Journal
ACS APPLIED MATERIALS & INTERFACES
Volume 10, Issue 42, Pages 36464-36474Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acsami.8b13255
Keywords
alignment; crystallization; solution processing; conjugated polymers; molecular weight
Funding
- NSF [1258425, IGERT-CIF21]
- Georgia Institute of Technology
- Brook Byers Institute for Sustainable Systems
- NSF IGERT NESAC traineeship from NSF [1069138]
- NSF FLAMEL IGERT traineeship program
Ask authors/readers for more resources
Understanding the role of the distribution of polymer chain lengths on process-structure-property relationships in semiconducting organic electronics has remained elusive due to challenges in synthesizing targeted molecular weights (M-w) and polydispersity indices. Here, a facile blending approach of various poly(3-hexylthiophene) (P3HT) molecular weights is used to investigate the impact of the distribution of polymer chain lengths on self-assembly into aggregates and associated charge transport properties. Low and high M-w samples were blended to form a highly polydisperse sample which was compared to a similar, medium M-w, control. Self-assembly was induced by preprocessing the polymer solution with UV irradiation and subsequent solution aging before deposition via blade-coating. Superior charge carrier (hole) mobilities were observed for the blend and control samples. Furthermore, their solution lifetimes exceeded 14 days. UV-vis spectral analysis suggests that low M-w P3HT lacks the mesoscale crystallinity required for percolative charge transport. In contrast, when the M-w is too high, the polymer rapidly aggregates, leading to paracrystalline disorder and structural inhomogeneity that interrupts charge-transfer pathways. The role of grain boundaries, fibrillar order, and macroscale alignment is characterized via grazing-incidence wide-angle X-ray scattering, atomic force microscopic, and optical microscopic techniques. The results presented here provide additional guidance on the interplay between polymer solubility, self-assembly, network interconnectivity, and charge transport to enable robust polymer ink formulations with reliable and reproducible performance attributes.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available