Au@NaYF4:Tb3+ core@shell nanostructures: Synthesis and construction of luminescence resonance energy transfer

Luminescence resonance energy transfer (LRET) system can be constructed using NaYF4:Tb3+ luminescence nanocrystals and gold nanoparticles (AuNPs) served as energy donor and acceptor, respectively. The AuNPs modified by cetyltrimethylammonium bromide (CTAB) were synthesized first and NaYF4:Tb3+ shells encapsulated Au cores via a hydrothermal method. The synthesized materials were well characterized by X-ray diffraction (XRD), Fourier-transform infrared spectra (FT-IR), Transmission electron microscopy (TEM), X-ray photoelectron spectrum (XPS), UV-vis absorption spectra (UV-vis) and photoluminescence (PL) measurement. The results indicate that the synthesized Au@NaYF4:Tb3+ core-shell nanoparticles have spherical morphology with a size of 80-90 nm and the shell layers of NaYF4:Tb3+ nanocrystals have pure cubic structure. The luminescence properties of Au@NaYF4:Tb3+ core-shell nanoparticles are same as those of NaYF4:Tb3+ particles. The LRET process was realized using the core-shell nanoarchitectures due to the absorption spectrum of AuNPs matches well with the major emission peaks of Tb3+ ions. The LRET experiments have successfully verified the energy transfer between NaYF4:Tb3+ nanocrystals and AuNPs. Additionally, the emission intensities of Tb3+ ions and the content of AuNPs exhibited a fair linear correlation.