Field-effect-tuned lateral organic diodes

Bal Mukund Dhar, Geetha S. Kini, Guoqiang Xia, Byung Jun Jung, Nina Markovic, Howard E. Katz

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


The operation of organic diodes in solar cells and light-emitting displays strongly depends on the properties of the interfaces between hole- and electron-carrying organic semiconductors. Such interfaces are difficult to characterize, as they are usually buried under the surface or exist as an irregular "bulk heterojunction." Using a unique fluorinated barrier layer-based lithographic technique, we fabricated a lateral organic p-n junction, allowing the first observation of the potential at an organic p-n interface simultaneously with the charge transport measurements. We find that the diode characteristics of the device (current output and rectification ratio) are consistent with the changes in the surface potentials near the junction, and the current-voltage curves and junction potentials are strongly and self-consistently modulated by a third, gate electrode. The generality of our technique makes this an attractive method to investigate the physics of organic semiconductor junctions. The lithographic technique is applicable to a wide variety of soft material patterns. The observation of built-in potentials makes an important connection between organic junctions and textbook descriptions of inorganic devices. Finally, these kinds of potentials may prove to be controlling factors in charge separation efficiency in organic photovoltaics.

Original languageEnglish
Pages (from-to)3972-3976
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number9
StatePublished - 2 Mar 2010


  • Built-in potential
  • Organic semiconductor
  • Rectification
  • Scanning kelvin probe microscopy
  • p-n junction


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