Locally-distributed electrode and method of fabrication

Abstract

A locally distributed electrode is made by placing a conducting metallic oxide layer and a counter electrode in contact with a noble metal electroplating solution and applying a negative potential to the metallic oxide layer relative to the counter electrode, such that the noble metal is electrodeposited from the solution preferentially at defect sites on a surface of the metallic oxide layer. The noble metal nuclei are selectively electrodeposited at the defect sites to form a locally distributed electrode made up of a dot matrix of metallic islands. For reversible electrochemical mirror (REM) devices, the presence of the noble metal renders mirror metal electrodeposition at the defect sites reversible so that the defects become part of the dot matrix electrode and extraneous deposition of the mirror metal on the conducting metallic oxide is avoided. This method avoids the use of expensive photolithography, is readily scalable to large areas, and produces electrodes that offer the optimum compromise between high current carrying capability and high light transmission.