Surface Immobilized Heteroleptic Copper Compounds as State Variables that Show Negative Differential Resistance

Surface immobilized bidentate heteroleptic Cu(I) compounds are synthesized using a surface outward sequential synthesis and are characterized using solid-state NMR and atomic force microscopy (AFM). Through use of chemical redox agents, the reversible switching characteristics of SiO 2 -immobilized Cu(I) compounds (tetrahedral) to Cu(II) (square planar) are verified via UV−visible absorption spectroscopy and electron paramagnetic resonance. Electrical properties of this system are characterized via preparation of a sandwich-type device using p + silicon and conductive AFM (cAFM). Current−Voltage (I−V) spectroscopy demonstrates that this system reproducibly switches between Cu(I) and Cu(II) states at approximately −0.8 and 2.3 V.