ABSTRACT
Pulsed laser ablation (PLA) is a unique method used to obtain
atoms, ions, and small molecules from solid targets because of
its high-energy output, the ability to adjust the power of the
laser, and the purity of the final product.1,2 Most experiments on
pulsed laser-solid interaction have been carried out in vacuum
(10−4 Pa)3 or in a low pressure background gas,4 aiming at thin film fabrication and cluster formation.1 One of the advantages of
the PLA method is that stoichiometric thin films can be prepared
with the same composition as the target materials. In addition,
metals, semiconductors, and ceramics with high melting point can
be obtained at lower temperatures. However, this method has some
disadvantages, such as the size of the granules on the surface of
thin films is not even, big particles exist in the surface, and a
high vacuum environment raises the preparation cost. Also, it is
difficult to obtain a thin film with big area using the PLA method.
Some researchers have attempted to produce new materials by PLA
in a static liquid medium. Figure 11.1 shows a typical schematic
diagram of the experimental apparatus of PLA in static liquid.5
Mafune´ and coworkers prepared small silver, gold, and platinum
clusters by laser ablation of ametal plate in the aqueous solution of a
surfactant, where the clusters are encapsulated by the surfactant. At
the same time, they also researched the influence of the preparation
conditions, such as the concentration of the surfactant and the
power of laser ablation, on the stability of the nanoparticles in the
solution.5−8 Yang and coworkers prepared nanocrystalline diamond and cubic C3N4 by laser ablation of a graphite target in acetone
solution and ammonia solution, respectively.9,10,11 Iwabuchi et al.12
prepared nanosized titania particles by PLA of a rutile single-crystal
target in water. Compagnini et al.13 reported PLA of gold and
silver in several liquids (mainly water, ethanol, and chloroform).
They observed the formation of metal sols by laser ablation in
water and ethanol and the formation of chloride compound sols
by laser ablation in chloroform. This revealed that the chemical
state of the formed nanoparticles depends mainly on the chemical
reactivity of the liquid. Liang et al.14 synthesized ultrafine SnO2−x nanocrystals by PLA of a tin metal plate in aqueous solutions of
sodium dodecyl sulfate and in pure water. Yeh and coworkers15
also prepared aluminum hydroxides by laser ablation of an Al rod
immersed in water solvent. During aging, bayerite, gibbsite, and
boehmite particles were formed simultaneously.
