Au/SiO2/QD core/shell/shell nanostructures with plasmonic-enhanced photoluminescence

作者：Yang Ping; Kawasaki Kazunori; Ando Masanori; Murase Norio^*

来源：Journal of Nanoparticle Research, 2012, 14(9): 1025.

DOI：10.1007/s11051-012-1025-z

• Quantum dot
• Au
• Nanoparticle
• Plasmon
• Photoluminescence
• Enhancement
• Sol-gel method

A sol-gel method has been developed to fabricate Au/SiO2/quantum dot (QD) core-shell-shell nanostructures with plasmonic-enhanced photoluminescence (PL). Au nanoparticle (NP) was homogeneously coated with a SiO2 shell with adjusted thickness through a Stober synthesis. When the toluene solution of hydrophobic CdSe/ZnS QDs was mixed with partially hydrolyzed 3-aminopropyltri-methoxysilane (APS) sol, the ligands on the QDs were replaced by a thin functional SiO2 layer because the amino group in partially hydrolyzed APS has strong binding interaction with the QDs. Partially hydrolyzed APS plays an important role as a thin functional layer for the transfers of QDs to water phase and the subsequent connection to aqueous SiO2-coated Au NPs. Although Au NPs were demonstrated as efficient PL quenchers when the SiO2 shell on the Au NPs is thin (less than 5 nm), we found that precise control of the spacing between the Au NP core and the QD shell resulted in QDs with an enhancement of 30 % of PL efficiency. The Au/SiO2/QD core/shell/shell nanostructures also reveal strong surface plasmon scattering, which makes the Au/SiO/QD core-shell-shell nanostructures an excellent dual-modality imaging probe. This technology can serve as a general route for encapsulating a variety of discrete nanomaterials because monodispersed nanostructures often have a similar surface chemistry.

• 出版日期2012-9