Ionic liquid-modified ZnO-based electron transport layer for inverted organic solar cells

In this work, a novel ionic liquid (IL) is demonstrated as an interface modification layer in photovoltaic devices to improve power conversion efficiency (PCE) in inverted organic solar cell (i-OSCs). As a result, the PTB7-Th:PC71BM-based devices using ZnO/IL as ETL layer exhibited over 15% PCE increment with enhanced short-circuit current density (Jsc) and fill factor (FF), compared with pure ZnO appliance in ETL. The ZnO layer modified with IL has a better electron extraction capability and lower work function, both of which contribute to better device performance.