Porphyrin derivatives are promising candidates for the generation of functional molecular architectures on surfaces. The unambiguous identification of individual porphyrin species is a prerequisite in this regard. We investigated a layer of intermixed tetraphenylporphyrins (TPP), namely 2HTPP, FeTPP and CoTPP at room temperature. Voltage-dependent STM imaging was successfully applied to discriminate the very similar porphyrins. The characteristic appearance of CoTPP at low negative voltages (>-0.4 V) can be traced back to a specific interaction of the Co dz2 orbital with the underlying Ag substrate. The dumbbell appearance observed for FeTPP over a wide bias range and for CoTPP at lower negative voltages (<-0.4 V) is in line with the well known saddle shape of the porphyrin macrocycle in the adsorbed state.
Product Literature and Free Software Download product information and XPMPro™ software. XPMPro™ is our SPM aquisition, analysis and data processing software.
1050 East Maple Road
Troy, MI 48083 USA
Tel: 248-577-5426 Fax: 248-577-5433
Copyright 1996 - 2007, RHK Technology, Inc.