Efficient Perovskite Light‐Emitting Diodes Processed with Green Solvents Enabling a Wide Antisolvent Time Window

Abstract Green solvent processing of perovskite light‐emitting diodes (PeLEDs) is a necessity for their future commercialization. However, the almost insoluble nature of perovskites in most green solvents strongly impedes the progress of green solvent‐processed PeLEDs. Here, a novel green solvent triethylene glycol (TEG) is used as the processing solvent for perovskites. TEG has better solubility for perovskite precursors than most reported green solvents. Moreover, it is found that the low vapor pressure of TEG solvent and stable precursor solution render a much wider time window for the so‐called antisolvent treatment than that of perovskite precursor solution in commonly dimethyl sulfoxide. High‐quality perovskite film can be readily synthesized with the antisolvent treatment at a time window of 70–100 s, and the resultant green PeLEDs demonstrate nearly identical light‐emitting efficiencies. Together with further interface modification, the optimized green PeLEDs processed with TEG exhibit an external quantum efficiency of 20.4% and a maximal luminance over 38000 cd m −2 . It is the first successful attempt to fabricate high‐efficiency PeLEDs utilizing green solvent and is enlightening for the development of high‐performance PeLEDs prepared with eco‐friendly solvents.