High performance inverted bulk heterojunction solar cells by incorporation of dense, thin ZnO layers made using atmospheric atomic layer deposition

A thin ZnO (<200 nm) film grown by Atmospheric Atomic Layer Deposition (AALD) in a matter of minutes was studied as a hole-blocking layer in poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61-buyric acid methyl ester (P3HT:PCBM) based inverted solar cells. These AALD ZnO layers were compact, had a high electron mobility of 3.4+0.1 cm2/Vs, had up to 100% transmittance to visible light, and a good wettability for the blend. Despite the very rapid, open atmosphere growth method, the cell performance was comparable with some of the best inverted bulk heterojunction P3HT:PCBM cells in the literature. The performance was also maintained after 200 days of storage in air in the dark.