Jinta Mathew (Author), Saim Emin (Author), Egon Pavlica (Author), Matjaž Valant (Author), Gvido Bratina (Author)

Abstract

We have studied submonolayer coverages of N,N-1H,1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDIF-CN2) on mechanically exfoliated graphene transferred onto SiO2 substrates. Our atomic force microscopy (AFM) data show that PDIF-CN2 forms irregularly-shaped 1.4 nm-high islands. From the selected area diffraction performed with transmission electron microscope (TEM) we conclude that this height corresponds to π−π stacks of molecules, which are inclined for 43° relative to the graphene surface. AFM also showed complete absence of PDIF-CN2 on single-layer graphene (SLG). Electric force microscopy revealed a marked difference in surface charge density between a single-layer graphene and bilayer graphene, with a higher surface charge on SLG than on the bilayer graphene. We associate this behavior with p− type doping of graphene due to the electrostatic dipole induced by the molecular water layer present at the graphene/SiO2 interface. The crucial role of the graphene/SiO2 interface in determining growth of PDIF-CN2 was further confirmed by TEM examination of PDIF-CN2 deposited onto unsupported SLG.

Keywords

atomic force microscopy;organic semiconductors;graphene;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UNG - University of Nova Gorica
UDC: 53
COBISS: 4780795 Link will open in a new window
ISSN: 0039-6028
Views: 4126
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Other data

URN: URN:SI:UNG
Type (COBISS): Not categorized
Pages: str. 16-20
Issue: ǂVol. ǂ664
Chronology: 2017
DOI: 10.1016/j.susc.2017.05.005
ID: 9631213