英国剑桥大学Yang, Xuyong团队报道了稳定钙钛矿八面体结构制备红色发光钙钛矿LEDs。相关研究成果于2024年6月12日发表在《自然》。

基于金属卤化物钙钛矿（PeLEDs）的发光二极管（LEDs）具有高色彩质量和易于溶液处理的特点，是全彩和高清晰度显示器的有前途的候选者。尽管使用溴化铅钙钛矿在绿色PeLEDs中取得了巨大成功，但使用碘基对应物实现纯红色（620–650nm）LEDs仍然具有挑战性，因为它们受到低本征带隙的限制。

该文中，研究人员报道了在整个纯红色区域高效且颜色稳定的PeLEDs，通过将双端锚定的配体分子掺入纯碘钙钛矿中，638nm处的峰值外量子效率达到28.7%。研究人员证明了有机嵌入阳离子的一个关键功能，是通过与暴露的铅离子配位和增强与碘的氢键来稳定铅-碘八面体。该分子协同促进光谱调制，促进钙钛矿量子阱之间的电荷转移，并减少碘在电偏压下的迁移。

研究人员实现了碘基钙钛矿膜的连续可调发射波长，并抑制了由于离子钙钛矿中铅碘的键能随着带隙的增加而降低，而导致的能量损失。重要的是，所得器件在100cdm²的初始亮度下，显示出卓越的光谱稳定性和超过7600min的半衰期。

附：英文原文

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

Author: 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

Issue&Volume: 2024-06-12

Abstract: 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 displays1,2,3,4. Despite the great success achieved in green PeLEDs with lead bromide perovskites5, it is still challenging to realize pure-red (620–650nm) 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 638nm, 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 7,600min at an initial luminance of 100cdm2.

DOI: 10.1038/s41586-024-07531-9

Source: https://www.nature.com/articles/s41586-024-07531-9