
An example of a gold foil peeled from single crystal silicon. Reprinted with permission from Naveen Mahenderkar et al., Science [355]:[1203] (2017)
Some day, your smartphone might completely conform to your wrist, and when it does, it might be covered in pure gold, thanks to researchers at Missouri S&T.
Writing in the March 17 issue of the journal Science, the S&T researchers say they have developed a way to “grow” thin layers of gold on single crystal wafers of silicon, remove the gold foils, and use them as substrates on which to grow other electronic materials. The research team’s discovery could revolutionize wearable or “flexible” technology research, greatly improving the versatility of such electronics in the future.
According to lead researcher Jay A. Switzer, the majority of research into wearable technology has been done using polymer substrates, or substrates made up of multiple crystals. “And then they put some typically organic semiconductor on there that ends up being flexible, but you lose the order that (silicon) has,” says Switzer, Donald L. Castleman/FCR Endowed Professor of Discovery in Chemistry at S&T.
Because the polymer substrates are made up of multiple crystals, they have what are called grain boundaries, says Switzer. These grain boundaries can greatly limit the performance of an electronic device.
“Say you’re making a solar cell or an LED,” he says. “In a semiconductor, you have electrons and you have holes, which are the opposite of electrons. They can combine at grain boundaries and give off heat. And then you end up losing the light that you get out of an LED, or the current or voltage that you might get out of a solar cell.”
Most electronics on the market are made of silicon because it’s “relatively cheap, but also highly ordered,” Switzer says.
“99.99 percent of electronics are made out of silicon, and there’s a reason – it works great,” he says. “It’s a single crystal, and the atoms are perfectly aligned. But, when you have a single crystal like that, typically, it’s not flexible.”
By starting with single crystal silicon and growing gold foils on it, Switzer is able to keep the high order of silicon on the foil. But because the foil is gold, it’s also highly durable and flexible.
“We bent it 4,000 times, and basically the resistance didn’t change,” he says.
The gold foils are also essentially transparent because they are so thin. According to Switzer, his team has peeled foils as thin as seven nanometers.
Switzer says the challenge his research team faced was not in growing gold on the single crystal silicon, but getting it to peel off as such a thin layer of foil. Gold typically bonds very well to silicon.
“So we came up with this trick where we could photo-electrochemically oxidize the silicon,” Switzer says. “And the gold just slides off.”
Photoelectrochemical oxidation is the process by which light enables a semiconductor material, in this case silicon, to promote a catalytic oxidation reaction.
Switzer says thousands of gold foils—or foils of any number of other metals—can be made from a single crystal wafer of silicon.
The research team’s discovery can be considered a “happy accident.” Switzer says they were looking for a cheap way to make single crystals when they discovered this process.
“This is something that I think a lot of people who are interested in working with highly ordered materials like single crystals would appreciate making really easily,” he says. “Besides making flexible devices, it’s just going to open up a field for anybody who wants to work with single crystals.”
Learn more: Research leads to a golden discovery for wearable technology
Receive an email update when we add a new ARTIFICIAL SYNAPSES article.
The Latest on: Wearable electronics
via Google News
The Latest on: Wearable electronics
- Thin Film Electronics ASA: Private placement successfully completedon March 1, 2021 at 3:19 pm
NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, IN WHOLE OR IN PART, DIRECTLY OR INDIRECTLY, IN OR INTO AUSTRALIA, CANADA, HONG KONG, JAPAN OR THE UNITED STATES OR ANY OTHER JURISDICTION IN WHICH THE ...
- Move Over Fitness Trackers, Here Come On-Skin Electronics That Look Like Stickerson February 25, 2021 at 11:29 am
Fitness trackers are all the rage, but what about an on-skin sensor that can track your health and help you and your healthcare provider monitor your health?
- Scientists invented a wearable that recharges in the most incredible wayon February 25, 2021 at 9:45 am
For all the technological advances that have been made in the consumer electronic space, batteries are still the biggest limitation. Allowing a device to charge without needing a plug is a huge ...
- Researchers develop a new wearable device that is powered by the users’ bodyon February 25, 2021 at 2:10 am
A new wearable device has been developed by researchers at CU Boulder. This device is unique since it is capable of transforming the human body into a biological battery, since it is powered by the ...
- Wearable Bioelectronics: Detecting COVID-19 With a Sticker on Your Skinon February 24, 2021 at 6:29 am
A University of Missouri engineer received a grant from the National Science Foundation to plan for large-scale manufacturing of an on-skin, wearable bioelectronic device. One day, a wearable, bioelec ...
- This Wearable Uses Your Body Heat as an Energy Sourceon February 23, 2021 at 8:00 pm
A team of researchers at the University of Colorado at Boulder have developed a wearable that can tap into its wearer’s natural body heat to virtually turn the human body into a battery, no ...
- New Wearable Device Turns Your Body Into a Biological Batteryon February 23, 2021 at 4:52 am
Researchers at CU Boulder have developed a new, low-cost wearable device that transforms the human body into a biological battery. The device, described in the journal Science Advances, is stretchy ...
- Wearable Electronics Market 2021 | Maintaining a Strong Outlook - Here's Whyon February 23, 2021 at 12:06 am
A recent systematic review report on “ Wearable Electronics Market 2021 Significant Trends, Growth Rate, Opportunities and Covid-19 Impact Analysis 2031 | Changing the Face of Electronics Industry”, ...
- New wearable device turns the body into a batteryon February 22, 2021 at 9:15 pm
Researchers at CU Boulder have developed a new, low-cost wearable device that transforms the human body into a biological battery.
via Bing News