Figure 9.

Single-molecule fluorescence enhancements of crystal violet (quantum-yield 2%) by a single gold nanorod. (a) Numerical calculation of the enhanced intensity around a single gold nanorod excited on resonance with its longitudinal plasmon. (b) Time trace of dye fluorescence with (green) and without (red) the presence of a gold nanorod. The nanorod is immobilized on a substrate while crystal violet diffuses freely in solution, causing spikes in intensity when it enters the particle's near-field. (c) Measured fluorescence enhancements for several individual gold nanorods, each with a different plasmon wavelength. The blue squares indicate an excitation wavelength of 594 nm, the red squares 633 nm. The open circles and dashed lines indicate the numerically calculated enhancement. Figure adapted with permission from ref (124). Copyright 2014 American Chemical Society.