EPFL researchers have made a groundbreaking discovery in the field of nanotechnology by developing a comprehensive model that unravels the quantum-mechanical effects behind photoluminescence in thin gold films. This discovery has the potential to significantly impact the development of solar fuels and batteries.

Luminescence, the process of emitting photons when exposed to light, has long been observed in semiconductor materials like silicon. By studying the nanoscale behavior of electrons as they absorb and re-emit light, researchers can gain valuable insights into semiconductor properties and use them to characterize electronic processes, such as those within solar cells.

Although it was discovered in 1969 that all metals exhibit luminescence to some extent, the exact mechanism behind this phenomenon has remained elusive over the years. Recent interest in light emission from metals, fueled by applications in nanoscale temperature mapping and photochemistry, has reignited discussions on its origins. However, it was not until now that a clear understanding of the process emerged.

Giulia Tagliabue, the head of the Laboratory of Nanoscience for Energy Technologies (LNET) at EPFL, explained that their research team achieved this breakthrough by working with high-quality gold films, ranging from 13 to 113 nanometers in thickness. By focusing laser beams on these ultra-thin films and analyzing the resulting photoluminescence, the researchers obtained detailed and unexpected data.

The complexity of the data prompted the collaboration of EPFL researchers with theoreticians from the Barcelona Institute of Science and Technology, the University of Southern Denmark, and the Rensselaer Polytechnic Institute in the United States. Together, they applied advanced quantum mechanical modeling techniques to interpret the experimental results.

The study, published in Light: Science & Applications, sheds new light on the quantum-mechanical effects driving photoluminescence in thin gold films. By gaining insights into this process, researchers hope to pave the way for advancements in solar energy technologies and battery development.