Tuning carrier transport properties of thienoisoindigo-based copolymers by loading fluorine atoms onto the diarylethylene-based electron-donating units

摘要

AbstractHerein, we demonstrate an effective fine-tuning of carrier transport properties in polymer semiconductors by loading fluorine atoms on polymericπ-systems. To a thienoisoindigo-based conjugated backbones, we?introduced dithiophenethene, difluorodithiophenethene, difluorodiphenylethene, and tetrafluorodiphenylethene units affording D?A copolymers, PTIDTE, PTIFDTE, PTIDFPE, and PTITFPE, respectively. PTIDTE and PTIDFPE exhibited unipolarp-channel transport properties with mobilities of 0.24 and 0.11?cm2?V?1?s?1, respectively, whereas PTIFDTE and PTITFPE afforded ambipolar transport properties with?the highest hole/electron mobilities of 0.072/0.017?cm2?V?1?s?1and 0.017/0.0034?cm2?V?1?s?1, respectively. Thin film microstructure studies (AFM and 2D-GIXRD) suggest that more ordered lamellar and?predominantly edge-on molecular packing mode formed in the PTIFDTE and PTITFPE thin films though they own inferior surface morphologies. The thienoisoindigo-based polymers' backbone conformations were purposed to interpret their different molecular packing mode in solid state, revealing that single conjugated backbone conformations are much easier to form for PTIFDTE and PTITFPE.