Li Ruiying, Cai Lei, Zou Yatao, Xu Hao, Tan Yeshu, Wang Yusheng, Li Junnan, Wang Xuechun, Li Ya, Qin Yuanshuai, Liang Dong, Song Tao, Sun Baoquan
Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, People's Republic of China.
ACS Appl Mater Interfaces. 2020 Aug 12;12(32):36681-36687. doi: 10.1021/acsami.0c07514. Epub 2020 Jul 31.
Unbalanced charge injection is one of the major issues that hampers the efficiency of perovskite light-emitting diodes (PeLEDs). Through engineering the device structure with multiple hole transport layers (HTLs), i.e., poly(9,9-dioctyl-fluorene-co--(4-butylphenyl)diphenylamine) (TFB)/poly(9-vinylcarbazole) (PVK) and nickel oxide (NiO)/TFB/PVK, efficient PeLED devices have been successfully demonstrated. However, in a typical solution-processed PeLED with multiple HTLs, the underlying conjugated HTL could be easily redissolved by the ink of the following one, which not only dramatically deteriorates the electrical property of HTLs but also influences the quality of the top perovskite films. In this work, through inserting a thin atomic layer-deposited aluminum oxide (AlO) layer between HTLs and the perovskite layer, an improved interfacial contact can be achieved, which enables us to obtain perovskite films with enhanced characteristics and balanced charge injection in the resultant PeLEDs. In addition, because of the proper refractive index (), the presence of the AlO layer also favors the light out-coupling of PeLEDs. As a result, we fabricate green PeLEDs with good repeatability and external quantum efficiency of 17.0%, which is approximately 60% higher than that of the control device without AlO. Our work provides a promising avenue to enhance interfacial contact between the charge transport layer and perovskite for efficient perovskite-based optoelectronic devices.
电荷注入不平衡是阻碍钙钛矿发光二极管（PeLEDs）效率的主要问题之一。通过设计具有多个空穴传输层（HTLs）的器件结构，即聚（9,9-二辛基芴-co-（4-丁基苯基）二苯胺）（TFB）/聚（9-乙烯基咔唑）（PVK）和氧化镍（NiO）/TFB/PVK，已成功展示了高效的PeLED器件。然而，在具有多个HTLs的典型溶液处理PeLED中，下层共轭HTL很容易被后续层的墨水重新溶解，这不仅会显著降低HTLs的电学性能，还会影响顶部钙钛矿薄膜的质量。在这项工作中，通过在HTLs和钙钛矿层之间插入一层薄的原子层沉积氧化铝（AlO），可以实现改进的界面接触，这使我们能够获得具有增强特性的钙钛矿薄膜，并在所得的PeLED中实现平衡的电荷注入。此外，由于适当的折射率（），AlO层的存在也有利于PeLED的光出射耦合。结果，我们制备了具有良好重复性且外量子效率为17.0%的绿色PeLED，这比没有AlO的对照器件高出约60%。我们的工作为增强电荷传输层与钙钛矿之间的界面接触以制备高效的基于钙钛矿的光电器件提供了一条有前景的途径。
