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

Abstract

Metal-enhanced luminescence of lanthanide complexes by noble metal nanoparticles has attracted much attention because of its high efficiency in improving the luminescent properties of lanthanide ions. Herein, nine kinds of europium and terbium complexes—RE(TPTZ)(ampca)3·3H2O, RE(TPTZ)(BA)3·3H2O, RE(phen)(ampca)3·3H2O, RE(phen)(PTA)1.5·3H2O (RE = Eu, Tb) and Eu(phen)(BA)3·3H2O (TPTZ = 2,4,6-tri(2-pyridyl)-s-triazine, ampca = 3-aminopyrazine-2-carboxylic acid, BA = benzoic acid, phen = 1,10-phenanthroline, PTA = phthalic acid)—have been synthesized. Meanwhile, seven kinds of core-shell Ag@SiO2 nanoparticles of two different core sizes (80–100 nm and 40–60 nm) and varied shell thicknesses (5, 12, 20, 30 and 40 nm) have been prepared. The combination of these nine types of lanthanide complexes and seven kinds of Ag@SiO2 nanoparticles provides an opportunity for a thorough investigation of the metal-enhanced luminescence effect. Luminescence spectra analysis showed that the luminescence enhancement factor not only depends on the size of the Ag@SiO2 nanoparticles, but also strongly relates to the composition of the lanthanide complexes. Terbium complexes typically possess higher enhancement factors than their corresponding europium complexes with the same ligands, which may result from better spectral overlap between the emission bands of Tb complexes and surface plasmon resonance (SPR) absorption bands of Ag@SiO2. For the complexes with the same lanthanide ion but varied ligands, the complexes with high enhancement factors are typically those with excitation wavelengths located nearby the SPR absorption bands of Ag@SiO2 nanoparticles. These findings suggest a combinatorial chemistry strategy is necessary to obtain an optimal metal-enhanced luminescence effect for lanthanide complexes.

Surface Alloying in Silver-Cobalt through a Second Wave Solution Combustion Synthesis Technique

“…Bimetallic nanoparticles have received great attention due to their multifunctionalities, selectivity, and activity over monometallic particles, and they are increasingly being applied to various areas, including electronics, optics, catalysis, and magnetics [ 1 , 2 , 3 , 4 , 5 , 6 ]. Bimetallic nanoparticles with different structures, like crown-jewel, hollow, heterostructure, core-shell, alloys, and porous structures, have been synthesized using various techniques, such as chemical methods, hydrothermal, impregnation, sol-gel, spray pyrolysis, and precipitation methods [ 7 , 8 , 9 , 10 , 11 ]. This structural diversity is due to the atomic distribution of the individual metals in bimetals.…”

Development of a rapid and simple tetracycline detection system based on metal-enhanced fluorescence by europium-doped AgNP@SiO2 core–shell nanoparticles

“…In many reference papers, the silica shell thickness of 20-50 nm is found to be effective for the luminescence enhancement of the lanthanide complex and frequently utilized for the MEF. [38][39][40] In principle, as the silica shell thickness increases over 20 nm, the radiative energy transfer becomes dominant as compared to the non-radiative energy transfer. Thus, 35 nm silica shell used in our work leads to the signicant uorescence enhancement through the radiative energy transfer from the excited AgNPs to the lanthanide complex (EuTc).…”

Towards Multi-Functional SiO2@YAG:Ce Core–Shell Optical Nanoparticles for Solid State Lighting Applications

“…It is clear that the absorption of YAG:Ce is not affected by SiO 2 . The relative intensity decrease in the absorption peak of the core-shell SiO 2 @YAG:Ce nanoparticles is possibly due to presence of SiO 2 particle that could change the dielectric constant (as a complete transparent materials) inside YAG:Ce shell and thus decrease the absorption intensities [55]. It is seen that the amount of SiO 2 nanoparticle in the core-shell system is not high enough to decrease the transmission of SiO 2 @YAG:Ce.…”