Inverted organic photovoltaics with a solution-processed ZnO/MgO electron transport bilayer. Issue 11 (2nd March 2021)

• Record Type: Journal Article
• Authors: Ierides, Ioannis; Squires, Isaac; Lucarelli, Giulia; Brown, Thomas M.; Cacialli, Franco
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 11(2021)
• Page Start: 3901
• Page End: 3910
• Publication Date: 2021-03-02
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0tc04955g
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Applying ultrathin MgO as the top component of a ZnO/MgO electron transport layer enhances the performance of organic photovoltaics. Abstract : Electron transport layers (ETLs) have been instrumental in breaking the efficiency boundaries of solution-processed photovoltaics. In particular, bilayer ETLs with an MgO top component have afforded tremendous success in various solution-processed systems, such as perovskite photovoltaics, however, their application in the promising technology of organic photovoltaics is limited. In this work, we fabricate organic photovoltaic devices incorporating a "bilayer" ZnO/MgO ETL instead of a single ZnO ETL, so as to reduce the leakage current and boost the power conversion efficiency. The ZnO/MgO ETL is shown to have a more uniform top surface and a lower work function compared to the single ZnO ETL which is expected to be beneficial to electron extraction. Furthermore, we demonstrate that insertion of the thin (≲ 10 nm) MgO interlayer in devices leads to a reduced leakage current and an increase in the shunt resistance. Application of the MgO interlayer boosts the short circuit current density and fill factor, and enhances the power conversion efficiency by ∼10% (relative increase) thereby demonstrating a facile approach to push the efficiency of organic photovoltaics to higher levels.