SOLID-STATE REDOX DIODE COMPOSED OF AN ELECTROPOLYMERIZED METALLOCENE LAYER AND A POLYMER ELECTROLYTE LAYER CONTAINING A REDOX COUPLE IN A MIXED-VALENT STATE

Redox bilayer devices, SnO2/poly-Cc+/PEO-Li+,Fc+/0/SnO2; SnO2/poly-Cc+/PEO-Li+,DDQ0/-/SnO2; SnO2/poly-Cc+/PEO-Li+, TCNQ0/-/SnO2 and SnO2/poly-Fc/PEO-Li+, TCNQ0/-/SnO2 have been constructed and their i vs. DELTA-E characteristics investigated. Poly-Cc+, poly-Fc and PEO represent polymers formed by electrochemical reduction of 1,1'-bis(1-chloro-2-formylvinyl)cobaltocenium salt and 1,1'-bis(chloromethyl)ferrocene, and cross-linked poly(ethylene oxide), respectively. All the devices show diode-like i vs. DELTA-E characteristics, which relate to the difference in redox potentials between the two layers, DELTA-E0'. The i vs. DELTA-E curves obtained can be analysed by a simple model assuming that the diffusion-controlled electron transfer at the interface of the layers and/or the charge diffusion in the polymer electrolyte layer limit the electron conduction rate.