Phase segregation mechanisms of small molecule‐polymer blends unraveled by varying polymer chain architecture
| Autor: | Jian Qin, Ming Shao, David Uhrig, Gong Gu, Jong K. Keum, Guoliang Li, Huada Lian, James F. Browning, Sanjib Das, Jihua Chen, Kai Xiao |
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| Rok vydání: | 2021 |
| Předmět: |
chemistry.chemical_classification
Materials science neutron reflectivity organic field‐effect transistors Polymer Small molecule polymer binders Chemical engineering Chain (algebraic topology) chemistry Phase (matter) TA401-492 Polymer blend phase separation Materials of engineering and construction. Mechanics of materials |
| Zdroj: | SmartMat, Vol 2, Iss 3, Pp 367-377 (2021) |
| ISSN: | 2688-819X |
| Popis: | As phase separation between the small‐molecule semiconductor and the polymer binder is the key enabler of blend‐based organic field‐effect transistors (OFETs) fabricated by low‐cost solution processing, it is crucial to understand the underlying phase separation mechanisms that determine the phase morphology, which significantly impacts device performance. Beyond the parameter space investigated in previous work, here we investigate the formation of blends by varying the branch architecture of the polymer binder and by shortening the solvent dry time using ultrasonic spray casting. The phase morphologies of the resulting blend films have been thoroughly characterized with a variety of techniques in three dimensions over multiple length scales, including AFM, energy‐filtered transmission electron microscope, and neutron reflectivity, and have been correlated with electrical transport performance. From the results, we have inferred that the phase morphology is kinetically determined, limited by the inherent slow movement of polymer macromolecules. The kinetic picture, supported by molecular dynamics modeling, not only consistently explains our observations but also resolves inconsistencies in previous works. The achieved mechanistic understanding will guide further optimization of blend‐based organic electronics, such as OFETs and organic photovoltaics. |
| Databáze: | OpenAIRE |
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