Vyacheslav Diev - Arylamine-Based Squaraine Donors for Use in Nanocrystalline Organic Solar Cells

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      Publication Details (including relevant citation   information):

      Nano   Lett.   2011, 11, 4261-4264.

      Abstract:

      Squaraine (SQ) dyes are notable for their exceptionally high   absorption coefficients extending from the green to the   near-infrared. In this work, we utilize the functionalized SQ   donor: 2,4-bis   [4-(N-phenyl-1-naphthylamino)-2,6-dihydroxyphenyl]   squaraine (1-NPSQ) by substitution of isobutylamines in the   common “parent SQ” with arylamines to improve stacking and hence   exciton and charge transport. The strong electron-withdrawing   arylamine group results in a highest occupied molecular orbital   energy of 5.3 eV, compared to 5.1 eV for the parent SQ, making   1-NPSQ a suitable donor when used with a C60 acceptor   in an organic photovoltaic cell. Optimized and thermally   annealed, nanocrystalline heterojunction   1-NPSQ/C60/bathocuproine solar cells with an open   circuit voltage of 0.90 ± 0.01 V, fill factor of 0.64 ± 0.01, and   short circuit current of 10.0 ± 1.1 mA/cm2 at 1 sun,   AM1.5G illumination (solar spectrally corrected) result in a   power conversion efficiency of 5.7 ± 0.6%. Crystallograpnic data   suggest that the intermolecular stacking of 1-NPSQ molecules is   closer than that of the parent SQ, thereby reducing the device   series resistance and increasing its fill factor.

      Address (URL): http://pubs.acs.org/doi/abs/10.1021/nl2022515