Sub-10 nm upconversion nanocrystals for long-term single-particle tracking.

ABSTRACT: Lanthanide-doped upconversion nanoparticles are attractive single-molecule imaging probes due to their high photostability and anti-Stokes luminescence. However, achieving both small particle size and strong brightness has remained a major challenge, as reducing size often leads to dimmer emission. Herein, we fabricate a sub-10 nm cascade actively protected upconversion nanoparticles, which shows a 33-fold enhanced upconversion efficiency at the single-particle level compared to larger ~19 nm conventional nanoparticles. Theoretical modeling and time-resolved measurements show that emission loss mainly comes from energy leakage of Er³⁺ ions to surface defects. By introducing a NaYbF₄ layer as photon-harvesting and protective intermediate layer, we minimize this energy

SUBMITTER: Qiu X 

PROVIDER: S-EPMC12552444 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature