Advances of Photon Upconversion Nanomaterials

Photon upconversion is a process where lower-energy near-infrared light is converted into higher-energy visible light. Nanoscience and nanotechnology have witnessed rapid development in lanthanide-doped upconversion nanoparticles (UCNPs) due to the excellent optical properties of their f–f electronic transitions, including high photostability, narrow emission bandwidths, long luminescence lifetimes, and large induced anti-Stokes shifts. These distinctive properties are highly attractive for extensive applications, ranging from biological imaging, night vision, ultrasensitive sensing, and controllable drug delivery, to security inks, optical tweezers, single-molecule tracking, full-color display, optical data storage, and super-resolution nanoscopy.

This Research Topic intends to collect the latest advances regarding the developments in upconversion nanosystems. Original Research, mini-review, and review articles in the fields ranging from materials synthesis, characterization, fabrication, and optical properties, to upconversion mechanism, energy transfer study, and the widespread applications of UCNPs are welcome. Progresses in any other fields which are related to the developments and applications of photon upconversion materials are also welcome.

Sub-topics include but are not limited to:
- Synthesis, fabrication, and functionalization of upconversion nanoparticles
- Optical properties of upconversion nanoparticles
- Energy transfer mechanisms of upconversion nanoparticles
- Hybrid upconversion nanosystems
- Single particle characterization and spectroscopy of upconversion nanoparticles
- Applications of upconversion nanosystems

Keywords: photon upconversion, spectroscopy, hybrid nanosystems, energy transfer, optical properties

Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.