World's smallest QR code can store data for thousands of years ‪—‬ but you need an electron microscope to see it

Scientists have created the smallest QR code in the world, measuring just 3.07 × 10⁻⁹ square inches (1.98 square micrometers). It can preserve data for thousands of years and it's so small that you need an electron microscope to see it.

Each pixel of the QR code is just 49 nanometers across, even smaller than a bacterium, ensuring its place as a Guinness World Record. It was created by etching its grid into a thin ceramic film with a focused ion beam. It's about 37% the size of the previous world record holder and about 0.0000004% the size of a standard 0.8-square-inch (2 cm²) QR code.

The code is too small for even an optical microscope to visualize because the pixels are smaller than the wavelength of visible light and the light waves won't be scattered by its minute details. Only an electron microscope, which fires electron beams with a wavelength in the picometer scale (10^-11 inches), can resolve it.

The creation of a data-storage unit on such a tiny scale opens up the potential for extremely high storage density. The scientists at TU Wien in Austria, who developed the QR code in collaboration with data-storage firm Cerabyte, estimate that over 2 terabytes of data could fit onto the surface area of a single A4 (8½ x 11) sheet of paper etched with the pixels — that's more data than you can keep on most consumer laptops.

In contrast, the same area covered in 0.8 square inch (2 cm²) Version 1 QR codes would hold only about 2.5 kilobytes, the equivalent of a page of plain text.

QR codes that can store data for millennia

Despite its record-breaking size, the QR code is even more impressive for its durability, the team said.

"Structures on the micrometer scale are nothing unusual today — it is even possible to fabricate patterns made of individual atoms," Paul Mayrhofer, head of the Thin Film Materials Science Research Group at TU Wien, said in a statement. "However, that alone does not result in a stable, readable code."

Magnetic storage solutions like hard drives and solid-state drives tend to degrade after about a decade, while optical media, such as CDs and DVDs, may last only 30 years. As a result, all of today's digital data is at risk of being lost to time if a more stable solution is not found.

Because of this potential for degradation, the team decided to make their QR code using a film of chromium nitride, a ceramic compound. Ceramics are known to remain stable under even extreme conditions, hence their usage in high-performance cutting tools. The scientists said the data their QR code stores could be preserved for millennia.

"With ceramic storage media, we are pursuing a similar approach to that of ancient cultures, whose inscriptions we can still read today," Alexander Kirnbauer, a senior scientist in the Thin Film Materials Science Research Group at TU Wien, said in the statement. "We write information into stable, inert materials that can withstand the passage of time and remain fully accessible to future generations."

A more eco-friendly solution to AI dependence

Another benefit of tiny ceramic QR codes is that they do not require energy input or cooling to preserve the data. Data centers, by contrast, require constant electricity to power servers and maintain cooling systems to prevent damage from overheating. They accounted for around 1.5% of the world's electricity consumption in 2024, according to the International Energy Agency.

A more environmentally friendly alternative to the massive carbon-guzzling data centers we depend on is urgently needed, especially as our reliance grows with the rapid expansion of artificial intelligence (AI). Market research firm IDC estimates that the amount of data the world produces in one year will have tripled from 173.4 zettabytes (173.4 billion TB) in 2024 to 527.5 ZB in 2029.

The team is now looking into other materials for their QR codes, techniques to increase writing speeds, and industrial-scale manufacturing methods. They also want to see if more complex data structures than QR codes can be written onto and read from ceramic films.