Premium
Synthetic Molecular Rectifier of a Langmuir–Blodgett Film Based on a Novel Asymmetrically Substituted Dicyano‐tri‐ tert ‐butylphthalocyanine
Author(s) -
Zhou S.,
Liu Y.,
Qiu W.,
Xu Y.,
Huang X.,
Li Y.,
Jiang L.,
Zhu D.
Publication year - 2002
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/1616-3028(20020101)12:1<65::aid-adfm65>3.0.co;2-x
Subject(s) - materials science , intermolecular force , intramolecular force , scanning tunneling microscope , highly oriented pyrolytic graphite , molecule , acceptor , mica , electron transfer , substrate (aquarium) , crystallography , nanotechnology , photochemistry , stereochemistry , organic chemistry , chemistry , condensed matter physics , physics , oceanography , geology , composite material
Abstract A novel asymmetrically substituted dicyano‐tri‐ tert ‐butylphthalocyanine ((CN) 2 BuPc) with rectifying behavior has been synthesized. The morphology and conductive properties of (CN) 2 BuPc Langmuir–Blodgett (LB) films on mica and highly ordered pyrolytic graphite (HOPG) substrates were studied by atomic force microscopy (AFM) and scanning tunneling microscopy (STM), in air at 22 °C. The average area of each (CN) 2 BuPc molecule obtained from the AFM topography in situ is ca. 73.6 Å 2 , which is in good agreement with the result of ca. 74 Å 2 obtained from the π– A isotherm curve of a LB film. This indicates that the molecules are standing edge‐on, tilted by 38° against the surface normal of the substrate. The conductive properties for the 7‐layer LB films of (CN) 2 BuPc were studied by STM with a tungsten tip. The asymmetric I – V curve revealed a type of rectifying behavior for a negative and a positive bias. A feature model of the intramolecular and intermolecular charge transfer is presented. It not only interprets electron transfer from electron‐donor to electron‐acceptor molecules via a molecular “bridge”, but also the tunneling effect through intermolecular charge transfer.