Synthesis and Spectroscopic Studies of Composite Gold Nanorods with a Double-Shell Structure Composed of Spacer and Cyanine Dye J-Aggregate Layers

Abstract

The composite gold nanorods (Au NRs) having a double-shell structure composed of Au NR (core), spacer layer (inner shell), and J-aggregate (JA) layer (outer shell) have been synthesized to examine the spectroscopic properties of the hybrid system in which the localized surface plasmon is coupled with the molecular exciton of JA. The spacer layer consisting of N,N,N-trimethyl(11-mercaptoundecyl)ammonium chloride plays a significant role in the formation of JA shell for several kinds of cyanine dyes. The absorption spectra of composite NRs are characterized by a distinct dip near the J-band when the plasmon energy of Au core is close to the exciton energy of JA shell, whereas a normal J-band peak appears when two energies are widely different from each other. The gradual change from the dip type to peak type absorption was observed when the plasmon energy was modulated by varying the aspect ratio of Au NR. Furthermore, composite NRs with thicker spacer layers have been fabricated by inserting the multilayer shell of polyelectrolytes between TMA and JA layers. They exhibited an alteration of the spectral line shape from the dip type to peak type with increase in the thickness of spacer layer. These observations have been interpreted in terms of the strength of the exciton-plasmon coupling, which is sensitive to the configuration of composite NRs as well as the relative difference between plasmon and exciton energies.

Plasmonic Fluorescent Nanocomposites of Cyanines Self-assembled upon Gold Nanoparticle Scaffolds

“…With 10 nm AuNPs-SA, the protein acts as a spacer layer protecting the fluorophores from quenching by AuNPs. 10,12,14,15 Hence, the LOD and LOQ values of 10 nm AuNPs-SA-nanocomposites were orders of magnitude smaller than 10 nm AuNPs-nanocomposites (Table 1). Our model (Fig.…”

“…3 During a literature review of chromophore assemblies on metal nanostructures, we found several papers reporting no fluorescent J-aggregates being formed or the fluorescence from such aggregates was quenched or photobleached. [4][5][6][7][8][9][10][11][12][13] Others reported a need for spacer layers in order to distance the aggregates from the noble nanometal surface for avoiding quench; 10,12,14,15 sometimes, even with a spacer layer no J-aggregation was observed with certain cyanines. 10 There were a few reports of J-aggregates on AgNPs 13,16,17 but not on AuNPs.…”

Coherent Plasmon-Exciton Coupling in Silver Platelet-J-aggregate Nanocomposites

“…These hybrid systems often consist of a core-shell geometry in which the localized surface plasmon resonance (LSPR) of the metallic core couples with the exciton resonance exhibited by a J-aggregate dye or a quantum dot shell. [1][2][3][4][5][6][7][8][9][10] This architecture provides a means of studying plasmon-exciton interactions, which have resulted in unique optical phenomena such as induced transparency. 1,2,[5][6][11][12] The ability to control the morphology and dimensions of the individual layers at the nanoscale, and the subsequent control of optical properties, are ultimately what drive this field of research.…”

Kinetics and mechanism of sodium (Z)-3-(5-chloro-2-((5-chloro-3-(3-sulfonatopropyl) benzothiazol-2(3H)-ylidene)methyl)benzo-thiazol-3-ium-3-yl)propane-1-sulfonate adsorption on gold nanoparticle colloids of different properties and size

“…Hibridne nanočestice koje se sastoje od jezgra plementog metala funkcionalizovanog omotačem koga čini organska boja su poznate zbog svojih neobičnih optičkih svojstava, uključujući ultrabrze indukovane transparencije, nelinearno ponašanje, Fano rezonancije sa asimetričnim oblikom linije rasejanja i pojačano fotoindukovano razdvajanje naelektrisanja [1,[10][11][12][13][14][15]. Pošto su cijanske boje jako fluorescentne [16], merenje fluorescentnih svojstava agregata čestica-boja može dati važan uvid za razumevanje molekulskih interakcija i reaktivnosti u ovakvim sistemima.…”

“…Pored toga, Sato i saradnici [10] su ispitivali elektrostatičku interakciju između negativno naelektrisane površine srebra i negativno naelektrisane slične tiocijanske boje koja ima parcijalno pozitivno naelektrisanje na hromofori. Hibridne nanočestice koje se sastoje od jezgra plementog metala funkcionalizovanog omotačem koga čini organska boja su poznate zbog svojih neobičnih optičkih svojstava, uključujući ultrabrze indukovane transparencije, nelinearno ponašanje, Fano rezonancije (vrsta fenomena rezonantnog rasejanja pri čemu se dobija asimetričan oblik linije rasejanja) i pojačano fotoindukovano razdvajanje naelektrisanja [1,[10][11][12][13][14][15]. Razjašnjavanje mehanizma i kinetike interakcije negativno naelektrisane površine nanočestice zlata sa negativno naelektrisanom tiocijanskom bojom daje bolji uvid za potencijalnu upotrebu ovih hibridnih struktura u budućnosti za dizajniranje sistema za konvertovanje svetlosne energije, primenu u molekulskoj optoelektronici i kod senzornih uređaja, u katalizi, prenosu lekova, nanoelektronici i medicinskoj dijagnostici.…”