Implications of the negative capacitance observed at forward bias in nanocomposite and polycrystalline solar cells

Iván Mora-Seró, Juan Bisquert, Francisco Fabregat-Santiago, Germà Garcia-Belmonte, Guillaume Zoppi, Ken Durose, Yuri Proskuryakov, Ilona Oja, Abdelhak Belaidi, Thomas Dittrich, Ramón Tena-Zaera, Abou Katty, Claude Lévy-Clément, Vincent Barrioz, Stuart J.C. Irvine

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Four different types of solar cells prepared in different laboratories have been characterized by impedance spectroscopy (IS): thin-film CdS/CdTe devices, an extremely thin absorber (eta) solar cell made with microporous TiO 2/In(OH) xS y/PbS/PEDOT, an eta-solar cell of nanowire ZnO/CdSe/CuSCN, and a solid-state dye-sensitized solar cell (DSSC) with Spiro-OMeTAD as the transparent hole conductor. A negative capacitance behavior has been observed in all of them at high forward bias, independent of material type (organic and inorganic), configuration, and geometry of the cells studied. The experiments suggest a universality of the underlying phenomenon giving rise to this effect in a broad range of solar cell devices. An equivalent circuit model is suggested to explain the impedance and capacitance spectra, with an inductive recombination pathway that is activated at forward bias. The deleterious effect of negative capacitance on the device performance is discussed, by comparison of the results obtained for a conventional monocrystalline Si solar cell showing the positive chemical capacitance expected in the ideal IS model of a solar cell.

Original languageEnglish
Pages (from-to)640-650
Number of pages11
JournalNano Letters
Issue number4
Publication statusPublished - 1 Apr 2006


ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Cite this

Mora-Seró, I., Bisquert, J., Fabregat-Santiago, F., Garcia-Belmonte, G., Zoppi, G., Durose, K., Proskuryakov, Y., Oja, I., Belaidi, A., Dittrich, T., Tena-Zaera, R., Katty, A., Lévy-Clément, C., Barrioz, V., & Irvine, S. J. C. (2006). Implications of the negative capacitance observed at forward bias in nanocomposite and polycrystalline solar cells. Nano Letters, 6(4), 640-650.