Reducing exciton-polaron annihilation in organic planar heterojunction solar cells

Bregt Verreet, Ajay Bhoolokam, Alyssa Brigeman, Rijul Dhanker, David Cheyns, Paul Heremans, Andre Stesmans, Noel C. Giebink, Barry P. Rand

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

We investigate the relationship between charge concentration, exciton concentration, and photocurrent generation in fullerene-containing heterojunction diodes. Impedance measurements on C60 diodes reveal a charge buildup at the C60/bathocuproine (BCP) interface that can be swept out under reverse bias. In solar cell structures, a similar charge buildup is observed in dark conditions, and increases as a function of incident light intensity. Photoluminescence measurements reveal that the C60 exciton concentration is voltage dependent, explained via the process of exciton-polaron annihilation. This process has a negative impact on the generated photocurrent of the solar cells and thereby decreases the fill factor. A combination of electroabsorption, photoluminescence, and impedance measurements reveal a decrease in charge buildup and the associated exciton-polaron annihilation through the use of a BCP/3,4,9,10-perylenetetracarboxylic bis-benzimidazole/Ag cathode.

Original languageEnglish (US)
Article number115304
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume90
Issue number11
DOIs
StatePublished - Sep 4 2014

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Reducing exciton-polaron annihilation in organic planar heterojunction solar cells'. Together they form a unique fingerprint.

  • Cite this

    Verreet, B., Bhoolokam, A., Brigeman, A., Dhanker, R., Cheyns, D., Heremans, P., Stesmans, A., Giebink, N. C., & Rand, B. P. (2014). Reducing exciton-polaron annihilation in organic planar heterojunction solar cells. Physical Review B - Condensed Matter and Materials Physics, 90(11), [115304]. https://doi.org/10.1103/PhysRevB.90.115304