TY - JOUR
T1 - Small-angle neutron scattering of P(NDI2OD-T2) solutions
T2 - Importance of network structure for data interpretation and film morphology
AU - Tan, Wen Liang
AU - Tang, Linjing
AU - Matsidik, Rukiya
AU - Bryant, Gary
AU - Martin, Tyler B.
AU - Sommer, Michael
AU - Huang, David M.
AU - McNeill, Christopher R.
N1 - Funding Information:
We acknowledge the support of the National Institute of Standards and Technology, U.S. Department of Commerce, in providing the neutron research facilities used in this work. This work was performed in part at Melbourne Centre for Nanofabrication (MCN) in the Victoria Node of the Australian National Fabrication Facility (ANFF). The authors acknowledge the facilities, and the scientific and technical assistance of the RMIT Microscopy & Microanalysis Facility (RMMF), a linked laboratory of Microscopy Australia, enabled by NCRIS. This work was also performed in part at the SAXS/WAXS beamline at the Australian, part of ANSTO. The work was supported by the Australian Research Council (DP190102100). C.R.M. thanks Dean DeLongchamp for hosting his sabbatical stay at NIST during which the SANS data was taken, and Monash University for supporting his Outside Studies Programme.
Publisher Copyright:
© 2024 American Chemical Society.
PY - 2024/1/23
Y1 - 2024/1/23
N2 - Small-angle neutron scattering (SANS) is used to study the solution-phase behavior of the well-studied n-type semiconducting polymer P(NDI2OD-T2). To provide a global overview of polymer behavior, four different molecular weight samples are studied in three different solvents and at three different temperatures. The SANS data are interpreted in terms of a hierarchical model combining a cylinder model to explain scattering from individual rigid chains/aggregates at high scattering vector, q, and a Guinier-Porod model to explain the upturn in scattering at low q that appears in the SANS patterns of the higher molecular weight samples. In this way, the scattering patterns of P(NDI2OD-T2) solutions with different molecular weights, different solvents, and at different temperatures can all be adequately modeled and parametrized in terms of varying cylinder length, cylinder width, and mass fractal dimension. To connect the SANS results to thin film microstructure and charge transport, thin films are prepared and studied with atomic force microscopy and organic field effect transistor (OFET) measurements. Significantly, excess network formation in solution is associated with a decrease in the in-plane alignment of polymer chains and decrease in OFET mobility. Thus, while increased aggregation can enhance chain ordering and charge transport in thin films, excess aggregation in the form of a compact entangled network of these aggregates can be detrimental to the formation of ordered structures during solution deposition.
AB - Small-angle neutron scattering (SANS) is used to study the solution-phase behavior of the well-studied n-type semiconducting polymer P(NDI2OD-T2). To provide a global overview of polymer behavior, four different molecular weight samples are studied in three different solvents and at three different temperatures. The SANS data are interpreted in terms of a hierarchical model combining a cylinder model to explain scattering from individual rigid chains/aggregates at high scattering vector, q, and a Guinier-Porod model to explain the upturn in scattering at low q that appears in the SANS patterns of the higher molecular weight samples. In this way, the scattering patterns of P(NDI2OD-T2) solutions with different molecular weights, different solvents, and at different temperatures can all be adequately modeled and parametrized in terms of varying cylinder length, cylinder width, and mass fractal dimension. To connect the SANS results to thin film microstructure and charge transport, thin films are prepared and studied with atomic force microscopy and organic field effect transistor (OFET) measurements. Significantly, excess network formation in solution is associated with a decrease in the in-plane alignment of polymer chains and decrease in OFET mobility. Thus, while increased aggregation can enhance chain ordering and charge transport in thin films, excess aggregation in the form of a compact entangled network of these aggregates can be detrimental to the formation of ordered structures during solution deposition.
UR - http://www.scopus.com/inward/record.url?scp=85182568736&partnerID=8YFLogxK
U2 - 10.1021/acs.macromol.3c01435
DO - 10.1021/acs.macromol.3c01435
M3 - Article
AN - SCOPUS:85182568736
SN - 0024-9297
VL - 57
SP - 691
EP - 706
JO - Macromolecules
JF - Macromolecules
IS - 2
ER -