Uniform and Large‐Area Cesium‐Based Quasi‐2D Perovskite Light‐Emitting Diodes Using Hot‐Casting Method,Advanced Materials Interfaces

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Uniform and Large‐Area Cesium‐Based Quasi‐2D Perovskite Light‐Emitting Diodes Using Hot‐Casting Method
Advanced Materials Interfaces ( IF 4.3 ) Pub Date : 2020-03-01 , DOI: 10.1002/admi.201902158
Da Bin Kim ₁ , Seungjin Lee ₂ , Chung Hyeon Jang ₁ , Jong Hyun Park ₁ , Ah‐young Lee ₁ , Myoung Hoon Song ₁

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Metal halide perovskites have deep valence band maximums (VBMs). For example, the VBM of CsPbBr₃ is 5.8–6.3 eV. Conjugated polymers can be a potential candidate for the hole transport layer because of their deep highest occupied molecular orbital levels, but their poor compatibility with a hydrophilic perovskite precursor results in the formation of a noncontinuous perovskite film. In addition, antisolvent dripping methods for fabricating perovskite films cause spatially inhomogeneous nucleation, which is undesirable for large‐scale applications. In this work, efficient and large‐area perovskite light‐emitting diodes (PeLEDs) are developed by introducing a poly(9‐vinylcarbazole) (PVK) interlayer and employing a hot‐casting method (substrate preheating). The PVK interlayer increases the depth of the VBM of NiO_x (from 5.1 to 5.5 eV), resulting in efficient hole injection. The thermal energy of the preheated substrate facilitates not only the growth of a continuous and pinhole‐free perovskite film, but also the formation of a highly crystalline and preferentially oriented perovskite structure, resulting in improved luminescence properties. Therefore, PeLEDs fabricated using an optimal preheating temperature show an improved external quantum efficiency (from 3.08% to 8.44%) with spatially uniform electroluminescence. Finally, the development of uniform and large‐area PeLEDs (with an active area of 12.8 cm²) is demonstrated.

中文翻译：

采用热浇铸法的均匀大面积铯基准2D钙钛矿发光二极管

金属卤化物钙钛矿具有深价带最大值（VBM）。例如，CsPbBr ₃的VBM为5.8–6.3 eV。共轭聚合物由于其最深的最高占据分子轨道能级而可能是空穴传输层的潜在候选者，但是它们与亲水性钙钛矿前体的相容性差导致形成不连续的钙钛矿膜。此外，用于制造钙钛矿薄膜的抗溶剂滴注方法会引起空间不均匀的形核，这对于大规模应用是不希望的。在这项工作中，通过引入聚（9-乙烯基咔唑）（PVK）中间层并采用热浇铸方法（基板预热），开发出了高效且大面积的钙钛矿型发光二极管（PeLED）。PVK中间层增加了NiO的VBM的深度_x（从5.1到5.5 eV），从而实现了有效的空穴注入。预热基板的热能不仅有助于连续且无针孔的钙钛矿膜的生长，而且还有助于形成高度结晶且优先取向的钙钛矿结构，从而改善了发光性能。因此，使用最佳预热温度制造的PeLED表现出改善的外部量子效率（从3.08％到8.44％）以及空间均匀的电致发光。最后，展示了均匀和大面积PeLED（有效面积为12.8 cm²）的开发。

更新日期：2020-03-01

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