Laser‐Based Printing: From Liquids to Microstructures

Assembly of materials into microstructures under laser guidance is attracting wide attention. The ability to pattern various materials and form 2D and 3D structures with micron/sub‐micron resolution and less energy and material waste compared with standard top‐down methods make laser‐based printing promising for many applications, for example medical devices, sensors, and microelectronics. Assembly from liquids provides a smaller feature size than powders and has advantages over other states of matter in terms of relatively simple setup, easy handling, and recycling. However, the simplicity of the setup conceals a variety of underlying mechanisms, which cannot be identified simply according to the starting or resulting materials. This progress report surveys the various mechanisms according to the source of the material—preformed or locally synthesized. Within each category, methods are defined according to the driving force of material deposition. The advantages and limitations of each method are critically discussed, and the methods are compared, shedding light on future directions and developments required to advance this field. Laser‐based printing where the precursors are in the liquid state is an evolving discipline, which is highly suited for deposition at the microscale, providing excellent resolution, minimal waste, and simple setups. This simplicity conceals a variety of underlying mechanisms, which are presented here in a unified manner according to the driving force for material assembly.