Tailoring PEIE capped ZnO binary cathode for solution-processed inverted organic solar cells

Abstract Very recently, the combination of aqueous solution ZnO and polyethyleneimine-ethoxylated (PEIE) has attracted special consideration as an outstanding cathode buffer layer for inverted organic solar devices. In this framework, the sol-gel technique was used to synthesis ZnO electron transporting layer for inverted polymer solar cells (i-PSCs), the molar ratios of zinc acetate dehydrate (ZAD) to ethanolamine (MEA) were set as 1:0.8, 1:1 and 1:2. We investigated ZnO combined with PEIE, using low temperature solution-processed, which can be an excellent cathode buffer layer for efficient inverted polymer solar cells (i-PSCs). A high-power conversion efficiency of 4.48% was achieved for ZnO (1:1)/PEIE cathode buffer layer-based device, which is higher than the controlled device with ZnO only.