TY - JOUR
T1 - Signatures of intracrystallite and intercrystallite limitations of charge transport in polythiophenes
AU - Vakhshouri, Kiarash
AU - Smith, Brandon H.
AU - Chan, Edwin P.
AU - Wang, Chenchen
AU - Salleo, Alberto
AU - Wang, Cheng
AU - Hexemer, Alexander
AU - Gomez, Enrique D.
N1 - Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/10/11
Y1 - 2016/10/11
N2 - Charge carrier mobilities in conjugated semicrystalline polymers depend on morphological parameters such as crystallinity, crystal orientation, and connectivity between ordered regions. Despite recent progress in the development of conducting polymers, the complex interplay between the aforementioned parameters and their impact on charge transport is not fully understood. By varying the casting solvents and thermal annealing, we have systematically modulated the crystallization of poly(3-hexylthiophene-2,5-diyl) (P3HT) and poly[2,5-bis(3-hexadecylthiophen-2-yl)thieno(3,2-b)thiophene] (PBTTT) thin films to examine the role of microstructure on charge mobilities. In particular, we achieve equal crystallinities through different processing routes to examine the role of structural parameters beyond the crystallinity on charge mobilities. As expected, a universal relationship does not exist between the crystallinity in either P3HT and PBTTT active layers and the charge mobility in devices. In P3HT films, higher boiling point solvents yield longer conjugation lengths, an indicator of stronger intracrystalline order, and therefore higher device mobilities. In contrast, the charge mobilities of PBTTT devices depend on the interconnectivity between crystallites and intercrystalline order in the active layer.
AB - Charge carrier mobilities in conjugated semicrystalline polymers depend on morphological parameters such as crystallinity, crystal orientation, and connectivity between ordered regions. Despite recent progress in the development of conducting polymers, the complex interplay between the aforementioned parameters and their impact on charge transport is not fully understood. By varying the casting solvents and thermal annealing, we have systematically modulated the crystallization of poly(3-hexylthiophene-2,5-diyl) (P3HT) and poly[2,5-bis(3-hexadecylthiophen-2-yl)thieno(3,2-b)thiophene] (PBTTT) thin films to examine the role of microstructure on charge mobilities. In particular, we achieve equal crystallinities through different processing routes to examine the role of structural parameters beyond the crystallinity on charge mobilities. As expected, a universal relationship does not exist between the crystallinity in either P3HT and PBTTT active layers and the charge mobility in devices. In P3HT films, higher boiling point solvents yield longer conjugation lengths, an indicator of stronger intracrystalline order, and therefore higher device mobilities. In contrast, the charge mobilities of PBTTT devices depend on the interconnectivity between crystallites and intercrystalline order in the active layer.
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U2 - 10.1021/acs.macromol.6b01086
DO - 10.1021/acs.macromol.6b01086
M3 - Article
AN - SCOPUS:84991384239
SN - 0024-9297
VL - 49
SP - 7359
EP - 7369
JO - Macromolecules
JF - Macromolecules
IS - 19
ER -