Controlling interchain interactions in conjugated polymers is critical to the development of high performance materials. These interchain interactions are dictated by the aggregation and self-assembly of conjugated polymers in solution and from processing steps, such as thermal annealing, in the solid state. Herein, a macrocyclic benzodithiophene building block for conjugated polymers is developed, and the properties of the resulting polymers are compared to analogous acyclic derivatives. The properties of small molecule macrocyclic BDT compounds show the influence of the side-chain substitution on the thermodynamic forces of self-assembly. Comparison of the optical properties of conjugated polymers with macrocyclic and acyclic side-chains in solution and the solid state reveals the ability of the macrocyclic side-chain to modify the structure of aggregates. Grazing incidence wide-angle X-ray scattering shows that the macrocyclic polymers can remain ordered in the solid state while having higher photoluminescence yields than the acyclic derivatives.
This work was supported through the NSF DMR 1436263. The authors also acknowledge the use of UCSB MRL Shared Experimental Facilities which are supported by the MRSEC Program of the NSF under Award No. DMR 1720256. BM would like to thank the DoD and ASEE for funding through the NDSEG Fellowship program. EL received support from a National Science Foundation Graduate Research Fellowships (DGE-1144085). LMK is grateful for an Elings Prize Postdoctoral Fellowship. PIR received partial support through LSAMP program of the National Science Foundation under Award no. DMR-1102531. Single crystal X-ray analysis was performed by Dr. Guang Wu at the UCSB X-ray Analysis Facilities. GIWAXS experiments were performed at the Stanford Synchrotron Radiation Lightsource (beamline 11-3). Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515.
