Energy level alignment at organic heterojunctions: Role of the charge neutrality level

H. Vázquez, W. Gao, F. Flores, Antoine Kahn

Research output: Contribution to journalArticle

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Abstract

We present a mechanism that explains the energy-level alignment at organic-organic (OO) semiconductor heterjunctions. Following our work on metal/organic interfaces, we extend the concepts of charge neutrality level (CNL) and induced density of interface states to OO interfaces, and propose that the energy-level alignment is driven by the alignment of the CNLs of the two organic semiconductors. The initial offset between the CNLs gives rise to a charge transfer across the interface, which induces an interface dipole and tends to align the CNLs. The initial CNL difference is reduced according to the screening factor S, a quantity related to the dielectric functions of the organic materials. Good quantitative agreement with experiment is found. Our model thus provides a simple and intuitive, yet general, explanation of the energy-level alignment at organic semiconductor heterojunctions.

Original languageEnglish (US)
Article number041306
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume71
Issue number4
DOIs
StatePublished - Jan 1 2005

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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