Numerical and experimental investigation of transparent and conductive TiOx/Ag/TiOx electrode

Indium Tin Oxide (ITO) is the most commonly used transparent and conductive electrode (TCE) for organic solar cells and other optoelectronic components. One possible alternative to ITO is to use an Oxide | Metal | Oxide multilayer TCE. A numerical and experimental study resulting in an optically and electrically optimized TiOx | Ag | TiOx (TAT) TCE is presented. Single Ag and TiOx layers as well as Ag | TiOx and TiOx | Ag bilayers are first investigated. Both oxide thicknesses are then adjusted to give to the TAT trilayer electrode its best transparency in the considered absorption spectral band. The metal layer thickness controls both electrical and optical (mainly in the near-infrared spectral range) properties of the electrode. Electrodes with such TiOx (37 nm)|Ag (13 nm)|TiOx (42 nm) design have been produced, which present excellent balance between transparency - 91% of solar energy in the target spectral band that passes through the multilayer - and sheet resistance - average value around 4.7 Ω/□.