Multilevel conductivity and conductance switching in supramolecular structures of an organic molecule

We have demonstrated conductance switching between multilevel states in devices based on Rose Bengal molecules embedded in supramolecular matrices. Two mechanisms, namely electroreduction and conformational change of the molecules, resulting in conjugation modification have been proposed to be applicable in these devices. In a low voltage region, reverse-bias induced electroreduction of Rose Bengal facilitated conjugation restoration in the backbone of the molecule and, hence, switching to a high-conducting state. At high biases, the two perpendicular planes present in Rose Bengal, which have permanent dipole moments, allowed forward-bias induced conformation change to occur, and results in conductance switching. We have demonstrated how the devices can switch between two pair of conducting states for random-access memory and read-only memory applications for several hours. (C) 2004 American Institute of Physics.