Study on silicon oxide coated on silver nanocrystal to enhance fluorescence intensity of rare earth complexes

Effect of the Composition of Lanthanide Complexes on Their Luminescence Enhancement by Ag@SiO2 Core-Shell Nanoparticles

“…When the SiO 2 shell is too thin, the distance between the europium complexes and silver core is so close that it may lead to non-radiative energy transfer from the europium complexes to the silver core. Thus, the emission intensities of the complex-doped Ag@SiO 2 nanocomposites with thinner silica shells are weaker than those of nanocomposites with thicker silica shells, in the range of 5–40 nm [ 35 , 36 ]. The core diameter of the nanoparticle also plays key roles in the enhancement effect.…”

“…The metal-enhanced luminescence of the lanthanide complex is considered to result from the following aspects [ 18 , 36 , 53 ]: (i) excitation enhancement due to increased light absorption; (ii) emission enhancement due to increased light absorption and radiative decay; (iii) quenching reduction due to decreased nonradiative decay. The varied enhancement factors of Tb and Eu complexes may be mainly attributed to the emission enhancement.…”

“…Two kinds of Ag nanoparticles, with particle sizes of 80–100 nm and 40–60 nm, respectively, were prepared by reducing AgNO 3 with sodium citrate in water, as described in previous works [ 36 , 37 ]. The Ag nanoparticles were collected by centrifugation and finally, dispersed in ethanol.…”

“…To achieve an optimized MEL effect on lanthanide complexes, many efforts have been paid to the size control of the nanoparticles and the distance adjustment between the particles and the lanthanide complexes [ 23 ]. For example, core-shell Ag@SiO 2 nanoparticles with core size of tens of nanometer and shell thicknesses between 20 to 50 nm are frequently found to be efficacious for the luminescence enhancement of Eu and Tb complexes [ 31 , 35 , 36 , 37 ]. The SiO 2 shell is important for avoiding the lanthanide complexes from having direct contact with the metal particles, which may lead to luminescence quench.…”

Fluorescence enhancement of europium complexes by core–shell Ag@SiO2 nanoparticles

“…Since the silica surface chemistry can covalently introduce versatile surface functionalities (e.g., COOH, CHO, NH 2 , or NCO) with readily available coupling agents [6,7], it is desirable to coat the metal nanoparticles with a shell of silica to permanently preserve their optical properties for effective functionalization [8][9][10]. Zhang et al have reported Ag@SiO 2 nanoparticles can enhance the fluorescence intensity of Rose Bengal [11][12][13], but the effect of Ag@SiO 2 nanoparticles on the fluorescence of lanthanide complexes are few reported [14,15].…”