Science News: 2021 Adv. Mater., High efficiency EQE 28.1%! PeLED Synergistic Dual-Additive Strategy

　　In September 2021, Advanced Materials (IF 30.849) journal published a study. Compared with 3D perovskite, quasi-2D perovskite has long been considered to have a good “energy funnel/cascade” structures and excellent optical properties. Although most quasi-2D perovskite light-emitting diodes (PeLEDs) exhibit high external quantum efficiency (EQE), the Auger recombination caused by high current density will make unsatisfactory operating stability.

　　The author here uses 18-crown-6 and poly (ethylene glycol) methyl ether acrylate (MPEG-MAA) as the additives and adopts a synergistic dual-additive strategy to produce perovskite films with low defect density and high environmental stability . Because the dual additives containing C-O-C bonds can not only effectively reduce the perovskite defects, but also destroy the self-aggregation of organic ligands, and induce the formation of perovskite nanocrystals with a quasi-core/shell structure. After thermal annealing, MPEG-MAA with its C-C bond can be polymerized to obtain a comb-like polymer, which further protects the passivated perovskite nanocrystals from the influence of water and oxygen.

　　Through experiments with quantum efficiency measurement and other instruments, it was found that state-of-the-art green PeLED has a normal EQE of 25.2% and a maximum EQE of 28.1%, and its device lifetime (T50) is increased over 10 times in air environment. Above, a novel and effective strategy is provided to make PeLEDs with high efficiency and long service life.