Enhanced Adhesion Energy at Oxide/Ag Interfaces for Low-Emissivity Glasses: Theoretical Insight into Doping and Vacancy Effects

Abstract

Low-emissivity glasses rely on multistacked architectures with a thin silver layer sandwiched between oxide layers. The mechanical stability of the silver/oxide interfaces is a critical parameter that must be maximized. Here, we demonstrate by means of quantum-chemical calculations that a low work of adhesion at interfaces can be significantly increased <i>via</i> doping and by introducing vacancies in the oxide layer. For the sake of illustration, we focus on the ZrO₂(111)/Ag(111) interface exhibiting a poor adhesion in the pristine state and quantify the impact of introducing n-type dopants or p-type dopants in ZrO₂ and vacancies in oxygen atoms (<i>n</i>V_O; with <i>n</i> = 1, 2, 4, 8, 10, 16), zirconium atoms (<i>m</i>V_Zr; with <i>m</i> = 1, 2, 4, 8), or both (<i>n</i>V_O + <i>m</i>V_Zr; with <i>m</i>/<i>n</i> = 1:2, 1:4, 2:2, 2:4). In the case of doping, interfacial electron transfer promotes an increase in the work of adhesion, from initially 0.16 to ∼0.8 J m^-2 (n-type) and ∼2.0 J m^-2 (p-type) at 10% doping. A similar increase in the work of adhesion is obtained by introducing vacancies, <i>e.g</i>., V_O [V_Zr] in the oxide layer yields a work of adhesion of ∼1.5-2.0 J m^-2 at 10% vacancies. An increase is also observed when mixing V_O and V_Zr vacancies in a nonstoichiometric ratio (<i>n</i>V_O + <i>m</i>V_Zr; with 2<i>n</i> ≠ <i>m</i>), while a stoichiometric ratio of V_O and V_Zr has no impact on the interfacial properties.