Publication detail

Robust Dipolar Layers between Organic Semiconductors and Silver for Energy-Level Alignment

KRAJŇÁK, T. STARÁ, V. PROCHÁZKA, P. PLANER, J. SKÁLA, T. BLATNIK, M. ČECHAL, J.

Original Title

Robust Dipolar Layers between Organic Semiconductors and Silver for Energy-Level Alignment

Type

journal article in Web of Science

Language

English

Original Abstract

The interface between a metal electrode and an organic semiconductor (OS) layer has a defining role in the properties of the resulting device. To obtain the desired performance, interlayers are introduced to modify the adhesion and growth of OS and enhance the efficiency of charge transport through the interface. However, the employed interlayers face common challenges, including a lack of electric dipoles to tune the mutual position of energy levels, being too thick for efficient electronic transport, or being prone to intermixing with subsequently deposited OS layers. Here, we show that monolayers of 1,3,5-tris(4-carboxyphenyl)benzene (BTB) with fully deprotonated carboxyl groups on silver substrates form a compact layer resistant to intermixing while capable of mediating energy-level alignment and showing a large insensitivity to substrate termination. Employing a combination of surface-sensitive techniques, i.e., low-energy electron microscopy and diffraction, X-ray photoelectron spectroscopy, and scanning tunneling microscopy, we have comprehensively characterized the compact layer and proven its robustness against mixing with the subsequently deposited organic semiconductor layer. Density functional theory calculations show that the robustness arises from a strong interaction of carboxylate groups with the Ag surface, and thus, the BTB in the first layer is energetically favored. Synchrotron radiation photoelectron spectroscopy shows that this layer displays considerable electrical dipoles that can be utilized for work function engineering and electronic alignment of molecular frontier orbitals with respect to the substrate Fermi level. Our work thus provides a widely applicable molecular interlayer and general insights necessary for engineering of charge injection layers for efficient organic electronics.

Keywords

charge injection layers; self-assembly; surfaces; photoelectron spectroscopy; energy levels; low-energy electron microscopy; scanning tunneling microscopy

Authors

KRAJŇÁK, T.; STARÁ, V.; PROCHÁZKA, P.; PLANER, J.; SKÁLA, T.; BLATNIK, M.; ČECHAL, J.

Released

29. 3. 2024

Publisher

American Chemical Society

Location

WASHINGTON

ISBN

1944-8252

Periodical

ACS applied materials & interfaces

Year of study

16

Number

14

State

United States of America

Pages from

18099

Pages to

18111

Pages count

13

URL

https://pubs.acs.org/doi/10.1021/acsami.3c18697

Full text in the Digital Library

http://hdl.handle.net/11012/245522

BibTex

@article{BUT188450,
  author="Tomáš {Krajňák} and Veronika {Stará} and Pavel {Procházka} and Jakub {Planer} and Tomáš {Skála} and Matthias {Blatnik} and Jan {Čechal}",
  title="Robust Dipolar Layers between Organic Semiconductors and Silver for Energy-Level Alignment",
  journal="ACS applied materials & interfaces",
  year="2024",
  volume="16",
  number="14",
  pages="18099--18111",
  doi="10.1021/acsami.3c18697",
  issn="1944-8252",
  url="https://pubs.acs.org/doi/10.1021/acsami.3c18697"
}