Double ETL in ITO-free poly-3-hexylthiophene-based organic solar cells

Energy level and power conversion efficiency were investigated in the inverted organic solar cells with configuration FTO/TiO 2 /P3HT:PC 61 BM/MoO 3 /Ag and FTO/PFN/P3HT:PC 61 BM/MoO 3 /Ag structures in a double electron transport layer (ETL) organic solar cell with configuration FTO/TiO 2 /PFN/P3HT:PC 61 BM/MoO 3 /Ag. The influence of TiO 2 and PFN as ETL was evaluated individually and together, in solar cells and an UV-Vis experiment, showing that the use of a double ETL can increase the efficiency up to 2.5 times compared to cells where only a single layer was used. The best cell built with double ETL showed a maximum efficiency of 4.29%.