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The effect of molecule size and shape on free charge generation, transport and recombination in all-thiophene dendrimer:fullerene bulk heterojunctions

Journal Article


Abstract


  • Charge mobilities of all-thiophene dendrimers were studied using the charge extraction by

    linearly increasing voltage technique (CELIV). Four dendrimers differing in size, shape and

    with and without trimethylsilyl (TMS) protecting groups have been compared yielding

    important structure–property correlations: The hole mobility of the dendrimers with 21

    or 42 thiophene units was found to be very similar and around 105 cm2 V1 s1, indicating

    that shape and size of the studied dendrimers have little effect on their charge transport

    properties. Hole mobility is decreased by a factor of 3–10 by incorporation of TMS groups,

    which is attributed to the intrinsically slower electron transfer rates between the TMS-protected

    dendrimer molecules. Bulk heterojunction solar cells using 1:2 mixtures of the thiophene

    dendrimers and the electron acceptor [6,6]-phenyl-C61 butyric acid methyl ester

    (PC61BM) were fabricated and their performances were analyzed. The decreased hole

    mobility in the blend, the unbalanced electron and hole mobility and a rather short charge

    carrier lifetime measured by charge extraction and transient absorption techniques are

    thought to be important factors that limit overall power conversion efficiency in theses

    devices. Improved free charge generation with increasing dendrimer size was observed,

    which was related to increased separation distance between electron and hole pairs.

UOW Authors


  •   Mozer, Attila
  •   Ma, Chang-Qi (external author)
  •   Wong, Wallace W.H.. (external author)
  •   David, Jones J. (external author)
  •   Bäuerle, Peter (external author)
  •   Wallace, Gordon

Publication Date


  • 2010

Citation


  • Mozer, A. J., Ma, C., Wong, W. W.H., David, J. J., Bäuerle, P. & Wallace, G. G. (2010). The effect of molecule size and shape on free charge generation, transport and recombination in all-thiophene dendrimer:fullerene bulk heterojunctions. Organic Electronics, 11 (4), 573-582.

Scopus Eid


  • 2-s2.0-77549088704

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/5324

Has Global Citation Frequency


Number Of Pages


  • 9

Start Page


  • 573

End Page


  • 582

Volume


  • 11

Issue


  • 4

Abstract


  • Charge mobilities of all-thiophene dendrimers were studied using the charge extraction by

    linearly increasing voltage technique (CELIV). Four dendrimers differing in size, shape and

    with and without trimethylsilyl (TMS) protecting groups have been compared yielding

    important structure–property correlations: The hole mobility of the dendrimers with 21

    or 42 thiophene units was found to be very similar and around 105 cm2 V1 s1, indicating

    that shape and size of the studied dendrimers have little effect on their charge transport

    properties. Hole mobility is decreased by a factor of 3–10 by incorporation of TMS groups,

    which is attributed to the intrinsically slower electron transfer rates between the TMS-protected

    dendrimer molecules. Bulk heterojunction solar cells using 1:2 mixtures of the thiophene

    dendrimers and the electron acceptor [6,6]-phenyl-C61 butyric acid methyl ester

    (PC61BM) were fabricated and their performances were analyzed. The decreased hole

    mobility in the blend, the unbalanced electron and hole mobility and a rather short charge

    carrier lifetime measured by charge extraction and transient absorption techniques are

    thought to be important factors that limit overall power conversion efficiency in theses

    devices. Improved free charge generation with increasing dendrimer size was observed,

    which was related to increased separation distance between electron and hole pairs.

UOW Authors


  •   Mozer, Attila
  •   Ma, Chang-Qi (external author)
  •   Wong, Wallace W.H.. (external author)
  •   David, Jones J. (external author)
  •   Bäuerle, Peter (external author)
  •   Wallace, Gordon

Publication Date


  • 2010

Citation


  • Mozer, A. J., Ma, C., Wong, W. W.H., David, J. J., Bäuerle, P. & Wallace, G. G. (2010). The effect of molecule size and shape on free charge generation, transport and recombination in all-thiophene dendrimer:fullerene bulk heterojunctions. Organic Electronics, 11 (4), 573-582.

Scopus Eid


  • 2-s2.0-77549088704

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/5324

Has Global Citation Frequency


Number Of Pages


  • 9

Start Page


  • 573

End Page


  • 582

Volume


  • 11

Issue


  • 4