Self-assembly of metal free porphyrin layers at copper-electrolyte interfaces: Dependence on substrate symmetry

摘要: abstract Available online 21 August 2012Keywords:Self-assemblyPorphyrinCyclic voltammogramScanning tunneling microscopy Combined Cyclic Voltammetry (CV) and in-situ Electrochemical Scanning Tunneling Microscopy (EC-STM)studies were employed to compare the self-assembly of redox-active 5,10,15,20-Tetrakis (4-trimethyl am-monium phenyl) porphyrin tetra (p-toluenesulfonate), abbreviated as [H 2 TTMAPP] +4 on Cu(100) andCu(111) electrode surfaces in 10 mM HCl solution. Under these conditions, both are chloridepre-covered with a c(2×2) Cl- cpffiffiffi3pCl-layer Cu(111), respectively. On sur-faces highly ordered layers spontaneously formed. The short range molecular arrange-ment is quadratic nature which can be described by affiffiffiffiffiffi58pffiffiffiffiffiffi58pR23° unit cell onthe Cl-Cu(100), (3×4) cpffiffiffi3pCl-Cu(111) substrate. Large scale domainsare formed orientation reflects symmetry substrate, namely onCu(100) [Cu(111)] equivalent domains rotated 90° [120°], Thus, different symmetryof respective substrate surface has an influence otherwise self-assembled organic molecules.© 2012 Elsevier B.V. All rights reserved.