MaWi-Kolloquium (Hybrid)

Prof. Dr. Peer Kirsch

Organic Electronics
Institute of Materials Science
Technical University of Darmstadt

Self-Assembled Monolayers for Molecular Electronics and Spintronics

Functionalized self-assembled monolayers (SAMs) can be used as active components in electronics and spintronics devices. In particular, SAMs composed of dipolar, conformationally flexible phosphonic acids enable electrically switchable tunnel junctions with memristive characteristics.^[1] The performance of such organic memristive devices is comparable to that of their state-of-the-art inorganic counterparts.^[2] The big advantage of organic systems is their intrinsic functional versatility: a rather complex property profile can be easily designed into the individual component molecules. A potential challenge of many SAM systems - thermal stability - was resolved by using thermally and chemically robust phosphonic acids as anchoring groups which are compatible with oxide and nitride substrate materials common in electronics industry. 

Another class of functional SAMs is composed of chiral compounds, such as binaphthol phosphates (BNP), which can act as electron spin filters. Phenomena around the interaction between electrons of different spin and chiral thin films are known as the chirality-induced spin selectivity (CISS) effect.^[3] The CISS effect of chiral SAMs can be utilized for simplified spintronics devices where the SAMs replaces the pinned magnetic layer.

[1] J. Dlugosch, H. Seim, A. Bora, T. Kamiyama, I. Lieberman, F. May, F. Müller-Plathe, A. Nefedov, S. Prasad, S. Resch, K. Saller, C. Seim, M. Speckbacher, F. Voges, M. Tornow, P. Kirsch, ACS Appl. Mater. Interfaces 2022, 14, 31044-31053 (doi: 10.1021/acsami.2c05264).
[2} P. Kirsch, J. M. Dlugosch, T. Kamiyama, C. Pfeiffer, H. Seim, S. Resch, F. Voges, I. Lieberman, A. N. Nalakath, Y. Liu, M. Zharnikov, M. Tornow, Small 2024, 2308072 (doi: 10.1002/smll.202308072).
[3] Review: P. Bloom, Y. Paltiel, R. Naaman, D. H. Waldeck, Chem. Rev. 2024, 124, 1950-1991 (doi: 10.1021/acs.chemrev.3c00661).

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