Establishing Substoichiometric Ag Oxidation and Its Physicochemical, Optoelectrical, and Structural Consequences for Ag Electrodes

Oxidation is adversely associated with inducing catastrophic degradation of the electrical and optical properties of Ag film electrodes. Existing information is largely distributed across thermodynamically favorable, stoichiometric, and higher oxidation states. However, this information is elusive in affording a better understanding of substoichiometric oxidation in extremely oxygen-deficient states because conventional perspectives disregard the plausibility of substoichiometric oxidation. This study presents computational and experimental evidence for the implementation of substoichiometric Ag oxidation with unique physicochemical properties that are clearly discordant with those of the stoichiometric and higher oxidation states. Further, characterization results confirmed the favorable contribution of extreme substoichiometric oxidation to morphological/structural improvements by hindering the oxidation-induced optoelectrical degradations of Ag film electrodes. The unexpected outcomes of substoichiometric oxidation can be attributed to the spontaneous reduction of the oxide phases under ambient atmosphere conditions at 20 °C and 40% relative humidity, owing to their thermodynamic instabilities, while successfully implementing the oxidation-mediated, two-dimensional growth of Ag films. These findings provide a comprehensive understanding beyond the conventional conclusions drawn from stoichiometric and higher oxide phases. Therefore, the precise control of substoichiometric oxidation facilitates the preparation of highly efficient Ag electrodes by successfully implementing ultralow optoelectrical losses and structural deficiencies for Ag films simultaneously.