Plasmon-enhanced fluorescence in gold nanorod-quantum dot coupled systems

Abstract

Plasmon-exciton coupling is of great importance to many optical devices and applications. One of the coupling manifestations is plasmon-enhanced fluorescence. Although this effect is demonstrated in numerous experimental and theoretical works, there are different particle shapes for which this effect is not fully investigated. In this work electrostatic complexes of gold nanorods and CdSe/CdZnS quantum dots were studied. Double-resonant gold nanorods have an advantage of the simultaneous enhancement of the absorption and emission when the plasmon bands match the excitation and fluorescence wavelengths of an emitter. A relationship between the concentration of quantum dots in the complexes and the enhancement factor was established. It was demonstrated that the enhancement factor is inversely proportional to the concentration of quantum dots. The maximal fluorescence enhancement by 10.8 times was observed in the complex with the smallest relative concentration of 2.5 quantum dots per rod and approximately 5 nm distance between them. Moreover, the influence of quantum dot location on the gold nanorod surface plays an important role. Theoretical study and experimental data indicate that only the position near the nanorod ends provides the enhancement. At the same time, the localization of quantum dots on the sides of the nanorods leads to the fluorescence quenching.

Light‐Induced Solid‐State Protrusion of Gold Nanowires and Their Derivatives for Sensing Applications

“…Comparison of the PL spectra indicates that an enhancement factor of ≈36 was achieved with the AuNRs (Figure 3e). This enhancement factor is approximately three times higher than Au nanorods [39] and six times higher than Ag microrings. [40] Fluorescence-lifetime spectra of the QDs show a decay time of 3.6 ns on the AuNRs, which is three times faster than that without AuNRs (Figure 3f).…”

Study on Surface Enhanced Raman Scattering of Au and Au@Al2O3 Spherical Dimers Based on 3D Finite Element Method

“…Therefore, it is quite meaningful to wrap Al 2 O 3 material on the Au core shell. At the same distance, there is a certain difference in the Raman enhancement factor under different excitation wavelengths, but it is basically in an order of magnitude, which also shows that the Au dimer has a wider excitation spectrum under different distance, making its application scope wider 27 . Figure 6 shows that the in uence of excitation wavelength on the nal Raman enhancement factor of the nal model with the increase of the thickness of Al 2 O 3 , however the in uence of excitation wavelength on the nal Raman enhancement factor of Au dimer increases with the increase of distance.…”

Strong increase in the effective two-photon absorption cross-section of excitons in quantum dots due to the nonlinear interaction with localized plasmons in gold nanorods

“…Alternatively, this may be a result of the enhanced absorption. 11 Regarding TPE PL, several studies have previously shown its strong enhancement in fluorescent organic dyes placed at the very short distances from metal nanostructures. [12][13][14][15][16][17] However, in these studies, the spectral conditions of the resonance between the plasmon modes and the fluorescence and absorption bands of the molecules were not specified, which made it difficult to correctly interpret the results.…”