(521i) Directing Multi-Scale Assembly and Alignment of Printed Conjugated Polymers

Self-assembly and crystallization have played a central role in the development of modern electronics and energy materials. Recent years, conjugated polymers have emerged as a new class of electronic and photoelectronic materials that are light-weight, flexible and can be solution printed at low cost and high throughput. Conjugated polymers have demonstrated potential uses in a diverse range of applications from transistors, thermoelectrics, sensors, light-emitting diodes to solar cells etc.

Charge transport in conjugated polymers is influenced over orders of magnitude by morphology parameters across all length scales, in particular crystallinity and molecular order within the domains and degree of alignment between the crystalline domains. The crystallization and morphology characteristics of rigid, short conjugated polymers stand in contrast to the traditionally studied flexible long chain polymers. In addition, during solution printing, the crystallization process is strongly coupled with the mass transport, fluid dynamics, and interfacial properties. Despite the critical importance of crystallization to morphology and charge transport, conjugated polymer crystallization remains poorly understood and challenging to control, particularly in the context of solution printing.

In this talk, we present new insights and strategies we recently developed for controlling multi-scale assembly of conjugated polymers that are directly compatible with solution printing. With high degree of control over thin film alignment, molecular packing and mesoscale structures, we further correlate these morphological characteristics with anisotropic charge transport properties towards establishing structure-property relationships and for understanding the interplay between intrachain and interchain charge transport.