Laser ablation in liquids for shape-tailored synthesis of nanomaterials: status and challenges.

Shape-and size-controlled synthesis of nanomaterials has been a long-term aim and challenge of modern nanotechnology. Despite many synthesis methods are still mainly focused on the production of near-spherical NPs, a number of emerging applications require nanomaterials of nonspherical shape and developed surface, which determine the functional performance of nanostructured devices. Laser ablation in liquids has been demonstrated as a clean, simple, and versatile NP synthesis method. However, the conditions of NP formation and growth are favouring the production of spherical NPs. There are fewer studies of shape control during laser ablation. With that in mind, this perspective article represents a view on the current stage of the development of laser ablation in liquids from the perspective of shape control of the forming nanomaterials. The key parameters influencing the NP shape are highlighted, including the composition of a liquid, laser focusing conditions and introduction of external fields, and the mechanism of their impact on the conditions for anisotropic NP formation and growth. The description of the methods developed for the control over nanomaterial morphology is summarized by the vision of the current challenges and development routes of laser ablation in liquids.