Speaker
Description
Amongst the various 3D metal additive manufacturing methods that have been recently reviewed [1], nanoprinting with focused electron beams offers the greatest shape flexibility and the smallest print size. The technology is rooted in the high-tech industry as a powerful maskless, minimally invasive nanofabrication platform for mask repair, cantilever probe functionalization, and biosensors.
A persisting challenge is the limited number of pure materials that can be reproducibly e-beam nanoprinted when typical volatile metalorganic molecules are involved. The removal of the organic ligands from the metal atom and the surface is governed by a delicate interplay of both surface mediated thermal and electron induced non-thermal mechanisms involved in this approach [2]. To achieve high metal content nanoprinting, for now, the paradigm is to use small ligands in metalorganic molecules. This may serve (i) reducing potential e-fragmentation of large ligands containing several atoms and bonds into non-volatile co-deposited fragments and (ii) enhance desorption of the ligands dissociated from the parent molecule. Recently, however, large ketoesterate ligands in Pd(tbaoac)2 and Cu(tbaoac)2 precusors were also shown to be removed by up to 90% of their initial presence in the molecule [3, 4].
Here we present our recent continuum modeling activities to rationalize the metal content to be expected in e-nanoprinted structures [5]. We consider the complete removal of ligands in terms of their mean surface residence time and their further fragmentation into non-volatile moieties by electrons. Solving the system of coupled differential equations defines the electron exposure parameters needed to perform e-nanoprinting within the ligand-desorption-driven regime for highest metal content. We conclude with a comparison to experiments.
References:
[1] A. Reiser et al., Adv. Funct. Mater. 2020, 1910491, DOI: 10.1002/adfm.201910491.
[2] I. Utke, P. Swiderek, K. Höflich, K. Madajska, J. Jurczyk, P. Martinovic, I.B. Szymanska, Coord. Chem. Reviews 445 (2021), 213851, https://doi.org/10.1016/j.ccr.2021.213851.
[3] C. Haverkamp, G. Sarau, M.N. Polyakov, I. Utke, M.V. Puydinger Dos Santos, S. Christiansen, K. Höflich, Beilstein J. Nanotechnol. 2018, 9, 1220–1227, doi:10.3762/bjnano.9.113.
[4] C. S. Jureddy, K. Maćkosz, A. Butrymowicz-Kubiak, I. B. Szymańska, P. Hoffmann, I. Utke, Beilstein J. Nanotechnol. 2025, 16, 530–539, https://doi.org/10.3762/bjnano.16.41.
[5] J. Jurczyk, L. Brockhuis, A. Fernández-Pacheco, I. Utke, Small Methods 2025, e01956, https://doi.org/10.1002/smtd.202501956