Fully‐Solution‐Processed Inverted Near‐Infrared LEDs Enabled by Wavelength‐Tunable and Oxidation‐Resistant Lead‐Tin Perovskite

Abstract Compared to APbI₃‐based perovskites (A = Cs⁺, MA⁺, FA⁺), ASnI₃‐based perovskites exhibit longer emission wavelengths and lower toxicity, emerging as promising candidates for near‐infrared light‐emitting diodes (NIR‐LEDs). However, the electroluminescence emission wavelengths of ASnI₃‐based perovskite LEDs remain below 950 nm, and face the challenge of the extreme susceptibility of Sn²⁺ to oxidation. In this study, the fabrication of high‐performance NIR‐LEDs using hybrid Pb‐Sn perovskites (FAPb_xSn_1−xI₃) are demonstrated with emission wavelengths tunable from 800 to 958 nm by optimizing the Pb:Sn ratios. Furthermore, 5‐aminovaleric acid (5‐AVA) as an antioxidant is introduced, which is capable of suppressing the oxidation of Sn²⁺, enhancing the stability and optoelectronic performance of the perovskite films. The optimized FAPb_0.5Sn_0.5I₃‐based NIR LED exhibits an emission peak at 958 nm with a maximum external quantum efficiency (EQE) of 2.5%, representing a record for band‐edge‐emitting perovskite LEDs with wavelengths above 950 nm. This work highlights the potential of hybrid Pb‐Sn perovskites for efficient and tunable NIR light sources, paving the way for their application in next‐generation optoelectronic devices.