Synthesis of folded H-stacking skipped π polymers consisting of different 2-substituted trimethylene tethering units and their optical and conductive property

Abstract

A series of polymers P1–P4 ([–CH2CH(Z)CH2–(π conjugated unit)–]n, where Z = a bulky substituent) were synthesized via the Suzuki–Miyaura coupling polymerization and predominantly existed in their folded H-stacking form in the solution and film, which was evidenced by ultraviolet absorption, fluorescent behavior, and X-ray diffraction analysis. The morphology of the polymers in the solid states was dependent on the structure of the Z group present. The conductive nature of P1–P4 was preliminarily demonstrated on hole-only devices. Moreover, a similar onset voltage was observed for P1–P3, which all contained the same π units; however, their current–voltage characteristics were highly dependent on the Z structure. P4, which contained cross-conjugated π units, exhibited a relatively high conductivity with a lower onset requirement.