Enhancing the Performance of 2D Tin‐Based Pure Red Perovskite Light‐Emitting Diodes through the Synergistic Effect of Natural Antioxidants and Cyclic Molecular Additives

Abstract Tin (Sn)‐based perovskites are being investigated in many optoelectronic applications given their similar valence electron configuration to that of lead‐based perovskites and the potential environmental hazards of lead‐based perovskites. However, the formation of high‐quality Sn‐based perovskite films faces several challenges, mainly due to the easy oxidation of Sn ²⁺ to Sn ⁴⁺ and the fast crystallization rate. Here, to develop an environmentally friendly process for Sn‐based perovskite fabrication, a series of natural antioxidants are studied as additives and ascorbic acid (VitC) is found to have a superior ability to inhibit the oxidation problem. A common cyclic molecule, 18‐Crown‐6, is further added as a second additive, which synergizes with VitC to significantly reduce the nonradiative recombination pathways in the PEA ₂ SnI ₄ film. This synergistic effect greatly improves the performance of 2D red Sn‐based PeLED, with a maximum external quantum efficiency of 1.87% (≈9 times that of the pristine device), a purer color, and better bias stability. This work demonstrates the potential of the dual‐additive approach in enhancing the performance of 2D Sn‐based PeLEDs, while the use of these environmentally friendly additives contributes to their future sustainability.