Tribo-corrosion of Ag and Ag-alloy ITO multilayers used in solar energy applications

The efficiency and long term reliability of multilayered films of Ag/Ag-alloy based indium tin oxide (ITO) used in solar energy applications depend on the surface integrity of the film. Surface integrity can be breached due to exposure to a harsh outdoor environment and mishandling. It is therefore important to study the tribo-corrosion properties of such film systems. Reciprocating polytetrafluoroethylene (PTFE) ball-on-film tests are conducted in a NaCl solution under moderate loading conditions and increasing number of cycles. Ag, Ag–Pd and Ag–Au alloy based ITO multilayers, deposited on a polymer substrate, are used and the tribo-corrosion resistance is investigated. Electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy are used, after testing, in order to characterize and determine the corrosion and wear mechanisms. The effect of the reciprocating cycles on the multilayer failure initiation and propagation is studied. The resulting tribo-corrosion mechanisms are observed using scanning electron and optical microscopy. Understanding the tribo-corrosion properties of such model multilayers can lead to increasing the efficiency and long term reliability of various solar energy and energy-efficient systems.