Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 29, 2020
Previous Article Next Article

Interface properties and dopability of an organic semiconductor: TAPP-Br variable as molecule but inert in the condensed phase

Author affiliations

Abstract

In situ infrared spectroscopy under ultra-high vacuum conditions reveals the behaviour of an example of a molecular compound, the n-conducting organic semiconductor (2,9-bis-(heptafluoropropyl)-4,7,11,14-tetrabromo-1,3,8,10-tetraazaperopyrene, TAPP-Br), upon condensation on various surfaces and as a mixture with typical dopants. The bending of molecules on Au(111) as previously established by inelastic electron scattering is seen also in infrared spectra of molecules on gold films, but clearly depends on temperature. It is indicated by modified infrared signals from C3F7 sidechain vibrations. If deposited onto MoO3, commonly used as p-dopant and interlayer material in organic electronics, infrared vibrational spectra are similarly modified while MoO3 deposition onto a preformed condensed layer did not produce any molecular change. Calcium, often used as an n-dopant, leads to further changes of the TAPP-Br vibrations in co-evaporated layers, specifically the modified C–C vibrations on the aromatic rings indicating charge transfer. Upon deposition of TAPP-Br on Ca films, a strong decrease of the metallic absorption of the Ca layer has been observed, which is typical for a chemical interface interaction. In contrast, for Ca deposition onto an already condensed TAPP-Br layer, a pronounced Ca island growth and thus enhanced diffusion and no significant vibrational changes are observed. Thus, chemical doping should be done before the molecules crystallize. Physisorption as well as chemisorption at interfaces strongly depend on the deposition sequence, which should be considered also for other organic semiconductors.

Graphical abstract: Interface properties and dopability of an organic semiconductor: TAPP-Br variable as molecule but inert in the condensed phase

Back to tab navigation

Supplementary files

Article information


Submitted
26 Mar 2020
Accepted
17 Jun 2020
First published
18 Jun 2020

J. Mater. Chem. C, 2020,8, 9898-9908
Article type
Paper

Interface properties and dopability of an organic semiconductor: TAPP-Br variable as molecule but inert in the condensed phase

M. Tzschoppe, C. Huck, A. Butkevich, B. Günther, C. Ulrich, J. N. Rose, L. H. Gade and A. Pucci, J. Mater. Chem. C, 2020, 8, 9898
DOI: 10.1039/D0TC01555E

Social activity

Search articles by author

Spotlight

Advertisements