Tuning of Ag-SPR band position in refractive index controlled inorganic-organic hybrid SiO2-PEO-TiO2 films

Abstract

Inorganic (silica-titania)-organic (polyethylene oxide) hybrid films with variable refractive index (RI) values were synthesized and Ag nanoparticles were generated in situ inside such hybrid films to develop coloured coatings specially on plastic substrates. The hybrid films and the corresponding Agincorporated films were prepared from sols derived from a mixture of silicon tetraethoxide (STE), 3-(glycidoxypropyl)trimethoxysilane (GPTMS), titanium tetraisopropoxide (TTIP) and silver nitrate following a sol-gel dip-coating method and cured at low temperature (90°C), followed by UV treatment with an energy equivalent to 5⋅3 ± 0⋅1 J cm -2 . The equivalent SiO 2 : SiO 1⋅5 (CH 2 ) 3 OCH 2 CH(CH 2 )O : TiO 2 : Ag molar ratios (nominal) of the final cured films are varied in the ranges (67⋅9-0) : 29⋅1 : (0-67⋅9) : 3. The refractive index values of the cured hybrid films were found to be increased systematically from 1⋅475 to 1⋅710 with increasing Ti-component. The Ag-SPR peak, in case of silica-polyethylene oxide host (RI = 1⋅475), observed at 419 nm, gradually red-shifted to 497 nm upon increasing the Ticomponent (equivalent TiO 2 content 67⋅9 mol%; RI = 1⋅710) of the film. As a consequence, a systematic change of Ag-SPR position yielded yellow, yellowish-orange, orange, brownish-orange and orangishbrown coloured coatings.

Protection and functionalisation of silver as an optical sensing platform for highly sensitive SPR based analysis

“…Much research has been aimed at exploiting the properties of silver to establish sensitive SPR detection platforms. [10][11][12] The use of silver films for biosensor applications is limited by three main problems: their poor adhesion to plastic substrates, their chemical instability in the air and in aqueous environments, which in turn presents the difficulty in using conventional liquid phase functionalization methods, as used for gold. 13 Hence, despite its high cost, gold is the primarily used metal for SPR based sensor applications owing to its good adhesion, chemical stability and ease of functionalisation.…”

“…Many research works have been carried out to address the problems of lack of chemical stability of silver and its functionalisation. 11,12,14 The protection of silver layer by various oxide coatings and amorphous carbon coatings has been reported. These methods require separate functionalization strategies.…”

Spontaneous generation and shape conversion of silver nanoparticles in alumina sol, and shaped silver nanoparticle incorporated alumina films

“…For many real applications e.g. nonlinear optics, 23 plasmon tuning to get different colour-coatings, 24,25 optical sensors based on plasmon shifting 26 etc. the NPs need to be embedded in a suitable film matrices.…”

Surface/Interface Synergetic Effect-Induced Great Optical Spectral Change with Ag Content for Ag Nanoparticles Dispersed in Mesoporous SiO₂

“…In studying or applying the SPR optical properties of Ag nanoparticles, SiO 2 is usually used as matrix or support of Ag nanoparticles because it is one of important integrated optical materials with optical transparency in UV optical region. Generally, SiO 2 is regarded as chemical inert substrate or matrix to some noble metals.Many influential factors on the SPR optical property had been investigated for Ag nanoparticles assembled in mesoporous SiO 2 [5][6][7][8][9]. Thereinto, the change in the size of Ag nanoparticles or Ag content usually just induces a slight change of the SPR peak position or the peak width or the…”

“…Many influential factors on the SPR optical property had been investigated for Ag nanoparticles assembled in mesoporous SiO 2 [5][6][7][8][9]. Thereinto, the change in the size of Ag nanoparticles or Ag content usually just induces a slight change of the SPR peak position or the peak width or the…”