Abstract
Eco-friendly Sn-based perovskites show significant potential for high-performance second near-infrared window light-emitting diodes (900 nm - 1700 nm). Nevertheless, achieving efficient and stable Sn-based perovskite second near-infrared window light-emitting diodes remains challenging due to the propensity of Sn(2+) to oxidize, resulting in detrimental Sn(4+)-induced defects and compromised device performance. Here, we present a targeted strategy to eliminate Sn(4+)-induced defects through moisture-triggered hydrolysis of tin tetrahalide, without degrading Sn(2+) in the CsSnI(3) film. During the moisture treatment, tin tetrahalide is selectively hydrolyzed to Sn(OH)(4), which provides sustained protection. As a result, we successfully fabricate second near-infrared window light-emitting diodes emitting at 945 nm, achieving a performance breakthrough with an external quantum efficiency of 7.6% and an operational lifetime reaching 82.6 h.