Transparent conducting layers and photovoltaic devices including the same

A tandem photovoltaic device comprising:

• a thin film junction comprising an absorber layer comprising cadmium and tellurium;
• a second junction electrically connected with the thin film junction, wherein the second junction is closer to a back side of the tandem photovoltaic device than the thin film junction;
• and
• a transparent conducting layer disposed between the thin film junction and the second junction, wherein:
• the transparent conducting layer comprises a high conductivity layer, a diffusion barrier layer, and a capping layer,
• the diffusion barrier layer comprises cadmium stannate,
• the capping layer comprises cadmium stannate,
• the high conductivity layer comprises cadmium oxide doped “++” type intrinsically or with an oxide dopant, and
• the high conductivity layer is between the diffusion barrier layer and the capping layer.