Spectroscopic properties of triangular silver nanoplates immobilized on polyelectrolyte multilayer-modified glass substrates

Abstract

Fabrication of surface-immobilized silver nanostructures with reproducible plasmonic properties by dip-coating technique is difficult due to shape alteration. To address this challenge, we used a polyelectrolyte multilayer to promote immobilization of as-received triangular silver nanoplates (TSNP) on a glass substrate through electrostatic interaction. The substrate-immobilized TSNP were characterized by absorption spectrophotometry and scanning electron microscopy. The bandwidth and peak position of localized surface plasmon resonance (LSPR) bands can be tuned by simply varying the concentration of the colloidal solution and immersion time. TSNP immobilized from a higher concentration of colloidal solution with longer immersion time produced broadened LSPR bands in the near-IR region, while a lower concentration with shorter immersion time produced narrower bands in the visible region. The shape of the nanoplates was retained even at long immersion time. Analysis of peak positions and bandwidths also revealed the point at which the main species of the immobilization had been changed from isolates to aggregates.

Electrostatic Deposition Kinetics of Colloidal Silver Nanoplates onto Optically and E-Beam Transparent Water-Insoluble Polycationic Films

“…Figure A shows that electrostatically deposited Ag NPls on TAG copolymer film demonstrate a characteristic in-plane LSPR peak around λ ≈ 620 nm, shifting to the red with the deposition time. The out-of-plane quadrupolar LSPR peak in the deposited Ag NPls almost disappears as compared to NPLs in colloidal solution (Figure S1) due to the preferential planar orientation of Ag NPls on the copolymer film (perpendicular to the randomly polarized incident light beam). ,, The corresponding TEM images in Figure B also confirm the preferential planar orientation of Ag NPls.…”

“…We set C S = 300 pmol/m 2 as an upper limit for the correct determination of the Ag NPls concentration by the optical method. The deviation from the linear C S –OD behavior above OD ≈ 0.4 is caused by reabsorption and collective plasmonic effects in the ensembles of close-packed and stacked Ag NPls (Figure B), which manifests as broadening of the LSPR peak in UV–vis spectra. − The value of the molar extinction coefficient for colloidal MUA-capped Ag NPls is 1.1 × 10 10 M –1 cm –1 . Using this value, we calculated volume concentrations C V by the Bouguer–Lambert–Beer law: C V = OD/(ε l ).…”

“…Such substrates can be prepared by various techniques. The widely used silanization technique is limited by bulk silicon, glass, and metal oxide substrates while suffering from low reproducibility. − Another popular method, the layer-by-layer (LbL) technique, uses deposition of particles onto polycationic polymers containing various amino groups: poly- l -lysine, , poly­(2-vinylpyridine), polyallylamine, − polyethylenimine, poly-[2-(methacryloyloxy)­ethyl] trimethylammonium chloride, poly­( N , N -(dimethylamino ethyl) methacrylate), poly­(diallyldimethylammonium chloride), polyacrylonitrile, chitosan, and amine-modified polyethylene terephthalate . Soaking flexible substrates (fabric, paper) with quaternary ammonium salts can also provide the electrostatic deposition of Ag NPls .…”

Employing cold atmospheric plasma (Ar, He) on Ag thin film and their influences on surface morphology and anti-bacterial activity of silver films for water treatment

“…Silver thin films have been employed for surface plasmon resonance (SPR) which has many usages especially in biology, medical sciences and environment. Some nano particles such as Ag, Cu and ZnO have attracted much interest due to their unique optical and antibacterial properties [2,3]. Nowadays, humans are looking for low cost and high efficiency methods for treating wastewater and sweetening water especially due to lack of safe and pure drinking water, Ag with anti-bacterial activity can be very helpful [3,4].…”

“…Some nano particles such as Ag, Cu and ZnO have attracted much interest due to their unique optical and antibacterial properties [2,3]. Nowadays, humans are looking for low cost and high efficiency methods for treating wastewater and sweetening water especially due to lack of safe and pure drinking water, Ag with anti-bacterial activity can be very helpful [3,4]. Microorganisms are part of the organic materials which are commonly present in the wastewater, which can affect human life.…”