Interdiffusion of molecular acceptors through organic layers to metal substrates mimics doping-related energy level shifts

Photoemission measurements reveal energy level shifts toward the Fermi level when a strong electron acceptor (tetrafluoro-tetracyanoquinodimethane, F4-TCNQ) is deposited on pristine layers of 4 , 4 ′ , 4 ″ -tris( N , N -diphenyl-amino)triphenylamine (TDATA) or 4 , 4 ′ -bis( N -carbazolyl)biphenyl (C...

Full description

Saved in:
Bibliographic Details
Published in:Applied physics letters 2009-08, Vol.95 (9), p.093305-093305-3
Main Authors: Duhm, Steffen, Salzmann, Ingo, Bröker, Benjamin, Glowatzki, Hendrik, Johnson, Robert L., Koch, Norbert
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Photoemission measurements reveal energy level shifts toward the Fermi level when a strong electron acceptor (tetrafluoro-tetracyanoquinodimethane, F4-TCNQ) is deposited on pristine layers of 4 , 4 ′ , 4 ″ -tris( N , N -diphenyl-amino)triphenylamine (TDATA) or 4 , 4 ′ -bis( N -carbazolyl)biphenyl (CBP). The shifts of the TDATA and CBP energy levels toward the Fermi level of the Au substrate could, in principle, arise from p -type doping of the intrinsic organic layers. While this indeed takes place in TDATA, doping of CBP by F4-TCNQ, i.e., charge transfer complex formation, does not occur. The shifts observed in CBP arise from the diffusion of F4-TCNQ toward the Au substrate, which modifies the buried metal surface potential, leading to a realignment of the energy levels of the organic overlayer.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.3213547