Zinc oxide-doped indium oxide (IZO): an amorphous transparent conducting oxide for use in tandem solar cells

Zinc oxide-doped indium oxide (IZO) is an amorphous transparent conducting oxide (TCO) exhibiting excellent properties for use in tandem solar cells. Similar to high mobility TCOs, it has a reduced absorption of near IR photons leading to an increased transmission to the bottom cell in a tandem stack. As a result, IZO is a potential replacement of traditional TCOs used as the top contact in the Cu(In,Ga)Se2 cell when used in a tandem solar cell. A monolithically fabricated dye-sensitized|Cu(In,Ga)Se2 tandem solar cell suffers from corrosion of the Cu(In,Ga)Se2 absorber by the DSC electrolyte. This paper reports the successful use of IZO to reduce the rate of etching compared to AZO of similar thickness, when used to prevent the etching of an Au substrate.