Structural transition and interconversion between the 2D self-assembled structures of pentacene.

The 2D self-assemblies and structural transitions of pentacene on a Cd(0001) surface have been investigated with low temperature scanning tunneling microscopy (STM). With increasing coverage, pentacene molecules show a structural evolution from the initial disordered gas-like phase through the porous network phase to the herringbone phase, and finally to the brickwall phase at the full monolayer. In particular, orientational frustration and cooperative rotation of pentacene molecules take place in the herringbone phase.

Spontaneous chiral resolution of pentahelicene molecules on Cd(0001).

Chiral resolution is of fundamental importance to conglomerate or racemate crystallization. Here we demonstrate that the spontaneous chiral resolution of pentahelicene racemates occurred in the monolayer domains. When deposited on a Cd(0001) surface, pentahelicene molecules crystallize into a commensurate (6 × 6)0° structure built mainly from homochiral trimers.

Structure transition of a C monolayer on the Bi(111) surface.

The interfacial structures of C molecules adsorbed on solid surfaces are essential for a wide range of scientific and technological processes in carbon-based nanodevices. Here, we report structural transitions of the C monolayer on the Bi(111) surface studied low-temperature scanning tunneling microscopy (STM). With an increase in temperature, the structure of the C monolayer transforms from local-order structures to a (√93 × √93) R20° superstructure, and then to a (11 × 11) R0° superstructure.