Fabrication of red-emitting perovskite LEDs by stabilizing their octahedral structure

• 成果类型: Article
• 署名作者: Kong, Lingmei; Sun, Yuqi; Zhao, Bin; Ji, Kangyu; Feng, Jie; Dong, Jianchao; Wang, Yuanzhi; Liu, Zirui; Maqbool, Shabnum; Li, Yunguo; Yang, Yingguo; Dai, Linjie; Lee, Wanhee; Cho, Changsoon; Stranks, Samuel D.; Friend, Richard H.; Wang, Ning; Greenham, Neil C.; Yang, Xuyong
• 署名单位: Shanghai University; University of Cambridge; Jilin University; University of Cambridge; Chinese Academy of Sciences; University of Science & Technology of China, CAS; Chinese Academy of Sciences; Shanghai Advanced Research Institute, CAS; Zhangjiang Laboratory; Fudan University; Pohang University of Science & Technology (POSTECH); Yonsei University
• 刊物名称: Nature
• ISSN/ISSBN: 0028-6725
• DOI: 10.1038/s41586-024-07531-9
• 发表日期: 2024-07-04
• 关键词: ion migration; diodes; EFFICIENCY; bright; nanocrystals; surface; passivation; suppression

摘要

Light-emitting diodes (LEDs) based on metal halide perovskites (PeLEDs) with high colour quality and facile solution processing are promising candidates for full-colour and high-definition displays1-4. Despite the great success achieved in green PeLEDs with lead bromide perovskites5, it is still challenging to realize pure-red (620-650 nm) LEDs using iodine-based counterparts, as they are constrained by the low intrinsic bandgap6. Here we report efficient and colour-stable PeLEDs across the entire pure-red region, with a peak external quantum efficiency reaching 28.7% at 638 nm, enabled by incorporating a double-end anchored ligand molecule into pure-iodine perovskites. We demonstrate that a key function of the organic intercalating cation is to stabilize the lead iodine octahedron through coordination with exposed lead ions and enhanced hydrogen bonding with iodine. The molecule synergistically facilitates spectral modulation, promotes charge transfer between perovskite quantum wells and reduces iodine migration under electrical bias. We realize continuously tunable emission wavelengths for iodine-based perovskite films with suppressed energy loss due to the decrease in bond energy of lead iodine in ionic perovskites as the bandgap increases. Importantly, the resultant devices show outstanding spectral stability and a half-lifetime of more than 7,600 min at an initial luminance of 100 cd m-2. Red-emitting perovskite LEDs were fabricated by stabilizing their octahedral structure with a ligand to yield devices with enhanced efficiency, spectral stability and lifetime.