Au20 (image) American Institute of Physics Share Print E-Mail Caption The researchers used Au20, gold nanoparticles with a tetrahedral structure, to show that fluorescence in ligand-protected gold clusters is an intrinsic property of the gold nanoparticles themselves. Credit Brune Usage Restrictions This image may be used only with appropriate credit. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.