The details of the research done by the LiU team were published in the journalNature Synthesis.

Scientists utilized an ancient technique

Due to the metal’s propensity to bunch together, scientists have long attempted but failed to create only one-atom-thick sheet of gold. However, LiU researchers achieved success with the help of a century-old technique employed by Japanese blacksmiths.

“If you make a material extremely thin, something extraordinary happens – as with graphene. The same thing happens with gold,” said Shun Kashiwaya, a researcher at the Materials Design Division at Linköping University, in a statement.

In its conventional form, gold typically manifests as a metal. However, when reduced to a single-atom-layer thickness, it undergoes a transformation, exhibiting semiconductor properties instead.

The scientists employed a three-dimensional base material with embedded gold between titanium and carbon layers to develop goldene. However, the process of coming up with goldene proved difficult. According to researchers, a portion of the advancement can be attributed to luck.

The underlying material was developed with entirely other applications in mind by the team. They began with titanium silicon carbide, a ceramic that is electrically conductive and contains tiny layers of silicon. To create a contact, the substance was then supposed to be covered in gold.

“But when we exposed the component to high temperature, the silicon layer was replaced by gold inside the base material,” said Lars Hultman, a professor of thin film physics at LiU, in a statement.

The researchers found titanium gold carbide, which is known as intercalation. They have had this titanium-gold carbide for a number of years, but they are unsure of how to exfoliate or pan out the gold effectively.

A new frontier in material science

Hultman stumbled upon a technique rooted in Japanese forging tradition, spanning over a century. Known as Murakami’s reagent, it adeptly removes carbon residue and alters the hue of steel, a technique employed in the craft of knife making, among others.

However, replicating the precise formula utilized by the traditional smiths proved unattainable. “I tried different concentrations of Murakami’s reagent and different time spans for etching. One day, one week, one month, several months. What we noticed was that the lower the concentration and the longer the etching process, the better. But it still wasn’t enough,” said Hultman.

Since light causes cyanide to form in the reaction and destroy gold, the etching must likewise be done in complete darkness. Stabilizing the gold sheets was the final step. A surfactant was applied to stop the exposed two-dimensional sheets from curling up. Here, a tenside—a lengthy molecule that divides and stabilizes the sheets—is involved.

The golden sheets reside within a solution akin to cornflakes in milk. By employing a type of “sieve,” researchers could gather the gold for examination. Subsequently, utilizing an electron microscope, they confirmed the success of their endeavor.

According to researchers, due to the fact that gold has two free bonds when it is two-dimensional, goldene has novel properties.

Future uses for this could include the conversion of carbon dioxide, hydrogen-producing catalysis, selective synthesis of molecules with added value, hydrogen production, water purification, communication, and much more. Furthermore, the quantity of gold utilized in contemporary applications can be significantly diminished.

The researchers at LiU will now look into the possibility of doing the same with other noble metals and determine potential future uses.