| 초록 |
The electron transport (ETL) layer improves power conversion efficiency (PCE) in organic photovoltaic cells (OPVs) by helping form ohmic contact between the active layer and the cathode metal. Here, we introduce ytterbium (Yb) as an electron transport layer in inverted OPVs where Yb is directly evaporated on indium tin oxide (ITO). The PCE of the inverted OPVs composed of ITO/Yb/P3HT:PCBM/MoO3/Ag reaches up to 4.3%, recording 71% of the fill factor (FF) in one sun irradiation. Over 80% of its original PCE is retained over 30 days. The results indicate that Yb in inverted OPVs is vastly superior to other ETLs as it improves the majority of the parameters including short circuit current, FF and PCE. In this report, we will discuss how Yb functions physically and optically in inverted OPVs, making it a promising candidate for achieving high PCE and good air stability simultaneously. |
