Luminescence transformation mechanisms of indocyanine green dye in the presence of gold nanorods

Spectral-luminescent manifestations of the plasmon-exciton interaction between gold nanorods (Au NRs) with average length and diameter of 35 $\pm$ 5 nm and 9 $\pm$ 2 nm, passivated by molecules of cetyltrimethylammonium bromide (CTAB) and the indocyanine green dye (ICG) molecules are found. Extinguishing of the ICG luminescence near Au NRs and its buildup are detected at spacial separation of hybrid nanosystem components achieved by a spherical shell of SiO$_2$ with an average thickness of 26 $\pm$ 5 nm formed on the Au NRs. The amplification of the luminescence with growth of the dielectric shell is provided due to blocking of steric transformations of ICG polymethine chain when the interaction emerges between the dye and the silicious shell, and the Purcell effect.