Enhanced upconversion luminescence on the plasmonic architecture of Au-Ag nanocages

Au-Ag nanocages with tunable surface plasmon resonance peaks were synthesized via the galvanic replacement reaction. These tunable nanocubes with strong plasmonic effect were further fabricated into thin films composed of a random assembly of Au-Ag nanocages, which show great broadening of surface plasmon resonance absorption. After optimizing, through coupling with the excitation light, the overall upconversion luminescence intensity of NaYF4:Yb3+, Er3+ on the surface of the Au-Ag nanocage film under 980 nm excitation was improved more than 15 fold.