Influence of electrospray deposition on C₆₀ molecular assemblies

Abstract

Maintaining clean conditions for samples during all steps of preparation and investigation is important for scanning probe studies at the atomic or molecular level. For large or fragile organic molecules, where sublimation cannot be used, high-vacuum electrospray deposition is a good alternative. However, because this method requires the introduction into vacuum of the molecules from solution, clean conditions are more difficult to be maintained. Additionally, because the presence of solvent on the surface cannot be fully eliminated, one has to take care of its possible influence. Here, we compare the high-vacuum electrospray deposition method to thermal evaporation for the preparation of C60 on different surfaces and compare, for sub-monolayer coverages, the influence of the deposition method on the formation of molecular assemblies. Whereas the island location is the main difference for metal surfaces, we observe for alkali halide and metal oxide substrates that the high-vacuum electrospray method can yield single isolated molecules accompanied by surface modifications.

Solution-Synthesized Extended Graphene Nanoribbons Deposited by High-Vacuum Electrospray Deposition

“…Still, the separation distance between OMeCGNRs in such structures remains visible, indicating the absence of alkyl chain intercalation. , Solvent is also observed for the FGNRs, as periodically aligned protrusions visible in Figure d. Their position correlates with the elbows of the herringbone reconstruction (HB), marked by the dashed lines, acting as a preferential adsorption site to trap the solvent molecules . Most of the FGNRs are also aligned along those elbows, indicating that they are oriented across the HB reconstruction.…”

“…The possibility to work with nonconducting substrates is also important to study the properties of adsorbates decoupled from metals. 34,47 Here, we show the successful HVESD of well-elongated GNRs on different surfaces maintained in UHV conditions. We provide comparison of three solution-synthesized GNRs exhibiting different average lengths, functional groups, and alkyl side chains.…”

“…Surrounding them, solvent molecules and possibly KBr material are found. HVESD is known to create defects on such surfaces that can influence the trapping of molecules. , Combined with ex situ cleavage of the KBr before the deposition in UHV, this can explain the presence of the irregular monatomic step edge as well as some defects influencing the FGNR stabilization. This is well visible on the three FGNRs adsorbed on an irregularly shaped KBr island, with a height of about 700 pm corresponding well to diatomic KBr (660 pm), visible in the top right corner of Figure a.…”

“…An advantage is the option to introduce species with a broad mass distribution from a single solution. The possibility to work with nonconducting substrates is also important to study the properties of adsorbates decoupled from metals. , …”

“…The possibility to work with nonconducting substrates is also important to study the properties of adsorbates decoupled from metals. 34 , 47 …”