Zinc Tin Oxide (ZTO) electron transporting buffer layer in inverted organic solar cell

► We introduce Zinc Tin Oxide (ZTO) as electron transporting layer in organic solar cell. ► Solution processed ZTO displays high electron mobility with excellent optical transparency. ► A comparative study of ZTO and TiOx buffer layers in inverted solar cells was performed. ► An efficiency of 3.05% was achieved for ZTO compared to 2.71% for TiOx.