Size-Dependent Energy Transfer between CdSe/ZnS Quantum Dots and Gold Nanoparticles

This Letter deals with the effect of the particle size on the energy transfer from CdSe/ZnS quantum dots to the proximal gold nanoparticles with different sizes. The 3 nm sized gold nanoparticles have negligible localized surface plasmon resonance (LSPR) absorption and quench the fluorescence emission of the quantum dots with a 1/d⁴ distance-dependence, indicating the nanometal surface energy transfer (NSET) mechanism. The 15 and 80 nm sized gold nanoparticles have strong LSPR absorption bands that overlap with the emission band of the quantum dots. The energy transfer efficiency depends on the 1/d⁶ separation distance, which is dominated by the dipole–dipole interaction according to Förster resonance energy transfer (FRET). The 80 nm sized gold nanoparticle displays higher quenching efficiency due to the increased spectral overlap of the LSPR band with the emission band of quantum dots.