Organic Photovoltaic Devices with Ga-doped ZnO$_{2}$ electrode

We report two organic photovoltaic devices using a Ga-doped ZnO$_{2}$ (GZO) film as a transparent conducting electrode. In the first structure, the conventional In$_{2}$O$_{3}$:Sn (ITO) hole-collecting anode was replaced by GZO and an efficiency of 0.35 {\%} was obtained. The second has the inverse structure where GZO was used as the electron-collecting cathode and gave a nonoptimized device efficiency of about 1.4 {\%}. Furthermore, this inverse structure of GZO devices provides a passivation layer to protect the active layer from the atmosphere.