Plasmonic enhancement of upconversion emission in Ag@NaYF4:Er3+/Yb3+ phosphor

In this article upconversion luminescence of silver nanoparticles(AgNPs) coated NaYF:Er/Ybphosphor nano-particles was investigated.The prepared samples were characterized through various techniques.The surface plasmon band is observed for prepared AgNPs by analyzing UV-vis measurements and is used to enhance the upconversion emission.From the upconversion measurement the emission bands are observed at 522,546,and 656 nm corresponding to the ~2 H→ 4~1,~4 S→~4 Iand ~4 F→~4 Ilevels,respectively.The upconversion emission intensity of the above bands is found to enhance for sample containing 1 mmol AgNPs.Decay time of ~4 Sand 4~Flevels is found to decrease on coating of AgNPs and hence intensity enhancement is assumed due to the surface plasmon resonance(SPR) effect.