Abstract: Ultrafast near-infrared absorption spectroscopy was used to investigate the influence of film morphology and excitation photon energy on the charge recombination (CR) dynamics in the initial nanosecond timescale in the P3HT/PC61BM blend films. With reference to the CS2-cast films, the solvent vapor annealed (SVA) ones show 2–3-fold improvement in hole mobility and more than 5-fold reduction in the polymer-localized trap states of holes. At Dt = 70 ps, the hole mobility (mh) and the bimolecular CR rate (gbi) of the SVA films are mh = 8.7 × 10−4 cm2×s−1×V−1 and gbi = 4.5 × 10−10 cm3×s−1, whereas at Dt = 1 ns they drop to 8.7 × 10−5 cm2×s−1×V−1 and 4.6 × 10−11 cm3×s−1, respectively. In addition, upon increasing the hole concentration, the hole mobility increases substantially faster under the above-gap photoexcitation than it does under the band-gap photoexcitation, irrespective of the film morphologies. The results point to the importance of utilizing the photogenerated free charges in the early timescales.
This is an open access article distributed under the
Creative Commons Attribution License which permits unrestricted use, distribution,
and reproduction in any medium, provided the original work is properly cited.
Export to BibTeX
MDPI and ACS Style
Zhang, W.; Zhao, N.-J.; Huo, M.-M.; Fu, L.-M.; Ai, X.-C.; Zhang, J.-P. Subnanosecond Charge Recombination Dynamics in P3HT/PC61BM Films. Molecules 2012, 17, 13923-13936.
Zhang W, Zhao N-J, Huo M-M, Fu L-M, Ai X-C, Zhang J-P. Subnanosecond Charge Recombination Dynamics in P3HT/PC61BM Films. Molecules. 2012; 17(12):13923-13936.
Zhang, Wei; Zhao, Ning-Jiu; Huo, Ming-Ming; Fu, Li-Min; Ai, Xi-Cheng; Zhang, Jian-Ping. 2012. "Subnanosecond Charge Recombination Dynamics in P3HT/PC61BM Films." Molecules 17, no. 12: 13923-13936.