1064-nm laser fragmentation of thin Au and Ag flakes in acetone for highly productive pathway to stable metal nanoparticles

Abstract

The laser-induced fragmentation of thin Au and Ag flakes in acetone by 1064-nm nanosecond laser (with the fluence typically ∼2J/cm2) potentially offers a highly productive pathway to stable metal nanoparticles in liquid. Acetone serves as a superior liquid medium that keeps fine metal nanoparticles free from precipitation even in such concentrated nanoparticle solutions exceeding ∼0.1M. Thin metal flakes have good capability to absorb the 1064-nm laser energy as efficiently as in the visible region. A part of the thus laser-heated molten flakes explosively split into submicroparticles, and some other significant part directly into fine nanoparticles. Both kinds of product particles have minor absorption cross-sections for subsequent laser pulses at 1064nm, and thus no longer fragment further. One of the two kinds of Ag flakes studied in this work yielded fine Ag nanoparticles at a remarkable high production rate of 1.1mg/min for the input laser power of only ∼0.65W.