Speaker
Description
The electron-induced crosslinking of self-assembled monolayers (SAMs) on surfaces can lead to the formation of mechanically stable carbon nanomembranes (CNMs). These membranes have applications in waterfiltration and can be functionalised to be used in biosensing [3]. The formation mechanism from a SAM to a CNM is still elusive [1] and the atomistic structure of the final CNM is also not accessible with most common experimental methods (TEM, AFM, XRD) [2].
We use slow electrons ($\lesssim 100\,\textrm{eV}$) to crosslink the SAM in-situ and monitor the crosslinking by Reflective Electron Energy Loss Spectroscopy (REELS) at various probing energies. Furthermore, we performed electron pair spectroscopy, where we detect the scattered primary electron in coincidence with a emitted secondary electron before and after crosslinking.
The REEL spectra show a gradual change of specific energy loss features, which can be linked to the disintegration of the molecular structure of the SAM. The pair emission spectroscopy allows us to correlate these specific loss features to energy dissipation branches with and without secondary electron emission.
We put our data in context to findings of ion-beam transmission spectroscopy of CNMs and model calculations for possible atomistic CNM structures [2].
References
[1] C. Neumann et al, Faraday Discuss., 227:61–79, 2021.
[2] F. Vukovic et al, J. Phys. Chem. C, 130(11):4244–4255, 2026.
[3] A. Turchanin et al, Adv. Mater., 28(29):6075–6103, 2016