Targeted elimination of tetravalent-Sn-induced defects for enhanced efficiency and stability in lead-free NIR-II perovskite LEDs

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2024年11月15日

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Xiang Guan,
Yuqing Li,
Yuanyuan Meng,
Kongxiang Wang,
Kebin Lin,
Yujie Luo,
Jing Wang,
Zhongtao Duan,
Hong Liu,
Liu Yang,
Lingfang Zheng,
Junpeng Lin,
Yalian Weng,
Fengxian Xie,
Jianxun Lu,
Zhanhua Wei

摘要

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 Sn²⁺ to oxidize, resulting in detrimental Sn⁴⁺-induced defects and compromised device performance. Here, we present a targeted strategy to eliminate Sn⁴⁺-induced defects through moisture-triggered hydrolysis of tin tetrahalide, without degrading Sn²⁺ in the CsSnI₃ 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.