HOPV12 - Blogs

4 th Hybrid and Organic Photovoltaic Conference -Uppsala 2012 190
C69 - Imaging the Bulk Nanoscale Morphology of Polymer:Fullerene Blend Thin-films
Using Helium Ion Microscopy
Andrew Pearson *a , Stuart Boden b , Darren Bagnall b , David Lidzey a , Cornelia Rodenburg c
a, Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH, GB
b, Electronics and Computer Science, University of Southampton, Highfield, Southampton, SO17 1BJ, GB
c, Engineering Materials, University of Sheffield, Mappin Street, Sheffield, S1 3JD , GB
The development of Organic Photovoltaics (OPVs) has seen the use of a wide range of
complimentary techniques for materials characterisation. Here we report and evaluate the use
of helium ion microscopy (HeIM) for imaging the nanoscale structure in samples applicable for
OPVs (1). For a poly(3-hexylthiophene)/[6,6]-phenyl C61-butric acid methyl ester (P3HT/PCBM)
blend thin-film subject to a thermal anneal at 140°C, we identify a network structure that is
not apparent at the film surface, with slightly elongated PCBM nanodomains.
Figure 1 HeIM image of a P3HT/PCBM (60:40 wt%) blend thin-film after thermal annealing at 140°C
The absence of similar features in blend thin-films subject to different annealing
treatments, or correlation between secondary electron yield and variations in surface
topography suggest the HeIM is capable at imaging spatial variations in chemical structure
with nanometer resolution. The calculated lateral spatial periodicity of the film (20±4nm) is
consistent with other studies of this system, demonstrating HeIM as a promising technique for
the characterization of organic semiconductor thin-films.
References
[1] Pearson, A. J.; Boden, S. A.; Bagnall, D. M.; Lidzey, D. G.; Rodenburg, C., Imaging the Bulk Nanoscale Morphology
of Organic Solar Cell Blends Using Helium Ion Microscopy. Nano Letters 2011, 11 (10), 4275-4281.
© SEFIN 2012