AIE Molecules UV-Filtering Effect Improves the Photostability of Organic Solar Cells

摘要

Due to the poor stability of organic solar cells (OSCs), especially ultravioletlight (UV) stability, they are not yet up to the standard for commercial applications.Inverted devices based on the ZnO electron transport layer (ETL) are relativelythermal- and air-stable, while their UV light stability is poor. Moreover,the active layer materials undergo severe degradation under UV light, whichalso causes the degradation of the device. Here, aggregation-induced emission(AIE) molecules as an optical barrier layer are coated between ZnO-ETL andactive layer to fabricate efficient OSCs with excellent UV photostability. AIEmolecules can avoid direct photodegradation of the active layer materials byabsorbing UV light. At the same time, they can passivate the oxygen defectson the ZnO surface and prevent photocatalytic degradation of the activelayer materials. Therefore, the ZnO/TPIZ-based devices maintain 84% of theoriginal power conversion efficiency (PCE) with continuous irradiation by5 mW cm~(-2) UV light (365 nm) for 1500 h, and similarly T_(80) for more than 700 hunder 20 mW cm~(-2) UV light exposure. Moreover, the ZnO/TPIZ-based devicesalso preserve excellent thermal stability accompanying the upgrading of PCE.