Scientists studying energy have discovered the secret behind gold’s luminous glow.

Luminescence, the emission of photons by a substance exposed to light, has been studied in semiconductor materials for many years. The behavior of electrons as they absorb and re-emit light can provide valuable information about the properties of semiconductors, making them useful probes for characterizing electronic processes, such as those in solar cells. In 1969 it was discovered that metals also luminesce to some extent, but the exact mechanism behind this phenomenon remained unclear for decades.

Recent developments in nanoscale temperature mapping and photochemical applications have sparked renewed interest in metal luminescence. Researchers from the Laboratory of Nanoscience for Energy Technologies (LNET) conducted a study focused on gold films to better understand this process. By developing high-quality gold films and analyzing the faint glow emitted by exposure to laser beams, they were able to collaborate with theorists to create a complete quantitative model of photoluminescence in gold.

Using a thin film of monocrystalline gold, produced with a new synthesis technique, the researchers observed quantum mechanical effects in films up to about 40 nanometers. This was unexpected, as such effects are typically only observed for metals below 10 nm. These observations provided important spatial information about where the photoluminescence process occurs in gold, making it a valuable probe for nanoscale research. Furthermore, gold’s photoluminescent signal could be used to measure the surface temperature of the material, providing a new approach to studying chemical reactions at the nanoscale.

The researchers believe that their findings will contribute significantly to studies in the field of energy research, especially in the field of solar fuel development. Metals such as gold and copper can play a crucial role in triggering important reactions such as the reduction of carbon dioxide (CO2) to carbon-based products such as solar fuels. Understanding these responses at a detailed level is essential for optimizing them and combating climate change. Luminescence offers a unique way to gain insight into the surface reactions of metals, providing a new avenue for research in this field.

Overall, the LNET team’s research sheds light on the photoluminescence process in gold and provides a comprehensive model that can be applied to other metals. Their research opens new possibilities for using luminescence as a tool for understanding chemical reactions on metal surfaces, with potential implications for various applications in energy research and beyond. By harnessing the unique properties of metal luminescence, scientists may be able to unlock a deeper understanding of fundamental processes and pave the way for innovative technological advances.