Polymeric Semiconductors: Molecular Ordering, Charge Transport and Macroscale Mobility - Elsa Reichmanis
From Kathryn Gentilello on February 27th, 2017
The performance of devices fabricated using polymeric semiconductors depends critically upon alignment of the polymer chains at the nano- through macro-scales. Significant structure-process- property relationships that allow for enhancement of long-range order will be described. For instance, a lyotropic liquid crystalline (LC) phase has been observed in poly-(3-hexylthiophene) (P3HT) via solvent-evaporation induced self-assembly. In-situ polarized Raman spectroscopy facilitated investigation of the evolution of structure that eventually was found to undergo a phase transition from an isotropic solution to LC phase. The insights gained through these investigations were applied to the design of an alternative, donor-acceptor (D-A) benzothiadiazole oligothiophene based copolymer material. For one family of copolymers, structural elements were found to provide for a span in hole mobility of approximately 3 orders of magnitude. Samples annealed at moderate temperatures exhibited mobilities in excess of 1 cm²/Vs. The lessons learned through these studies may allow for simple, controllable, and cost-effective methodologies for achieving high-performance plastic electronic devices.