Impact of Copper and Silicon Targets on Chemical Reaction Pathways during Pulsed Laser Ablation in Acetone

Pulsed laser ablation in liquid (PLAL) is often performed in organic solvents to prevent oxidation of metal nanoparticles (NPs). Due to the formation of reactive radical species from the decomposition of solvent molecules during ablation, carbon shells can be deposited on the metal NPs, and stable byproducts can be formed. In this work, we investigate how copper and silicon targets impact the distribution of reaction products obtained from the ablation of acetone with 4 ps laser pulses. Whereas ablation of copper produced Cu NPs with amorphous carbon containing various functional groups adsorbed to their surfaces, ablation of silicon produced Si NPs with less carbon on their surfaces and fluorescent carbon dot byproducts in solution. Compared with ablation in acetone alone, the presence of a copper or silicon target reduces the yield of molecular byproducts from the recombination of acetone radicals. Additionally, ablated copper species were found to catalyze the formation of pinacol as a byproduct. These results, demonstrating that different target materials can change the chemical reaction pathways during laser ablation in organic solvents, can inform the design of reaction conditions to produce NPs by PLAL in organic liquids with desired properties for various applications.