Enhanced Electrochemical Stability of TiO2-Protected, Al-doped ZnO Transparent Conducting Oxide Synthesized by Atomic Layer Deposition

Transparent, conductive coatings on porous, three-dimensional materials are often used as the current collector for photoelectrode designs in photoelectrochemical applications. These structures allow for improved light trapping and absorption in chemically synthesized, photoactive overlayers while minimizing parasitic absorption in the current collecting layer. Atomic layer deposition (ALD) is particularly useful for fabricating transparent conducting oxides (TCOs) like Sn-doped In2O3 (ITO) and Al-doped ZnO (AZO) for structured materials because the deposition is specific to exposed surfaces. Unlike line-of-sight deposition methods (evaporation, spray pyrolysis, sputtering), ALD can access the entire complex interface to make a conformal transparent conductive layer. While ITO and AZO can be grown by ALD, they are intrinsically soluble in the acidic and basic environments common for electrochemical applications like water splitting. To take advantage of the unique characteristics of ALD in these applicati...