Exciton Transfer of Azobenzene Derivatives in Self-Assembled Mono layers

Diphenyl-diazene and its derivative bis[(1,1')-biphenyl-4-yl]-diazene were found to have innovative technological applications when arranged in self-assembled monolayers (SAMs). This is due to their switching capability after photoisomerization that is preserved also when they are in a close-packed assembly over the metal surface forming SAMs. One of the possible phenomena that may hinder the photoisomerization process is the intermolecular excitonic transfer. Understanding this possibility is therefore of the utmost importance. For doing so, we tackled a quantum mechanical (QM) study that begins from the exploration of the electronic excited state properties of a single molecule, to the intermolecular exciton couplings computed at different theory levels, until the excitonic diffusion dynamics, evaluated both within a frozen SAM portion and as an average along a molecular dynamics (MD) simulation.