Electronic and Photochemical Passivation by a Classic Sunscreen Material Leading to Reduced V_oc Losses and Enhanced Stability in Organic Solar Cells

Abstract

Organic solar cells (OSCs) have been a popular topic of research for a long time. As a well-known electron transport layer (ETL) material for inverted device architecture, sol-gel-derived zinc oxide (ZnO) displays certain defective surfaces that cause excessive charge recombination and lower device performance. While ultraviolet (UV)-light soaking is sometimes necessary for the ZnO layer to function properly, the latter can also cause the photodegradation of conjugated organic semiconductors. The photostability of OSCs has always been a hot research topic, as the radiation of UV light may cause changes in the material's properties, and that, in turn, may cause rapid attenuation of the devices. Herein, ZnO is modified by inserting the commonly used sunscreen ingredient benzophenone-3 (BP-3) between the photoactive layer, consisting of a PM6:Y6 blend, and ZnO to reduce the impact of UV radiation on the photosensitive layer. The addition of BP-3 successfully enhances the photovoltaic parameters, and a remarkable open-circuit voltage (V oc ) value of 0.887 V is obtained for PM6:Y6-based inverted solar cells, corresponding to a V oc loss as small as 0.547 V. Finally, the application of this strategy increases the device's power conversion efficiency from 12.44 to 13.71% and provides improved UV stability.

High-efficiency ultrathin flexible organic solar cells with a bilayer hole transport layer

“…1–8 In recent years, with the rapid development of active layer materials and interface engineering, the power conversion efficiency (PCE) of single-junction organic solar cells has surpassed 19%. 9–22 However, the lightweight and flexible characteristics of organic solar cells will not be reflected in rigid devices. 23–30 The fabrication of organic solar cells on ultrathin substrates (typically <10 μm in thickness), distinguished by excellent mechanical flexibility and conformable attachment, presents promising applications in the realm of wearable devices.…”