Many-Body Description of STM-Induced Fluorescence of Charged Molecules

A scanning tunneling microscope is used to study the fluorescence of a model charged molecule (quinacridone) adsorbed on a sodium chloride (NaCl)-covered metallic sample. Fluorescence from the neutral and positively charged species is reported and imaged using hyperresolved fluorescence microscopy. A many-body model is established based on a detailed analysis of voltage, current, and spatial dependences of the fluorescence and electron transport features. This model reveals that quinacridone adopts a palette of charge states, transient or not, depending on the voltage used and the nature of the underlying substrate. This model has a universal character and clarifies the transport and fluorescence mechanisms of molecules adsorbed on thin insulators.

Automated summary

A scanning tunneling microscope was used to investigate the fluorescence of a charged molecule (quinacridone) adsorbed on a metallic sample covered with sodium chloride. The fluorescence from both neutral and positively charged species was observed and analyzed using hyperresolved fluorescence microscopy. A many-body model was developed based on the analysis of voltage, current, and spatial dependences of fluorescence and electron transport features. This model reveals that the charge states of quinacridone can vary transiently or permanently depending on the voltage and substrate properties.