Inverted Polymer Solar Cells Using Inkjet Printed ZnO as Electron Transport Layer: Characterization and Degradation Study

Abstract

In this work, stability and degradation of inverted organic solar cells (iOSCs) partially manufactured under air environment are analyzed. The degradation of iOSCs fabricated with inkjet printed ZnO and with spin coated PFN as electron transport layer (ETL) is compared. The PTB7 and PC <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">70</sub> BM materials are used as donor and acceptor in the active layer, respectively, for all photovoltaic devices. During all the degradation study of the iOSCs, performance parameters such as open circuit voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OC</sub> ), short circuit current density (J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SC</sub> ), fill factor (FF) and Power conversion efficiency (PCE), are extracted from the current density - voltage measurements (J-V) under dark and light conditions. The PCE of the unencapsulated iOSCs with PFN as ETL, left under N2, decreased to 80% after 58 h, while the same PCE reduction for iOSCs with inkjet printed ZnO as ETL, occurred after 189 h. Under air environment, the PCE of unencapsulated iOSCs fabricated with ZnO as ETL devices decreases to 80% after 160 h.