Rectification in Supramolecular Zinc Porphyrin/Fulleropyrrolidine Dyads Self‐Organized on Gold(111) |
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| Authors: | Francesca Matino? Dr Valentina Arima Dr Manuel Piacenza Dr Fabio Della Sala Dr Giuseppe Maruccio Dr Ray J Phaneuf? Prof Roberta Del Sole Dr Giuseppe Mele Dr Giuseppe Vasapollo Prof Giuseppe Gigli Prof Roberto Cingolani Prof Ross Rinaldi Prof |
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| Institution: | 1. National Nanotechnology Laboratory (CNR‐INFM), Distretto Tecnologico ISUFI, Università del Salento via Arnesano, 73100 Lecce (Italy), Fax: (+39)?832‐298230;2. Current address: Institut für Experimentelle und Angewandte Physik der Christian‐Albrechts‐Universit?t Kiel, 24118 Kiel (Germany);3. Department of Materials Science and Engineering, University of Maryland and Laboratory for Physical Science, College Park, 20740 Maryland (USA);4. Dipartimento di Ingegneria dell'Innovazione, Università del Salento via Arnesano, 73100 Lecce (Italy) |
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| Abstract: | Self‐assembled donor/acceptor dyads are of current interest as they are biomimetic to the natural photosynthetic conversion system. Herein, we present an ultrahigh‐vacuum scanning tunneling microscopy and scanning tunneling spectroscopy (UHV‐STM/STS) study of ex situ self‐assembled supramolecular dyads consisting of fulleropyrrolidines (PyC2C60) axially ligated to zinc(II) tetraphenylporphyrin (ZnTPP), self organized on a 4‐aminothiophenol (4‐ATP) self‐assembled monolayer on gold(111). These dyads show both bias‐polarity‐dependent apparent height in STM images and highly rectifying behavior in tunneling spectroscopy. First‐principles density functional theory calculations clarify the conformational and electronic properties of the 4‐ATP/ZnTPP/PyC2C60 system. Interestingly, we find easier tunneling for electrons moving from the acceptor side of the dyads to the donor side, in the inverse‐rectifying sense with respect to previously reported molecular rectifiers. Such behavior cannot be explained as an elastic resonant tunneling process, but it can by using a model based on the Aviram–Ratner mechanism. |
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| Keywords: | donor– acceptor systems fullerenes molecular electronics porphyrinoids scanning probe microscopy |
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