Nanopipette-based electrochemical methods rapidly develop into highly versatile and powerful tools in nanoscience for a variety of applications from imaging and sensing to nanoscale fabrication. Herein, we present advanced three-dimensional printing approaches for the fabrication of complex features using state-of-the-art nanopipette-based scanning probe techniques. Hollow cantilevers for atomic force microscope (AFM), known also as FluidFM probes,¹ and pulled double-barrel glass capillaries are employed for precise local delivery of precursor species using pressure-controlled fluid flow and fluxes given by electrophoretic migration of ions. The intrinsic advantage of these concepts is the automated feedback mechanism, based either on the detection of mechanical forces (FluidFM) or on variation of ionic current through the nanopipette, that allows to maintain a constant distance (typically, from a few to several tens of nanometers) between the probe and a growing printed feature. This ensures precise control of the electrodeposition process and enables rapid fabrication of high-aspect ratio features at rates approaching hundreds of nm s^-1. These new techniques open avenues for the architecture of a variety of features using continuous deposition and voxel-by-voxel printing strategy,² and also enable in situ read-out of the printed patterns thanks to the primary functionality of nanopipette methods as scanning probe microscopy tools.³

References

1. Hirt et al., RSC Adv., 5, 84517 (2015)

2. Hirt et al., Adv. Mater., 28, 2311 (2016)

3. Momotenko et al., ACS Nano, 10, 8871 (2016)