Controlling the Morphology and Efficiency of Hybrid ZnO:Polythiophene Solar Cells Via Side Chain Functionalization

Stefan D. Oosterhout, L. Jan Anton Koster, Svetlana S. van Bavel, Joachim Loos, Ole Stenzel, Ralf Thiedmann, Volker Schmidt, Bert J. Campo, Thomas J. Cleij, Laurence Lutzen, Dirk Vanderzande, Martijn M. Wienk, Rene A. J. Janssen*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

79 Citations (Web of Science)

Abstract

The efficiency of polymer – metal oxide hybrid solar cells depends critically on the intimacy of mixing of the two semiconductors. The effect of side chain functionalization on the morphology and performance of conjugated polymer:zno solar cells is investigated. Using an ester-functionalized side chain poly(3-hexylthiophene-2,5-diyl) derivative (p3ht-e), the nanoscale morphology of zno:polymer solar cells is significantly more intimately mixed compared to zno:poly(3-hexylthiophene-2,5-diyl) (zno:p3ht), as evidenced experimentally from a 3d reconstruction of the phase separation using electron tomography. Photoinduced absorption reveals nearly quantitative charge generation for the zno:p3ht-e blend but not for zno:p3ht, consistent with the results obtained from solving the 3d diffusion equation for excitons formed in the polymer within the two experimental zno morphologies. For thin zno:p3ht-e active layers (~50 nm) this yields a significant improvement of the solar cell performance. For thicker cells, however, the reduced hole mobility and a reduced percolation of zno pathways hinders charge carrier collection, limiting the power conversion efficiency.
Original languageEnglish
Pages (from-to)90-96
JournalAdvanced Energy Materials
Volume1
Issue number1
DOIs
Publication statusPublished - 1 Jan 2011
Externally publishedYes

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