Enhancement and Quenching Regimes in Metal−Semiconductor Hybrid Optical Nanosources

Abstract

We report on the emission of hybrid nanosources composed of gold nanoparticles coupled with quantum dots. The emission relies on energy transfer from the quantum dots to gold nanoparticles which could be de-excited through radiative plasmon relaxation. The dependence of the emission efficiency is studied systematically as a function of the size of gold nanoparticles and interdistance between gold nanoparticles and quantum dots. We demonstrate a size-dependent transition between quenching and enhancement and a nonradiative energy transfer from the quantum dots to the gold nanoparticles.

Wavelength, Concentration, and Distance Dependence of Nonradiative Energy Transfer to a Plane of Gold Nanoparticles

“…By understanding the distance and concentration dependence of a particular MNP-fluorophore system, the optimum conditions for high sensitivity can be determined. The distance, wavelength and concentration dependences of the quenching process of molecular dyes and QDs by MNPs can be analysed using theories describing non-radiative energy transfer between dipoles within both FRET [13][14][15] and NSET formalisms. 4,5,10 For many applications semiconductor QDs offer advantages over the typically used molecular dyes, such as their narrow and tunable emission lines, higher photostability and high quantum yields.…”

Bilayer hybrid nanoimprinting method for fabricating embedded silver nanostructure arrays with enhanced photoluminescence

“…The given pattern sizes were chosen to minimize the nonradiative PL decay. 27 Bilayered resists were imprinted under increasing pressures up to ∼50 bar at 150°C for 20 min in a vacuum chamber, and then subsequently exposed to a UV lamp (energy intensity ∼35.5 mW∕cm 2 ) for 3 min while imprinted with the stamp. The quality of the pattern transferred to the underlying UV-curable resist was evaluated after mold release and removal of upper thermal resist layer.…”

“…Relevant previous studies have attempted to selectively infiltrate metal nanoparticles directly into nanopattern holes 23,24 or have used a template stripping method. [25][26][27][28] For example, the embedding of gold (Au) nanowires into an indium tin oxide anode layer was achieved by spin coating and surface energy-driven confinement of Au nanoparticles into the grating grooves. 23 In this case, strong coupling between the waveguide mode and the plasmon resonance nanowire in the transverse magnetic field mode could enhance direct-current conductivity and conferred unique optical behaviors.…”

Plasmonic Purcell factor and coupling efficiency to surface plasmons. Implications for addressing and controlling optical nanosources

“…Following SERS, metal enhanced fluorescence (MEF) leads to enhancement factor of the order of tens [45,46,47,48,49,50] with possible applications to nanotheranostics [51,52]. The fluorescence increase results from excitation field enhancement and emission rate modification (Purcell effect).…”