Liu Hui, Shi Guangyi, Khan Rashid, Chu Shenglong, Huang Zongming, Shi Tongfei, Sun Haiding, Li Yaping, Zhou Hongmin, Xiao Peng, Chen Tao, Xiao Zhengguo
Department of Physics, CAS Key Laboratory of Strongly coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
School of Microelectronics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
Adv Mater. 2024 Feb;36(8):e2309921. doi: 10.1002/adma.202309921. Epub 2023 Dec 8.
Metal halide perovskite light-emitting diodes (PeLEDs) are attracting increasing attention due to their potential applications in flat panel lighting and displays. The solution process, large-area fabrication, and flexibility are attractive properties of PeLEDs over traditional inorganic LEDs. However, it is still very challenging to deposit uniform perovskite films on flexible substrates using a blade or slot-die coating, as the flexible substrate is not perfectly flat. Here, the inkjet printing technique is adopted, and the key challenges are overcome step-by-step in preparing large-area films on flexible substrates. Double-hole transporting layers are first used and a wetting interfacial layer to improve the surface wettability so that the printed perovskite droplets can form a continuous wet film. The fluidic and evaporation dynamics of the perovskite wet layer is manipulated to suppress the coffee ring effect by solvent engineering. Uniform perovskite films are obtained finally on flexible substrates with different perovskite compositions. The peak external quantum efficiency of the inkjet-printed PeLEDs reaches 14.3%. Large-area flexible PeLEDs (4 × 7 cm ) also show very uniform emission. This work represents a significant step toward real applications of large-area PeLEDs in flexible flat-panel lighting.
金属卤化物钙钛矿发光二极管（PeLEDs）因其在平板照明和显示领域的潜在应用而受到越来越多的关注。与传统无机发光二极管相比，PeLEDs的溶液法制备工艺、大面积制造能力和柔韧性是其吸引人的特性。然而，使用刮刀或狭缝式涂布在柔性基板上沉积均匀的钙钛矿薄膜仍然极具挑战性，因为柔性基板并非完全平整。在此，采用了喷墨印刷技术，并在柔性基板上制备大面积薄膜的过程中逐步克服了关键挑战。首次使用了双空穴传输层和一个润湿界面层来改善表面润湿性，以便印刷的钙钛矿液滴能够形成连续的湿膜。通过溶剂工程控制钙钛矿湿层的流体动力学和蒸发动力学，以抑制咖啡环效应。最终在具有不同钙钛矿组成的柔性基板上获得了均匀的钙钛矿薄膜。喷墨印刷的PeLEDs的峰值外量子效率达到了14.3%。大面积柔性PeLEDs（4×7厘米）也显示出非常均匀的发光。这项工作朝着大面积PeLEDs在柔性平板照明中的实际应用迈出了重要一步。
