Writing Self‐Erasing Images using Metastable Nanoparticle “Inks”

Mission Impossible: Metal nanoparticles (NPs) coated with photoresponsive ligands are used as “inks” for self‐erasing “paper” whereby light‐induced self‐assembly of the NPs is transduced into local color changes (see picture). Depending on the degree of self‐assembly, multicolor images can be written using only one type of NP ink. Duration of image erasure is regulated by the surface concentration of photoactive groups and can range from seconds to days.