题目： | Long-range order enabled stability in quantum dot light-emitting diodes |
作者： | Ya-Kun Wang1# Haoyue Wan2#, Sam Teale2,3, Luke Grater2, Feng Zhao1, Zhongda Zhang1, Hong-Wei Duan1, Muhammad Imran2, Sui-Dong Wang1, Sjoerd Hoogland2 & Liang-Sheng Liao1* |
单位： | 1Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, People’s Republic of China. 2Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada. 3Clarendon Laboratory, University of Oxford, Oxford, United Kingdom. |
摘要： | Light-emitting diodes (LEDs) based on perovskite quantum dots (QDs) have produced external quantum efficiencies (EQEs) of more than 25% with narrowband emission1,2, but these LEDs have limited operating lifetimes. We posit that poor long-range ordering in perovskite QD films—variations in dot size, surface ligand density and dot-to-dot stacking—inhibits carrier injection, resulting in inferior operating stability because of the large bias required to produce emission in these LEDs. Here we report a chemical treatment to improve the long-range order of perovskite QD films: the diffraction intensity from the repeating QD units increases three-fold compared with that of controls. We achieve this using a synergistic dual-ligand approach: an iodide- rich agent (aniline hydroiodide) for anion exchange and a chemically reactive agent (bromotrimethylsilane) that produces a strong acid that in situ dissolves smaller QDs to regulate size and more effectively removes less conductive ligands to enable compact, uniform and defect-free films. These films exhibit high conductivity (4×10−4Sm−1), which is 2.5-fold higher than that of the control, and represents the highest conductivity recorded so far among perovskite QDs. The high conductivity ensures efficient charge transportation, enabling red perovskite QD-LEDs that generate a luminance of 1,000cdm−2 at a record-low voltage of 2.8V. The EQE at this luminance is more than 20%. Furthermore, the stability of the operating device is 100 times better than previous red perovskite LEDs at EQEs of more than 20%. |
影响因子： | 64.8 |
分区情况： | 一区 |
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责任编辑：郭佳