Understanding the Role of Ion Migration in the Operation of Perovskite Light-Emitting Diodes by Transient Measurements
Understanding the Role of Ion Migration in the Operation of Perovskite Light-Emitting Diodes by Transient Measurements
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DOI：
10.1021/acsami.0c14269
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发表时间：
2020-10-28
影响因子：
9.5
通讯作者：
So, Franky
中科院分区：
文献类型：
--
作者：
Dong, Qi;Mendes, Juliana;So, Franky
钙钛矿型发光二极管因其高效率近年来受到人们的广泛关注。尽管最近在器件效率方面取得了进展，但对这些器件的工作机制，特别是离子迁移的影响，仍然不是很清楚。在这项工作中，通过测量瞬时电致发光和电流响应来研究离子迁移的作用，在几十毫秒的时间尺度上，电流和效率都表现出缓慢的响应。电荷注入动力学的结果表明，电流的缓慢响应是由于卤化物离子在阳极界面的迁移和积累，促进了空穴注入，导致了强烈的电荷不平衡。此外，电荷复合动力学的结果表明，效率的缓慢响应归因于离子迁移促进的电荷注入的增强，从而导致有利于双分子辐射复合的载流子密度的增加。通过对电荷注入动力学和复合动力学的综合分析，我们最终对离子迁移在器件运行中的作用进行了全面的描述。
Perovskite light-emitting diodes have been gaining attention in recent years due to their high efficiencies. Despite of the recent progress made in device efficiency, the operation mechanisms of these devices are still not well understood, especially the effects of ion migration. In this work, the role of ion migration is investigated by measuring the transient electro-luminescence and current responses, with both the current and efficiency showing a slow response in a time scale of tens of milliseconds. The results of the charge injection dynamics show that the slow response of the current is attributed to the migration and accumulation of halide ions at the anode interface, facilitating hole injection and leading to a strong charge imbalance. Further, the results of the charge recombination dynamics show that the slow response of the efficiency is attributed to enhanced charge injection facilitated by ion migration, which leads to an increased carrier density favoring bimolecular radiative recombination. Through a combined analysis of both charge injection and recombination dynamics, we finally present a comprehensive picture of the role of ion migration in device operation.