High thermal stability of cross-linked aromatic self-assembled monolayers: Nanopatterning via selective thermal desorption

An extremely high thermal stability of electron cross-linked biphenyl self-assembled monolayers (SAMs) is reported. The authors found that pristine biphenylthiol SAMs desorb at $∼400K$ from gold surfaces, which is induced by a breaking of C–S bonds. Despite of a similar bond cleavage in cross-linked SAMs, these remain on the surface up to $1000K$⁠, which is the highest temperature reported for a SAM. When patterns of pristine and cross-linked SAMs are heated, the pristine regions desorb, and the cross-linked regions remain on the surface. The authors show that this thermal desorption lithography can be utilized for the fabrication of molecular surface nanostructures.