Electronic Properties of Polymer-Fullerene Solar Cells

Abstract

We studied the electronic transport properties of conjugated polymer/fullerene based solar cells by means of temperature and illumination intensity dependent current-voltage characteristics, admittance spectroscopy and light-induced electron spin resonance. The short-circuit current density increases with temperature at all light illumination intensities applied, i.e., from 100 mW/cm2 to 0.1 mW/cm2 (white light), whereas a temperature independent behavior was expected. An increase of the open-circuit voltage from 850 mV to 940 mV was observed, when cooling down the device from room temperature to 100 K. The fill factor depends strongly on temperature with a positive temperature coefficient in the whole temperature range. In contrast, the light intensity dependence of the fill factor shows a maximum of 52% at intermediate illumination intensities (3 mW/cm2) and decreases subsequently, when increasing the intensity up to 100 mW/cm2. Further studies by admittance spectroscopy revealed two frequency dependent contributions to the device capacitance. One, as we believe, originates from trapping states located at the interface between composite and metal electrode with an activation energy of EA=180 meV, and the other one is from very shallow bulk states with EA=10 meV. The origin of the latter is possibly the thermally activated conductivity. The photo-generation of charge carriers and their fate in these blends have been studied by light-induced electron spin resonance. We can clearly distinguish between photo-generated electrons and holes in the composites due to different spectroscopic splitting factors (g-factors). Additional information on the environmental axial symmetry of the holes located on the polymer chains as well as on a lower, rhombic, symmetry of the electrons located on the methanofullerene molecules has been obtained. The origin of the signals and parameters of the g-tensor have been confirmed from studies on a hole doped polymer.

This is a preview of subscription content, access via your institution.

References

  1. 1.

    G. Yu, J. Gao, J. C. Hummelen, F. Wudl, and A. J. Heeger, Science 270, 1789 (1995).

    CAS  Article  Google Scholar 

  2. 2.

    S. E. Shaheen, C. J. Brabec, F. Padinger, T. Fromherz, J. C. Hummelen, and N. S. Sariciftci, Appl. Phys. Lett. 78, 841 (2001)

    CAS  Article  Google Scholar 

  3. 3.

    M Gransträm, K. Petritsch, A. C. Arias, A. Lux, M. R. Andersson, and R. H. Friend, Nature 395, 257 (1998).

    Article  Google Scholar 

  4. 4.

    C. J. Brabec, S. E. Shaheen, M. T. Rispens, J. C. Hummelen, R. A. J. Janssen, D. Meissner, and N. S. Sariciftci, Proceedings of the QUANTSOL 2001, p. 28, Kirchberg, Austria.

  5. 5.

    J. J. M. Halls, A. C. Arias, J. D. MacKenzie, W. Wu, M. Inbasekaran, E. P. Woo, and R. H. Friend, Adv. Mater. 12, 498 (2000).

    CAS  Article  Google Scholar 

  6. 6.

    N. S. Sariciftci, L. Smilowitz, A. J. Heeger, and F. Wudl, Science 258, 1474 (1992).

    CAS  Article  Google Scholar 

  7. 7.

    C. J. Brabec, G. Zerza, G. Cerullo, S. De Silvestri, S. Luzzati, J. C. Hummelen, and N. S. Sariciftci (unpublished).

  8. 8.

    E. H. Nicollian and A. Goetzberger, Appl. Phys. Lett. 7, 216 (1965).

    CAS  Article  Google Scholar 

  9. 9.

    R. Herberholz, M. Igalson, and H. W. Schock, J. Appl. Phys. 83, 318 (1998).

    CAS  Article  Google Scholar 

  10. 10.

    V. Dyakonov, G. Zoriniants, M. Scharber, C. J. Brabec, R. A. J. Janssen, J. C. Hummelen, and N. S. Sariciftci, Phys. Rev. B 59, 8019 (1999).

    CAS  Article  Google Scholar 

  11. 11.

    K. Mäbius, Z. Naturforsch. 20a, 1093 (1965).

    Article  Google Scholar 

  12. 12.

    V. Dyakonov, D. Godovsky, J. Parisi, C. J. Brabec, N. S. Sariciftci, J. C. Hummelen, J. De Ceuster, E. Goovaerts, Synth. Met. 1, 8937 (2001).

    Google Scholar 

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to N. S. Sariciftci.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Dyakonov, V., Riedel, I., Deibel, C. et al. Electronic Properties of Polymer-Fullerene Solar Cells. MRS Online Proceedings Library 665, 71 (2000). https://doi.org/10.1557/PROC-665-C7.1

Download citation