K W Hipps - Investigation of Metal Free Naphthalocyanine Vapor Deposited on Au(111)

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      Publication Details (including relevant citation   information):

      Wiggins, Bryan, Hipps, K. W. The Journal of Physical   Chemistry C 2014 118 (8) 4222-4230

      Abstract: Naphthalocyanines (Ncs) are promising   candidates for future components in electronic devices and   applications. To maximize the efficiency of Nc devices, it is   critical to understand their structural and electronic properties   and how these are impacted by deposition methods. The formation   of a metal free naphthalocyanine (H2Nc) self-assembled monolayer   on a Au(111) crystal was investigated by scanning tunneling   microscopy under ultra-high-vacuum conditions at room   temperature. A rigorous purification and processing procedure was   developed to produce high purity, low defect, and well-ordered   monolayers. High-resolution STM images reveal epitaxial growth of   H2Nc on Au(111) with the observed structure having a molecular   spacing of 1.6 ± 0.05 nm, with molecules orientated slightly off   (roughly 2.5°) the low density packing direction of Au(111). A   commensurate structure having 4 molecules per unit cell and unit   cell parameters of A = 3.25 ± 0.05 nm, B = 3.17 ± 0.05 nm, and α   = 87.5 ± 2° is proposed. Orbital-mediated tunneling spectroscopy   was used to examine the electronic properties of individual   molecules within the thin film. The first ionization potential   and electron affinity of H2Nc adsorbed on Au(111) were measured   to be −0.68 ± 0.03 and 1.12 ± 0.02 eV, relative to the Fermi   energy.

      Address (URL): http://dx.doi.org/10.1021/jp4115282