Polarization-driven self-organization of silver nanoparticles in 1D and 2D subwavelength gratings for plasmonic photocatalysis

Abstract

One of the main challenges in plasmonics is to conceive large-scale, low-cost techniques suitable for the fabrication of metal nanoparticle patterns showing precise spatial organization. Here, we introduce a simple method based on continuous-wave laser illumination to induce the self-organization of silver nanoparticles within high-index thin films. We show that highly regular and homogeneous nanoparticle gratings can be produced on large areas using laser-controlled self-organization processes. This very versatile technique can provide 1D and 2D patterns at a subwavelength scale with tunable features. It does not need any stabilization or expensive devices, such as those required by optical or electron lithography, and is rapid to implement. Accurate in-plane and in-depth characterizations provide valuable information to explain the mechanisms that lead to pattern formation and especially how 2D self-organization can fall into place with successive laser scans. The regular and homogeneous 2D self-organization of metallic NPs with a single laser scan is also reported for the first time in this article. As the reported nanostructures are embedded in porous TiO, we also theoretically explore the interesting potential of organization on the photocatalytic activity of Ag-NP-containing TiO porous films, which is one of the most promising materials for self-cleaning or remediation applications. Realistic electromagnetic simulations demonstrate that the periodic organization of silver nanoparticles can increase the light intensity within the film more than ten times that produced with randomly distributed nanoparticles, leading as expected to enhanced photocatalytic efficiency.

Triangular laser-induced submicron textures for functionalising stainless steel surfaces

“…Hexagonal self-organisation of nanoparticles was observed by irradiating TiO2 thin films and silver nanoparticles with green CW circularly polarised light [39]. It is suggested that the mesoporous characteristic of TiO2 facilitates the movement of nanoparticles.…”

Three-Dimensional Self-Organization in Nanocomposite Layered Systems by Ultrafast Laser Pulses

“…The mesoporous titania film is elaborated by a sol-gel process. The sol contains titanium tetraisopropoxide (TTIP, Aldrich; 97%), acetylacetone (AcAc, Aldrich; 99%), hydrochloric acid (HCl, Roth; 37%), ethanol (EtOH, Carlo Erba; absolute), Pluronic P123 ((PEO) 20 (PPO) 70 (PEO) 20 , Aldrich; MW: 5000) and de-ionized water (H 2 O) with the following molar ratios: TTIP/P123/ethanol/HCl/H 2 O/AcAc = 1:0.025:28.5:0.015:29.97:0.5. Pluronic P123 is a symmetric triblock copolymer constituted of poly(ethylene oxide)(PEO) and poly (propylene oxide) (PPO).…”

Picosecond laser writing of Ag−SiO2 nanocomposite nanogratings for optical filtering

“…To solve this issue, a well-optimized laser treatment is particularly promising, namely because of the control possibilities that lasers can provide. In fact, lasers are known to be a powerful surface structuring tool [9] that can also be used for growing and tailoring the properties of nano-objects [10,11], and, particularly, for nanoparticle formation in solid matrices [12].…”

“…In this case, additional possibilities related with nanoparticle presence [13,14] and with laser beam focusing in the in bulk were explored [15]. The photocontrolled organization of metallic NPs in T iO 2 and SiO 2 films was also demonstrated [12]. Additionally, self-organized nanostructures were shown to be formed by scanning CW laser irradiation [16] and even femtosecond laser pulses [17].…”