Abstract
In this paper, we investigated the recombination dynamics of photogenerated charge carriers in a poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) blend system with donor-acceptor ratio of 1:1 before and after solvent annealing treatment. The technique of transient photocurrent and photovoltage measurements were used, and charge carriers were photogenerated by a 7 ns laser pulse at room temperature (298 K). In transient photocurrent measurement, we observed some differences in the saturation extracted charge in P3HT:PCBM solar cells with different power efficiencies. In addition, the bimolecular recombination coefficient β is found to be 3.5×10−13 cm3 s−1 for annealed devices, while 9.5×10−12 cm3 s−1 for as-cast devices. In the transient photovoltage measurement, we found that the photovoltage decay can be fitted by power-law equation at long time scale. The exponent parameter α is 2.6 for annealed devices, which can be described as trap-free bimolecular recombination; α is 1.76 for as-cast device due to the trap-limited bimolecular recombination. These experimental results indicate that the nanomorphology of active layer indeed have influence on charge carriers dynamics in P3HT:PCBM blend systems.
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Li, D., Xing, Y., Yue, H. et al. Influence of nanostructure on the device performance and charge recombination dynamics of P3HT:PCBM solar cells. Chin. Sci. Bull. 57, 3436–3441 (2012). https://doi.org/10.1007/s11434-012-5204-1
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DOI: https://doi.org/10.1007/s11434-012-5204-1