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Fermi level pinned molecular donor/acceptor junctions : Reduction of induced carrier density by interfacial charge transfer complexes

Beyer, Paul ; Meister, Eduard ; Florian, Timo ; Generalov, Alexander LU ; Brütting, Wolfgang ; Koch, Norbert and Opitz, Andreas (2020) In Journal of Materials Chemistry C 8(43). p.15199-15207
Abstract

Increased hole density in an electron donor-type organic semiconductor can be achieved by deposition of a strong acceptor-type molecular layer on top, and has been shown to enable adjusting the carrier density in organic field effect transistors (OFETs). This interfacial charge transfer is due to simultaneous Fermi level (EF) pinning of the donor's highest occupied level and the acceptor's lowest unoccupied level. Here, we investigate the electrical properties of such an EF-pinned junction formed by diindenoperylene (DIP, as donor) and hexafluoro-tetracyano-naphthoquinodimethane (F6, as acceptor) in OFETs, as well as its electronic properties by photoelectron spectroscopy and electrostatic modelling. We find that, in addition to the... (More)

Increased hole density in an electron donor-type organic semiconductor can be achieved by deposition of a strong acceptor-type molecular layer on top, and has been shown to enable adjusting the carrier density in organic field effect transistors (OFETs). This interfacial charge transfer is due to simultaneous Fermi level (EF) pinning of the donor's highest occupied level and the acceptor's lowest unoccupied level. Here, we investigate the electrical properties of such an EF-pinned junction formed by diindenoperylene (DIP, as donor) and hexafluoro-tetracyano-naphthoquinodimethane (F6, as acceptor) in OFETs, as well as its electronic properties by photoelectron spectroscopy and electrostatic modelling. We find that, in addition to the EF-pinning induced integer charge transfer across the interface, DIP and F6 form charge transfer complexes (CPXs) at their junction. The molecularly thin CPX interlayer acts as insulator and significantly reduces the density of carriers induced on either side of the junction, compared to a scenario without such an interlayer. CPX formation is thus unfavourable for the effectiveness of controlling carrier density at molecular donor/acceptor junctions by EF-pinning. This journal is

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Materials Chemistry C
volume
8
issue
43
pages
9 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85096218126
ISSN
2050-7534
DOI
10.1039/d0tc02774j
language
English
LU publication?
yes
id
dfe1875a-7063-4db4-be6c-90bb8f68ddda
date added to LUP
2021-01-15 12:30:15
date last changed
2022-04-19 03:54:17
@article{dfe1875a-7063-4db4-be6c-90bb8f68ddda,
  abstract     = {{<p>Increased hole density in an electron donor-type organic semiconductor can be achieved by deposition of a strong acceptor-type molecular layer on top, and has been shown to enable adjusting the carrier density in organic field effect transistors (OFETs). This interfacial charge transfer is due to simultaneous Fermi level (EF) pinning of the donor's highest occupied level and the acceptor's lowest unoccupied level. Here, we investigate the electrical properties of such an EF-pinned junction formed by diindenoperylene (DIP, as donor) and hexafluoro-tetracyano-naphthoquinodimethane (F6, as acceptor) in OFETs, as well as its electronic properties by photoelectron spectroscopy and electrostatic modelling. We find that, in addition to the EF-pinning induced integer charge transfer across the interface, DIP and F6 form charge transfer complexes (CPXs) at their junction. The molecularly thin CPX interlayer acts as insulator and significantly reduces the density of carriers induced on either side of the junction, compared to a scenario without such an interlayer. CPX formation is thus unfavourable for the effectiveness of controlling carrier density at molecular donor/acceptor junctions by EF-pinning. This journal is </p>}},
  author       = {{Beyer, Paul and Meister, Eduard and Florian, Timo and Generalov, Alexander and Brütting, Wolfgang and Koch, Norbert and Opitz, Andreas}},
  issn         = {{2050-7534}},
  language     = {{eng}},
  number       = {{43}},
  pages        = {{15199--15207}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Journal of Materials Chemistry C}},
  title        = {{Fermi level pinned molecular donor/acceptor junctions : Reduction of induced carrier density by interfacial charge transfer complexes}},
  url          = {{http://dx.doi.org/10.1039/d0tc02774j}},
  doi          = {{10.1039/d0tc02774j}},
  volume       = {{8}},
  year         = {{2020}},
}