The introduction of laser ablation in liquid (LAL) was first reported

by Patil and coworkers in 1987, who used a pulsed laser to ablate

a pure iron target in water to form iron oxides with metastable

phases.1 This method involves a solid target being immersed in

a liquid medium and a laser beam is focused through the liquid

onto the target surface. Following their work, Ogale2 extended the

potential of LAL for the surface modification of metals, such as

metallic oxidation, nitriding, and carbiding. This pioneering work

opened new routes for processing of materials based on the laser

ablation of solids in various liquids. Since then, LAL has become a

successful material fabrication technique, allowing versatile design

through choosing suitable solid targets and confining liquids.

Compared to conventional physical methods (including chemical

vapor deposition,3 vapor phase transport,4 and pulsed laser abla-

tion in vacuum5) and chemical methods (including hydrothermal

methods,6 soft-template,7 and use of various surfactants8,9), the

technique of LAL has many distinct advantages. These include (i)

a chemically “simple and clean” synthesis as the final product

is usually obtained without byproducts and there is no need for

further purification; (ii) low cost of experimental setup and easily

controlled parameters; and (iii) the extreme confined conditions and

induced high-temperature, high-pressure region favor the formation

of unusual metastable phases. These advantages allow the designer

to combine selected solid targets and liquids to fabricate compound

nanostructures with desired functions.