Efficient and Stable Red Perovskite Light‐Emitting Diodes with Operational Stability >300 h
Hanming Li, Hong Lin, Dan Ouyang, Canglang Yao, Can Li, Jiayun Sun, Yilong Song, Yufeng Wang, Yufeng Wang, Yanfa Yan, Yong Wang, Yong Wang, Qingfeng Dong, Wallace C. H. Choy
Abstract
Abstract The long‐term operational stability of perovskite light‐emitting diodes (PeLEDs), especially red PeLEDs with only several hours typically, has always faced great challenges. Stable β‐CsPbI 3 nanocrystals (NCs) are demonstrated for highly efficient and stable red‐emitting PeLEDs through incorporation of poly(maleic anhydride‐ alt ‐1‐octadecene) (PMA) in synthesizing the NCs. The PMA can chemically interact with PbI 2 in the precursors via the coupling effect between O groups in PMA and Pb 2+ to favor crystallization of stable β‐CsPbI 3 NCs. Meanwhile, the cross‐linked PMA significantly reduces the Pb Cs anti‐site defect on the surface of the β‐CsPbI 3 NCs. Benefiting from the improved crystal phase quality, the photoluminescence quantum yield for β‐CsPbI 3 NCs films remarkably increases from 34% to 89%. The corresponding red‐emitting PeLEDs achieves a high external quantum efficiency of 17.8% and superior operational stability with the lifetime, the time to half the initial electroluminescence intensity ( T 50 ) reaching 317 h at a constant current density of 30 mA cm −2 .