Goldene

Goldene was synthesized as a free-standing material in 2024 by a team at Linköping University in Sweden. They made a disputed claim about the goldene work reported in 2022 by a team at New York University Abu Dhabi contained multiple layers but that was not true.

The team used a material containing silicene between layers of titanium carbide. Gold layered on top of this combination diffused into the structure and replaced the silicon. Etching away the titanium carbide released free-standing goldene sheets that were up to 100 nanometres wide. The etching was performed using Murakami's reagent, in a 100-year-old technique used to decorate ironwork by Japanese blacksmiths. Surfactant molecules formed a barrier between goldene and the surrounding liquid, to stop the sheets from adhering.

The team is exploring the potential for preparing goldene from other non-van der Waals Au-intercalated phases, including developing etching schemes.

Forming 2D allotropes of metals such as gold has been difficult because metal atoms tend to cluster together and form nanoparticles instead of nanosheets.

The material displayed Au 4f binding energy increase of 0.88 eV. The material is a semiconductor, with the valence band maximum 50 meV below the Fermi level.

Potential applications includes sensing and catalysis.