Photo-thermal study of a layer of randomly distributed gold nanoparticles: from nano-localization to macro-scale effects

Abstract

We present an experimental characterization and a comprehensive theoretical modeling of macroscopic plasmonic heat production that takes place in a single layer of small gold nanoparticles (GNPs), randomly distributed on a glass substrate, covered with different host media and acted on by a resonant radiation. We have performed a detailed experimental study of the temperature variations of three different systems, obtained by varying the density of nanoparticles. Due to the macroscopic dimension of the spot size, the used laser irradiates a huge number of nanoparticles, inducing a broad thermo-plasmonic effect that modifies the thermal conductivity of the entire system; starting from the state of art, we have implemented a simple model that enables to evaluate the resulting new thermal conductivity. We have also extended our theoretical approach to the macroscale, including an analysis of the effects predicted for different NP densities and laser spot size values, as well as for different values of the laser intensity, which can be as low as 0.05 W cm −2 . Theoretically predicted temperature variations are in excellent agreement with experimental results.

Antimicrobial Effects of Chemically Functionalized and/or Photo-Heated Nanoparticles

“…Indeed, by starting from the value of σabs at a particular working wavelength, it is possible to calculate the localized temperature around the MNP (see Figure 2 and Equation (4)). By changing size, metal, structure and surrounding medium (dielectric permittivity εm and thermal conductivity km) it is possible to change the temperature around MNPs [56,59].…”

“…It is important to take into account that the effective temperature depends on the number of MNPs acted on by the electromagnetic wave, because each MNP contributes to the heating process through a heat transfer to the surrounding medium. Therefore the temperature will depend on the arrangement (in a line, a surface or a bulk) and on the MNP density [59].…”

Photoinduced Temperature Gradients in Sub‐Wavelength Plasmonic Structures: The Thermoplasmonics of Nanocones

“…Furthermore, the electromagnetic and thermal response of the whole device can be strongly dependent on the collective effects of neighboring particles as demonstrated in previous reports. [62][63][64] Indeed, determining the photothermal response of an array of nanocones is not trivial [18] and requires a dedicated study as an important intermediate step toward applications employing a great number of nanocones. Regarding the potential application areas, it can be envisioned the possibility of nanoscale delivery of heat to small bodies like molecules or cells, to thermally induce the nanosynthesis of materials or to locally activate nanofabrication processes, to enhance optical nanotweezers owing to the presence of high degree of temperature gradient [21] also in conjunction with nanofluidics control, [7,65] or even for thermoelectric power generating devices.…”

Sunlight-Driven Photothermal Effect of Composite Eggshell Membrane Coated with Graphene Oxide and Gold Nanoparticles

“…Palermo et al investigated the LSPR induced heat generation from a monolayer one-dimensional (1D) grating of AuNPs prepared by photo-reduction in a poly (vinyl alcohol) (PVA) matrix doped with HAuCl 4 onto a glass substrate, under resonant laser radiation [9]. Comprehensive theoretical modeling was developed to study the plasmonic heat production from a single layer of randomly distributed AuNPs and compared with the experimental results [10]. The influencing factors of the photothermal conversion of AuNPs solutions, including nanoparticle size, the exciting laser intensity, and the presence of guest dye molecules, were also investigated [11].…”