In situ characterization of lifetime and morphology in operating bulk heterojunction organic photovoltaic devices by impedance spectroscopy

Benjamin J. Leever, Christopher A. Bailey, Tobin J. Marks, Mark C. Hersam, Michael F. Durstock

Research output: Contribution to journalArticle

178 Citations (Scopus)


Time-dependent charge transport in operating poly(3-hexylthiophene):[6,6]- phenyl-C 61-butyric acid methyl ester (P3HT:PCBM) bulk heterojunction organic photovoltaic (OPV) devices has been characterized with impedance spectroscopy. Devices with varied composition and morphology were measured over a range of illumination intensities ranging from dark conditions to 1 sun and applied bias voltages ranging from 0.0 V to 0.75 V. Using an equivalent circuit model, materials properties such as dielectric constant and conductivity were determined and found to be in agreement with values measured by other methods. Average carrier lifetimes were also extracted from the model and found to correlate with measured power conversion efficiencies. At the short circuit condition and ∼1 sun illumination, the average electron lifetime was found to vary from 7.8 to 22 μs for devices with power conversion efficiencies ranging from 2.0 to 2.5%. These results suggest that impedance spectroscopy is an effective tool for predicting how processing parameters can impact device performance in organic bulk heterojunction photovoltaic devices.

Original languageEnglish
Pages (from-to)120-128
Number of pages9
JournalAdvanced Energy Materials
Issue number1
Publication statusPublished - Jan 1 2012


ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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