Fig. 1. Schematic diagram of LSPR-regulated fluorescence mechanism based on the Jablonski energy level

Fig. 2. Comparison of simulated and experimental LSPR resonance peak positions of Au@SiO₂ core-shell structures. (a) Simulated extinction spectra of gold nanoparticles and Au@SiO₂ nanoparticles obtained by Lumerical FDTD Solutions software; (b) experimental extinction spectra of gold nanoparticles and Au@SiO₂ nanoparticles in colloidal solution

Fig. 3. Fabrication and characterization of the LSPR substrate based on electrostatic self-assembly of Au@SiO₂. (a) Schematic diagram of the fabrication process of the LSPR substrate based on electrostatic self-assembly of Au@SiO₂ and the fluorescent dye film on the substrate; (b) absorption spectra of the colloidal solution of 100 nm Au@SiO₂-9 nm and the LSPR substrate based on electrostatic self-assembly of 100 nm Au@SiO₂-9 nm; (c) scanning electron microscopy (SEM) image of the LSPR substrate based on electrostatic self-assembly of 100 nm Au@SiO₂-9 nm; (d) transmission electron microscopy (TEM) image of 100 nm Au@SiO₂-9 nm; (e) the diameter distribution of the gold core in Au@SiO₂ nanoparticles

Fig. 4. Matching between the absorption peaks of Au@SiO₂ NPs and the emission spectra of fluorescent materials. (a) Matching between the absorption peaks of Au@SiO₂ NPs and the emission spectrum of SABF₂ fluorescent material; (b) matching between the absorption peak of Au@SiO₂ NPs and the emission spectrum of 0F-2NHBoc fluorescent material

Fig. 5. Experimental analysis on LSPR-regulated fluorescence enhancement and changes in fluorescence lifetime. (a) Schematic diagram of the fluorescence signal testing apparatus on an LSPR substrate; (b) schematic diagram of LSPR-regulated fluorescence enhancement mechanism based on Jablonski energy level; (c) comparison of fluorescence signals of SABF₂ on glass substrate and LSPR substrates with different silica shell thicknesses of Au@SiO₂; (d) comparison of fluorescence signals of 0F-2NHBoc on glass substrate and LSPR substrates with different silica shell thicknesses of Au@SiO₂; (e) comparison of fluorescence upper-state lifetimes of SABF₂ on glass substrate and LSPR substrates with different silica shell thicknesses of Au@SiO₂; (f) comparison of fluorescence upper-state lifetimes of 0F-2NHBoc on glass substrate and LSPR substrates with different silica shell thicknesses of Au@SiO₂

Fig. 6. Experimental analysis on LSPR-regulated photobleaching inhibition. (a) Schematic diagram of LSPR-regulated photobleaching inhibition based on the Jablonski energy level; (b) comparison of photobleaching for SABF₂ on glass substrate and LSPR substrates with different silica shell thicknesses of Au@SiO₂ over 600 s; (c) comparison of photobleaching for SABF₂ on glass substrate and LSPR substrate with a 9 nm silica shell thickness of Au@SiO₂ over 1 h; (d) comparison of photobleaching for 0F-2NHBoc on glass substrate and LSPR substrates with different silica shell thicknesses of Au@SiO₂ over 600 s; (e) comparison of photobleaching for 0F-2NHBoc on glass substrate and LSPR substrate with a 9 nm silica shell thickness of Au@SiO₂ over 1 h

Fig. 7. LSPR-regulated fluorescence enhancement, upper-state lifetime shortening, and photobleaching suppression for SABF₂ (left) and 0F-2NHBoc (right)