An experimental study of thermal diffusivity of Au nanoparticles: effects of concentration particle size

Abstract

In this article, Au nanoparticles in polyvinylpyrrolidone (PVP) solution were prepared by gamma radiation at different concentrations. The solutions were irradiated at doses of 50 kGy for making different sizes. The average sizes of particle in the prepared samples were measured using the nanophox machine. A dual-beam mode-mismatched thermal lens (TL) method was used to investigate the effect of thermal diffusivity of samples. The TL measurement was carried out using a green diode laser (wavelength 532 nm, 60 mW) and a He-Ne laser (wavelength 632.8 nm, 0.5 mW) for excitation source and probe beam, respectively. The results showed that the thermal diffusivity of samples enhances with the growth of particle size and density of solutions. This increment can be attributed to phonon scattering at interface of particlesliquid and contact between the nanoparticles and surrounded liquid.

Using Femtosecond Laser Pulses to Explore the Nonlinear Optical Properties of Au NP Colloids That Were Synthesized by Laser Ablation

“…Generally, the thermal effect in the samples increased when the time interval between the laser pulses was shorter than the thermal diffusion time of the sample, i.e., when , where is the beam diameter and is the thermal diffusion coefficient (where is the thermal conductivity, is the specific heat capacity, and is the density of the Au NPs). The selected femtosecond laser had a time of about 12.5 ns between the laser pulses, which was much shorter than the thermal diffusion time of the Au NPs [ 45 , 46 ]. This meant that the samples were not able to return to their equilibrium state within the time between the laser pulses.…”

Synthesis and characterization of BiVO4 nanoparticles for environmental applications

“…To overcome this critical issue, nanomaterials have been considered as a suitable candidate in this eld owing to their unique physical and chemical properties such as increased surface to volume ratio, high diffusivity, and excellent reactivity. 4,5 In particular, metal oxide nanoparticles (NPs) are identied as ideal candidates for degrading organic pollutants in contaminated water and effective destruction of pathogens. 6,7 Among the wide range of metal oxide NPs, titanium dioxide (TiO 2 ) is widely investigated in the elds of photocatalysis and antibacterial activity as the result of its remarkable physiochemical properties inclusive of stability and super nontoxicity.…”

Initial dynamic thermal dissipation modes enhance heat dissipation in gold nanoparticle–polydimethylsiloxane thin films

“…Shahariari et al showed that thermal diffusivity of a material increased with concentration from greater electron-phonon relaxation and subsequent phonon scattering at the nanoparticle media interface. Larger thermal diffusivities allow for increased thermal propagation, thus implying faster changes from the dynamic driving force to the steady-state driving force [31]. Additionally, Howard et al demonstrated a plateau of thermal energy transfer from AuNPs, which allows for lower concentration AuNP-PDMS films to have a greater change in slope at a smaller concentration than for larger AuNP concentrations, matching measured results [20].…”