Fullerene-based bistable devices and associated negative differential resistance effect

We have observed bistability in single layer devices made from fullerenes (C60) mixed with polystyrene (PS) and sandwiched between two Al electrodes. By merely changing the concentration of C60 in PS we found three distinctly different device properties, namely a true insulator, a bistable device switching between an OFF and an ON state having ON-OFF current ratios larger than 10(4) and a write-once, read-many times (WORM) device. An additional negative differential resistance (NDR) was observed in the ON state of both the bistable and WORM devices leading to multilevel switching capability of the devices. This opens up a wide range of application possibilities of such devices in disposable printable electronics. (c) 2005 Elsevier B.V. All rights reserved.