Scanning Tunneling Microscopy Imaging of Thiourea Self-assembled Adlayers on Silver (111)

V. BRUNETTI; B. BLUM; R. C. SALVAREZZA; A. J. ARVIA

ACTA MICROSCOPICA

Año: 2001 p. 147 - 147

0798-4545

p class="MsoNormal" style="text-align: justify;">Structural aspects of thiourea-silver (111) adlayer formation are investigated by ex-situ scanning tunneling microscopy (STM) imaging at room temperature. Thiourea adlayers are produced by immersion of the silver substrate in aqueous 50mM thiourea under open circuit potential for immersion times ranging from a few seconds up to 45 s. Images resulting after 10 s immersion reveal coexisting dilute disordered and ordered adsorbate regions. Ordered hexagonal adsorbate arrangements with d = 0.38 ± 0.01 nm and d = 0.43 ± 0.01 nm are obtained. Adsorbate lattice distances are discussed in terms of different molecular arrangements. The electrochemical response of thiourea adlayers on silver (111) resembles that obtained for sulphur and sulphur-containing organica molecules on silver (111).