Golden Plasmophores with Tunable Photoluminescence and Outstanding Thermal and Photothermal Stability

Among various hybrid nanomaterials, the combination of plasmonic nanoparticles and fluorophores in a single multifunctional nanoplatform, so-called plasmophores, has attracted significant attention in different fields such as dark field, fluorescence, and photoacoustic imaging, biosensing, photothermal, and photodynamic therapy. Herein, author report a facile and controlled synthesis route of hybrid nanoplatforms composed of fluorescent gold nanoclusters (GNCs) coupled to plasmonic gold nanorods (GNRs) using controlled silica (SiO2) dielectric spacers of different thicknesses from now on referred to as GNR@SiO2@GNC plasmophores. The results show different degrees of plasmon-enhanced fluorescence of the GNCs in their plasmophore hybrid system when placed at different distances from the plasmonic cores of the GNRs. On the other hand, these plasmophores show enhanced thermal stability compared to GNRs@CTAB (CTAB, cetyl trimethyl ammonium bromide). This results also demonstrated that upon annealing at elevated temperatures (800-1000 degrees C), the GNRs in the plasmophores are more thermally stable and robust than the GNRs@CTAB. More surprisingly, despite the commonly reported very low melting temperature of smaller-size nanocrystals, the GNCs in the plasmophores showed high thermal stability and do not exhibit significant structural changes at elevated temperatures (800-1000 degrees C). This study presents a controlled synthesis of GNRs@SiO2@GNCs plasmophores, where fluorescent gold nanoclusters are coupled to plasmonic gold nanorods through silica spacers. Silica thickness control enables precise positioning of GNCs relative to GNR plasmonic cores, resulting in varying plasmon-enhanced fluorescence. The system's enhanced thermal stability and apparent photothermal stability make it promising for diverse applications, including multiplexed imaging and photothermal therapy. image