Chemical potential pinning due to equilibrium electron transfer at metal/C{sub 60}-doped polymer interfaces

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.364154· OSTI ID:526501

Heller, C M; Campbell, I H; Smith, D L ^[1]; Barashkov, N N; Ferraris, J P ^[2]

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1. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2. The University of Texas at Dallas, Richardson, Texas 75080 (United States)

We report electroabsorption measurements of the built-in electrostatic potential in metal/C{sub 60}-doped polymer/metal structures to investigate chemical potential pinning due to equilibrium electron transfer from a metal contact to the electron acceptor energy level of C{sub 60} molecules in the polymer film. The built-in potentials of a series of structures employing thin films of both undoped and C{sub 60}-doped poly[2-methoxy, 5-(2{sup {prime}}-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) were measured. For undoped MEH-PPV, which has an energy gap of about 2.4 eV, the maximum built-in potential is about 2.1 eV, whereas for C{sub 60}-doped MEH-PPV the maximum built-in potential decreases to 1.5 eV. Electron transfer to the C{sub 60} molecules close to the metal interface pins the chemical potential of the metal contact near the electron acceptor energy level of C{sub 60} and decreases the built-in potential of the structure. From the systematic dependence of the built-in potential on the metal work function we find that the electron acceptor energy level of C{sub 60} in MEH-PPV is about 1.7 eV above the hole polaron energy level of MEH-PPV. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 526501
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 7 Vol. 81; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION
DOPED MATERIALS
ELECTRON TRANSFER
ELECTROSTATICS
ENERGY GAP
ENERGY LEVELS
FILMS
FULLERENES
INTERFACES
METALS
PHOTOCONDUCTIVITY
POLARONS
POLYMERS
POTENTIALS
WORK FUNCTIONS