Paterno, Giuseppe; Warren, Anna J.; Spencer, Jacob; Evans, Gwyndaf; Sakai, Victoria Garcia; Blumberger, Jochen; Cacialli, Franco
Micro-focused X-ray diffraction characterization of high-quality [6,6]-phenyl-C-61-butyric acid methyl ester single crystals without solvent impurities
JOURNAL OF MATERIALS CHEMISTRY C, 1:5619-5623, 2013

We report the preparation of high-quality, solvent-free [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM) large single crystals (size up to 0.5 mm) by slow drying of a chlorobenzene solution at room temperature. The monoclinic structure containing four PCBM molecules per unit cell was successfully solved (R-factor = 0.0512) via micro-focused X-ray diffraction and employed as a reliable experimental model for further molecular dynamics simulations. We find that the first peak of the simulated fullerene-fullerene radial distribution function is centred at 10.05 angstrom, giving a nearest neighbour coordination number of 7.0. The work reported herein provides the structural basis for a fundamental understanding of charge transport in this important functional material that is particularly relevant to organic solar cells.

DOI:10.1039/c3tc31075b

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