TY - JOUR
T1 - Controlling the Morphology and Efficiency of Hybrid ZnO:Polythiophene Solar Cells Via Side Chain Functionalization
AU - Oosterhout, Stefan D.
AU - Koster, L. Jan Anton
AU - van Bavel, Svetlana S.
AU - Loos, Joachim
AU - Stenzel, Ole
AU - Thiedmann, Ralf
AU - Schmidt, Volker
AU - Campo, Bert J.
AU - Cleij, Thomas J.
AU - Lutzen, Laurence
AU - Vanderzande, Dirk
AU - Wienk, Martijn M.
AU - Janssen, Rene A. J.
PY - 2011/1/1
Y1 - 2011/1/1
N2 - 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.
AB - 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.
U2 - 10.1002/aenm.201000022
DO - 10.1002/aenm.201000022
M3 - Article
SN - 1614-6832
VL - 1
SP - 90
EP - 96
JO - Advanced Energy Materials
JF - Advanced Energy Materials
IS - 1
ER -