If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.


Molecular Electronics

Glowing dyes could store digital data for the long term

Encoding data as dots of fluorescent dyes would be simpler and cheaper than DNA-based storage

by Prachi Patel, special to C&EN
November 8, 2021

The nozzle of an inkjet printer deposits dots that are mixtures of seven different colored dyes, which then give off a spectrum of light that is read with a fluorescence detector. In this example, the presence of four different dyes encodes “01001101.”
Credit: Adapted from ACS Cent. Sci.
A new data storage system uses mixtures of seven different dyes to represent a string of digital bits (a 1 or 0) that encode a text character. The first of the eight bits needed is always 0 and is left blank. A fluorescence microscope is used to read the data.

Current data storage technologies such as optical disks and magnetic hard drives and tapes can store an impressive amount of information. But the data typically lasts less than 2 decades. As a low-cost, potentially longer-lasting solution, researchers have now stored data in tiny dots of glowing dye molecules (ACS Cent. Sci. 2021, DOI: 10.1021/acscentsci.1c00728).

The researchers used an inkjet printer to deposit droplets of fluorescent dye solutions on an epoxy surface. Every droplet contains a mixture of up to seven different dye colors, with each color representing one bit of digital data and its presence or absence representing a 1 or 0. In this way, each droplet forms the code for various text characters. The researchers use a fluorescence microscope to decipher the individual colors and read the data.

Fluorescence image of an array of dots encoding 14,075 kilobytes of text, with an inset showing a close-up of the colored dots along with a 100 micrometer scale bar.
Credit: ACS Cent. Sci.
A fluorescence microscope image shows a grid of printed fluorescent dye droplets that encode 14,075 text characters from Michael Faraday’s paper, “Experimental researches in electricity.”

The dye-based memory is a way to store information using molecules. Molecular techniques could, in theory, pack hundreds of times as much data into the same space as optical and magnetic storage systems. And unlike those systems, molecules could store data for thousands of years without needing a constant power source or deteriorating. That makes molecules promising for long-term storage of large volumes of information such as movie and book archives and scientific data.

Synthetic DNA is so far the most studied molecule for data storage. But storing and then reading data requires synthesizing and then sequencing the DNA, which are both time consuming, says George M. Whitesides, a chemist at Harvard University and a board member at the data storage solution start-up Datacule. The dye system, by contrast, is “simple and low cost.”

Using their dye-based system, Whitesides and his colleagues were able to write, store, and read a digitized image of Michael Faraday and more than 14,000 characters of text from one of his seminal research papers. They could write at an average speed of 16 bytes per second and read at a rate of about 59 bytes per second. What’s more, they could read the data more than 1,000 times before the dyes lost their intense glow and got significantly harder to read.

The dots were spaced 30 µm apart, but by reducing that distance to 1 µm, the researchers should be able to get a density of 0.8 gigabits/cm2, comparable with the 1.28 Gbits/cm2 density of magnetic tape. The dyes are stable in ambient conditions, and the researchers estimate that they could last approximately 10 billion years before they start decaying.

The low cost would be the main advantage of the dye-based system over magnetic tape and DNA storage, says Robert Grass, a chemical engineer at the Swiss Federal Institute of Technology (ETH), Zürich. It is a good example of repurposing existing technologies for a new need. “The beauty of it is its simplicity,” he says. “Our world needs a lot of data. It is important that we keep searching for new technologies with unique data-carrying abilities, as there is no one-size-fits-all solution to data storage.”


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.