Solvent-Induced Anti-Aggregation Evolution on Small Molecule Electron-Transporting Layer for Efficient, Scalable, and Robust Organic Solar Cells

摘要

The severe aggregation property of the small molecule electron-transportinglayer (ETL) not only deteriorates the photovoltaic performanceand operational reliability but also constrains its compatibility withlarge-scale coating techniques. Herein, by applying N,N′-Bis{3-[3-(Dimethylamino)propylamino]propyl}perylene-3,4,9,10-tetracarboxylicdiimide (PDINN) (a well-known ETL) as a demo, a solvent-inducedanti-aggregation (SIAA) strategy is proposed to cope with these hurdlesvia the mixing of ethanol and trifluoroethanol solvents at an optimalvolume ratio. In situ photoluminescence and dynamic light scatteringsynergistically reveals the suppressed aggregation behavior of the SIAAtreatedPDINN dispersion during the film-forming process. Owing tothis amendment, the film quality and electron-transport capability ofthe PDINN layer are remarkably enhanced. In consequence, based onthe PM6:L8-BO system, a champion power conversion efficiency (PCE)of 19.0% together with an impressive fill factor of 80.6% is harvested. A1 cm2 device with an excellent PCE of 16.6% is also fabricated using thedoctor-blading SIAA-treated PDINN ink. More strikingly, this SIAA treatmentimpels better reliability under long-term shelf-lifetime and thermalstress periods. This work provides a promising and tractable approachto address the inherent self-aggregation issue of electron-transportingmaterials, which is beneficial for the development of efficient and stableorganic optoelectronic devices.