Effect of temperature on the amino acid-assisted formation of metal islands

Abstract

Understanding that life on this planet may have originated under extreme circumstances, such as high temperatures and acidic conditions, it would be extremely beneficial to study how simple biological molecules, like amino acids, behave under these scenarios. Importantly, this is possible through the use of electrochemical scanning tunneling microscopy, which can be used to both image and electrochemically manipulate the model systems under consideration. Earlier reports have examined the similarities between studies conducted at ultrahigh vacuum or low temperature and electrochemical conditions with both finding that amino acid molecules trap diffusing metal atoms on surfaces to form 2D ad-islands. Critically, all of the past work was conducted at room temperature. In this report, it has been found that as the temperature of the Au(111) surface was increased, the islands grew by 14% at 300 K and 40% at 305 K, relative to room temperature. Additionally, the increased surface temperature allowed for the formation of islands that were one atomic step higher than those observed at room temperature. Higher surface temperatures not only allowed for the observation of larger immobilized adatom islands, but they also demonstrated how temperature can be used as another method to control surface modification and molecular assembly. Not only is this work critical for a basic understanding of the role between temperature and surface diffusion, but it also begins to mimic how surfaces may have behaved during the emergence of life on Earth.