Light-induced in situ active tuning of the LSPR of gold nanorods over 90  nm

Abstract

We demonstrate an easy and controllable method for light-induced active tuning of the longitudinal surface plasmon resonance (LSPR) of gold nanorods (AuNRs) over ∼ 94 n m . The red-shift of the LSPR can be controlled by varying the time of exposure to a 532 nm laser. The tuning is achieved by photo-induced dissolution of individual AuNRs by sodium dodecyl sulfate (SDS) under continuous illumination. The dissolution of the AuNRs increases the aspect ratio, and consequently the LSPR exhibits a gradual but large redshift. A key feature is that it is possible to selectively tune the LSPR of a specific AuNR in a group while leaving the others totally unaffected. Such controllable, light-induced, post-synthesis fine-tuning of the LSPR is useful for tailoring the plasmonic response of individual AuNRs for a wide range of applications.

d-Band Holes React at the Tips of Gold Nanorods

“…While a redshift in the absence of plasmon excitation is consistent with our previous work as well as studies by others, 37,48,51,52 some reports found blueshifts in the absence of plasmon excitation, assigned to potentially lower ligand coverage at the tips. 35,41,53−55 Here, we immobilized nanorods on a substrate, and plasma cleaned them before dissolution experiments were performed.…”

“…While a redshift in the absence of plasmon excitation is consistent with our previous work as well as studies by others, ,,, some reports found blueshifts in the absence of plasmon excitation, assigned to potentially lower ligand coverage at the tips. ,,− Here, we immobilized nanorods on a substrate, and plasma cleaned them before dissolution experiments were performed. Studies in which nanoparticles were also plasma or ozone cleaned all reported redshifts too, while studies that reported blueshifts did not attempt to remove the ligands (see summary in Table S1).…”

“…Studies in which nanoparticles were also plasma or ozone cleaned all reported redshifts too, while studies that reported blueshifts did not attempt to remove the ligands (see summary in Table S1). ,,,,− Since clear evidence has been presented that an oxygen plasma is effective in removing organic ligands, , it is likely that our plasma cleaning removed at least enough ligands from the nanorods to disrupt the surrounding surfactant bilayer and to hence allow chloride ion access to all parts of the nanorods. Finally, our observed dissolution anisotropy under illumination cannot be a result of nonuniform ligand coverage, because otherwise nanorods would also dissolve more from the tips in the dark.…”

Mild and Rapid Light‐Driven Suzuki‐Miyaura Reactions Catalyzed by AuPd Nanoparticles in Water at Room Temperature

“…The optical properties of gold nanoparticles are well known. [ 33 , 34 , 35 ] In order to investigate these properties, the as‐prepared nanoparticles were studied by UV‐Vis absorption spectroscopy (Figure 1 c). The gold nanoparticles show maximum absorption at 524 nm assigned as the localized surface plasmon resonance (LSPR).…”

“…The optical properties of gold nanoparticles are well known [33–35] . In order to investigate these properties, the as‐prepared nanoparticles were studied by UV‐Vis absorption spectroscopy (Figure 1c).…”