Electrochromism and Photochromism in MoO3 Films

Abstract

Electrical properties of amorphous evaporated electrochromic (molybdenum trioxide) films were studied in various ambients. It is shown that at a given applied voltage there is a "humidity threshold" below which coloration does not occur. The transient behavior of the current and remnant voltage in low humidity (precoloration), high humidity (postcoloration), and in the transition stage is shown to be consistent with an electrochemical interpretation of the coloration process. Changes in solubility upon electrical coloration and u.v. photocoloration verify that a chemical change accompanies the color change.