Buried Interface Modification Strategy for Efficient Tin‐Based Perovskite Light‐Emitting Diodes

Tin (Sn)-based perovskites show great potential for environmentally friendly and high-performance light-emitting diodes (LEDs). However, the development of Sn-based perovskite LEDs (PeLEDs) lags significantly behind that of lead-based perovskites. This is mainly due to the faster crystallization rate of Sn-based perovskites that leads to a higher defect density in Sn-based perovskite films, thereby serious nonradiative recombination. Here, we demonstrated a buried interface modification (BIM) strategy to regulate the crystallization kinetics of Sn-based perovskite films by using carboxylate as multifunctional surface modifiers. We reveal that the buried interface is critical to improve the nucleation and crystallization of Sn-based perovskite films. As a result, efficient near-infrared Sn-based PeLEDs were achieved with an external quantum efficiency (EQE) of 11.9%. This work suggests an efficient and elegant route to obtain high-performance Sn-based perovskite films and devices.