Two-dimensional closely-packed gold nanoislands: A platform for optical data storage and carbon dot generation

[Display omitted] •Closely-packed Au nanoparticles exhibit polarization and wavelength dependent hot spots.•Closely-packed Au nanoparticles can emit efficiently hot electron intraband luminescence.•Optical data storage with polarization and wavelength multiplexing is demonstrated.•Localized temperature distribution can be obtained in closely-packed Au nanoparticles.•Optical data storage and carbon dot generation can be simultaneously realized. Polymer films doped with gold (Au) nanoparticles have been successfully employed to realize optical data storage and carbon dot generation. However, such nanomaterials are not expected to have a long lifetime because polymers are not stable against humidity and heat. Here, we propose the use of two-dimensional closely-packed Au nanoparticles deposited on a silica substrate as the platform for realizing simultaneously high-density optical data storage and efficient carbon dot storage. The hot spots formed by plasmonic coupling between Au nanoparticles enable the realization of polarization and wavelength multiplexing in optical data storage with high quality and low energy. In addition, strongly localized temperature distribution can be achieved in closely-packed Au nanoparticles exploited to produce luminescent carbon quantum dots by using direct laser writing. Our findings indicate the potential applications of this new nanomaterial in the fabrication of novel photonic devices for optical data storage, optical display, and optical sensing in the future.