Multifunctional Glycinamide Hydrochloride Interface Bridging Enables Efficient Tin Perovskite Light-Emitting Diodes

Recently, tin-based perovskite light-emitting diodes (PeLEDs) have received extensive attention owing to their near-infrared (NIR) emission and environmental friendliness. However, tin perovskite films are prone to rapid Sn²⁺ oxidation and uncontrollable crystallization, which usually leads to undesirable device performance. Herein, we propose a multifunctional molecular bridging strategy based on glycinamide hydrochloride (GlyACl) for constructing efficient tin-based NIR PeLEDs. We demonstrate that the C═O and -NH₂ groups in the GlyACl molecule form coordination bonds and hydrogen bonds with perovskite and PEDOT: PSS, respectively, thereby effectively suppressing the oxidation of Sn²⁺, reducing defect density, and regulating the crystallization of tin perovskite films. Moreover, GlyACl-mediated buried interface modification endows the perovskite layer with an undulant morphology, which is favorable for enhancing light output coupling efficiency. Benefiting from these effects, the performance of FA_0.9Cs_0.1SnI₃ NIR PeLEDs is remarkably enhanced, with the maximum EQE rising from 6.32% to 10.80%, and the operational lifetime increasing to 9 times that of the control device. This research underscores the significance of buried interface engineering and establishes a viable route toward efficient tin PeLEDs.