder why apples have have lost their sweet flavors?

like many other fruits & maple syrup, apples need months of freezing cold climate to properly set for the following year

"warm" winters are bad for the winter wheat crop
which needs a good covering of snow to insulate the fragile wheat shoots
from the threat of unpredictable ravages from snap freezes

China has caused their own health problems
by encouraging the northern Chinese to switch their diets from "peasant" millet & yams
to eating high-tone, low nutrition polished rice
from southern China & USA

for years now, i have been slow baking apples to produce snitz
the slow baking concentrates the flavor & brings out the sugars
like with oven baking sweet potatoes

it would be a pleasure to once again taste a ripe-picked apple before i die
i doubt if i will be that lucky

anthropocene driven climate change is a stochastic process

Aug 17, 2019
Rrwillsj, the sweetness of rotten apples
a freezing cold winter would actually improve temperate crops
if you wonder why apples have have lost their sweet flavors?

like many other fruits & maple syrup, apples need months of freezing cold climate to properly set for the following year

"warm" winters are bad for the winter wheat crop
which needs a good covering of snow to insulate the fragile wheat shoots
from the threat of unpredictable ravages from snap freezes

Rrwillsj, you're not a mole infiltrating the climate change community, hollowing them out from the inside, like a worm in a rotten apple by any chance?

p.s. when you put your mind to it, there is a sort of connection with our circuits overheating and anthropogenic global circuit heating!
or rrwillsj, is it simply you textualised in the wrong thread by mistake?
by the way interesting info into why apples have lost their bite

Aug 17, 2019
...the insulator is effective because the atomic heat vibrations are dampened and lose much of their energy as they pass through each layer.
Now this quote seems to make no sense because this seems to in effect is claiming they have found a way to magically make some of the heat energy magically disappear out of existence and that breaks the first law of thermodynamics by breaking the conservation of energy law.
So is this quote a misquote or misedit?
Or have I misinterpreted this above quote? -perhaps they were trying to say the heat is merely reflected back to its source rather than canceled out of existence?
If none of the above, can anyone explain how this can be so?

Aug 17, 2019
My above misedit;
"...seems to in effect is claiming..."
should be
"...seems to in effect be claiming..."

Aug 17, 2019
ahh granny, good points there
thank you for providing me the opportunity to clarify my intent

actually my comments were a knee-jerk reaction to the sillyegghead's diatribe
wishing for suffering & deprivation on the rest of Humanity

the actuality may surprise his ignorance
it is amusing to imagine the little worm seu, freezing his buns off during years of record-setting heatwaves

Aug 20, 2019
....which won't happen. And rrwillsj will have to eat her snot as she shivers in the coming ice age.
And rrwillsj spews her funk into THIS phorum while not realising that she's in the wrong place.

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