A hierarchical view on material formation during pulsed-laser synthesis of nanoparticles in liquid.

Shyjumon Ibrahimkutty,Tomy Dos Santos Rolo,Dmitry Karpov,Tilo Baumbach,Andreas Menzel,Philipp Wagener,Anton Plech,Stephan Barcikowski

doi:10.1038/srep16313

Abstract

Pulsed-laser assisted nanoparticle synthesis in liquids (PLAL) is a versatile tool for nanoparticle synthesis. However, fundamental aspects of structure formation during PLAL are presently poorly understood. We analyse the spatio-temporal kinetics during PLAL by means of fast X-ray radiography (XR) and scanning small-angle X-ray scattering (SAXS), which permits us to probe the process on length scales from nanometers to millimeters with microsecond temporal resolution. We find that the global structural evolution, such as the dynamics of the vapor bubble can be correlated to the locus and evolution of silver nanoparticles. The bubble plays an important role in particle formation, as it confines the primary particles and redeposits them to the substrate. Agglomeration takes place for the confined particles in the second bubble. Additionally, upon the collapse of the second bubble a jet of confined material is ejected perpendicularly to the surface. We hypothesize that these kinetics influence the final particle size distribution and determine the quality of the resulting colloids, such as polydispersity and modality through the interplay between particle cloud compression and particle release into the liquid.

Highlights

XS experiment, while a fixed silver plate (99.99%) was irradiated for the XR with less than 100 shots before changing the targe
The optimisation of PLAL towards size[3] and yield control[50] of the harvested nanoparticles demands an understanding of the primary processes
This can only be achieved by a simultaneous observation of macroscopic and nanoscopic kinetics

Summary

Introduction

XS experiment, while a fixed silver plate (99.99%) was irradiated for the XR with less than 100 shots before changing the targe. The optimisation of PLAL towards size[3] and yield control[50] of the harvested nanoparticles demands an understanding of the primary processes. This study has combined time-resolved X-ray methods to study the structural kinetics of particle formation temporally and spatially correlated to the macroscopic bubble formation process during PLAL.

Results

Conclusion