An SEM Study of the Nature of the Electrochemical Deposit in Reversible Electrodeposition Displays

SEM‐x‐ray spectroscopic studies of display cells based on reversible electrodeposition (RED's) conclusively show that the deposit is composed of elemental silver, regardless of its color (gold, gray, black, red‐brown, etc.) A gold deposit is shown to consist of finely dispersed (colloidal) silver particles, while the black deposit consists of a spongy type of deposit of elemental silver. This fact means that the mechanism of operation of these dispersive displays is due to collective electromagnetic scattering effects of colloidal silver. Confirming evidence that particles form in‐depth contacts is also presented.