Switching at the Nanoscale: Light- and STM-Tip-Induced Switch of a Thiolated Diarylethene Self-Assembly on Au(111)

Abstract

The light-induced and STM-tip-induced switching of photochromic thiol functionalized terphenylthiazole-based diarylethene self-assembly on Au(111) has been investigated in ambient conditions. For such a purpose, we took advantage of the formation of highly ordered domains of opened-ring (1o) or closed-ring (1c) diarylethene isomers. We evidenced a STM-tip-induced switching for the 1o isomer characterized by a tip bias threshold of 1000 mV above which switching of all molecules of the ordered 1o domains occurs into the 1c isomer. In contrast, switching from 1c form into 1o form is not observed at the same tunnelling conditions within a domain formed by ordered 1c molecules. We compared tip-induced switching of ordered 1o domains and switching of single 1o isomers embedded in 1c domains. This led to the demonstration that the process of switching of the 1o isomer is determined by geometry of the molecules but also that the stability of the switched 1c isomer depends on the nature of the surrounding isomers. We also compare tip-induced switching and switching under the action of external UV light irradiation of ordered 1o domains. In contrast with STM tip-induced switching, the UV light induces switching of 1o domains into their stable 1c form, in agreement with a collective switching under irradiation, which cannot occur under the action of STM tip.

Photochromic Diarylethenes Designed for Surface Deposition: From Self‐Assembled Monolayers to Single Molecules

“…Intriguingly, they found that if a single o form is embedded in a SAM of c forms, conversion of the former to the latter is induced by lower bias voltages and found to be stable. These results indicate strong environmental effects on the switching process …”

“…For terarylenes, two studies on STM of SAMs of 3 (Figure a) were reported. The switching unit was a terthiazole derivative functionalized with a long alkyl chain spacer group terminated by a thiol to anchor the molecule on an Au(111) surface . In a preliminary letter, Lacaze and co‐workers deposited ethanol solutions of o forms and a mixture of o and c forms on a metallic surface.…”

“…The switching unit was a terthiazole derivative functionalized with a long alkyl chain spacer group terminated by a thiol to anchor the molecule on an Au(111) surface. [65,66] In a preliminary letter, Lacaze and co-workers deposited ethanol solutions of o forms and a mixture of o and c forms on a metallic surface. Upon evaporation of solvent and STM imaging, they showed that the two isomers could be distinguished on the Au surface by a subtle difference in contrast of the STM images and differences in packing parameters.…”

Optical properties of gold nanoparticles decorated with furan-based diarylethene photochromic molecules

“…This can be overcome by using a short, insulating alkyl chain as linker to decouple the photochromic core from the surface electrons i.e. reducing molecular π-electron interaction with surface atoms [32] . However, these alkyl groups are highly resistive thus diminishing applicability of the resulting hybrid system as molecular electronics element.…”

“…In some studies this was overcome by adapting the linking groups to the electrode material. This efficiently separates (decouples) the MOs of the electronic system from the electrodes thus enabling at least the ring-closing reaction [2,18,32] .…”