Synthesis, crystal structures, optoelectronic properties and resistive memory application of π-conjugated heteroaromatic molecules

Abstract

Three π-conjugated small molecules DPBT, DEPBT and DEPBPy, based on bithiazole or bipyridine were designed and synthesized. In DEPBT and DEPBPy, the central core and terminal phenyl groups are connected by CC double bonds, whereas in DPBT, they are combined through C–C single bonds. The effects of the molecular structural changes on their crystal structures, optoelectronic properties and thin film morphologies were comparatively studied. In addition, their resistive memory performance was primarily investigated for the first time. Both DEPBT- and DEPBPy-based devices exhibit typical binary memory behavior, while DPBT-based device presents no memory property. The experimental results confirm that the introduction of CC bridged bonds into molecules could enhance the molecular interaction, which plays an important role in the molecular arrangement on the thin film, and has a significant contribution to charge transport in memory devices. This work demonstrates that aryl vinyl terminated bithiazoles and bipyridines both are good promising candidates for organic memory storage.