Reversible and Persistent Electrical Bistability in Single Crystals of a Self-Assembled π-Conjugated Tetraaryl System:  A Submicrometer Scale Electrical Characterization

A new π-conjugated electroactive 4,4‘-bipyridinium that bears two pyridazone self-complementary units was prepared and characterized. The new system readily assembles and forms at least two stable charge-transfer crystalline structures having a thermal population of unpaired electrons. The crystals of one phase exhibit electrical bistability, displaying either high (ON) and low (OFF) conductivity, at the same applied bias, depending on the electrical history of the system. The relation between the supramolecular structure of the crystals and their electrical properties is also discussed.