Electronic displays that hover mid-air seem to be the stuff of science fiction. But these concepts could be more likely to become a reality with advances in transparent electronics, according to researchers and market analysts.
A recent report from IDTechEx analyzed the field’s research pipeline and industry efforts, concluding that by the year 2041, the market would be worth over $20 billion. What’s behind this technology and why is a meteoric rise on the horizon?
Transparent FETs at the Heart of Clear Electronics
The device at the heart of transparent electronics is the transparent field-effect transistor (TFET), which is often a thin-film transistor.
Transparent electronics prototypes using a 2D semiconductor. Image used courtesy of TechXplore
A standard thin-film transistor consists of three layers: conducting, semiconducting, and insulating. TFETs do the same, but they use materials with high transparency to create very thin transistors.
Originally, these devices were created using indium-zinc-oxide for the gate electrode, a transparent material that was easily manufacturable. The problem is that most transparent conductors are polycrystalline, giving them low electron mobility and limiting the efficacy of these transistors.
Further research has been able to improve these original designs, and now TFETs are being developed using compound wide-bandgap semiconductors, namely GaN and SiC, offering significantly higher mobilities.
Advances in manufacturing and semiconductor physics are still needed, but as further advances in 2D-semiconductors are realized, more flexible and transparent electronics are likely to become a market reality in the form of LCD, mini-LED, micro-LED, QD, and OLED displays.
Transparent Displays, Solar Panels, and Smart Windows
The most exciting aspect of transparent electronics is its potential applications.
One promising use case is that of transparent display technologies. Conventional displays require a backlight, which can consume significant amounts of power. Transparent displays, on the other hand, use an ambient backlight. New billboards and street signs with transparent displays may appear as if they’re floating in mid-air. Likewise, windows may be able to function as displays.
Transparent display concept. Image from Azo Materials
Another application includes transparent energy harvesting. Researchers, like those at Michigan State University, have looked to transparent solar panels to both absorb the sun’s light and see through the photovoltaic cell at the same time. Integrated into the windows of a high rise, transparent solar panels may generate as much as 0.5 MW and possibly more if they darken in response to the sun.
A third application postulated is windows with embedded sensors, which would allow the window to adjust transparency upon changes in the environment. For example, if a window senses that a room is too hot, it can become less transparent to help cool it down (and vice versa). Beyond this, integrated chemical and radiation sensors could easily be included in these devices.
Gaining Traction in Automotive Markets
These applications are not an exhaustive list of the possible use cases of transparent electronics.
For instance, the IDTechEx report claims that transparent electronics will strike a chord with automotive and locomotive developers. In fact, a Chinese railway recently developed LG OLED train windows that include interactive, LED displays. Hyundai has also expressed interest in implementing transparent solar panels in the roof of future EVs.
Have you worked on any transparent or stretchable electronic projects? What surprised you about working with this technology at the circuit level? Share your experience in the comments below.