Thermal diffusivity of neutral red dye using dual beam thermal lens technique: A comparison on the effects using nano pulsed laser ablated silver and gold nanoparticles

Abstract

Silver and gold nanoparticles were prepared in polymeric solution of polyvinylpyrrolidone in ethanol by laser ablation and studied its effects on the optical and thermal properties of neutral red dye. Optical absorption spectra and the transmission electron microscopy images of the prepared samples have confirmed that the nanoparticles are spherical in shape. The average particle size obtained for silver nanoparticles is 19 nm and that for gold is 9 nm. The fluorescence intensity of the dye molecule is found to decrease with the addition of metal nanoparticles which can be attributed to the scattering of light by nanoparticles. Dual beam thermal lens technique is employed to measure the thermal diffusivity of the dye – nanoparticle mixture. Thermal diffusivity of the mixture is found to decrease as the volume percentage of nanoparticle increases. The reduction is more for dye – gold nanoparticle mixture compared to dye – silver nanoparticle, and is explained on the basis of high interfacial thermal resistance of lighter particles.