Tuning the surface potential of Ag surfaces by chemisorption of oppositely-oriented thiolated carborane dipoles

Adsorption of oriented carborane dipoles on a silver surface

“…The solvent effect is a complicated issue and was limited in this study to the use of two solvents, methanol, and chloroform. While the former one is an environmentally more friendly solvent, the latter provided useful data for comparison with the previously published study . Consistently with data reported therein, pristine SAMs of A and B shift the surface work function in opposite directions: a SAM of A increases and a SAM of B decreases the WF of silver surfaces.…”

“…In this study, we show how the surface potential can be modified by means of self‐assembled monolayers consisting of two isomeric species ( A and B ). We demonstrate that co‐adsorption of both positional isomers can be used to finely shift the surface potential (work function) within a range of ∼1 V which also significantly exceeds the range reported for this system previously . The SAMs deposited from the respective solutions at ambient conditions are analyzed by Kelvin Probe Force Microscope (KPFM) which is used to measure the local potential changes Δ ϕ (Δ ϕ = −ΔWF) and thus to probe not only the pristine monolayers but especially the mixed monolayers assembled on a silver surface through the competitive adsorption of both isomers, A and B .…”

“…The two SH groups are attached to the carbon atoms in positions 1 and 2 (in case of isomer A ), or to the boron atoms in the positions 9 and 12 ( B ), which has a strong effect on their chemical and physical properties . Both molecules exhibit relatively strong inherent dipole moments of 3.7 D ( A ) and 5.5 D ( B ) and have been studied particularly as modifiers of gold surfaces . Scanning Tunneling Microscopic (STM) investigation of closely related molecules assembled on Au{111} showed almost defect‐free SAMs with hexagonal close‐packed patterns .…”

Carboranes in the chemist's toolbox

“…o-Carborane thiols such as 1,2-and 9,12-(HS) 2 C 2 B 10 H 10 serve as building-blocks in the self-assembly of monolayers on copper, 104 silver, 105,106 and gold. o-Carborane thiols such as 1,2-and 9,12-(HS) 2 C 2 B 10 H 10 serve as building-blocks in the self-assembly of monolayers on copper, 104 silver, 105,106 and gold.…”

“…o-Carborane thiols such as 1,2-and 9,12-(HS) 2 C 2 B 10 H 10 serve as building-blocks in the self-assembly of monolayers on copper, 104 silver, 105,106 and gold. 105 On the other hand, the 9,12-isomer affords excellent protection for silver surfaces against corrosion by H 2 S. 106 A study of the deposition of 1-[HS(CH 2 ) 3 -tricyclo-(CH 2 ) 3 ]-pcarborane polycrystalline monolayers on a Au(111) surface revealed a major shift in the highest occupied molecular orbital (HOMO) to a level 2.2 eV below that of oligophenylene derivatives, a potentially useful observation in the design of carborane-based molecular electronic devices. 105 On the other hand, the 9,12-isomer affords excellent protection for silver surfaces against corrosion by H 2 S. 106 A study of the deposition of 1-[HS(CH 2 ) 3 -tricyclo-(CH 2 ) 3 ]-pcarborane polycrystalline monolayers on a Au(111) surface revealed a major shift in the highest occupied molecular orbital (HOMO) to a level 2.2 eV below that of oligophenylene derivatives, a potentially useful observation in the design of carborane-based molecular electronic devices.…”