Enhanced emission of NaYF4:Yb,Er/Tm nanoparticles by selective growth of Au and Ag nanoshells

Abstract

We report a novel, simple strategy to efficiently enhance the fluorescence of metal-coated up-conversion nanoparticles (UCNPs), NaYF 4 :Yb,Er/Tm. The UCNPs are functionalized with a polyamidoamine generation 1 (PAMAM G1) dendrimer, followed by a continuous growth of gold (Au) or silver (Ag) nanoshells to selectively enhance the up-converted green, violet and blue emissions (.20 fold).

Preparation of gold nanoparticle coated NaYF4:Yb,Er,Gd nanoparticles and their application for AFP detection in the red region

“…Its application was limited by its emission rate because of its surface quenching, particularly for the large specific surface area/volume ratio of nanoparticles and relatively small crosssectional area of photon absorption. 19 A new, simple method to maximize the conversion of the quantum yield and exploration of the optimal combination of rare earth atoms with different main matrices is needed. Surface plasmon resonance (SPR) also arises due to the collective oscillation of electrons on noble metal nanoparticles, which has a beneficial effect depending on the position of the SPR peak and the distance of the luminophore from the noble metal surface.…”

“…Surface plasmon resonance (SPR) also arises due to the collective oscillation of electrons on noble metal nanoparticles, which has a beneficial effect depending on the position of the SPR peak and the distance of the luminophore from the noble metal surface. 19,20 When noble NPs are excited by incident light and the overall vibration frequencies of the incident photon match the noble metal NPs' vibration frequencies, the nanoparticles strongly absorb photon energy, and a surface plasmon phenomenon occurs. 19,21 Interactions between the surface plasmons of gold metallic surfaces and luminescence of QD surfaces 22,23 for enzyme detection have been investigated.…”

Photochemically grown silver nanodecahedra with precise tuning of plasmonic resonance

“…As most of these applications are based on optical properties, the precise tuning of the LSPR band is essential to meet the special conditions required by such applications [7][8][9][10][11][12] . The characteristics of the LSPR band are significantly associated with the nanoparticle size and shape, whose control has been the most efficient method to successfully tune the LSPR band [13][14][15] .…”

Fabrication of Au-Ag nanocage@NaYF4@NaYF4:Yb,Er Core-Shell Hybrid and its Tunable Upconversion Enhancement

“…Although various UCNPs@metal core-shell structures have been designed to boost UCL in colloids, however, the luminescent enhancements for those hybrid UCNPs are not obvious in colloidal solutions2122232425. The enhancement factors in those hybrids usually concentrated in several times or even quenched.…”