Efficient and Thermally Stable Organic Solar Cells via a Fully Halogen-Free Active Blend and Solvent

Abstract

The state-of-the-art organic solar cells (OSCs) are basically based on halogenated active materials and solvents. However, halogens/halides could be detrimental to the stability of OSCs due to their corrosiveness to the interface and the electrode. On the other hand, the introduction of halogens, especially the use of halogen solvents, could cause hazards to the environment, further limiting the application of OSCs. Thus, it is meaningful to explore and develop efficient and stable OSCs based on halogen-free materials and solvents. It is demonstrated that fully halogen-free OSCs deliver efficient performance as well with an efficiency of 10.42%, based on the nonhalogenated active blend PBDB-T:ITIC and the nonhalogenated processing solvent CS2. More importantly, superior thermal stability is achieved for the halogen-free cells, with 95% of the initial efficiency retained in 1400 h under 85 °C in a N2 atmosphere, due to the stabilized blend morphology and impeded corrosion of the metal electrode. These results provide insights into the thermal degradation of OSCs and suggest possible rules/directions for the design of active materials and selection of solvents to achieve efficient and thermally stable OSCs.

A Fused-Ring Electron Acceptor with Phthalimide-Based Ending Groups for Efficient Ternary Organic Solar Cells

“…In order to push the PCE of PM6:Y6 OPVs to a new level, the additive strategy, − solvent strategy, − transport layer strategy, , and ternary strategy − , have been studied. Among them, the ternary strategy is one of the most effective and convenient ways .…”