Materials processing has proved to be a rich area for applications of laser technologies. The ability to deliver large energies with high precision and accuracy has facilitated laser materials processing techniques of cutting, welding, ablating, and curing. Laser-driven additive manufacturing processes such as laser powder sintering, laser forward transfer and other laser direct write (LDW) techniques have demonstrated potential to drastically expand the reach of next generation two and 3D patterning across diverse technologies. However, a major roadblock that faces the wide dissemination of these approaches is the limited range of materials that are compatible, particularly 3D printing processes operating at the finest scales (nano to micro) such as multiphoton lithography (MPL) which has been generally limited to photocurable polymers and resists. Thus, recent studies have begun to explore direct patterning of metals such as silver and gold. We recently showed that nanocrystalline platinum and palladium could be patterned using MPL via a photo-reduction mechanism. Unfortunately, this procedure is not readily translatable to other aqueous metal ion solutions given the wide range of reduction potentials across, for instance, the transition metals and the limited availability of suitable photo-activatable reducing agents. However, we have found that patterns could be extending from an existing metal in a metal ion precursor solution using a continuous wave (CW; as opposed to high-energy pulses required to initiate multiphoton processes) laser beam. Calculating a steady state temperature rise at the ‘hot edge’ (where the laser focus and metal interact) of &gt; 1000K, we reasoned that the precursor could be thermally precipitated or reduced, as these conditions are analogous to hydro/solvothermal chemistry. We show that translation of these laser thermal voxels (LTVs) provides a general route for surface patterning at ~ 1 micron scale of a wide range of metals and metal oxides, including functional nickel metal, a historically challenging direct write material.

Patterning diverse metallic materials directly from solution using laser thermal voxels

253rd National Meeting (2017)

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