Self-Assembled Monolayer and Multifunctional Additive Improve Tin-Perovskite Crystallization for Near-Infrared LEDs Exceeding 20% EQE
Jiacheng Liu, Bufan Yu, Yue Liang, Qing Du, Shangwei Feng, Yutong Pan, Youran Lin, Lei Ying, Lei Wang, Jiangshan Chen, Dongge MaAbstract
Eco-friendly tin (Sn)-based perovskites are highly promising for near-infrared light-emitting diodes (PeLEDs), but their electroluminescence performance currently lags behind that of their lead-based counterparts due to unsatisfactory crystallization and severe Sn2+ oxidation. Herein, we demonstrate a progressive optimization strategy to enhance the Sn-based perovskite crystallization by employing a self-assembled monolayer (SAM) of 2PACz:PFNBr as the buried interface and subsequently incorporating isophthalic dihydrazide (IPDH) as a bulk additive. The 2PACz:PFNBr SAM effectively retards rapid crystallization and facilitates controlled nucleation, ensuring high crystal quality of Sn-based perovskite films. Furthermore, the multifunctional IPDH additive improves crystallization uniformity and inhibits Sn2+ oxidation, resulting in homogeneous perovskite films with minimized defect density. Ultimately, the champion device demonstrates a record external quantum efficiency (EQE) of 20.15%, a maximum radiance of 125 W sr–1 m–2, and a stable emission peak at 890 nm, setting a new benchmark for Sn-based near-infrared PeLEDs.