Recently, Swedish scientists have successfully created gold foil with a thickness of only a single atomic layer, discovering its new characteristics that make it applicable in various fields such as medicine and chemistry.
Graphene, composed of a single layer of carbon atoms, has been used in batteries, materials, aerospace, and has sparked great interest in 2D materials among people.
Nanomaterials derived from gold can be utilized in electron microscopy, electronics, materials science, biochemical sensing, optical detection, drug delivery, disease treatment, electronic engineering, and template crystallization, making it a widely researched and renowned nanomaterial.
However, most nanoscale gold cannot be achieved in a single atomic layer thickness, making the synthesis of such gold foil a challenge in the scientific community. Scientists are seeking better methods to transform gold into a 2D form while exploring new applications.
Researchers have aimed to eliminate the titanium metal (Ti) and carbon (C) elements found in titanium carbide gold (Ti3AuC2) to obtain 2D gold foil. The key is to remove the other elements, leaving only the gold atoms sandwiched between them, in order to produce the desired 2D single-layer gold foil.
Recently, scientists at Linköping University in Sweden drew inspiration from a method used in Japanese forging techniques that can erode carbon residues and change the steel color during the knife-making process. They washed away titanium carbide to reveal the single atomic thickness gold foil, referred to as “Goldene.” Their findings were published in the scientific journal “Nature” on April 16.
Upon observing solutions containing Goldene using various instruments, the team found that the gold foils mostly existed in thin sheets ranging in size from several nanometers to 100 nanometers. These gold foils could freely float, stack on each other, entwine with each other without clumping together, and some existed in the form of nano gold particles, similar to the existence of graphene.
To further understand the differences between 2D Goldene and gold, experiments were conducted to test and observe 2D Goldene comprehensively. They discovered that 2D Goldene is stable, possesses good tensile and compressive properties, and its gold atoms continuously adsorb other elements due to the presence of two free bonds (free electrons), allowing it to attract other elements. This is contrary to the original characteristics of gold, which has difficulty reacting with other elements and is typically used in vessels and medical instruments.
The continuous adsorption of other elements makes it possible for applications in carbon dioxide conversion, hydrogen catalysis, water purification, communication, and even potential use in cancer treatment. Furthermore, in current applications of gold, the usage of gold can be significantly reduced.
Shun Kashiwaya, a researcher at Linköping University’s materials design department, mentioned to the university newsroom, “When you make a material very thin, as with graphene, unusual things happen. The same situation is now occurring with gold. We know that when gold becomes a single atomic layer thick, its original properties change.”
The researchers stated that their next step would involve investigating if other precious metals can be separated and transformed into 2D materials, expanding their applications to various fields.