For years, advancements in electronics moved toward miniaturization—the more high-tech things became, the smaller they became. Now, technology has another goal: transparent electronics. While not all of these devices are completely transparent, they offer an unprecedented degree of visibility that promises to revolutionize sensing and display technology.
Like their name implies, transparent electronics are electronics that you can see through. This is achieved by either using transparent materials to begin with, or relying on opaque materials in tiny amounts and special configurations to allow light to pass through. As an example, high-resolution printing techniques allow for the creation of nanowire arrays that can conform to different surfaces, offer unobstructed vision, and let light pass through. That opens them up to use in displays, medical sensors, and photovoltaic devices.
Researchers at Japan's Osaka University recently created a silver nanowire network that they used to detect electrophysiological signals from leaves. The arrays themselves were flexible, so they could easily bend to fit the leaves they were studying, and transparent enough to allow researchers to perform visual assessments.
Similarly, researchers at the Chinese Academy of Sciences created a molybdenum disulfide-based transistor using a type of vapor deposition process. This could be the key to producing large transparent electronic devices, and may be more scalable than other methods.
Automotive manufacturer Hyundai is also working out ways to incorporate transparent electronics in its vehicle designs. Currently, their plans are to include transparent solar arrays in the roofs of its electric vehicles, allowing them to generate a portion of their own electricity without sacrificing aesthetics or functionality.
LG Electronics, a big-name television and digital signage manufacturer, is also working on adding transparent electronic technology to its offerings. They recently partnered with Assa Abloy, an automated door manufacturer, to design and test glass automatic doors with built-in digital advertising displays.
Right now, the next steps are to refine designs and scale up the manufacturing process. While research is promising, the resulting electronics still need refinement. The researchers at Osaka University, for example, plan to add a layer of graphene to the surface of their nanowires in order to make the array's resistance more uniform. Meanwhile, researchers at the Chinese Academy of Sciences are working to improve the quality of their molybdenum disulfide-based transistors, while exploring other potential applications for this technology.
On the manufacturing end, if transparent electronics are going to be viable, they need to be relatively inexpensive and simple to produce. Additive manufacturing is useful for creating thin, flexible, transparent arrays, but its utility starts to drop off when it comes to making large components. Not only would scientists need to create large-scale nanowire arrays, they'd need to develop specialized printing technology to produce them. The atomic layer deposition technique developed by the Chinese Academy of Sciences may be a more useful method for turning out larger components.
Transparent electronics are likely going to start showing up more and more in the advertising, automotive, aerospace, agricultural, and biomedical fields—in short, anywhere where visibility is key. LG Electronics already plans to use this technology to create automatic doors that advertise to passers by. In a post-COVID world, transparent electronics could also be used to create a touchless interface and screen visitors before allowing them to enter buildings.
Hyundai already plans to use this technology to improve their electric vehicles, but transparent electronics could also be invaluable for creating heads-up displays. They could theoretically offer speed, direction, traffic, and other information without obstructing drivers' vision. In Germany, researchers are developing ways to use this tech to create headlight glass that allows driverless vehicles to steer by following radar signals.
The aerospace industry will likely take a similar turn, creating heads-up displays and interfaces for manned vehicles, transparent solar panels, and radar receivers. Since transparent electronics are thin and flexible, they are also very lightweight (an important consideration in an industry where sending something into space can cost as much as $10,000 per pound).
In the agricultural field, transparent electronics are already being used to allow greenhouses to generate a portion of the electricity they consume. Panels of glass let light in to feed plants, while converting sunlight to electricity to keep fans, sensors, and hydroponic systems running. This is one of the most exciting potential applications for this tech—virtually any surface can become a solar panel, without changing how it looks or functions.
Transparent electronics are also ideal for biomedical devices. Wearable medical sensors can be obtrusive and obvious, while transparent sensors would be more discreet. It would also allow patients and physicians to more easily monitor the skin underneath the sensors.
While some transparent electronics are already in use, the technology is still being refined. As more researchers explore how to better create and implement these devices, we're going to see more and more of them crop up in daily life—from cars, to greenhouses, to medical devices, and more.
