Upconversion luminescence quenching mechanism of single Au nanoparticles decorated NaYF4: Yb3+, Er3+ hexagonal disk

Obvious UCL quenching in single Au nanoparticles decorated NaYF4: Yb3+, Er3+ hexagonal disk has been observed. Employing by cavity quantum optics theory, we argued that the quenching was mainly induced by the nonradiative ET originated from the higher mode Purcell factor. [Display omitted] •Obvious UCL quenching in single Au decorated NaYF4: Yb3+, Er3+ hexagonal disk was observed.•The cavity quantum optics theory has been employed to analyze the quenching mechanism.•We concluded that the quenching was mainly caused by the higher mode Purcell factor induced nonradiative ET. Different amounts of Au nanoparticles decorated NaYF4: Yb3+, Er3+ hexagonal disks were synthesized by using a hydrothermal strategy. In comparsion with single NaYF4: Yb3+, Er3+ hexagonal disk, the average upconversion quenching factors for the green and red upconversion emission bands of single Au nanoparticles decorated hexagonal disk increased obviously with the increasing of the amounts of uploaded Au nanoparticles. The local field distribution accompanied with the enhancement factors were obtained by finite element method. Based on the cavity quantum optics theory, a quantitative analysis for the Au nanoparticles induced quenching was addressed. The results show that the presence of the higher mode Purcell factors induced nonradiative energy transfer from the upconverter to the Au nanoparticles, which contributed to the quenching significantly. The modest weakening of local fields only played a minor role. It could offer a novel theory guidance for the seeking of the novel plasmonic nanostructure-upconverter hybrid system.