TY - JOUR
T1 - Tuning the Morphology of All-Polymer OPVs through Altering Polymer–Solvent Interactions
AU - Pavlopoulou, Eleni
AU - Kim, Chang Su
AU - Lee, Stephanie S.
AU - Chen, Zhihua
AU - Facchetti, Antonio
AU - Toney, Michael F.
AU - Loo, Yueh-Lin
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-C1-015-21
Acknowledgements: We acknowledge funding from the Photovoltaics Program of ONR (N00014-11-10328), the MRSEC program at the NSF through Princeton Center for Complex Materials (DMR-0819860), and the Solar Initiative at the NSF (DMR-10135217). Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. M.F.T. thanks the Center for Advanced Molecular Photovoltaics (CAMP) (Award No KUS-C1-015-21), made possible by King Abdullah University of Science and Technology (KAUST).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
PY - 2014/8/27
Y1 - 2014/8/27
N2 - © 2014 American Chemical Society. In this work, we investigated the effects of solvent(s)-polymer(s) interactions on the morphology of all-polymer bulk-heterojunction (BHJ) active layers cast from cosolutions. We demonstrate that altering the interactions between the solvent and both the donor and acceptor polymers in the cosolution prior to film-casting induces different solid-state morphological characteristics that subsequently leads to differences in the device performance of organic photovoltaics (OPV). Poly(3-hexylthiophene), P3HT, was codissolved poly[[N,N'-bis(2-octyldodecyl)-napthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5 ′-(2,2 ′-bithiophene)], P(NDI2OD-T2), or otherwise known as ActivInk N2200, in dichlorobenzene, chlorobenzene, and xylene. According to the qualitative interaction map we propose, all three solvents exhibit favorable interactions with P3HT. The extent of incompatibility these solvents exhibit with P(NDI2OD-T2), however, varies, with xylene as the worst solvent for P(NDI2OD-T2) among those examined. Polymer-polymer interactions in xylene are, thus, more favorable compared to P(NDI2OD-T2)-xylene interactions. Grazing-incidence wide-angle X-ray scattering measurements on the cast films suggest that this preferential affinity between the two polymers disrupts crystallization in the blends; P(NDI2OD-T2) crystallinity decreases and, concurrently, results in shorter P3HT coherence lengths. Significant mixing of the two polymers is also evidenced. OPVs comprising P3HT and P(NDI2OD-T2) active layers cast from xylene exhibit the best device characteristics compared to OPVs whose active layers are cast from di- or mono-chlorobenzene. We attribute the improved OPV performance for the xylene-cast active layer to the presence of a more intermixed network of nanocrystalline domains of the two polymers, which originates from the affinity of P3HT and P(NDI2OD-T2) in the parent cosolution.
AB - © 2014 American Chemical Society. In this work, we investigated the effects of solvent(s)-polymer(s) interactions on the morphology of all-polymer bulk-heterojunction (BHJ) active layers cast from cosolutions. We demonstrate that altering the interactions between the solvent and both the donor and acceptor polymers in the cosolution prior to film-casting induces different solid-state morphological characteristics that subsequently leads to differences in the device performance of organic photovoltaics (OPV). Poly(3-hexylthiophene), P3HT, was codissolved poly[[N,N'-bis(2-octyldodecyl)-napthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5 ′-(2,2 ′-bithiophene)], P(NDI2OD-T2), or otherwise known as ActivInk N2200, in dichlorobenzene, chlorobenzene, and xylene. According to the qualitative interaction map we propose, all three solvents exhibit favorable interactions with P3HT. The extent of incompatibility these solvents exhibit with P(NDI2OD-T2), however, varies, with xylene as the worst solvent for P(NDI2OD-T2) among those examined. Polymer-polymer interactions in xylene are, thus, more favorable compared to P(NDI2OD-T2)-xylene interactions. Grazing-incidence wide-angle X-ray scattering measurements on the cast films suggest that this preferential affinity between the two polymers disrupts crystallization in the blends; P(NDI2OD-T2) crystallinity decreases and, concurrently, results in shorter P3HT coherence lengths. Significant mixing of the two polymers is also evidenced. OPVs comprising P3HT and P(NDI2OD-T2) active layers cast from xylene exhibit the best device characteristics compared to OPVs whose active layers are cast from di- or mono-chlorobenzene. We attribute the improved OPV performance for the xylene-cast active layer to the presence of a more intermixed network of nanocrystalline domains of the two polymers, which originates from the affinity of P3HT and P(NDI2OD-T2) in the parent cosolution.
UR - http://hdl.handle.net/10754/599845
UR - https://pubs.acs.org/doi/10.1021/cm502112z
UR - http://www.scopus.com/inward/record.url?scp=84908013286&partnerID=8YFLogxK
U2 - 10.1021/cm502112z
DO - 10.1021/cm502112z
M3 - Article
SN - 0897-4756
VL - 26
SP - 5020
EP - 5027
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 17
ER -