Two-Factor Phase Separations in Mixed-Halide Quasi-2D Perovskite LEDs: Dimensionality and Halide Segregations
Two-Factor Phase Separations in Mixed-Halide Quasi-2D Perovskite LEDs: Dimensionality and Halide Segregations
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DOI：
10.1021/acsenergylett.3c01009
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发表时间：
2023-08
影响因子：
22
通讯作者：
Seok Joo Yang;Kan Wang;Yanqi Luo;Jee Yung Park;Hanjun Yang;Aidan H Coffey;Ke Ma;Jiaonan Sun
中科院分区：
文献类型：
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作者：
Seok Joo Yang;Kan Wang;Yanqi Luo;Jee Yung Park;Hanjun Yang;Aidan H Coffey;Ke Ma;Jiaonan Sun
准二维卤化物钙钛矿作为一种有前途的发光二极管（LED）材料，由于其在量子限制和卤化物合金形成中的可调谐性，以调节能带隙和发射颜色，引起了人们的极大兴趣。然而，关于异质量子阱厚度和卤化物偏析的双因素相分离仍然是准2D钙钛矿LED中的关键问题，导致低的外部量子效率（EQE）和色移。在此，我们比较了使用不同阳离子的准二维钙钛矿薄膜，以揭示有机阳离子化学设计的关键贡献。虽然在传统的准2D钙钛矿薄膜中混合卤素离子会导致微米级的不均匀性，但新的扩展和扭曲的共轭阳离子抑制了双因素相分离，导致超过25%的高EQE和跨越红色和近红外区域的可控发射波长。这项工作的基本见解将为未来推进材料设计和器件性能提供指导。
Quasi-2D halide perovskites have attracted much interest as a promising material for light-emitting diodes (LEDs) due to their tunability in quantum confinement and halide alloy formation to modulate the energy bandgap and emission color. However, two-factor phase separations with respect to heterogeneous quantum-well thicknesses and halide segregation are still crucial issues in quasi-2D perovskite LEDs, leading to low external quantum efficiencies (EQEs) and color shifts. Herein, we compare quasi-2D perovskite films using different cations to unveil the key contributions from the chemical design of organic cations. While mixing halide ions in conventional quasi-2D perovskite films induces micrometer-scale heterogeneity, new extended and twisted conjugated cations suppress the two-factor phase separations, leading to high EQEs of over 25% and controllable emission wavelengths across red and near-infrared regions. The fundamental insights in this work will provide guidance for advancing materials design and device performance in the future.