Push‐Pull Effect Enables Large‐Area Lead‐Free Perovskite Light‐Emitting Diodes via Electron Directional Transfer

Abstract

Tin (Sn) perovskites have emerged as viable candidates for high‐performance, lead‐free perovskite light‐emitting diodes (PeLEDs). However, the limited availability of efficient and stable Sn perovskites, and the development of large‐area Sn PeLEDs encourage further research. Here, FPEA2SnI4 (FPEAI, 4‐fluoro‐phenethylammonium iodide) perovskite is reported as a potential emitter for PeLEDs. To overcome the anisotropic carrier transport in layered FPEA2SnI4 perovskites, an electronic push‐pull effect strategy is introduced by incorporating 6‐amino‐4‐hydroxy‐2‐naphthalenesulfonic acid (γ acid) molecule in FPEA2SnI4 perovskites. The unique electronically push‐pull configuration of γ acid establishes a cross‐layer electron transfer channel, which mitigates electron aggregation within the organic layers, enhances electron injection and directional transfer, and effectively promotes radiative recombination. Furthermore, multifunctional γ acid provides multiple interaction sites for Sn perovskites, reducing defect state density and stabilizing FPEA2SnI4 perovskites. Leveraging the enhanced robustness of FPEA2SnI4 films with γ acid, a large‐area Sn PeLED with an active area of 2.25 cm2, achieves a maximum luminance (Lmax) of 371 cd m−2, a peak external quantum efficiency (EQE) of 15.49%, and an operational half‐lifetime of 71.6 h at 100 cd m−2. These findings underscore the application potential of Sn PeLEDs in the realms of solid‐state lighting and planar display.