Unlocking the potential of CsPbI₃ perovskite as stable red phosphors by zeolite skeleton

CsPbI₃ perovskite-based phosphors are ideal candidates for red/near-infrared light-emitting diodes (LEDs). However, they suffer from poor stability and low photoluminescence quantum yields (PLQYs). Herein, CsPbI₃@zeolite composites with bright, deep-red, solid-state fluorescence have been successfully developed by a high-temperature calcination followed by water treatment strategy. The composites possess PLQYs of 31.1% and exceptional stability even comparable to that of commercial phosphors. Such properties are rarely reported in solid-state CsPbI₃ perovskite systems. Studies show that removing the non-luminous by-products and controlling the thickness of the zeolite shell are essentials for enhancing the PLQYs, and the excellent stability results from the tight encapsulation of CsPbI₃ perovskite by the host skeleton. As a proof of concept, standard red and white LEDs with a maximal luminous efficiency of 57.3 lm/W and excellent long-term operation stability are constructed based on the as-made composites. This work unlocks the application potential of CsPbI₃ perovskite as stable red phosphors.