Modulation of up-conversion luminescence of lanthanide(III) ion co-doped NaYF4 nanoparticles using gold nanorods

We have investigated the influence of gold nanorods (Au NRs) proximity on the up-conversion luminescence of lanthanide-doped NaYF4 nanoparticles (NPs). The measurements were performed on two different systems. We used solvent evaporation method to assemble NaYF4:2%Tm3+, 20%Yb3+ NPs/Au NRs thin films, and colloidal water blend suspensions of mixed NaYF4:2%Tm3+, 20%Yb3+ or NaYF4:2%Er3+, 20%Yb3+ NPs with Au NRs. The coupling of the NaYF4:2%Tm3+, 20%Yb3+ and NaYF4:2%Er3+, 20%Yb3+ NPs emission with the surface plasmon of Au NRs was found to lead to effective modulation of Tm3+ and Er3+ ions luminescence. As the result of NPs and Au NRs being in close contact the rate of excitation could be increased, but also quenching by energy transfer and nonradiative relaxation has been observed.

► The plasmonic interaction between gold nanorods and Tm(Er)/Yb co-doped NaYF4 have been investigated. ► Assembling NaYF4:Tm, Yb and Au NRs in thin films led to weak fluorophore–metal interaction. ► For water blend of NaYF4:Tm, Yb and Au NRs we observed either luminescence attenuation or enhancement. ► For water blend NaYF4:Er, Yb green luminescence was nonradiatively quenched by the Au NRs.