| Autor: |
De Jonghe-Risse, Jelissa, Heier, Jakob, Nüesch, Frank, Moser, Jacques-E. |
| Zdroj: |
Journal of Materials Chemistry A; 5/28/2015, Vol. 3 Issue 20, p10935-10941, 7p |
| Abstrakt: |
Photoinduced electron transfer in light-absorbing materials is the first step towards charge separation and extraction in small molecule-based organic solar cells. The excited state dynamics of the cyanine dye cation Cy3 paired with a tetraphenylborate counter-anion (Cy3-B) was studied in pristine solid-state films of the dye and in blends with the electron acceptor material PCBM. Here we show that photoexcited Cy3-B in pure films undergoes intra-ion pair reductive quenching on the picosecond time scale, while in blends with PCBM sub-picosecond formation of the Cy3 oxidized species is observed upon electron injection from the dye excited state into the fullerene. Kinetic competition between light-induced electron- and hole transfer processes strongly depends on the PCBM content in the blends. A high PCBM loading produces a fully intermixed phase, where the cyanine oxidized states appear on ultrashort (＜160 fs) time scales. Lower PCBM contents, in contrast, lead to a Cy3-B segregated phase on top of the intermixed phase and slower excited state quenching. These findings show that the phase morphology indeed controls to a large extent the efficiency of primary photoinduced charge separation, on which small molecule-based organic photovoltaic cells rely. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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