TY - JOUR
T1 - Breaking the Bimolecular Crystal
T2 - The Effect of Side-Chain Length on Oligothiophene/Fullerene Intercalation
AU - Burnett, Edmund K.
AU - Cherniawski, Benjamin P.
AU - Rosa, Stephen J.
AU - Smilgies, Detlef M.
AU - Parkin, Sean
AU - Briseno, Alejandro L.
N1 - Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/4/24
Y1 - 2018/4/24
N2 - Polymer/fullerene bimolecular crystal formation has been investigated using a variety of conjugated polymers and fullerenes to understand the design rules that influence donor-acceptor interaction. Modifications of the polymer by varying the substitution side-chain position, density, and branching have demonstrated the importance of the "pocket" dimensions (free volume between side chains where the fullerene resides) for controlling intercalation. Yet the effect of pocket height has not been systematically explored because of the solubility limitations in polymers. In this report, we present an experimental investigation into the effect of the pocket height by synthesizing poly[2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene] dimers with varied side chain lengths and track the morphological changes of the dimer/fullerene blends using grazing-incidence X-ray scattering, thermal measurements, and photoluminescence quenching. We identify two regimes: (1) oligomers with side chains greater than or equal to heptyl (C7) form bimolecular crystals and (2) oligomers with less than or equal to hexyl (C6) form amorphous blends. This work provides the first observation of an order-to-disorder transition mediated by side-chain length in donor-fullerene intercalated blends.
AB - Polymer/fullerene bimolecular crystal formation has been investigated using a variety of conjugated polymers and fullerenes to understand the design rules that influence donor-acceptor interaction. Modifications of the polymer by varying the substitution side-chain position, density, and branching have demonstrated the importance of the "pocket" dimensions (free volume between side chains where the fullerene resides) for controlling intercalation. Yet the effect of pocket height has not been systematically explored because of the solubility limitations in polymers. In this report, we present an experimental investigation into the effect of the pocket height by synthesizing poly[2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene] dimers with varied side chain lengths and track the morphological changes of the dimer/fullerene blends using grazing-incidence X-ray scattering, thermal measurements, and photoluminescence quenching. We identify two regimes: (1) oligomers with side chains greater than or equal to heptyl (C7) form bimolecular crystals and (2) oligomers with less than or equal to hexyl (C6) form amorphous blends. This work provides the first observation of an order-to-disorder transition mediated by side-chain length in donor-fullerene intercalated blends.
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U2 - 10.1021/acs.chemmater.7b04702
DO - 10.1021/acs.chemmater.7b04702
M3 - Article
AN - SCOPUS:85045935022
SN - 0897-4756
VL - 30
SP - 2550
EP - 2556
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 8
ER -