A generally applicable method has been developed for fabricating highly transparent ultrathin Ag films on both glass and plastic substrates using the self-assembled monolayer modified ZnO/Ag/ZnO tri-layer structure. The resulting films show remarkably low surface roughness with very high transparency (>80% between 400 and 600 nm) and low surface resistance (8.61 Omega/square). With an inverted architecture, the devices based on the SAM modified tri-layer UTMF electrode show superior performance and mechanical properties than those using ITO electrode on both glass and plastic substrates.