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

In this article, Au nanoparticles inpolyvinylpyrrolidone (PVP) solution were prepared bygamma radiation at different concentrations. The solutionswere irradiated at doses of 50 kGy for making differentsizes. The average sizes of particle in the prepared sampleswere measured using the nanophox machine. A dual-beammode-mismatched thermal lens (TL) method was used toinvestigate the effect of thermal diffusivity of samples. TheTL measurement was carried out using a green diode laser(wavelength 532 nm, 60 mW) and a He–Ne laser (wavelength632.8 nm, 0.5 mW) for excitation source and probebeam, respectively. The results showed that the thermaldiffusivity of samples enhances with the growth of particlesize and density of solutions. This increment can beattributed to phonon scattering at interface of particles–liquid and contact between the nanoparticles and surroundedliquid.