One-pot synthesis of Au/Ag bimetallic nanoparticles to modulate the emission of CdSe/CdS quantum dots

Abstract

In this work, the gold/silver bimetallic nanoparticles (Au/Ag NPs) have been synthesized via a facile one-pot protocol involving co-reduction of chloroauric acid and silver nitrate with N, Ndimethylformamide (DMF) solvent in the presence of water soluble polyvinylpyrrolidone (PVP). The morphology of obtained Au/Ag NPs can be readily modified by changing reaction time and relative concentration ratio of gold/silver precursor. Subsequently, the synthesized Au/Ag NPs have been employed to modulate the fluorescent emission of CdSe/CdS quantum dots (QD) in the solution phase on the basis of plasmon controlled fluorescence. The experimental results demonstrated that the fluorescent emission of CdSe/CdS QD can be either obviously quenched or enhanced, depending on the spectral overlap and local distances control between CdSe/CdS QD and Au/Ag bimetallic NPs. Specifically, the as-synthesized Au/Ag NPs significantly quenched the fluorescent emission of CdSe/CdS QD and the quenching effect was enhanced when the plasmonic wavelength of Au/Ag NPs was tuned towards fluorescent emission wavelength of CdSe/CdS QDs. On the contrary, the fluorescent emission of CdSe/CdS QD can be obviously enhanced in the presence of SiO 2 coated Au/Ag NPs with appropriate layer thickness.

Photoluminescence modification of europium(iii)-doped MAl2O4 (M = Zn, Mg) spinels induced by Ag@SiO2 core–shell nanoparticles

“…In this type of structure, silver and gold nanoparticles are capped with a thin layer of SiO 2 , which acts as a separator and stabilizer of the nanoparticles. 19,24 At room temperature, the compounds used to study SEL or SHINEF include both organic and inorganic fluorophores, with quantum dots being the best known, [25][26][27] along with organometallic complexes. 28,29 Meanwhile, at low temperatures, an organic dye was employed for SEL studies.…”

Surface-enhanced luminescence of Cr3+-doped ZnAl2O4 and MgAl2O4 using Ag@SiO2 and Au@SiO2 core–shell nanoparticles

“…The latter can be studied by using techniques, such as surface-enhanced Raman scattering (SERS), surface-enhanced fluorescence (SEF), and metal-enhanced phosphorescence (MEP). [17][18][19][20][21][22] SEF has been widely studied for organic molecules and some inorganic luminophores, such as quantum dots, [23][24][25] whereas MEP has been studied using organic dyes 19,20 and organometallic complexes at room temperature. 21,22 In the previously mentioned studies luminescent compounds with excited-state lifetimes were used within the nanosecond time range.…”