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

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 Sn²⁺ to Sn⁴⁺ 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 PEA₂SnI₄ 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.