Two electronically delocalized molecules were designed as models to understand how molecular shape impacts the tradeoff between solubility and crystallization tendencies in molecular semiconductors. The more soluble compound TT contains a non-planar bithiophene central fragment, whereas CT has a planar cyclopentadithiophene unit. Calorimetry studies show that CT can crystallize more easily than TT. However, absorption spectroscopy shows that the initially amorphous TT film can eventually form crystals in which the molecular shape is significantly more planar. Two thermally reversible polymorphs for TT were observed by XRD and grazing-incidence wide-angle X-ray scattering (GIWAXS) measurements. These findings are relevant within the context of designing soft semiconductors that exhibit high solubility and a tendency to provide stable organized structures with desirable electronic properties.
|Original language||English (US)|
|Number of pages||4|
|Journal||Angewandte Chemie - International Edition|
|State||Published - Aug 1 2017|
Bibliographical noteFunding Information:
Work at UCSB was supported by the Office of Naval Research (ONR, Awards N00014-14-1-0580, N00014-16-1-2520, and N00014-17-1-2208) and the China Postdoctoral Science Foundation (No. 2016T90030). C. Z. and F. H. are supported by the Natural Science Foundation of China (No. 21520102006, 51603010, and 51521002). DFT studies at Georgia Tech were funded by the ONR (N00014-17-1-2208). XRD measurements were completed at the Materials Research Laboratory at UCSB, supported by NSF grant DMR-1121053. Use of the Stanford Synchrotron Radiation Lightsource, was supported by the Department of Energy, Office of Basic Energy Sciences (DE-AC02-76SF00515).
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
- conjugated molecules
- molecular topology
- organic semiconductors
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