Visible Discrimination of Broadband Infrared Light by Dye-Enhanced Upconversion in Lanthanide-Doped Nanocrystals

Figure 8

Demonstration of dye-induced upconversion of NaYF₄ nanoparticles doped with Er³⁺ as both sensitizer and activator (NaY_0.85Er_0.15F₄). Plot (a) is for excitation at 785 nm where the attached DyL800 dye absorbs, but Er³⁺ does not; the characteristic erbium upconversion spectrum is seen for the dye-attached nanoparticles (black curve) while no upconversion is seen for the control without attached dye (blue curve). Plot (b) is for excitation at 801 nm where Er³⁺ absorbs, but where absorption of the dye is less.