High-performance deep-red light-emitting diodes (LEDs) are important for biomedical and agricultural applications. However, the development of bright and stable solution-processed deep-red LEDs remains challenging. Here we design a switchable interfacial deprotonation reaction between the perovskite and electron-transporting layer to fabricate high-quality CsPbI₃ perovskite films, leading to stable and bright deep-red LEDs. Our approach starts with a precursor solution containing guanidine hydroiodide and a layer of alkaline zinc hydroxide. On annealing, the interfacial reaction is switched on, leading to the formation of high-quality CsPbI₃. The alkaline zinc hydroxide layer is simultaneously converted in situ to alkalescent ZnO, which prevents the formation of the undesirable yellow-phase CsPbI₃ perovskite. As a result, our perovskite LEDs based on CsPbI₃ demonstrate a long half-lifetime of approximately 33.6 h under a driving current density of 100 mA cm^–2 and an exceptionally high radiance of around 1,980 W sr⁻¹ m^–2. Moreover, by partly substituting iodide with bromide, we achieve bright deep-red perovskite LEDs with an emission wavelength of 691 nm and an operational half-lifetime of 50.3 h at 100 mA cm^–2.

高性能深红色发光二极管 (LED) 对于生物医学和农业应用非常重要。然而，开发明亮且稳定的溶液加工深红色 LED 仍然具有挑战性。在这里，我们设计了钙钛矿和电子传输层之间的可切换界面去质子化反应，以制造高质量的CsPbI ₃钙钛矿薄膜，从而产生稳定、明亮的深红色LED。我们的方法从含有氢碘酸胍和一层碱性氢氧化锌的前体溶液开始。退火时，界面反应启动，导致形成高质量的 CsPbI ₃。碱性氢氧化锌层同时原位转化为碱性ZnO，这防止了不希望的黄相CsPbI ₃钙钛矿的形成。因此，我们基于 CsPbI _{3 的钙钛矿 LED 在 100 mA cm} ^–2的驱动电流密度下表现出约 33.6 h 的长半衰期和约 1,980 W sr ^-1 m ^–2的极高辐射率。^{此外，通过用溴化物部分替代碘化物，我们获得了明亮的深红色钙钛矿LED，其发射波长为691 nm，在100 mA cm –2}下的工作半衰期为50.3 h 。