Digital selective laser methods for nanomaterials: From synthesis to processing

Laser has long been used for material processing, and its applications to nanomaterials for their direct synthesis, positioning and processing are currently active fields of study. The main mechanism of typical laser processes is photothermal reaction by a focused laser that remotely generates confined temperature field at a desired position with high controllability. The laser-induced elevated temperature enables direct synthesis of nanomaterials in both gas and liquid environment as well as photophysical processing of nanomaterials through melting or vaporization, represented by laser sintering and ablation processes, in spatially selective manners. On the other hand, recent advances in laser process further incorporates not only different optical responses such as optical forces and photochemical reactions for more advanced manipulation of nanomaterials, but also the interaction between electromagnetic waves, nanostructures and underlying substrates to facilitate novel processing those cannot be achieved by any other means including laser nanowelding for percolation network and laser thinning for two dimensional nanomaterials. At the same time, the shortcomings of laser process in nanomaterial processing such as limited resolution and low throughput are tackled through introducing different optical schemes together with the integration with other systems. In this review, we summarize the development and current status of digital selective laser methods for nanomaterials in broad aspects that cover from nanomaterial synthesis to its processing.