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

Luminescence resonance energy transfer (LRET) system can be constructed using NaYF 4 :Tb 3+ luminescence nanocrystals and gold nanoparticles (AuNPs) served as energy donor and acceptor, respectively. The AuNPs modified by cetyltrimethylammonium bromide (CTAB) were synthesized first and NaYF 4 :Tb 3+ 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@NaYF 4 :Tb 3+ core–shell nanoparticles have spherical morphology with a size of 80–90   nm and the shell layers of NaYF 4 :Tb 3+ nanocrystals have pure cubic structure. The luminescence properties of Au@NaYF 4 :Tb 3+ core–shell nanoparticles are same as those of NaYF 4 :Tb 3+ 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 Tb 3+ ions. The LRET experiments have successfully verified the energy transfer between NaYF 4 :Tb 3+ nanocrystals and AuNPs. Additionally, the emission intensities of Tb 3+ ions and the content of AuNPs exhibited a fair linear correlation.